Emergency Department Use in Adolescent and Young Adult Cancer Early Survivors from 2006 to 2020.

Purpose: Understanding emergency department (ED) use in adolescent and young adult (AYA) survivors could identify gaps in AYA survivorship. Methods: We conducted a cohort study of 7925 AYA survivors (aged 15-39 years at diagnosis) who were 2-5 years from diagnosis in 2006-2020 at Kaiser Permanente Southern California. We calculated ED utilization rates overall and by indication of the encounter (headache, cardiac issues, and suicide attempts). We estimated rate changes by survivorship year and patient factors associated with ED visit using a Poisson model. Results: Cohort was 65.4% women, 45.8% Hispanic, with mean age at diagnosis at 31.3 years. Overall, 38% of AYA survivors had ≥1 ED visit (95th percentile: 5 ED visits). Unadjusted ED rates declined from 374.2/1000 person-years (PY) in Y2 to 327.2 in Y5 (p change < 0.001). Unadjusted rates declined for headache, cardiac issues, and suicide attempts. Factors associated with increased ED use included: age 20-24 at diagnosis [relative risk (RR) = 1.30, 95% CI 1.09-1.56 vs. 35-39 years]; female (RR = 1.27, 95% CI 1.11-1.47 vs. male); non-Hispanic Black race/ethnicity (RR 1.64, 95% CI 1.38-1.95 vs. non-Hispanic white); comorbidity (RR = 1.34, 95% CI 1.16-1.55 for 1 and RR 1.80, 95% CI 1.40-2.30 for 2+ vs. none); and public insurance (RR = 1.99, 95% CI 1.70-2.32 vs. private). Compared with thyroid cancer, cancers associated with increased ED use were breast (RR = 1.45, 95% CI 1.24-1.70), cervical (RR = 2.18, 95% CI 1.76-2.71), colorectal (RR = 2.34, 95% CI 1.94-2.81), and sarcoma (RR = 1.39, 95% CI 1.03-1.88). Conclusion: ED utilization declined as time from diagnosis elapsed, but higher utilization was associated with social determinants of health and cancer types.

Late endocrine diseases in survivors of adolescent and young adult cancer in California: a population-based study.

BACKGROUND: Cancer survivors have increased risk of endocrine complications, but there is a lack of information on the occurrence of specific endocrinopathies at the population-level. METHODS: We used data from the California Cancer Registry (2006-2018) linked to statewide hospitalisation, emergency department, and ambulatory surgery databases. We estimated the cumulative incidence of and factors associated with endocrinopathies among adolescents and young adults (AYA, 15-39 years) who survived ≥2 years after diagnosis. RESULTS: Among 59,343 AYAs, 10-year cumulative incidence was highest for diabetes (4.7%), hypothyroidism (4.6%), other thyroid (2.2%) and parathyroid disorders (1.6%). Hypothyroidism was most common in Hodgkin lymphoma, leukaemia, breast, and cervical cancer survivors, while diabetes was highest among survivors of leukaemias, non-Hodgkin lymphoma, colorectal, cervical, and breast cancer. In multivariable models, factors associated with increased hazard of endocrinopathies were treatment, advanced stage, public insurance, residence in low/middle socioeconomic neighbourhoods, older age, and non-Hispanic Black or Hispanic race/ethnicity. Haematopoietic cell transplant was associated with most endocrinopathies, while chemotherapy was associated with a higher hazard of ovarian dysfunction and hypothyroidism. CONCLUSIONS: We observed a high burden of endocrinopathies among AYA cancer survivors, which varied by treatment and social factors. Evidence-based survivorship guidelines are needed for surveillance of these diseases.

Late venous thromboembolism in survivors of adolescent and young adult cancer: A population-based study in California.

INTRODUCTION: Venous thromboembolism (VTE), a common complication in cancer patients, occurs more often during the initial phase of treatment. However, information on VTE beyond the first two years after diagnosis ('late VTE') is scarce, particularly in young survivors. METHODS: We examined the risk of, and factors associated with, late VTE among adolescents and young adults (AYA, 15-39 years) diagnosed with cancer (2006-2018) who survived ≥2 years. Data were obtained from the California Cancer Registry linked to hospitalization, emergency department and ambulatory surgery data. We used non-parametric models and Cox proportional hazard regression for analyses. RESULTS: Among 59,343 survivors, the 10-year cumulative incidence of VTE was 1.93 % (CI 1.80-2.07). The hazard of VTE was higher among those who had active cancer, including progression from lower stages to metastatic disease (Hazard Ratio (HR) = 10.41, 95 % confidence interval (CI): 8.86-12.22), second primary cancer (HR = 2.58, CI:2.01-3.31), or metastatic disease at diagnosis (HR = 2.38, CI:1.84-3.09). The hazard of late VTE was increased among survivors who underwent hematopoietic cell transplantation, those who received radiotherapy, had a VTE history, public insurance (vs private) or non-Hispanic Black/African American race/ethnicity (vs non-Hispanic White). Patients with leukemias, lymphomas, sarcoma, melanoma, colorectal, breast, and cervical cancers had a higher VTE risk than those with thyroid cancer. CONCLUSIONS: VTE risk remained elevated ≥2 years following cancer diagnosis in AYA survivors. Active cancer is a significant risk factor for VTE. Future studies might determine if late VTE should prompt evaluation for recurrence or second malignancy, if not already known.

Survival After Contralateral Secondary Breast Cancer by Age Group in California.

PURPOSE: Breast cancer (BC) is the most common secondary cancer and has poorer survival than primary BC (pBC) after any prior malignancy. For BC survivors, developing a contralateral secondary BC (CSBC) is the most frequent second-cancer event and is currently treated similarly to pBC. Identifying survival differences between pBC and CSBC could influence future counseling and treatments for patients with CSBC. METHODS: Women (≥15 years) diagnosed with pBC from 1991 to 2015 in the California Cancer Registry (n = 377,176) were compared with those with CSBC (n = 15,586) by age group (15-39 years, n = 406; 40-64 years, n = 6814; ≥ 65 years, n = 8366). Multivariable logistic regression models assessed factors associated with CSBC. Multivariable Cox proportional hazards regression models assessed BC-specific survival (BCSS), while accounting for the competing risk of death. RESULTS: Across all ages, CSBC patients were more likely to have smaller tumors (T2 vs. T1a; 15-39 yeras: OR 0.25, CI 0.16-0.38; 40-64 years: OR 0.41, CI 0.37-0.45; ≥ 65 years: OR 0.46, CI 0.42-0.51) and lymph node-negative disease (positive vs. negative; 15-39 years: OR 0.86, CI 0.69-1.08; 40-64 years: OR 0.88, CI 0.83-0.93; ≥ 65 years: OR 0.89, CI 0.84-0.94). Additionally, CSBC was associated with worse survival compared with pBC across all ages (15-39 years: HR 2.73, CI 2.30-3.25; 40-64 years: HR 2.13, CI 2.01-2.26; ≥ 65 years: HR 1.52, CI 1.43-1.61). CONCLUSION: BCSS is worse among all women diagnosed with CSBC compared with pBC, with the strongest impact seen in adolescent and young adult women. Worse survival after CSBC, despite associations with smaller tumors and lymph node negativity, suggests that CSBC may need eventual treatment reconsideration.

Changes in Surgical Management of the Axilla Over 11 Years - Report on More Than 1500 Breast Cancer Patients Treated with Neoadjuvant Chemotherapy on the Prospective I-SPY2 Trial.

BACKGROUND: Axillary surgery after neoadjuvant chemotherapy (NAC) is becoming less extensive. We evaluated the evolution of axillary surgery after NAC on the multi-institutional I-SPY2 prospective trial. METHODS: We examined annual rates of sentinel lymph node (SLN) surgery with resection of clipped node, if present), axillary lymph node dissection (ALND), and SLN and ALND in patients enrolled in I-SPY2 from January 1, 2011 to December 31, 2021 by clinical N status at diagnosis and pathologic N status at surgery. Cochran-Armitage trend tests were calculated to evaluate patterns over time. RESULTS: Of 1578 patients, 973 patients (61.7%) had SLN-only, 136 (8.6%) had SLN and ALND, and 469 (29.7%) had ALND-only. In the cN0 group, ALND-only decreased from 20% in 2011 to 6.25% in 2021 (p = 0.0078) and SLN-only increased from 70.0% to 87.5% (p = 0.0020). This was even more striking in patients with clinically node-positive (cN+) disease at diagnosis, where ALND-only decreased from 70.7% to 29.4% (p < 0.0001) and SLN-only significantly increased from 14.6% to 56.5% (p < 0.0001). This change was significant across subtypes (HR-/HER2-, HR+/HER2-, and HER2+). Among pathologically node-positive (pN+) patients after NAC (n = 525) ALND-only decreased from 69.0% to 39.2% (p < 0.0001) and SLN-only increased from 6.9% to 39.2% (p < 0.0001). CONCLUSIONS: Use of ALND after NAC has significantly decreased over the past decade. This is most pronounced in cN+ disease at diagnosis with an increase in the use of SLN surgery after NAC. Additionally, in pN+ disease after NAC, there has been a decrease in use of completion ALND, a practice pattern change that precedes results from clinical trials.

Breast Conservation Surgery and Mastectomy Have Similar Locoregional Recurrence After Neoadjuvant Chemotherapy: Results From 1462 Patients on the Prospective, Randomized I-SPY2 Trial.

Neoadjuvant chemotherapy (NAC) increases rates of successful breast-conserving surgery (BCS) in patients with breast cancer. However, some studies suggest that BCS after NAC may confer an increased risk of locoregional recurrence (LRR). We assessed LRR rates and locoregional recurrence-free survival (LRFS) in patients enrolled on I-SPY2 (NCT01042379), a prospective NAC trial for patients with clinical stage II to III, molecularly high-risk breast cancer. Cox proportional hazards models were used to evaluate associations between surgical procedure (BCS vs mastectomy) and LRFS adjusted for age, tumor receptor subtype, clinical T category, clinical nodal status, and residual cancer burden (RCB). In 1462 patients, surgical procedure was not associated with LRR or LRFS on either univariate or multivariate analysis. The unadjusted incidence of LRR was 5.4% after BCS and 7.0% after mastectomy, at a median follow-up time of 3.5 years. The strongest predictor of LRR was RCB class, with each increasing RCB class having a significantly higher hazard ratio for LRR compared with RCB 0 on multivariate analysis. Triple-negative receptor subtype was also associated with an increased risk of LRR (hazard ratio: 2.91, 95% CI: 1.8-4.6, P < 0.0001), regardless of the type of operation. In this large multi-institutional prospective trial of patients completing NAC, we found no increased risk of LRR or differences in LRFS after BCS compared with mastectomy. Tumor receptor subtype and extent of residual disease after NAC were significantly associated with recurrence. These data demonstrate that BCS can be an excellent surgical option after NAC for appropriately selected patients.

Shifting paradigms for the treatment of ductal carcinoma in situ: Less is more.

Ductal carcinoma in situ is a diverse disease in which only 50% of lesions progress to invasive carcinoma, but unfortunately, all patients receive similar treatment recommendations independent of the disease variability. De-escalation is the philosophy that treatment for this disease should be differentiated based on the likelihood of future progression and recurrence. Four surgical trials are looking at the possibility of removing surgical intervention, the current mainstay of treatment, from the algorithm. Molecular assays have been developed to help differentiate the risk of an ipsilateral breast tumor recurrence and potentially guide the postsurgical utility of radiation therapy. Primary endocrine therapy is also being explored as an alternative to standard local therapy. Ductal carcinoma in situ therapy is a very complicated algorithm that should be discussed and treated through shared decision-making.

Secondary Breast Cancer Sociodemographic Characteristics and Survival by Age Group.

BACKGROUND: Secondary cancers account for 16% of all new cancer diagnoses, with breast cancer (BC) the most common secondary cancer. We have shown that secondary BC has unique characteristics and decreased survival compared with primary BC in adolescent and young adults (AYA; 15-39 years old). However, older BC populations are less well studied. METHODS: Females (age ≥ 15 years) diagnosed with primary BC during 1991-2015 (n = 377,167) and enrolled in the California Cancer Registry were compared with those with secondary BC (n = 37,625) by age (15-39, 40-64, ≥ 65 years). We examined BC-specific survival (BCSS) accounting for other causes of death as a competing risk using multivariable Cox proportional hazards regression. RESULTS: Most secondary BC patients were of older age (15-39, n = 777; 40-64, n = 15,848; ≥ 65, n = 21,000). Compared with primary BC treatment, secondary BCs were more often treated with mastectomy and less often with chemotherapy and/or radiation. BCSS was shorter in secondary BC patients than primary BC patients, but the survival difference between secondary and primary BC diminished with age [15-39 hazard ratio (HR): 2.09, 95% confidence interval (CI) 1.83-2.39; 40-64 HR: 1.51; 95% CI 1.44-1.58; ≥ 65 HR: 1.14; 95% CI 1.10-1.19]. Survival differences were most pronounced in women with hormone receptor positive disease and Hispanic and Asian/Pacific Islanders 40-64 years of age. CONCLUSIONS: When BC is diagnosed following a prior cancer of any organ site, BCSS is worse than when compared with patients for whom BC is the primary diagnosis, suggesting that we may need to tailor our treatments for women with secondary BC.

Chemotherapy After Diagnosis of Malignant Bowel Obstruction is Associated with Superior Survival for Medicare Patients with Advanced Malignancy.

BACKGROUND: Although malignant bowel obstruction (MBO) often is a terminal event, systemic therapies are advocated for select patients to extend survival. This study aimed to evaluate factors associated with receipt of chemotherapy after MBO and to determine whether chemotherapy after MBO is associated with survival. METHODS: This retrospective cohort study investigated patients 65 years of age or older with metastatic gastrointestinal, gynecologic, or genitourinary cancers who were hospitalized with MBO from 2008 to 2012 using the Surveillance, Epidemiology, and End Results (SEER)-Medicare database. Fine and Gray models were used to identify factors associated with receipt of chemotherapy accounting for the competing risk of death. Cox models identified factors associated with overall survival. RESULTS: Of the 2983 MBO patients, 39% (n = 1169) were treated with chemotherapy after MBO. No differences in receipt of chemotherapy between the surgical and medical patients were found in the univariable analysis (subdistribution hazard ratio [SHR], 0.96; 95% confidence interval [CI], 0.86-1.07; p = 0.47) or multivariable analysis (SHR, 1.12; 95% CI, 1.00-1.26; p = 0.06). Older age, African American race, medical comorbidities, non-colorectal and non-ovarian cancer diagnoses, sepsis, ascites, and intensive care unit stays were inversely associated with receipt of chemotherapy after MBO (p < 0.05). Chemotherapy with surgery was associated with longer survival than surgery (adjusted hazard ratio [aHR], 2.97; 95% CI, 2.65-3.34; p < 0.01) or medical management without chemotherapy (aHR, 4.56; 95% CI, 4.04-5.14; p < 0.01). Subgroup analyses of biologically diverse cancers (colorectal, pancreatic, and ovarian) showed similar results, with greater survival related to chemotherapy (p < 0.05). CONCLUSIONS: Chemotherapy plays an integral role in maximizing oncologic outcome for select patients with MBO. The data from this study are critical to optimizing multimodality care for these complex patients.

The Role of Radiation Therapy in Addition to Lumpectomy and Hormone Therapy in Men 70 Years of Age and Older with Early Breast Cancer: A NCDB Analysis.

PURPOSE: Current treatment guidelines for male breast cancer are guided by female-only trials despite data suggesting distinct clinicopathologic differences between sexes. We sought to evaluate whether radiation therapy (RT) after lumpectomy was associated with equivalent survival among men > 70 years of age with stage I, estrogen receptor (ER) positive tumors, as seen in women from the Cancer and Leukemia Group B (CALGB) 9343 trial. METHODS: We performed a retrospective analysis of 752 stage I, ER-positive male breast cancer patients ≥ 70 years who were treated with hormone therapy and surgery, with or without RT, from the National Cancer Database between 2004 and 2014. Patients were categorized based on surgery and RT (lumpectomy alone, lumpectomy with RT, and mastectomy alone). Multivariable Cox proportional hazards regression analysis was used to compare overall survival between treatment groups. RESULTS: Most patients underwent total mastectomy, with only 32.6% treated with lumpectomy. Of those who underwent lumpectomy, 72.7% received adjuvant RT. In multivariate analysis, there was no statistical difference in overall survival when comparing lumpectomy alone and lumpectomy with RT (aHR 0.72 [95% CI 0.38-1.37], p = 0.31) or when comparing lumpectomy (alone or with RT) and mastectomy (aHR 1.28 [95% CI 0.88-1.87], p = 0.20). CONCLUSIONS: In this national sample of elderly men with ER-positive early-stage disease treated with endocrine therapy, there were no significant differences in overall survival when comparing lumpectomy alone and lumpectomy with RT, or lumpectomy (alone or with RT) and mastectomy. These results suggest that less aggressive treatment may be appropriate for a subset of male breast cancer patients.

Characteristics and Outcomes for Secondary Breast Cancer in Childhood, Adolescent, and Young Adult Cancer Survivors Treated with Radiation.

BACKGROUND: Radiotherapy is used to treat many adolescent and young adult (AYA) and childhood cancer patients and is a risk factor for secondary breast cancer. While premenopausal breast cancer is inherently more aggressive, no studies to date have evaluated the characteristics and breast cancer-specific survival (BCSS) of premenopausal secondary breast cancer after radiotherapy in AYA and childhood cancer survivors. METHODS: Female patients ages 12 to 50 diagnosed with primary breast cancer from 1988 to 2014 (n = 107,751) were obtained from the California Cancer Registry and compared with similar aged patients with secondary breast cancer who were treated with radiotherapy for their primary tumor (n = 1,147) from ages 12 to 39. We examined BCSS using multivariable Cox proportional hazards regression. RESULTS: The secondary breast cancer cohort was more likely to be Hispanic or Black, be 35 to 45 years of age, have earlier stage tumors, be higher grade, have no lymph node involvement, and be hormone receptor negative. All women showed worse BCSS for large tumor size, lymph node involvement, and hormone receptor-negative status. BCSS was worse for women with secondary breast cancer both overall (hazard ratio, 1.98; 95% confidence interval, 1.77-2.23) and in all subgroups considered. Associations were most pronounced in Hispanics, Asian/Pacific Islanders, and younger women, as well as those with earlier stage, lymph node-negative, and hormone receptor-positive disease. CONCLUSIONS: BCSS is significantly decreased among all survivors of childhood and AYA cancer treated with radiotherapy that develop a secondary breast cancer, including women with good prognostic features. IMPACT: Therefore, we may need to consider alternative and even more aggressive treatment in what were considered low-risk populations previously.

Disparities in the Occurrence of Late Effects following Treatment among Adolescent and Young Adult Melanoma Survivors.

BACKGROUND: Melanoma is the third most common cancer in the adolescent and young adult (AYA) population; however, no studies have addressed the occurrence of adverse health conditions following melanoma treatment in these survivors. METHODS: Data for patients ages 15 to 39 years diagnosed with cutaneous melanoma from 1996 to 2012 and surviving ≥2 years were obtained from the California Cancer Registry and linked to statewide hospitalization data. The influence of age at diagnosis, sex, race/ethnicity, neighborhood socioeconomic status (SES), health insurance, and surgery on the development of adverse health conditions was evaluated using Cox proportional hazards regression models. RESULTS: Of 8,259 patients, 35.3% were male, 83.3% were non-Hispanic White, 82.4% had private health insurance, and 60.5% were considered high SES. In Cox regression models, males had an increased risk of developing adverse health conditions across all systems, including cardiac [HR, 1.73, 95% confidence interval (CI), 1.47-2.03], lymphedema (HR, 1.56; 95% CI, 1.37-1.77), hematologic disorders (HR, 1.17; 95% CI, 1.03-1.33), major infection/sepsis (HR, 1.59; 95% CI, 1.39-1.82), and second cancers (HR, 1.51; 95% CI, 1.31-1.74). Patients with public/no insurance (vs. private) had a greater risk of developing all studied adverse health conditions, including subsequent cancers (HR, 2.34; 95% CI, 1.94-2.82). AYA patients residing in low SES neighborhoods had similar increased risk of developing adverse health conditions. CONCLUSIONS: Of AYA melanoma survivors, males, those with public/no health insurance, and those living in low SES neighborhoods had a greater likelihood of developing adverse health conditions. IMPACT: Strategies to improve surveillance and secondary prevention of these adverse health conditions are needed among AYA melanoma survivors, specifically for the at-risk populations identified.

Breast Conserving Surgery Compared With Mastectomy in Male Breast Cancer: A Brief Systematic Review.

The surgical guidelines for male breast cancer (MBC) have been largely guided by female-predominant clinical trials. Because no clinical trial has been conducted to examine the surgical treatment of MBC, we performed a systematic review comparing the survival of patients with MBC who had undergone breast conserving surgery (BCS) and those who had undergone mastectomy and evaluated the patients' radiotherapy compliance after BCS. We performed a systematic search of electronic databases to find MBC cohort studies that had reported ≥ 1 survival outcome (disease-free survival [DFS], disease-specific survival [DSS], or overall survival [OS]) stratified by surgical treatment (BCS and/or mastectomy) and/or radiotherapy compliance with BCS. A total of 1 prospective and 9 retrospective cohort studies were included, with the number of patients ranging from 7 to 6039. Of the BCS patients, compliance with postoperative radiotherapy was low (range, 27%-46%), with the exception of 1 single-institution prospective study that reported 86% compliance (6 of 7 patients). The pooled estimate for all patients with MBC was 83% (95% confidence interval [CI], 78%-88%) for 5-year DSS and 66% (95% CI, 63%-70%) for 5-year OS. Most studies reported no differences in DFS, DSS, or OS for BCS and mastectomy. BCS is a reasonable treatment approach for MBC because it was associated with oncologic outcomes similar to those with mastectomy. However, the low rates of radiotherapy compliance among male patients who underwent BCS is concerning and highlights the importance of shared decision-making with patients with MBC when selecting a surgical treatment strategy.

Building a comprehensive mentoring academy for schools of health.

Formal mentoring programs are increasingly recognized as critical for faculty career development. We describe a mentoring academy (MA) developed for faculty across tracks (i.e., researchers, clinicians, educators) within a "school of health" encompassing schools of medicine and nursing. The program is anchored dually in a clinical and translational science center and a school of health. The structure includes the involvement of departmental and center mentoring directors to achieve widespread uptake and oversight. A fundamental resource provided by the MA includes providing workshops to enhance mentoring skills. Initiatives for junior faculty emphasize establishing and maintaining strong mentoring relationships and implementing individual development plans (IDPs) for career planning. We present self-report data on competency improvement from mentor workshops and data on resources and barriers identified by junior faculty (n = 222) in their IDPs. Mentors reported statistically significantly improved mentoring competency after workshop participation. Junior faculty most frequently identified mentors (61%) and collaborators (23%) as resources for goal attainment. Top barriers included insufficient time and time-management issues (57%), funding limitations (18%), work-life balance issues (18%), including inadequate time for self-care and career development activities. Our MA can serve as a model and roadmap for providing resources to faculty across traditional tracks within medical schools.

Timing of Surgery and Internal Medicine Clerkships and Surgery Shelf Examination Scores.

BACKGROUND: Many medical students believe that third-year clerkship rotation sequence affects their success. We hypothesized that students who completed the internal medicine clerkship before the surgery clerkship received higher surgery shelf examination scores compared with the students who did not. MATERIALS AND METHODS: Deidentified academic data including preclinical data and National Board of Medical Examiners shelf examination scores for surgery for all third-year medical students at a single institution from 2012 to 2017 were analyzed. Students who did not complete all six core clerkships during the standard third-year time frame were excluded. Data were analyzed using 2-tailed t-tests and Z-scores. RESULTS: Four hundred and twenty four students were included in the study. Average undergraduate grade point average, Medical College Admission Test scores, and United States Medical Licensing Examination Step 1 scores showed no significant differences between groups. In aggregate, average shelf examination scores of students who completed the internal medicine clerkship before the surgery clerkship were significantly higher than those of students who did not. When the average shelf examination scores for the two groups were analyzed by individual rotation slot, no significant difference was found between the two groups. CONCLUSIONS: Initially, it appeared that students who completed the internal medicine clerkship before the surgery clerkship scored higher on their surgery shelf examinations. When the data were analyzed by individual rotation slot, we found no difference between the students who had already completed the internal medicine clerkship and those who had not. Experience over the year rather than completion of the internal medicine rotation was associated with higher surgery shelf examination scores.

Is Breast-Conserving Therapy Appropriate for Male Breast Cancer Patients? A National Cancer Database Analysis.

BACKGROUND: Current treatment guidelines for male breast cancer are predominantly guided by female-only clinical trials. With scarce research, it is unclear whether breast-conserving therapy (BCT) is equivalent to mastectomy in men. We sought to compare overall survival (OS) among male breast cancer patients who underwent BCT versus mastectomy. METHODS: We performed a retrospective analysis of 8445 stage I-II (T1-2 N0-1 M0) male breast cancer patients from the National Cancer Database (2004-2014). Patients were grouped according to surgical and radiation therapy (RT). BCT was defined as partial mastectomy followed by RT. Multivariable and inverse probability of treatment-weighted (IPTW) Cox proportional hazards models were used to compare OS between treatment groups, controlling for demographic and clinicopathologic characteristics. RESULTS: Most patients underwent total mastectomy (61.2%), whereas 18.2% underwent BCT, 12.4% underwent total mastectomy with RT, and 8.2% underwent partial mastectomy alone. In multivariable and IPTW models, partial mastectomy alone, total mastectomy alone, and total mastectomy with RT were associated with worse OS compared with BCT (p < 0.001 all). Ten-year OS was 73.8% for BCT and 56.3, 58.0 and 56.3% for other treatment approaches. Older age, higher T/N stage, histological grade, and triple-negative receptor status were associated with poorer OS (p < 0.05). Subgroup analysis by stage demonstrated similar results. CONCLUSIONS: In this national sample of male breast cancer patients, BCT was associated with greater survival. The underlying mechanisms of this association warrant further study, because more routine adoption of BCT in male breast cancer appears to translate into clinically meaningful improvements in survival.