Phase II Trial of Five-Fraction Accelerated Partial Breast Irradiation (APBI) Using Noninvasive Image-Guided Breast Brachytherapy (NIBB).

PURPOSE/OBJECTIVE(S): NIBB has potential advantages over other APBI techniques by delivering highly conformal radiation with minimal collateral dose to the heart and lung compared with external beam techniques, but unlike other brachytherapy techniques NIBB is non-invasive. Previous data has shown encouraging outcomes using a 10-fraction regimen. To improve efficiency, convenience, and cost, reduction in the fraction number is desirable. Final results of a prospective phase II trial are reported. MATERIALS/METHODS: NIBB APBI was delivered using 28.5Gy in 5 fractions daily over 1 week. Patient eligibility criteria required: invasive carcinoma ≤2.0 cm or DCIS ≤3.0 cm, ER positive (if invasive), lymph node negative, LVI absent, and lumpectomy with margins negative by 2mm. The primary endpoint was grade ≥ 2 subcutaneous fibrosis/induration <30%. Secondary endpoints included any late toxicity, cosmetic outcome, and local control. RESULTS: 40 patients were treated with a median follow-up of 59.7 months. The mean age was 67 years (50-89 years) and tumor size was 1.0cm (0.3-2.0cm). 80% had invasive carcinoma. The mean breast separation with compression was 6.7cm (3.5-8.9cm). The 5-year actuarial local control was 96.6% and overall survival was 96.9%. Grade 2 and 3 late toxicities were 15% and 0%, respectively. The rate of grade 2 subcutaneous fibrosis/induration was 2.5% (+/-2.5%) meeting the study's primary endpoint. The most common late toxicity of any grade was skin telangiectasia; 22.5% grade 1 and 15% grade 2. Only breast separation was associated with telangiectasia risk, p=0.002. Overall cosmetic outcome was excellent, good, and fair/poor in 75%, 25%, and 0%, respectively. CONCLUSIONS: NIBB APBI delivered in 5 fractions results in a low rate of late toxicity and a high rate of good/excellent cosmetic outcomes. Telangiectasia risk can be minimized by keeping breast separation ≤7.0cm. The local failure rate was appropriately low. Further investigation of this technique is warranted.

Impact of age on treatment response in men with prostate cancer treated with radiotherapy.

Objective: To analyse the effect of age at diagnosis on clinical outcomes of localized prostate cancer (PCa) treated with radiation therapy. Subjects and methods: We identified 12 784 patients with intermediate- or high-risk localized PCa treated with radiation therapy (RT) and neoadjuvant androgen deprivation therapy (ADT) between 2000 and 2015 from nationwide Veterans Affairs data. Patients were grouped into three age categories (≤59, 60-69, and ≥70 years old). Outcomes included immediate PSA response (3-month post-RT PSA and 2-year PSA nadir, grouped into <0.10 ng/ml, 0.10-0.49 ng/ml, and ≥0.50 ng/ml), biochemical recurrence, and PCa-specific mortality. Multivariable regression models included ordinal logistic regression for short-term PSA outcomes, Cox regression for biochemical recurrence, and Fine-Gray competing risks regression for PCa-specific mortality. Results: A total of 2136 patients (17%) were ≤59 years old at diagnosis, 6107 (48%) were 60-69 years old, and 4541 (36%) were ≥70 years old. Median follow-up was 6.3 years. Younger age was associated with greater odds of higher 3-month PSA group (≤59 vs. ≥70: adjusted odds ratio [aOR] 1.90, 95% CI 1.64-2.20; p < 0.001) and higher 2-year PSA nadir group (≤59 vs. ≥70: aOR 1.89, 95% CI 1.62-2.19, p < 0.001). Younger age was associated with greater risk of biochemical recurrence (≤59 vs. ≥70: adjusted hazard ratio 1.45, 95% CI 1.26-1.67, p < 0.001) but not PCa-specific mortality (p = 0.16). Conclusion: In a large nationwide sample of US veterans treated with ADT and RT for localized PCa, younger age was associated with inferior short-term PSA response and higher risk of biochemical recurrence.

Evaluation of dose differences between intracavitary applicators for cervical brachytherapy using knowledge-based models.

PURPOSE: Currently, there is a lack of patient-specific tools to guide brachytherapy planning and applicator choice for cervical cancer. The purpose of this study is to evaluate the accuracy of organ-at-risk (OAR) dose predictions using knowledge-based intracavitary models, and the use of these models and clinical data to determine the dosimetric differences of tandem-and-ring (T&R) and tandem-and-ovoids (T&O) applicators. MATERIALS AND METHODS: Knowledge-based models, which predict organ D2cc, were trained on 77/75 cases and validated on 32/38 for T&R/T&O applicators. Model performance was quantified using ΔD2cc=D2cc,actual-D2cc,predicted, with standard deviation (σ(ΔD2cc)) representing precision. Model-predicted applicator dose differences were determined by applying T&O models to T&R cases, and vice versa, and compared to clinically-achieved D2cc differences. Applicator differences were assessed using a Student's t-test (p < 0.05 significant). RESULTS: Validation T&O/T&R model precision was 0.65/0.55 Gy, 0.55/0.38 Gy, and 0.43/0.60 Gy for bladder, rectum and sigmoid, respectively, and similar to training. When applying T&O/T&R models to T&R/T&O cases, bladder, rectum and sigmoid D2cc values in EQD2 were on average 5.69/2.62 Gy, 7.31/6.15 Gy and 3.65/0.69 Gy lower for T&R, with similar HRCTV volume and coverage. Clinical data also showed lower T&R OAR doses, with mean EQD2 D2cc deviations of 0.61 Gy, 7.96 Gy (p < 0.01) and 5.86 Gy (p < 0.01) for bladder, rectum and sigmoid. CONCLUSIONS: Accurate knowledge-based dose prediction models were developed for two common intracavitary applicators. These models could be beneficial for standardizing and improving the quality of brachytherapy plans. Both models and clinical data suggest that significant OAR sparing can be achieved with T&R over T&O applicators, particularly for the rectum.

Knowledge-based dose prediction models to inform gynecologic brachytherapy needle supplementation for locally advanced cervical cancer.

PURPOSE: The use of interstitial needles, combined with intracavitary applicators, enables customized dose distributions and is beneficial for complex cases, but increases procedure time. Overall, applicator selection is not standardized and depends on physician expertise and preference. The purpose of this study is to determine whether dose prediction models can guide needle supplementation decision-making for cervical cancer. MATERIALS AND METHODS: Intracavitary knowledge-based models for organ-at-risk (OAR) dose estimation were trained and validated for tandem-and-ring/ovoids (T&R/T&O) implants. Models were applied to hybrid cases with 1-3 implanted needles to predict OAR dose without needles. As a reference, 70/67 hybrid T&R/T&O cases were replanned without needles, following a standardized procedure guided by dose predictions. If a replanned dose exceeded the dose objective, the case was categorized as requiring needles. Receiver operating characteristic (ROC) curves of needle classification accuracy were generated. Optimal classification thresholds were determined from the Youden Index. RESULTS: Needle supplementation reduced dose to OARs. However, 67%/39% of replans for T&R/T&O met all dose constraints without needles. The ROC for T&R/T&O models had an area-under-curve of 0.89/0.86, proving high classification accuracy. The optimal threshold of 99%/101% of the dose limit for T&R/T&O resulted in classification sensitivity and specificity of 78%/86% and 85%/78%. CONCLUSIONS: Needle supplementation reduced OAR dose for most cases but was not always required to meet standard dose objectives, particularly for T&R cases. Our knowledge-based dose prediction model accurately identified cases that could have met constraints without needle supplementation, suggesting that such models may be beneficial for applicator selection.

Outcomes of Black men with prostate cancer treated with radiation therapy in the Veterans Health Administration.

BACKGROUND: Population-based studies demonstrate that Black men in the United States have an increased risk of death from prostate cancer. Determinants of racial disparities are multifactorial, including socioeconomic and biologic factors. METHODS: The authors conducted a pooled analysis of patients derived from 152 centers within the Veterans Health Administration. The cohort included men who had nonmetastatic prostate diagnosed between 2001 and 2015 and received definitive radiation therapy. The primary endpoint was prostate cancer-specific mortality (PCSM). Secondary endpoints included all-cause mortality (ACM) and the time from a prostate-specific antigen level ≥4 ng/mL to biopsy and radiation therapy. A Cox regression model was performed to adjust for differences between clinical parameters. RESULTS: Among the 31,131 patients included in the cohort, 9584 (30.8%) were Black. The 10-year cumulative incidence of death from prostate cancer was lower in Black men compared with White men (4.0% vs 4.8%; P = .004). In a competing risk model, Black race was associated with a decreased risk of PCSM (subdistribution hazard ratio, 0.79; 95% CI, 0.69-0.92; P = .002). Similarly, the 10-year cumulative incidence of death from any cause was lower in Black men (27.6% vs 31.8%; P < .001). In multivariable analysis, Black men had a 10% decreased risk of ACM (hazard ratio, 0.90; 95% CI, 0.85-0.95; P < .001). CONCLUSIONS: The current results indicate relatively lower PCSM and ACM among Black men who were included in a large Veterans Health Administration cohort and received radiation therapy as primary treatment for nonmetastatic prostate cancer. There is an ongoing need to continue to understand and mitigate the factors associated with disparities in health care outcomes.

Testosterone therapy does not increase the risks of prostate cancer recurrence or death after definitive treatment for localized disease.

BACKGROUND: The safety of testosterone therapy (TT) after definitive treatment for localized prostate cancer remains undefined. We analyzed the risks of biochemical recurrence and mortality in men receiving TT after treatment for localized prostate cancer. METHODS: Cohort analysis using the national US Veterans Affairs Informatics and Computing Infrastructure. We identified 69,984 patients with localized prostate cancer diagnosed from 2001 to 2015 treated with surgery or radiation. We coded receipt of TT after treatment as a time-dependent covariate; used the National Death Index to identify cause of death; and defined biochemical recurrence as PSA > 0.2 ng/mL after surgery and nadir + 2 ng/mL after radiation. We analyzed recurrence and mortality using cumulative incidence curves, Fine-Gray competing risk regression, and Cox regression. RESULTS: This cohort included 28,651 surgery patients and 41,333 radiation patients, of whom 469 (1.64%) and 543 (1.31%), respectively, received TT with a median follow-up of 6.95 years. Comparing testosterone users to nonusers, there were no between-group differences in biochemical recurrence, prostate cancer-specific mortality, or overall mortality after surgery [hazard ratios (HR): 1.07; HR: 0.72 (p = 0.43); and HR: 1.11 (p = 0.43), respectively] or radiation [HR: 1.07; HR: 1.02 (p = 0.95); and HR: 1.02 (p = 0.86), respectively]. Limitations included lack of detailed data on TT duration and serum testosterone concentrations. CONCLUSIONS: In this multi-ethnic national cohort, TT did not increase the risks of biochemical recurrence or prostate cancer-specific or overall mortality after surgery or radiation. These data suggest that TT is safe in appropriate men after definitive treatment of localized prostate cancer.

A knowledge-based organ dose prediction tool for brachytherapy treatment planning of patients with cervical cancer.

PURPOSE: The purpose of this study is to explore knowledge-based organ-at-risk dose estimation for intracavitary brachytherapy planning for cervical cancer. Using established external-beam knowledge-based dose-volume histogram (DVH) estimation methods, we sought to predict bladder, rectum, and sigmoid D2cc for tandem and ovoid treatments. METHODS AND MATERIALS: A total of 136 patients with loco-regionally advanced cervical cancer treated with 456 (356:100 training:validation ratio) CT-based tandem and ovoid brachytherapy fractions were analyzed. Single fraction prescription doses were 5.5-8 Gy with dose criteria for the high-risk clinical target volume, bladder, rectum, and sigmoid. DVH estimations were obtained by subdividing training set organs-at-risk into high-risk clinical target volume boundary distance subvolumes and computing cohort-averaged differential DVHs. Full DVH estimation was then performed on the training and validation sets. Model performance was quantified by ΔD2cc = D2cc(actual)-D2cc(predicted) (mean and standard deviation). ΔD2cc between training and validation sets were compared with a Student's t test (p < 0.01 significant). Categorical variables (physician, fraction-number, total fractions, and case complexity) that might explain model variance were examined using an analysis of variance test (Bonferroni-corrected p < 0.01 threshold). RESULTS: Training set deviations were bladder ΔD2cc = -0.04 ± 0.61 Gy, rectum ΔD2cc = 0.02 ± 0.57 Gy, and sigmoid ΔD2cc = -0.05 ± 0.52 Gy. Model predictions on validation set did not statistically differ: bladder ΔD2cc = -0.02 ± 0.46 Gy (p = 0.80), rectum ΔD2cc = -0.007 ± 0.47 Gy (p = 0.53), and sigmoid ΔD2cc = -0.07 ± 0.47 Gy (p = 0.70). The only significant categorical variable was the attending physician for bladder and rectum ΔD2cc. CONCLUSION: A simple boundary distance-driven knowledge-based DVH estimation exhibited promising results in predicting critical brachytherapy dose metrics. Future work will examine the utility of these predictions for quality control and automated brachytherapy planning.

Phase 1 Trial of Concurrent Gemcitabine and Cisplatin with Image Guided Intensity Modulated Radiation Therapy for Locoregionally Advanced Cervical Carcinoma.

PURPOSE: The use of concurrent doublet chemotherapy with radiation for locoregionally advanced cervical cancer (LACC) is limited by gastrointestinal and hematologic toxicity. By reducing radiation dose to bowel and bone marrow, image guided intensity modulated radiation therapy (IG-IMRT) may improve chemotherapy tolerance. The goal of this study was to determine whether IG-IMRT could lead to improved tolerance to concurrent cisplatin and gemcitabine for LACC. METHODS AND MATERIALS: We conducted an open-label, nonrandomized, prospective phase 1 dose escalation trial at a tertiary academic cancer center (ClinicalTrials.gov identifier: NCT01554410). We enrolled patients with stage IB-IVA cervical cancer, with either an intact cervix or posthysterectomy with residual/recurrent pelvic or paraortic nodal involvement, undergoing radical pelvic or extended field chemoradiation therapy. Treatment consisted of chemoradiation with IG-IMRT (45-47.6 Gy, 25-28 fractions to the pelvis ± paraortic nodes with simultaneous nodal boost to 53.2-59.4 Gy, 28 fractions) plus 5 cycles of concurrent weekly cisplatin 40 mg/m2 with escalating doses of gemcitabine (50, 75, 100, or 125 mg/m2). Cohorts were separated preregistration according to whether the patient received pelvic or extended field IG-IMRT and whether gemcitabine followed (CG) or preceded (GC) cisplatin delivery. Dose-limiting toxicity (DLT) events were monitored up to 30 days after chemoradiation therapy. The primary endpoint was maximum tolerated dose (MTD) resulting in DLT probability ≤20%. RESULTS: Between February 2011 and June 2019, 35 patients were registered. Overall, 7 patients (20.0%) experienced DLTs. For the pelvic field cohort, the estimated MTD was 100 mg/m2 with GC sequencing, which is higher than the previously reported MTD for this regimen. The extended field cohort was closed after 2 of 3 patients experienced a DLT at the first dose level. CONCLUSIONS: IG-IMRT can permit higher doses of concurrent gemcitabine with cisplatin and pelvic radiation for LACC. However, acute toxicity remains a factor with this regimen, depending on radiation volume and chemotherapy sequencing.

Associations among statins, preventive care, and prostate cancer mortality.

BACKGROUND: Increasing evidence indicates an association between statins and reduced prostate cancer-specific mortality (PCSM). However, significant bias may exist in these studies. One particularly challenging bias to assess is the healthy user effect, which may be quantified by screening patterns. We aimed to evaluate the association between statin use, screening, and PCSM in a dataset with detailed longitudinal information. METHODS: We used the Veterans Affairs Informatics and Computing Infrastructure to assemble a cohort of patients diagnosed with prostate cancer (PC) between 2000 and 2015. We collected patient-level demographic, comorbidity, and tumor data. We also assessed markers of preventive care utilization including cholesterol and prostate specific antigen (PSA) screening rates. Patients were considered prediagnosis statin users if they had at least one prescription one or more years prior to PC diagnosis. We evaluated PCSM using hierarchical Fine-Gray regression models and all-cause mortality (ACM) using a cox regression model. RESULTS: The final cohort contained 68,432 men including 40,772 (59.6%) prediagnosis statin users and 27,660 (40.4%) nonusers. Prediagnosis statin users had higher screening rates than nonusers for cholesterol (90 vs. 69%, p < 0.001) and PSA (76 vs. 67%, p < 0.001). In the model which excluded screening, prediagnosis statin users had improved PCSM (SHR 0.90, 95% CI 0.84-0.97; p = 0.004) and ACM (HR 0.96, 95% CI 0.93-0.99; p = 0.02). However, after including cholesterol and PSA screening rates, prediagnosis statin users and nonusers showed no differences in PCSM (SHR 0.98, 95% CI 0.91-1.06; p = 0.59) or ACM (HR 1.02, 95% CI 0.98-1.05; p = 0.25). CONCLUSION: We found that statin users tend to have more screening than nonusers. When we considered screening utilization, we observed no relationship between statin use before a prostate cancer diagnosis and prostate cancer mortality.

Survival of African American and non-Hispanic white men with prostate cancer in an equal-access health care system.

BACKGROUND: African American (AA) men in the general US population are more than twice as likely to die of prostate cancer (PC) compared with non-Hispanic white (NHW) men. The authors hypothesized that receiving care through the Veterans Affairs (VA) health system, an equal-access medical system, would attenuate this disparity. METHODS: A longitudinal, centralized database of >20 million veterans was used to assemble a cohort of 60,035 men (18,201 AA men [30.3%] and 41,834 NHW men [69.7%]) who were diagnosed with PC between 2000 and 2015. RESULTS: AA men were more likely to live in regions with a lower median income ($40,871 for AA men vs $48,125 for NHW men; P < .001) and lower high school graduation rates (83% for AA men vs 88% for NHW men; P < .001). At the time of diagnosis, AA men were younger (median age, 63.0 years vs 66.0 years; P < .001) and had a higher prostate-specific antigen level (median, 6.7 ng/mL vs 6.2 ng/mL; P < .001), but were less likely to have Gleason score 8 to 10 disease (18.8% among AA men vs 19.7% among NHW men; P < .001), a clinical T classification ≥3 (2.2% vs 2.9%; P < .001), or distant metastatic disease (2.7% vs 3.1%; P = 0.01). The 10-year PC-specific mortality rate was slightly lower for AA men (4.4% vs 5.1%; P = .005), which was confirmed in multivariable competing-risk analysis (subdistribution hazard ratio, 0.85; 95% CI, 0.78-0.93; P < .001). CONCLUSIONS: AA men diagnosed with PC in the VA health system do not appear to present with more advanced disease or experience worse outcomes compared with NHW men, in contrast to national trends, suggesting that access to care is an important determinant of racial equity.

Implementation of peer-review quality rounds for gynecologic brachytherapy in a high-volume academic center.

PURPOSE: While peer review is critical for quality and safety in radiotherapy, there are neither formal guidelines nor format examples for brachytherapy (BT) peer review. We report on a gynecologic BT peer-review method implemented at a high-volume academic center. METHODS AND MATERIALS: We analyzed discussions at bimonthly gynecologic BT peer-review rounds between July and December 2018. Rounds consisted of 2-5 attending physicians with gynecologic BT expertise, 1-2 BT physicists, and trainees. Peer-review targets included clinical case review, contours, implant technique, dose/fractionation, and target/organ-at-risk (OAR) dosimetry. The projected/final target and OAR dosimetry were analyzed. RESULTS: 55 separate implants from 44 patients were reviewed. Implants were mostly reviewed after the first BT fraction (n = 16, 29%) or at another time point during BT (n = 20, 36%). One (2%) implant was presented prospectively. The applicator type and BT technique were reviewed for all implants. Dose/fractionation was evaluated for 46 implants (84%); contours were discussed for 21 (38%). Target and OAR dosimetry were reviewed for 54 (98%) and 28 implants (51%), respectively. Six cases (11%) underwent minor changes to the applicator type to improve target and/or OAR dosimetry. One case (2%) had a major change recommended to the dose/fractionation. CONCLUSIONS: Gynecologic BT peer review may enhance BT quality by allowing for implant optimization and formal review of challenging cases, ultimately improving medical decision-making and team communication. Peer review should be implemented in centers offering gynecologic BT.

Tobacco smoking and death from prostate cancer in US veterans.

BACKGROUND: Cigarette smoking is a risk factor for mortality in several genitourinary cancers, likely due to accumulation of carcinogens in urine. However, in prostate cancer (PC) the link has been less studied. We evaluated differences in prostate cancer-specific mortality (PCSM) between current smokers, past smokers, and never smokers diagnosed with PC. METHODS: This was a retrospective cohort study of PCSM in men diagnosed with PC between 2000 and 2015 treated in the US Veterans Affairs health care system, using competing risk regression analyses. RESULTS: The cohort included 73,668 men (current smokers: 22,608 (30.7%), past smokers: 23,695 (32.1%), and never smokers: 27,365 (37.1%)). Median follow-up was 5.9 years. Current smoker patients were younger at presentation (median age current: 63, never: 66; p < 0.001), and had more advanced disease stage (stage IV disease current: 5.3%, never: 4.3%; p < 0.04). The 10-year incidence of PCSM was 5.2%, 4.8%, and 4.5% for current, past, and never smokers, respectively. On competing risk regression, current smoking was associated with increased PCSM (subdistribution hazard ratio: 1.14, 95% confidence interval: (1.05-1.24), p = 0.002), whereas past smoking was not. Hierarchical regression suggests that this increased risk was partially attributable to tumor characteristics. CONCLUSIONS: Smoking at the time of diagnosis is associated with a higher risk of dying from PC as well as other causes of death. In contrast, past smoking was not associated with PCSM suggesting that smoking may be a modifiable risk factor. PC diagnosis may be an important opportunity to discuss smoking cessation.

Impact of marital status on receipt of brachytherapy and survival outcomes in locally advanced cervical cancer.

PURPOSE: Marriage has been associated with enhanced survival among cancer patients, but conflicting correlations have been suggested in cervical cancer. We assessed the impact of marital status on receipt of brachytherapy and survival in women with locally advanced cervical cancer. METHODS AND MATERIALS: Three thousand, eight hundred and twelve patients with Stage IB2-IVA cervical cancer diagnosed from 2006 to 2015 treated with external beam radiotherapy were identified from the California Cancer Registry. Chi-square tests were used to compare patient characteristics by marital status and boost type. The association of marital status with brachytherapy (BT) receipt was assessed using multiple logistic regression. Fine and Gray competing risks and Cox proportional hazards regressions were used to estimate cervical cancer-specific survival (CCSS) and overall survival (OS), respectively. RESULTS: Most women were unmarried (58.8%). Half (50.4%) received BT, while 33.1% received no boost; most (86.3%) received chemotherapy. Unmarried women had similar odds of receiving BT as married women (OR = 1.07, 95% CI: 0.90-1.28, p = 0.4370) but were less likely to receive chemotherapy (84.3% vs. 89.1%, p < 0.0001). Singlehood was significantly associated with worse CCSS (subdistribution hazard ratio = 1.21, 95% CI: 1.03-1.42, p < 0.0174) and OS (hazard ratio = 1.18, 95% CI: 1.03-1.36, p < 0.0153). Not receiving a radiation boost was also significantly associated with worse CCSS (subdistribution hazard ratio = 1.21, 95% CI: 1.02-1.43, p = 0.0317) and OS (hazard ratio = 1.21, 95% CI: 1.05-1.40, p = 0.0100). CONCLUSIONS: There were no differences in BT receipt in married vs. unmarried patients. However, unmarried patients had worse CCSS and OS and were less likely to receive chemotherapy. Interventions targeting social factors are needed to improve outcomes in this vulnerable population.

Association of Treatment With 5α-Reductase Inhibitors With Time to Diagnosis and Mortality in Prostate Cancer.

Importance: 5α-Reductase inhibitors (5-ARIs), commonly used to treat benign prostatic hyperplasia, reduce serum prostate-specific antigen (PSA) concentrations by 50%. The association of 5-ARIs with detection of prostate cancer in a PSA-screened population remains unclear. Objective: To test the hypothesis that prediagnostic 5-ARI use is associated with a delayed diagnosis, more advanced disease at diagnosis, and higher risk of prostate cancer-specific mortality and all-cause mortality than use of other or no PSA-decreasing drugs. Design, Setting, and Participants: This population-based cohort study linked the Veterans Affairs Informatics and Computing Infrastructure with the National Death Index to obtain patient records for 80 875 men with American Joint Committee on Cancer stage I-IV prostate cancer diagnosed from January 1, 2001, to December 31, 2015. Patients were followed up until death or December 31, 2017. Data analysis was performed from March 2018 to May 2018. Exposures: Prediagnostic 5-ARI use. Main Outcomes and Measures: The primary outcome was prostate cancer-specific mortality (PCSM). Secondary outcomes included time from first elevated PSA (defined as PSA≥4 ng/mL) to diagnostic prostate biopsy, cancer grade and stage at time of diagnosis, and all-cause mortality (ACM). Prostate-specific antigen levels for 5-ARI users were adjusted by doubling the value, consistent with previous clinical trials. Results: Median (interquartile range [IQR]) age at diagnosis was 66 (61-72) years; median [IQR] follow-up was 5.90 (3.50-8.80) years. Median time from first adjusted elevated PSA to diagnosis was significantly greater for 5-ARI users than 5-ARI nonusers (3.60 [95% CI, 1.79-6.09] years vs 1.40 [95% CI, 0.38-3.27] years; P < .001) among patients with known prostate biopsy date. Median adjusted PSA at time of biopsy was significantly higher for 5-ARI users than 5-ARI non-users (13.5 ng/mL vs 6.4 ng/mL; P < .001). Patients treated with 5-ARI were more likely to have Gleason grade 8 or higher (25.2% vs 17.0%; P < .001), clinical stage T3 or higher (4.7% vs 2.9%; P < .001), node-positive (3.0% vs 1.7%; P < .001), and metastatic (6.7% vs 2.9%; P < .001) disease than 5-ARI nonusers. In a multivariable regression, patients who took 5-ARI had higher prostate cancer-specific (subdistribution hazard ratio [SHR], 1.39; 95% CI, 1.27-1.52; P < .001) and all-cause (HR, 1.10; 95% CI, 1.05-1.15; P < .001) mortality. Conclusions and Relevance: Results of this study demonstrate that prediagnostic use of 5-ARIs was associated with delayed diagnosis and worse cancer-specific outcomes in men with prostate cancer. These data highlight a continued need to raise awareness of 5-ARI-induced PSA suppression, establish clear guidelines for early prostate cancer detection, and motivate systems-based practices to facilitate optimal care for men who use 5-ARIs.

The impact of daily bladder filling on small bowel dose for intensity modulated radiation therapy for cervical cancer.

Research demonstrates that instructing patients to have a full bladder for pelvic radiotherapy results in highly variable bladder volumes at daily treatment. We aimed to determine bladder volume variation in patients with intact cervical cancer treated with intensity-modulated radiotherapy (IMRT) on an empty bladder and estimate the difference in radiation dose to the small bowel compared to treating on a full bladder. We identified 29 patients treated with IMRT from 2010 to 2013 who underwent 2 planning computed tomography (CT) scans, 1 with a full bladder followed by 1 with an empty bladder. Interfractional variation in bladder volume was measured using 782 daily cone beam computed tomography (CBCT) scans. To estimate dose to small bowel, radiation plans were created on both empty and full bladder CT scans using an automated knowledge-based planning modeling program. Mean bladder volume with empty bladder instructions was 67 ± 26 cc compared to 91 ± 43 cc for no bladder instructions and 154 ± 54 cc for full bladder instructions (p < 0.001). There was a significant reduction in the absolute bladder volume variation in patients given empty bladder instructions compared to full bladder instructions (p < 0.05) The intraclass correlation coefficient showed low reliability of bladder filling across all groups (p = 0.6). The average bowel V45 for the empty bladder plans was 188 cc, compared to 139 cc for the full bladder plans (p < 0.05). More plans created on an empty bladder exceeded Quantitative Analyses of Normal Tissue Effects in the Clinic (QUANTEC) guidelines but this was not significant (31% vs 14%, p = 0.12). Reliability of bladder volume at the time of radiation treatment is low, regardless of bladder filling instructions, although an empty bladder reduces absolute variation in bladder volume. Radiation planning on an empty bladder predicts a larger volume of small bowel receiving 45 Gy compared to a full bladder, although bowel dose on average is still within QUANTEC guidelines (V45 < 195 cc).

The Impact of Surgeons on the Likelihood of Mastectomy in Breast Cancer.

OBJECTIVE: This study evaluates the impact of individual surgeons and institutions on the use of mastectomy or breast conserving surgery (BCS) among elderly women with breast cancer. SUMMARY OF BACKGROUND DATA: Current literature characterizes patient clinical and demographic factors that increase likelihood of mastectomy use. However, the impact of the individual provider or institution is not well understood, and could provide key insights to biases in the decision-making process. METHODS: A retrospective cohort study of 29,358 women 65 years or older derived from the SEER-Medicare linked database with localized breast cancer diagnosed from 2000 to 2009. Multilevel, multivariable logistic models were employed, with odds ratios (ORs) used to describe the impact of demographic or clinical covariates, and the median OR (MOR) used to describe the relative impact of the surgeon and institution. RESULTS: Six thousand five hundred ninety-four women (22.4%) underwent mastectomy. Unadjusted rates of mastectomy ranged from 0% in the bottom quintile of surgeons to 58.0% in the top quintile. On multivariable analysis, the individual surgeon (MOR 1.97) had a greater impact on mastectomy than did the institution (MOR 1.71) or all other clinical and demographic variables except tumor size (OR 3.06) and nodal status (OR 2.95). Surgeons with more years in practice, or those with a lower case volume were more likely to perform mastectomy (P < 0.05). CONCLUSION: The individual surgeon influences the likelihood of mastectomy for the treatment of localized breast cancer. Further research should focus on physician-related biases that influence this decision to ensure patient autonomy.

Subcastrate Testosterone Nadir and Clinical Outcomes in Intermediate- or High-Risk Localized Prostate Cancer.

PURPOSE: It is unclear if additional serum testosterone suppression below the castrate threshold of 50 ng/dL improves clinical outcomes in patients with localized prostate cancer undergoing definitive therapy. METHODS AND MATERIALS: We examined the association of subcastrate testosterone nadir with prostate-specific antigen (PSA) response and long-term clinical outcomes in 764 U.S. veterans with intermediate- or high-risk localized prostate cancer treated with androgen deprivation therapy and definitive radiation therapy from 2000 to 2015. Patients were categorized into testosterone nadir groups based on the minimum testosterone measurement during continuous gonadotropic-releasing hormone agonist therapy (<20 ng/dL vs 20-49 ng/dL). Outcomes included PSA response (3-month post-radiation therapy PSA and 2-year PSA nadir; multivariable linear regression) and long-term clinical outcomes (biochemical recurrence, metastasis, and prostate cancer-specific mortality; Fine-Gray competing risk regression). RESULTS: A testosterone nadir of 20 to 49 ng/dL was associated with higher 3-month post-radiation therapy PSA compared to <20 ng/dL (ß = 0.16, 95% confidence interval [CI], 0.06-0.26, P = .001) and higher 2-year PSA nadir (ß = 0.12, 95% CI, 0.04-0.21, P = .005). Compared to the <20-ng/dL group, the 20 to 49-ng/dL group showed higher 10-year biochemical recurrence rates (28.1% vs 18.3%) and metastasis rates (12.9% vs 7.8%) persisting on multivariable analyses (biochemical recurrence: sub-distribution hazard ratio [SDHR], 1.62 for 20-49 ng/dL, 95% CI, 1.07-2.45, P = .02; metastasis: SDHR, 2.19, 95% CI, 1.21-3.94, P = .009). There was a trend toward inferior prostate cancer-specific mortality for the 20 to 49-ng/dL group (SDHR, 1.95, 95% CI, 0.90-4.22, P = .09). CONCLUSIONS: Additional serum testosterone suppression below 50 ng/dL was associated with improved PSA responses and lower rates of biochemical recurrence and metastasis in this cohort of patients with localized prostate cancer.

Five fraction accelerated partial breast irradiation using noninvasive image-guided breast brachytherapy: Feasibility and acute toxicity.

PURPOSE: To improve efficiency, convenience, and cost, a prospective phase II trial was initiated to evaluate accelerated partial breast irradiation delivered with noninvasive image-guided breast brachytherapy (NIBB) via five once-daily fractions. METHODS AND MATERIALS: Women ≥50 years old with early-stage breast cancer undergoing breast conserving surgery were enrolled. Eligibility criteria included invasive carcinoma ≤2.0 cm or ductal carcinoma in situ ≤3.0 cm, ER positive (if invasive), lymph node negative, LVI absent, and margins negative by 2 mm. Patients received a total dose of 28.5 Gy in five daily fractions. NIBB was delivered using two orthogonal axes for each fraction. Applicators were selected to encompass the lumpectomy cavity with a 1.0 cm clinical target volume margin and 0 to 0.5 cm planning target volume margin. Acute and late toxicity was assessed based on CTCAE v3.0. RESULTS: Forty patients with a mean age of 67 years underwent protocol treatment. Mean tumor size was 1.0 cm (0.3-2.0 cm). Eighty percent had invasive carcinoma and the remainder had ductal carcinoma in situ. Mean tumor bed volume was 21 cc (5-79 cc) and mean breast volume was 1319 cc (499-3044 cc). Mean breast separation with compression was 6.7 cm (3.5-8.9 cm). All patients tolerated well. Median discomfort with compression was 1 (range: 0-7) on a 10-point pain scale. Acute skin reaction was Grade 0-1 in 70%, Grade 2 in 28%, and Grade 3 in 3%. Acute skin toxicity was not associated with breast size but was associated with larger breast separation with compression (p < 0.01) and larger applicator size (p < 0.01). No Grade 3+ late toxicity or local recurrences have been observed at a median followup of 14 months. CONCLUSIONS: Accelerated partial breast irradiation delivered using NIBB over five daily fractions is a convenient treatment option that is feasible and well tolerated.

Definitive Radiation Therapy and Survival in Clinically Node-Positive Prostate Cancer.

PURPOSE: The survival benefit of combined radiation therapy (RT) and androgen deprivation therapy (ADT) compared with ADT alone for clinically lymph node-positive prostate cancer remains controversial. METHODS AND MATERIALS: We identified patients with clinically node-positive, nonmetastatic prostate cancer diagnosed between 2000 and 2015 and treated with ADT (n = 450) or ADT-RT (n = 198) from a national Veterans Affairs database. We compared prostate cancer-specific mortality (PCSM) and all-cause mortality (ACM) between treatment groups using multivariable competing-risks regression and Cox regression, respectively. An interaction term between ADT-RT and prostate-specific antigen (PSA) level (dichotomized about the median) was included in the multivariable models. RESULTS: ADT-RT was associated with improved PCSM among patients with PSA levels less than the median of 26 ng/mL (sub-distribution hazard ratio, 0.50; 95% confidence interval [CI] 0.28-0.88; P = .02) but not greater than the median (hazard ratio [HR], 1.15; 95% CI 0.67-1.96; P = .62) (P = .038 for interaction). ADT-RT was also associated with improved ACM among patients with PSA levels less than the median (HR, 0.38; 95% CI 0.25-0.57; P < .001) but not greater than the median (HR, 0.91; 95% CI 0.60-1.38; P = .66) (P = .004 for interaction). CONCLUSIONS: Definitive treatment with ADT-RT is associated with improved PCSM and ACM among patients with clinically node-positive prostate cancer and lower baseline PSA levels. Patients with clinically node-positive disease appear to be a heterogeneous cohort, with a subset who may achieve long-term survival with combined RT and ADT.