Search NASA⌕ Search

SEARCH · Search NASA

Results for “Multivariate Analysis”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 667 records · Page 37
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Quantitative resilience evaluation on recovery from emergency situations in nuclear power plants

Here, this paper mainly introduces how to develop a resilience evaluation model by quantifying the relationship between resilience and resilience components in regard to recovering from emergency situations in nuclear power plants (NPPs). It is an extension of the author’s previous researches. To develop the model, the first step was to analyze event reports published in Republic of Korea in terms of resilience factors from different safety perspectives. Second, statistical methods such as factor analysis, principal component analysis, and multivariate regression analysis were applied to the dataset to identify relations among resilience factors and develop a quantitative resilience evaluation model for recovery from emergency situations in NPPs. Third, the model was validated using the recent event report data released in Korea. Lastly, we present a discussion on how to apply the quantitative resilience evaluation model to results from stress tests performed in Korea.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2015

Long-term measurements of submicrometer aerosol chemistry at the Southern Great Plains (SGP) using an Aerosol Chemical Speciation Monitor (ACSM)

In this study the long-term trends of non-refractory submicrometer aerosol (NR-PM1) composition and mass concentration measured by an Aerosol Chemical Speciation Monitor (ACSM) at the Atmospheric Radiation Measurement (ARM) program's Southern Great Plains (SGP) site are discussed. NR-PM1 data was recorded at ~30 min intervals over a period of 19 months between November 2010 and June 2012. Positive Matrix Factorization (PMF) was performed on the measured organic mass spectral matrix using a rolling window technique to derive factors associated with distinct sources, evolution processes, and physiochemical properties. The rolling window approach also allows us to capture the dynamic variations of the chemical properties in the organic aerosol (OA) factors over time. Three OA factors were obtained including two oxygenated OA (OOA) factors, differing in degrees of oxidation, and a biomass burning OA (BBOA) factor. Back trajectory analyses were performed to investigate possible sources of major NR-PM1 species at the SGP site. Organics dominated NR-PM1 mass concentration for the majority of the study with the exception of winter, when ammonium nitrate increases due to transport of precursor species from surrounding urban and agricultural areas and also due to cooler temperatures. Sulfate mass concentrations have little seasonal variation with mixed regional and local sources. In the spring BBOA emissions increase and are mainly associated with local fires. Isoprene and carbon monoxide emission rates were obtained by the Model of Emissions of Gases and Aerosols from Nature (MEGAN) and the 2011 U.S. National Emissions Inventory to represent the spatial distribution of biogenic and anthropogenic sources, respectively. The combined spatial distribution of isoprene emissions and air mass trajectories suggest that biogenic emissions from the southeast contribute to SOA formation at the SGP site during the summer.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

Potential influence of interleukin-6 on the therapeutic effect of gefitinib in patients with advanced non-small cell lung cancer harbouring EGFR mutations

Highlights: • Overexpression of IL-6 in tumour cells is postulated to be a potential mechanism for the resistance or low sensitivity to EGFR-TKIs in preclinical models. • We found that patients with IL-6-postitive, EGFR-mutant tumours clearly exhibited worse progression-free survival than those with IL-6-negative, EGFR-mutant, non-small-cell lung cancer (NSCLC). • Tumour IL-6 levels might indicate a subpopulation of EGFR-mutant NSCLC that benefits less from gefitinib monotherapy. Although epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) are a key therapy used for patients with EGFR-mutant non-small cell lung cancer (NSCLC), some of whom do not respond well to its therapy. Cytokine including IL-6 secreted by tumour cells is postulated as a potential mechanism for the primary resistance or low sensitivity to EGFR-TKIs. Fifty-two patients with advanced EGFR-mutant NSCLC who had received gefitinib were assessed retrospectively. The protein expression of IL-6 in the tumour cells was assessed by immunostaining and judged as positive if ≥ 50 of 100 tumour cells stained positively. Of the 52 patients, 24 (46%) and 28 (54%) were defined as IL-6-postitive (group P) and IL-6-negative (group N), respectively. Group P had worse progression-free survival (PFS) than that of group N, which was retained in the multivariate analysis (hazard ratio: 2.39; 95 %CI: 1.00–5.68; p < 0.05). By contrast, the PFS after platinum-based chemotherapy did not differ between groups P and N (p = 0.47). In cell line-based model, the impact of IL-6 on the effect of EGFR-TKIs was assessed. The combination of EGFR-TKI and anti-IL-6 antibody moderately improved the sensitivity of EGFR-TKI in lung cancer cell with EGFR mutation. Interestingly, suppression of EGFR with EGFR-TKI accelerated the activation of STAT3 induced by IL-6. Taken together, tumour IL-6 levels might indicate a subpopulation of EGFR-mutant NSCLC that benefits less from gefitinib monotherapy.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Platelet-derived growth factor receptor alpha (PDGFRα) is overexpressed in NK/T-cell lymphoma and mediates cell survival

Nasal-type natural killer/T-cell lymphoma (NKTCL) is a subtype of non-Hodgkin lymphoma (NHL) that is clinically aggressive and has a poor prognosis. Platelet-derived growth factor receptors (PDGFRs) and their ligands (PDGFs) play important roles in angiogenesis, cancer cell proliferation, survival, migration and poor prognosis in various tumours. However, the significance of PDGFRs in NKTCL remains unknown. Herein, the present study aimed to investigate the important role of PDGFRα in pathogenesis, progression and prognisis of NKTCL. Firstly, we performed immunohistochemical staining, qRT-PCR and western blotting to determine PDGFRα expression in formalin-fixed, paraffin-embedded tissue sections from 78 NKTCL cases and in cell lines. Secondly, correlations between PDGFRα expression and NKTCL clinical parameters and prognosis were analysed. Moreover, a biological assessment of PDGFRα blockade in two NKTCL cell lines was conducted through proliferation assay, cell-cycle evaluation and apoptosis detection by flow cytometry analyses. Furthermore, we detected in vivo activity of imatinib in mouse model of NKTCL. We found that the expression of PDGFRα was significantly higher in NKTCL tissues compared to the reactive lymphoid hyperplasia of the nasopharynx (P = 0.028). High PDGFRα expression was strongly associated with a high LDH level (P = 0.028) and III-IV stage (P = 0.013). NKTCL patients with high PDGFRα expression displayed a reduced median overall survival time and progression-free survival time when compared with those with low PDGFRα expression (P = 0.011, P = 0.005, respectively). Cox multivariate analysis showed that III-IV stage (P = 0.024) and high PDGFRα expression (P = 0.003) were independent prognostic factors in NKTCL patients. Biological assessment assays in two NKTCL cell lines revealed that a specific PDGFR antagonist, imatinib, inhibited cell viability, blocked cell cycle progression at G0/G1 stage and induced apoptosis. Similarly, the in vivo assay showed that imatinib delayed mouse model tumour growth. In conclusion, NKTCL tumour cells have prominent PDGFRα expression, which can serve as a candidate prognostic marker. PDGFR antagonists have significant biological effect on NKTCL and may be useful therapeutic agents for treatment of NKTCL.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2012

Urinary strontium and the risk of breast cancer: A case-control study in Guangzhou, China

Strontium has been widely used in industries like electronic and pharmacy. It has a carcinogenic potential, however, and no study has been conducted to evaluate its effects on cancer risk. The aim of this study was to explore the possible association between strontium and breast cancer risk in a case-control study including 240 incident invasive breast cancer patients and 246 age-matched controls. We measured the urinary concentrations of strontium by inductively coupled plasma mass spectrometry, and conducted face-to-face interviews to obtain information on potential breast cancer risk factors. Multivariable analysis was used to estimate the association. Creatinine-adjusted levels [median (25th, 75th) {mu}g/g] of strontium were 155.59 (99.05, 230.70) in the breast cancer patients and 119.62 (81.97, 163.76) in the controls. Women in the highest tertile of strontium showed 124% increased risk of breast cancer, when compared with those in the lowest tertile after adjustment for the potential risk factors [OR (95% CI): 2.24 (1.42-3.81)]. This association was particularly strong for HER2 positive breast cancer [OR (95% CI): 10.92 (3.53-33.77)], and only occurred among premenopausal women. These results suggest a potential role of strontium in the development of breast cancer and urge further studies on the environmental contamination and the physiological and pathological mechanisms of strontium.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2011

Reirradiation of Large-Volume Recurrent Glioma With Pulsed Reduced-Dose-Rate Radiotherapy

Purpose: Pulsed reduced-dose-rate radiotherapy (PRDR) is a reirradiation technique that reduces the effective dose rate and increases the treatment time, allowing sublethal damage repair during irradiation. Patients and Methods: A total of 103 patients with recurrent glioma underwent reirradiation using PRDR (86 considered to have Grade 4 at PRDR). PRDR was delivered using a series of 0.2-Gy pulses at 3-min intervals, creating an apparent dose rate of 0.0667 Gy/min to a median dose of 50 Gy (range, 20-60) delivered in 1.8-2.0-Gy fractions. The mean treatment volume was 403.5 {+-} 189.4 cm{sup 3} according to T{sub 2}-weighted magnetic resonance imaging and a 2-cm margin. Results: For the initial or upgraded Grade 4 cohort (n = 86), the median interval from the first irradiation to PRDR was 14 months. Patients undergoing PRDR within 14 months of the first irradiation (n = 43) had a median survival of 21 weeks. Those treated {>=}14 months after radiotherapy had a median survival of 28 weeks (n = 43; p = 0.004 and HR = 1.82 with a 95% CI ranging from 1.25 to 3.10). These data compared favorably to historical data sets, because only 16% of the patients were treated at first relapse (with 46% treated at the second relapse, 32% at the third or fourth relapse, and 4% at the fourth or fifth relapse). The median survival since diagnosis and retreatment was 6.3 years and 11.4 months for low-grade, 4.1 years and 5.6 months for Grade 3, and 1.6 years and 5.1 months for Grade 4 tumors, respectively, according to the initial histologic findings. Multivariate analysis revealed age at the initial diagnosis, initial low-grade disease, and Karnofsky performance score of {>=}80 to be significant predictors of survival after initiation of PRDR. Conclusion: PRDR allowed for safe retreatment of larger volumes to high doses with palliative benefit.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Prostate-Specific Antigen Halving Time While on Neoadjuvant Androgen Deprivation Therapy Is Associated With Biochemical Control in Men Treated With Radiation Therapy for Localized Prostate Cancer

Purpose: To assess whether the PSA response to neoadjuvant androgen deprivation therapy (ADT) is associated with biochemical control in men treated with radiation therapy (RT) for prostate cancer. Methods and Materials: In a cohort of men treated with curative-intent RT for localized prostate cancer between 1988 and 2005, 117 men had PSA values after the first and second months of neoadjuvant ADT. Most men had intermediate-risk (45%) or high-risk (44%) disease. PSA halving time (PSAHT) was calculated by first order kinetics. Median RT dose was 76 Gy and median total duration of ADT was 4 months. Freedom from biochemical failure (FFBF, nadir + 2 definition) was analyzed by PSAHT and absolute PSA nadir before the start of RT. Results: Median follow-up was 45 months. Four-year FFBF was 89%. Median PSAHT was 2 weeks. A faster PSA decline (PSAHT {<=}2 weeks) was associated with greater FFBF (96% vs. 81% for a PSAHT >2 weeks, p = 0.0110). Those within the fastest quartile of PSAHTs ({<=} 10 days) achieved a FFBF of 100%. Among high-risk patients, a PSAHT {<=}2 weeks achieved a 4-yr FFBF of 93% vs. 70% for those with PSAHT >2 weeks (p = 0.0508). Absolute PSA nadir was not associated with FFBF. On multivariable analysis, PSAHT (p = 0.0093) and Gleason score (p = 0.0320) were associated with FFBF, whereas T-stage (p = 0.7363) and initial PSA level (p = 0.9614) were not. Conclusions: For men treated with combined ADT and RT, PSA response to the first month of ADT may be a useful criterion for prognosis and treatment modification.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Long-Term Follow-Up and Risk of Cancer Death After Radiation for Post-Prostatectomy Rising Prostate-Specific Antigen

Purpose: The results of salvage radiation therapy for rising prostate-specific antigen (PSA) levels after radical prostatectomy appear favorable, but the ultimate outcome is uncertain, given the relatively short follow-up in most studies. We report on a group of patients at a median follow-up of 13.9 years after salvage radiation therapy. Methods and Materials: From 1990 to 1995, 92 patients were referred postoperatively for radiation for a rising PSA level. PSA level at the time of referral ranged from 0.1 to 30.5 ng/ml (median, 1.5 ng/ml). The median time from surgery to radiation was 2.1 years (range,, 0.3-7.4 years). Radiation was directed to the prostatic fossa only with a median dose of 6,500 cGy (range, 6,000-7,000 cGy). Results: Eighty-five patients experienced a PSA drop after radiation, as predicted by Gleason score and PSA level at the start of radiation. Five- and 10-year biochemical failure free survival (BFFS) was 35% and 26%, respectively, and overall survival was 86% and 67%, respectively. Median survival was 12.0 years, and median BFF was 2.3 years. The presurgery PSA level was not predictive, but the PSA level at the start of radiation predicted a response. Patients with Gleason 8 to 9 cancers had a significantly higher progression rate than those with lower Gleason scores. There were no significant differences in outcomes based on pathology findings (none vs. positive margins vs. positive seminal vesicles). Overall, 22 (24%) patients died directly from prostate cancer, resulting in a 10-year cancer-specific survival rate of 82%. Multivariate analysis risk factors for dying of cancer were Gleason's score (8 to 9) and PSA at the start of radiation therapy (>1.0 ng/ml). Conclusions: Patients have a good response to salvage radiation therapy. A small but durable subgroup appears to have permanent control. In those for whom therapy fails, radiation delays the need for other salvage therapy, indicating at least a transient benefit to most patients.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Postradiation Metabolic Tumor Volume Predicts Outcome in Head-and-Neck Cancer

Purpose: To explore the prognostic value of metabolic tumor volume measured on postradiation {sup 18}F-fluorodeoxyglucose positron emission tomography (PET) imaging in patients with head-and-neck cancer. Methods and Materials: Forty-seven patients with head-and-neck cancer who received pretreatment and posttreatment PET/computed tomography (CT) imaging along with definitive chemoradiotherapy were included in this study. The PET/CT parameters evaluated include the maximum standardized uptake value, metabolic tumor volume (MTV{sub 2.0}-MTV{sub 4.0}; where MTV{sub 2.0} refers to the volume above a standardized uptake value threshold of 2.0), and integrated tumor volume. Kaplan-Meier and Cox regression models were used to test for association between PET endpoints and disease-free survival and overall survival. Results: Multiple postradiation PET endpoints correlated significantly with outcome; however, the most robust predictor of disease progression and death was MTV{sub 2.0}. An increase in MTV{sub 2.0} of 21cm{sup 3} (difference between 75th and 25th percentiles) was associated with an increased risk of disease progression (hazard ratio [HR]= 2.5, p = 0.0001) and death (HR = 2.0, p = 0.003). In patients with nonnasopharyngeal carcinoma histology (n = 34), MTV{sub 2.0} <18 cm{sup 3} and MTV{sub 2.0} {>=}18 cm{sup 3} yielded 2-year disease-free survival rates of 100% and 63%, respectively (p = 0.006) and 2-year overall survival rates of 100% and 81%, respectively (p = 0.009). There was no correlation between MTV{sub 2.0} and disease-free survival or overall survival with nasopharyngeal carcinoma histology (n = 13). On multivariate analysis, only postradiation MTV{sub 2.0} was predictive of disease-free survival (HR = 2.47, p = 0.0001) and overall survival (HR = 1.98, p = 0.003). Conclusions: Postradiation metabolic tumor volume is an adverse prognostic factor in head-and-neck cancer. Biomarkers such as MTV are important for risk stratification and will be valuable in the future with risk-adapted therapies.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Intensity-Modulated Radiotherapy Reduces Gastrointestinal Toxicity in Patients Treated With Androgen Deprivation Therapy for Prostate Cancer

Purpose: Androgen deprivation therapy (AD) has been shown to increase late Grade 2 or greater rectal toxicity when used concurrently with three-dimensional conformal radiotherapy (3D-CRT). Intensity-modulated radiotherapy (IMRT) has the potential to reduce toxicity by limiting the radiation dose received by the bowel and bladder. The present study compared the genitourinary and gastrointestinal (GI) toxicity in men treated with 3D-CRT+AD vs. IMRT+AD. Methods and Materials: Between July 1992 and July 2004, 293 men underwent 3D-CRT (n = 170) or IMRT (n = 123) with concurrent AD (<6 months, n = 123; {>=}6 months, n = 170). The median radiation dose was 76 Gy for 3D-CRT (International Commission on Radiation Units and Measurements) and 76 Gy for IMRT (95% to the planning target volume). Toxicity was assessed by a patient symptom questionnaire that was completed at each visit and recorded using a Fox Chase Modified Late Effects Normal Tissue Task radiation morbidity scale. Results: The mean follow-up was 86 months (standard deviation, 29.3) for the 3D-CRT group and 40 months (standard deviation, 9.7) for the IMRT group. Acute GI toxicity (odds ratio, 4; 95% confidence interval, 1.6-11.7; p = .005) was significantly greater with 3D-CRT than with IMRT and was independent of the AD duration (i.e., <6 vs. {>=}6 months). The interval to the development of late GI toxicity was significantly longer in the IMRT group. The 5-year Kaplan-Meier estimate for Grade 2 or greater GI toxicity was 20% for 3D-CRT and 8% for IMRT (p = .01). On multivariate analysis, Grade 2 or greater late GI toxicity (hazard ratio, 2.1; 95% confidence interval, 1.1-4.3; p = .04) was more prevalent in the 3D-CRT patients. Conclusion: Compared with 3D-CRT, IMRT significantly decreased the acute and late GI toxicity in patients treated with AD.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Race and Survival Following Brachytherapy-Based Treatment for Men With Localized or Locally Advanced Adenocarcinoma of the Prostate

Purpose: We investigated whether race was associated with risk of death following brachytherapy-based treatment for localized prostate cancer, adjusting for age, cardiovascular comorbidity, treatment, and established prostate cancer prognostic factors. Methods: The study cohort was composed of 5,360 men with clinical stage T1-3N0M0 prostate cancer who underwent brachytherapy-based treatment at 20 centers within the 21st Century Oncology consortium. Cox regression multivariable analysis was used to evaluate the risk of death in African-American and Hispanic men compared to that in Caucasian men, adjusting for age, pretreatment prostate-specific antigen (PSA) level, Gleason score, clinical T stage, year and type of treatment, median income, and cardiovascular comorbidities. Results: After a median follow-up of 3 years, there were 673 deaths. African-American and Hispanic races were significantly associated with an increased risk of all-cause mortality (ACM) (adjusted hazard ratio, 1.77 and 1.79; 95% confidence intervals, 1.3-2.5 and 1.2-2.7; p < 0.001 and p = 0.005, respectively). Other factors significantly associated with an increased risk of death included age (p < 0.001), Gleason score of 8 to 10 (p = 0.04), year of brachytherapy (p < 0.001), and history of myocardial infarction treated with stent or coronary artery bypass graft (p < 0.001). Conclusions: After adjustment for prostate cancer prognostic factors, age, income level, and revascularized cardiovascular comorbidities, African-American and Hispanic races were associated with higher ACM in men with prostate cancer. Additional causative factors need to be identified.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

The Number of Pathologically Positive Lymph Nodes and Pathological Tumor Depth Predicts Prognosis in Patients With Poorly Differentiated Squamous Cell Carcinoma of the Oral Cavity

Purpose: The objective of this retrospective study was twofold: (1) to investigate prognostic factors for clinical outcomes in patients with poorly differentiated oral cavity squamous cell carcinoma and (2) to identify specific prognostic subgroups that may help to guide treatment decisions. Methods and Materials: We examined 102 patients with poorly differentiated oral cavity squamous cell carcinoma. All patients were followed for at least 24 months after surgery or until death. The 5-year rates of local control, neck control, distant metastasis, disease-free, disease-specific, and overall survival served as main outcome measures. Results: The 5-year rates were as follows: local control (79%), neck control (64%), distant metastases (27%), disease-free survival (48%), disease-specific survival (52%), and overall survival (42%). Multivariable analysis showed that the number of pathologically positive nodes ({>=}4 vs. {<=}3) was a significant predictor of neck control, distant metastasis, and disease-free, disease-specific, and overall survival rates. In addition, the presence of tumor depth of {>=}11 mm (vs. <11 mm) was a significant predictor of distant metastasis, disease-specific survival, and overall survival rates. The combination of the two predictors (26.5%, 27/102) was independently associated with poorer neck control (p = 0.0319), distant metastasis (p < 0.0001), and disease-free (p < 0.0001), disease-specific (p < 0.0001), and overall survival (p < 0.0001) rates. Conclusions: In patients with poorly differentiated oral cavity squamous cell carcinoma, the presence of at least 4 pathologically positive lymph nodes and of a pathological tumor depth {>=}11 mm identifies a subset of subjects with poor clinical outcomes. Patients carrying both risk factors are suitable candidates for the development of novel therapeutic approaches.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2012

Influence of Androgen Deprivation Therapy on All-Cause Mortality in Men With High-Risk Prostate Cancer and a History of Congestive Heart Failure or Myocardial Infarction

Purpose: It is unknown whether the excess risk of all-cause mortality (ACM) observed when androgen deprivation therapy (ADT) is added to radiation for men with prostate cancer and a history of congestive heart failure (CHF) or myocardial infarction (MI) also applies to those with high-risk disease. Methods and Materials: Of 14,594 men with cT1c-T3aN0M0 prostate cancer treated with brachytherapy-based radiation from 1991 through 2006, 1,378 (9.4%) with a history of CHF or MI comprised the study cohort. Of these, 22.6% received supplemental external beam radiation, and 42.9% received a median of 4 months of neoadjuvant ADT. Median age was 71.8 years. Median follow-up was 4.3 years. Cox multivariable analysis tested for an association between ADT use and ACM within risk groups, after adjusting for treatment factors, prognostic factors, and propensity score for ADT. Results: ADT was associated with significantly increased ACM (adjusted hazard ratio [AHR] = 1.76; 95% confidence interval [CI], 1.32-2.34; p = 0.0001), with 5-year estimates of 22.71% with ADT and 11.62% without ADT. The impact of ADT on ACM by risk group was as follows: high-risk AHR = 2.57; 95% CI, 1.17-5.67; p = 0.019; intermediate-risk AHR = 1.75; 95% CI, 1.13-2.73; p = 0.012; low-risk AHR = 1.52; 95% CI, 0.96-2.43; p = 0.075). Conclusions: Among patients with a history of CHF or MI treated with brachytherapy-based radiation, ADT was associated with increased all-cause mortality, even for patients with high-risk disease. Although ADT has been shown in Phase III studies to improve overall survival in high-risk disease, the small subgroup of high-risk patients with a history of CHF or MI, who represented about 9% of the patients, may be harmed by ADT.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2012

Feasibility and Acute Toxicity of Hypofractionated Radiation in Large-breasted Patients

Purpose: To determine the feasibility of and acute toxicity associated with hypofractionated whole breast radiation (HypoRT) after breast-conserving surgery in patients excluded from or underrepresented in randomized trials comparing HypoRT with conventional fractionation schedules. Methods and Materials: A review was conducted of all patients consecutively treated with HypoRT at University of Chicago. All patients were treated to 42.56 Gy in 2.66 Gy daily fractions in either the prone or supine position. Planning was performed in most cases using wedges and large segments or a 'field-in-field' technique. Breast volume was estimated using volumetric measurements of the planning target volume (PTV). Dosimetric parameters of heterogeneity (V105, V107, V110, and maximum dose) were recorded for each treatment plan. Acute toxicity was scored for each treated breast. Results: Between 2006 and 2010, 78 patients were treated to 80 breasts using HypoRT. Most women were overweight or obese (78.7%), with a median body mass index of 29.2 kg/m{sup 2}. Median breast volume was 1,351 mL. Of the 80 treated breasts, the maximum acute skin toxicity was mild erythema or hyperpigmentation in 70.0% (56/80), dry desquamation in 21.25% (17/80), and focal moist desquamation in 8.75% (7/80). Maximum acute toxicity occurred after the completion of radiation in 31.9% of patients. Separation >25 cm was not associated with increased toxicity. Breast volume was the only patient factor significantly associated with moist desquamation on multivariable analysis (p = 0.01). Patients with breast volume >2,500 mL experienced focal moist desquamation in 27.2% of cases compared with 6.34% in patients with breast volume <2,500 mL (p = 0.03). Conclusions: HypoRT is feasible and safe in patients with separation >25 cm and in patients with large breast volume when employing modern planning and positioning techniques. We recommend counseling regarding expected increases in skin toxicity in women with a PTV volume >2,500 mL.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2012

Predicting Chest Wall Pain From Lung Stereotactic Body Radiotherapy for Different Fractionation Schemes

Purpose: Recent studies with two fractionation schemes predicted that the volume of chest wall receiving >30 Gy (V30) correlated with chest wall pain after stereotactic body radiation therapy (SBRT) to the lung. This study developed a predictive model of chest wall pain incorporating radiobiologic effects, using clinical data from four distinct SBRT fractionation schemes. Methods and Materials: 102 SBRT patients were treated with four different fractionations: 60 Gy in three fractions, 50 Gy in five fractions, 48 Gy in four fractions, and 50 Gy in 10 fractions. To account for radiobiologic effects, a modified equivalent uniform dose (mEUD) model calculated the dose to the chest wall with volume weighting. For comparison, V30 and maximum point dose were also reported. Using univariable logistic regression, the association of radiation dose and clinical variables with chest wall pain was assessed by uncertainty coefficient (U) and C statistic (C) of receiver operator curve. The significant associations from the univariable model were verified with a multivariable model. Results: 106 lesions in 102 patients with a mean age of 72 were included, with a mean of 25.5 (range, 12-55) months of follow-up. Twenty patients reported chest wall pain at a mean time of 8.1 (95% confidence interval, 6.3-9.8) months after treatment. The mEUD models, V30, and maximum point dose were significant predictors of chest wall pain (p < 0.0005). mEUD improved prediction of chest wall pain compared with V30 (C = 0.79 vs. 0.77 and U = 0.16 vs. 0.11). The mEUD with moderate weighting (a = 5) better predicted chest wall pain than did mEUD without weighting (a = 1) (C = 0.79 vs. 0.77 and U = 0.16 vs. 0.14). Body mass index (BMI) was significantly associated with chest wall pain (p = 0.008). On multivariable analysis, mEUD and BMI remained significant predictors of chest wall pain (p = 0.0003 and 0.03, respectively). Conclusion: mEUD with moderate weighting better predicted chest wall pain than did V30, indicating that a small chest wall volume receiving a high radiation dose is responsible for chest wall pain. Independently of dose to the chest wall, BMI also correlated with chest wall pain.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2012

Similar Survival With Breast Conservation Therapy or Mastectomy in the Management of Young Women With Early-Stage Breast Cancer

Purpose: To evaluate survival outcomes of young women with early-stage breast cancer treated with breast conservation therapy (BCT) or mastectomy, using a large, population-based database. Methods and Materials: Using the Surveillance, Epidemiology, and End Results (SEER) database, information was obtained for all female patients, ages 20 to 39 years old, diagnosed with T1-2 N0-1 M0 breast cancer between 1990 and 2007, who underwent either BCT (lumpectomy and radiation treatment) or mastectomy. Multivariable and matched pair analyses were performed to compare overall survival (OS) and cause-specific survival (CSS) of patients undergoing BCT and mastectomy. Results: A total of 14,764 women were identified, of whom 45% received BCT and 55% received mastectomy. Median follow-up was 5.7 years (range, 0.5-17.9 years). After we accounted for all patient and tumor characteristics, multivariable analysis found that BCT resulted in OS (hazard ratio [HR], 0.93; 95% confidence interval [CI], 0.83-1.04; p = 0.16) and CSS (HR, 0.93; CI, 0.83-1.05; p = 0.26) similar to that of mastectomy. Matched pair analysis, including 4,644 BCT and mastectomy patients, confirmed no difference in OS or CSS: the 5-, 10-, and15-year OS rates for BCT and mastectomy were 92.5%, 83.5%, and 77.0% and 91.9%, 83.6%, and 79.1%, respectively (p = 0.99), and the 5-, 10-, and 15-year CSS rates for BCT and mastectomy were 93.3%, 85.5%, and 79.9% and 92.5%, 85.5%, and 81.9%, respectively (p = 0.88). Conclusions: Our analysis of this population-based database suggests that young women with early-stage breast cancer have similar survival rates whether treated with BCT or mastectomy. These patients should be counseled appropriately regarding their treatment options and should not choose a mastectomy based on the assumption of improved survival.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2012

Is Primary Prostate Cancer Treatment Influenced by Likelihood of Extraprostatic Disease? A Surveillance, Epidemiology and End Results Patterns of Care Study

Purpose: To examine the patterns of primary treatment in a recent population-based cohort of prostate cancer patients, stratified by the likelihood of extraprostatic cancer as predicted by disease characteristics available at diagnosis. Methods and Materials: A total of 157,371 patients diagnosed from 2004 to 2008 with clinically localized and potentially curable (node-negative, nonmetastatic) prostate cancer, who have complete information on prostate-specific antigen, Gleason score, and clinical stage, were included. Patients with clinical T1/T2 disease were grouped into categories of <25%, 25%-50%, and >50% likelihood of having extraprostatic disease using the Partin nomogram. Clinical T3/T4 patients were examined separately as the highest-risk group. Logistic regression was used to examine the association between patient group and receipt of each primary treatment, adjusting for age, race, year of diagnosis, marital status, Surveillance, Epidemiology and End Results database region, and county-level education. Separate models were constructed for primary surgery, external-beam radiotherapy (RT), and conservative management. Results: On multivariable analysis, increasing likelihood of extraprostatic disease was significantly associated with increasing use of RT and decreased conservative management. Use of surgery also increased. Patients with >50% likelihood of extraprostatic cancer had almost twice the odds of receiving prostatectomy as those with <25% likelihood, and T3-T4 patients had 18% higher odds. Prostatectomy use increased in recent years. Patients aged 76-80 years were likely to be managed conservatively, even those with a >50% likelihood of extraprostatic cancer (34%) and clinical T3-T4 disease (24%). The proportion of patients who received prostatectomy or conservative management was approximately 50% or slightly higher in all groups. Conclusions: There may be underutilization of RT in older prostate cancer patients and those with likely extraprostatic disease. Because more than half of prostate cancer patients do not consult with a radiation oncologist, a multidisciplinary consultation may affect the treatment decision-making process.

62 RADIOLOGY AND NUCLEAR MEDICINE↗