Freedman, Rachel A.

635 Background: Prospective data on efficacy, quality of life, and treatment-related toxicities in older adults with breast cancer are limited. The ATOP trial (NCT03587740) evaluated T-DM1 in older adults and demonstrated favorable 5-year invasive disease-free survival. Here, we report patient-reported adverse events (AEs) and health-related quality of life (HRQOL) findings from ATOP. Methods: ATOP was a single-arm, phase II, multicenter study of adjuvant T-DM1 for those aged 60 with stage I-III HER2+ breast cancer. Protocol therapy included postoperative administration of T-DM1 (3.6 mg/kg) every 21 days for one year (17 cycles). PRO-CTCAE (assessing specific symptoms) and EQ-5D (a measure of HRQOL) surveys were administered electronically or on paper at baseline (pre-treatment), on Day 1 of each treatment cycle, and at a single 6–12-month post-treatment time point. Participants who responded to the baseline and at least one follow-up survey were included in the PRO analysis. EQ-5D changes from baseline were assessed using general linear mixed models. Summary statistics were used to assess PRO-CTCAE scores to evaluate which symptoms developed between baseline and 1 subsequent survey(s) and their severity. Results: Among the 111 patients enrolled on ATOP (median age=71, range 60-88 years), 98 responded to the baseline survey and 1 subsequent survey(s). 1435 surveys were returned that included at least one PRO-CTCAE response, and 1661 surveys were returned that included EQ-5D. The Table displays the % of participants who reported PRO-CTCAE symptoms that worsened from baseline to any severity level (scores >0) or to a severe level (scores ≥3). More than 60% of survey respondents reported new or increased dry mouth, fatigue, muscle aches, decreased appetite, nausea, pain, and/or numbness/tingling at some point during or after treatment, but these were usually not severe. EQ-5D scores did not change significantly from baseline at any time point. Conclusions: In this adjuvant trial for patients aged >60, participation rates for PRO data collection were high. Reassuringly, global HRQOL was not impacted by T-DM1, and though frequently reported, the vast majority of patient-reported symptoms were mild. Future analyses of this trial will focus on duration and predictors (clinical and biomarker-based) of severe AEs, agreement between patient-reported and clinician-reported AEs, and whether sharing PRO reports with clinicians impacted clinician-reported AE grades. Clinical trial information: NCT03587740 . Most common new or worsening symptoms reported via PRO-CTCAE in ATOP (n=95). Symptom % with score >0 n (%) with score 3+ Dry mouth 79% 26% Fatigue 71% 29% Muscle aches 69% 20% Decreased appetite 69% 12% Nausea 67% 6% Pain 66% 21% Numbness/tingling 65% 9% Blurry vision 60% 4% Mouth or throat sores 60% 5%

Abstract Purpose: There are limited prospective data on the efficacy, tolerability, and functional impact of treatments for older and frail adults with HER2+ early breast cancer. We report the first-ever, US-based adjuvant trial dedicated to this population. Methods: We conducted a single arm, phase II, multicenter, investigator-initiated study of adjuvant ado-trastuzumab emtansine (T-DM1) in patients aged 60 and older with stage I-III HER2+ breast cancer who either declined standard adjuvant therapy or were deemed by their physician not to be candidates for standard treatment for any reason. Protocol therapy included postoperative administration of T-DM1 (3.6 mg/kg) every 21 days for one year (17 cycles). The primary endpoint was 5-year invasive disease-free survival (iDFS) with a 2-sided 90% confidence interval. Secondary endpoints presented here are toxicity and 3-year iDFS, invasive breast cancer-free survival (iBCFS), and overall survival (OS). All survival analyses were evaluated using Kaplan Meier methods and began at the time of C1D1 of T-DM1. Results: ATOP enrolled 111 evaluable patients during 2015-2020; median follow-up is 4.9 years (IQR 4.2-5.5). The median age was 71 (range 60-88); 50.4% were aged >70 and 11.7% were aged >80. Overall, 69.4% had stage I, 26.1% had stage II, and 4.5% had stage III disease; 70.3% had hormone receptor-positive tumors. The 5-year iDFS = 84.2% (90% CI 77.1-92.0%). The 3-year iDFS = 91.2% (90% CI 85.9%, 96.9%) and iBCFS = 94.1% (90% CI 89.7-98.8%) (see Table for event details); 3-year OS = 96.1% (90% CI 92.4-99.9%). In total, there were 3 distant recurrences and 2 breast cancer-related deaths. Overall, 82% reported grade 2+ toxicity during treatment; the most common grade 2+ events were fatigue (30.6%) and peripheral sensory neuropathy (19.8%). The most frequent grade 3 events were liver function abnormality, anemia, decreased neutrophil count, and neuropathy (<5% for each); one patient (0.9%) had grade 4 thrombocytopenia. Sixty-five (58.6%) completed all 17 cycles of protocol therapy; 27 (24.3%) completed 10-16 cycles, and 19 (17.1%) completed 1-9 cycles. Reasons for early treatment discontinuation in the remaining 41.4% included toxicity (28.8%), patient withdrawal (6.3%), other (3.6%), disease progression (0.9%), death on study (0.9%, deemed unrelated to treatment), and other complicating disease (0.9%). Conclusions: The ATOP trial demonstrated a favorable 5-year iDFS and manageable toxicity among older adults with early stage HER2+ breast cancer. Although iDFS was numerically worse than historical controls (i.e., 5-year iDFS in the ‘ATEMPT’ trial by Tolaney et al. J Clin Oncol, 2024 was 97% [95% 95.2-98.7]), ATOP’s participants had higher-risk cancers, advanced age, and more competing non-breast cancer events. Future endpoints will include in-depth analyses of patient-reported outcomes, biomarkers of aging, and longitudinal functional status. Citation Format: R. A. Freedman, H. Heiling, K. J. Ruddy, L. Rogak, M. Sedrak, A. Dueck, H. Liu, A. Fraettarelli, S. Atanasov, M. DeMeo, P. Lange, A. Perilla Glen, S. Sinclair, D. Dillon, J. Mortimer, M. Fenton, J. Walsh, L. Spring, H. Muss, N. Sinclair, E. Hamilton, C. Dang, S. Giordano, M. Faggen, S. Lo, C. Kuzma, S. Lemke, P. Stella, R. Mowat, M. Wilkinson, J. Rauch, N. Tayob, E. Winer. Adjuvant Ado-Trastuzumab Emtansine (T-DM1) for Older Patients with HER2+ Breast Cancer - Results from the ATOP Study [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS3-11-04.

Abstract PURPOSE: Treatment options for patients (pts) with HER2+ BCBM remain limited. We previously reported that neratinib monotherapy is associated with a volumetric central nervous system objective response rate (CNS ORR) of 8%, whereas the combination of neratinib and capecitabine resulted in a volumetric CNS ORR of 49% (in lapatinib-naïve pts). Preclinical data suggest that neratinib may overcome resistance to trastuzumab-emtansine (T-DM1) and that the combination has potential CNS efficacy. Here, we report results of neratinib plus T-DM1 in pts with HER2+ BCBM. PATIENTS AND METHODS: In this prospective, multicenter, phase II study, pts with measurable HER2+ BCBM received neratinib 160 mg orally once daily plus T-DM1 3.6 mg/kg IV every 21 days in three parallel-enrolling cohorts. Cohort 4A enrolled pts with previously untreated brain metastases. Cohort 4B enrolled pts with BCBM progressing after prior local CNS-directed therapy without prior exposure to T-DM1. Cohort 4C enrolled pts with BCBM progressing after prior local CNS-directed therapy who had previous exposure to T-DM1. Diarrhea prophylaxis with colestipol and loperamide was required during cycle 1. Cohorts 4A and 4B were single-stage with a planned enrollment of 20 patients; cohort 4C had a two-stage design, with a requirement for at least 1 of the first 9 pts to achieve a response in order to enroll a total of 24 patients. The primary endpoint was Response Assessment in Neuro-Oncology-Brain Metastases (RANO BM) in each cohort separately. Correlative studies included patient-reported outcomes (PROs) for gastrointestinal toxicity. RESULTS: We enrolled 6, 17, and 21 patients to cohorts 4A, 4B, and 4C, during 11/07/2018 – 11/01/2021. Enrollment was stopped prematurely due to slow accrual. Across Cohorts 4A-4C, the median number of prior lines of chemotherapy prior to enrollment was 2 (range 1-10); 25% received prior lapatinib and no patients received prior tucatinib. In cohorts 4B and 4C (prior CNS-treated cohorts), 33% had prior CNS surgery and >94% had prior CNS radiation. Among evaluable patients, CNS ORR in cohorts 4A (n=6), 4B (n=16), and 4C (n=21) was 50.0% (95% CI 18.8- 81.2%), 25.0% (95% CI 8.3-52.6%), and 38.1% (95% CI 19.0-61.3%), respectively. Median (range) number of cycles completed for 4A, 4B, and 4C was 4.5 (1-15), 4 (range 0-49+), and 6 (0-23); three patients on Cohort 4B remain on protocol therapy (cycles 14, 45, and 49). The overall survival at 12-months for cohorts 4A, 4B, and 4C was 83.3% (95% CI, 58.3-100%), 86.2% (95% CI 70-100%), and 83.3% (95% CI 67.6-100%). Diarrhea was the most common grade 3 toxicity (19.0–33.3% across cohorts); one grade 4 liver function event occurred in cohort 4B. Updated efficacy results will be reported at the meeting; PRO analyses are ongoing. CONCLUSION: Intracranial activity was observed for the combination of neratinib plus T-DM1 across all three enrolled cohorts, including those with prior T-DM1 exposure, suggesting synergistic effects of this treatment combination. Our data provide additional evidence for consideration of neratinib-based combinations in pts with HER2+ BCBM. Citation Format: Rachel Freedman, Siyang Ren, Nabihah Tayob, Rebecca Gelman, Karen L. Smith, Raechel Davis, Alyssa Pereslete, Victoria Attaya, Christine Cotter, Wendy Y. Chen, Cesar Augusto Santa-Maria, Catherine Van Poznak, Beverly Moy, Adam M. Brufsky, Michelle Melisko, Ciara C. O’Sullivan, Nadia Ashai, Yasmeen Rauf, Julie Nangia, Dario Trapani, Jennifer Savoie, Robyn Burns, Antonio C. Wolff, Eric Winer, Mothaffar Rimawi, Ian Krop, Nancy U. Lin. Translational Breast Cancer Research Consortium Trial 022: Neratinib and Trastuzumab-Emtansine for HER2+ Breast Cancer Brain Metastases (BCBM) [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD7-03.

Abstract Introduction: Patients at extremes of age may be particularly vulnerable to poor physical and mental health after treatment for breast cancer; we examined factors associated with poor health in older breast cancer survivors. Methods: The Mayo Clinic Breast Disease Registry (MCBDR) is a prospective longitudinal cohort study that enrolls Mayo Clinic Rochester patients diagnosed with stage 0-4 breast cancer (BC). In 2020, we mailed a survey to 1,273 MCBDR participants aged 77+. Three PROMIS-10 items were used to assess overall health, mental health, and physical function. Self-reported comorbidities were also collected. Multivariate logistic regression analysis was used to identify significant (p<0.05) predictors of overall health, mental health, and physical function. Independent variables included demographics, clinical characteristics, and comorbidities. Results: 848/1273 MCBDR participants (67%) responded, 842 reporting their overall health. Median age at survey return was 82 years (range 77-100), and the median time since cancer diagnosis was 12 years. Excellent or very good overall health, mental health, and physical function were reported by 48%, 63.5%, and 77.1%, respectively. Older age was associated with poorer self-reported overall health, as were heart disease, diabetes, and lung disease, reported by 18%, 14%, and 7%, respectively (p<0.05 for all; see Table). Only heart disease was statistically significantly associated with poorer mental health (p=0.03). Physical function was reportedly better in survivors without a history of diabetes, stroke, or lung disease (p<0.05 for all), and in those who were closer to their cancer diagnosis (p=0.03). Tumor characteristics were not associated with overall health, mental health, or physical function. Conclusions: Comorbidities are common and impact self-reported overall health, mental health, and physical function in older breast cancer survivors. Table: Multivariate logistic regression model for overall health Overall health self-reported as excellent or very good No Yes Total p-value (N=437) (N=405) (N=842) Age at survey (years) <.001 Mean (SD) 82.8 (4.22) 81.7 (3.85) 82.3 (4.08) Median (range) 82.0 (77.0, 96.0) 81.0 (77.0, 100.0) 82.0 (77.0, 100.0) Years from cancer diagnosis to survey 0.708 Mean (SD) 12.1 (5.16) 11.8 (5.47) 11.9 (5.31) Median (range) 12.2 (3.1, 36.9) 11.5 (3.1, 36.4) 12.0 (3.1, 36.9) T stage T2 or higher, n (%) 0.276 No 357 (81.7%) 337 (83.2%) 694 (82.4%) Yes 80 (18.3%) 68 (16.8%) 148 (17.6%) N stage N1 or higher, n (%) 0.185 No 376 (86.0%) 339 (83.7%) 715 (84.9%) Yes 61 (14.0%) 66 (16.3%) 127 (15.1%) M stage M1, n (%) 0.313 No 434 (99.3%) 404 (99.8%) 838 (99.5%) Yes 3 (0.7%) 1 (0.2%) 4 (0.5%) Race, n (%) 0.460 Non-White 13 (3.0%) 8 (2.0%) 21 (2.5%) White 424 (97.0%) 397 (98.0%) 821 (97.5%) Heart disease, n (%) <.001 No 334 (76.4%) 353 (87.2%) 687 (81.6%) Yes 103 (23.6%) 52 (12.8%) 155 (18.4%) High blood pressure, n (%) 0.376 No 168 (38.4%) 188 (46.4%) 356 (42.3%) Yes 269 (61.6%) 217 (53.6%) 486 (57.7%) Stroke, n (%) 0.195 No 407 (93.1%) 392 (96.8%) 799 (94.9%) Yes 30 (6.9%) 13 (3.2%) 43 (5.1%) Diabetes, n (%) <.001 No 355 (81.2%) 370 (91.4%) 725 (86.1%) Yes 82 (18.8%) 35 (8.6%) 117 (13.9%) Lung disease, n (%) 0.023 No 394 (90.2%) 386 (95.3%) 780 (92.6%) Yes 43 (9.8%) 19 (4.7%) 62 (7.4%) Liver disease, n (%) 0.345 No 425 (97.3%) 401 (99.0%) 826 (98.1%) Yes 12 (2.7%) 4 (1.0%) 16 (1.9%) Kidney disease, n (%) 0.240 No 408 (93.4%) 392 (96.8%) 800 (95.0%) Yes 29 (6.6%) 13 (3.2%) 42 (5.0%) Citation Format: Dhauna Karam, Robert A. Vierkant, Shawna Ehlers, Rachel A. Freedman, Nicole Larson, Charles L. Loprinzi, Fergus Couch, Janet Olson, Kathryn J. Ruddy. Physical function, mental health, and overall health of older breast cancer survivors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5262.

Abstract Introduction: The irreversible pan-HER inhibitor NER showed modest single agent activity for HER2mut MBC in Part I of MutHER trial. In Part II, we hypothesized that (1) N+F would improve activity in estrogen receptor positive (ER+) HER2mut MBC due to ER-HER2 crosstalk and (2) dual HER2 blockade by adding trastuzumab at disease progression (PD) could overcome resistance. Methods: Pts with ER+HER2mut MBC were enrolled to 2 cohorts (FUL treated or naive) to receive N+F with diarrhea prophylaxis. ER- pts received NER in an exploratory ER- cohort. Trastuzumab was added at PD if approved by insurance. Simon's Minimax 2-stage phase II design with the primary endpoint of clinical benefit rate (CBR: rates of complete/partial response [CR/PR] plus stable disease [SD] >24 weeks [wks]), with anticipated vs null hypothesis being CBR of 55% vs 35% (FUL treated) or 65% vs 40% (FUL naïve) with 80% power, 1 sided 0.05 alpha, was used. Secondary endpoints included progression free survival (PFS) and adverse events (AEs). Serial blood samples were analyzed for circulating tumor DNA (ctDNA) by Guardant360 for concomitant mutations, HER2mut variant allele frequency (VAF) dynamics, and resistance mechanisms. Results: Between Sep. 2015 and Oct. 2020, 40 pts with HER2mut MBC were enrolled, completing the 1st stage of each ER+ cohort. 35 pts (21 FUL treated, 10 FUL naïve, 4 ER-) were evaluable for response, with median age 63 (35-82) years, 3 (0-12) prior MBC regimen, lobular BC in 13 (37%) and visceral mets in 32 (91%) pts. 21 (68%) ER+ pts had prior CDK4/6 inhibitor. All but 1 pt has come off study due to PD. Table 1 shows the efficacy by cohort. Further enrollment is closed per protocol. Adding trastuzumab at PD induced CB in 4 (3 PR, 1 SD≥24 wks) of 5 pts (1 ER-, 4 ER+), with PFS 28 (95% CI 18~NA) wks. Common AEs across cohorts were diarrhea (G3 21%) and fatigue (G3 5%). No G4 AEs. ctDNA HER2mut was detected in 72% (23/32) baseline (BL) samples tested. In pts with paired samples, HER2mut VAF decreased at C1D15/C2D1 from BL in 75% (15/20) and rose in 89% (16/18) at PD. Acquired HER2mut, including the T798I gatekeeper mutation, were detected in 2 pts at PD. Mutations in TP53 (53%), PIK3CA (43%), and CDH1 (35%) were common, but none significantly associated with PFS in all or ER+ pts. Conclusions: NER, or N+F, is active for HER2mut MBC with good tolerability. Adding trastuzumab at PD induced further response, supporting dual HER2 blockade for HER2mut MBC. Table 1.EfficacyCohortFUL treatedFUL naïveER-Best Response, n evaluablen = 21n = 10n = 4CR, n100PR, n431SD (≥ 24 wks), n300SD (< 24 wks), n1030PD, n343CBR, n with CB/total n evaluable, % (95% CI)8 of 20*, 40% (19~64%)3 of 10, 30% (7~65%)1 of 4, 25% (0.6~81%)mPFS (95% CI), wks, ITT (n)24 (16~31) wks, (n = 24)20 (8~NA) wks, (n = 11)8.5 (8~NA) wks, (n = 5)*20 of 21 pts are evaluable for CBR in the FUL treated Cohort as 1 pt had SD as best response and treatment is still ongoing. ITT (intent to treat) population is used for mPFS estimate. Citation Format: Cynthia X. Ma, Jingqin Luo, Rachel A. Freedman, Timothy Pluard, Julie Nangia, Janice Lu, Frances Valdez-Albini, Melody Cobleigh, Jason Jones, Nancy U. Lin, Eric Winer, P. Kelly Marcom, Shana Thomas, Jill Anderson, Brittney Haas, Kimberly M. Hamann, Richard Bryce, Alshad S. Lalani, Lisa Carey, Matthew Goetz, Feng Gao, Gretchen Kimmick, Mark Pegram, Matthew J. Ellis, Ron Bose. A phase II trial of neratinib (NER) or NER plus fulvestrant (FUL) (N+F) in HER2 mutant, non-amplified (HER2mut) metastatic breast cancer (MBC): Part II of MutHER [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT026.

BackgroundThis study was aimed at examining the risks of subsequent primary cancers (SPCs) among breast cancer survivors by hormone receptor (HR) status and age at diagnosis.MethodsData from 12 Surveillance, Epidemiology, and End Results registries were used to identify 431,222 breast cancer survivors (at least 1 year) diagnosed between the ages of 20 and 84 years from 1992 to 2015. Risks of SPCs were measured as the standardized incidence ratio (SIR) and the excess absolute risk (EAR) per 10,000 person‐years. Poisson regression was used to test the difference in SIRs by HR status.ResultsIn comparison with the general population, the risk of new cancer diagnoses among survivors was 20% higher for those with HR‐positive cancers (SIR, 1.20; 95% confidence interval [CI], 1.19‐1.21; EAR, 23.3/10,000 person‐years) and 44% higher for those with HR‐negative cancers (SIR, 1.44; 95% CI, 1.41‐1.47; EAR, 45.2/10,000 person‐years), with the risk difference between HR statuses statistically significant. The higher risk after HR‐negative cancer was driven by acute nonlymphocytic leukemia and breast, ovarian, peritoneal, and lung cancers. By age at diagnosis, the total EAR per 10,000 person‐years ranged from 15.8 (95% CI, 14.1‐17.5; SIR, 1.11) among late‐onset (age, 50‐84 years) HR‐positive survivors to 69.4 (95% CI, 65.1‐73.7; SIR, 2.24) among early‐onset (age, 20‐49 years) HR‐negative survivors, with subsequent breast cancer representing 73% to 80% of the total EAR. After breast cancer, the greatest EARs were for ovarian cancer among early‐onset HR‐negative survivors, lung cancer among early‐ and late‐onset HR‐negative survivors, and uterine corpus cancer among late‐onset HR‐positive survivors.ConclusionsRisks of SPCs after breast cancer differ substantially by subtype and age. This suggests that more targeted approaches for cancer prevention and early‐detection strategies are needed in survivorship care planning.

Abstract Cancer is a disease of aging and, as the world's population ages, the number of older persons with cancer is increasing and will make up a growing share of the oncology population in virtually every country. Despite this, older patients remain vastly underrepresented in research that sets the standards for cancer treatments. Consequently, most of what we know about cancer therapeutics is based on clinical trials conducted in younger, healthier patients, and effective strategies to improve clinical trial participation of older adults with cancer remain sparse. For this systematic review, the authors evaluated published studies regarding barriers to participation and interventions to improve participation of older adults in cancer trials. The quality of the available evidence was low and, despite a literature describing multifaceted barriers, only one intervention study aimed to increase enrollment of older adults in trials. The findings starkly amplify the paucity of evidence‐based, effective strategies to improve participation of this underrepresented population in cancer trials. Within these limitations, the authors provide their opinion on how the current cancer research infrastructure must be modified to accommodate the needs of older patients. Several underused solutions are offered to expand clinical trials to include older adults with cancer. However, as currently constructed, these recommendations alone will not solve the evidence gap in geriatric oncology, and efforts are needed to meet older and frail adults where they are by expanding clinical trials designed specifically for this population and leveraging real‐world data.

Abstract Background: The clinical utility of routine annual mammogram after curative-intent treatment for male breast cancer is uncertain. There is potentially greater value after lumpectomy (as surveillance for ipsilateral recurrence) than mastectomy (as screening for a new contralateral cancer). The goal of this study was to assess real world use of mammography in men during the first year after lumpectomy or mastectomy to treat breast cancer. Methods: Administrative claims data from OptumLabs Data Warehouse (a large US database that includes privately insured patients and Medicare Advantage-insured enrollees from all 50 states and of all ages and ethnic and racial groups) were used to identify men treated with breast surgery for a new diagnosis of breast cancer between 2007 and 2017. We required continuous coverage starting at least 6 months prior to the non-metastatic breast cancer diagnosis and continuing until at least 13 months after the breast surgery. Our primary endpoint was the proportion of patients who had at least one mammogram during the year (13-month period, to allow for scheduling and other logistical delays) after lumpectomy or mastectomy. Univariate and multivariate testing were performed to identify predictors of mammography (with p<0.05 used as the threshold for statistical significance for both). Our secondary endpoint was the proportion with at least one mammogram within 24 months of surgery, performed in a subset who maintained their insurance coverage for at least that duration. Results: The 13-month analysis included 730 men with a median age at diagnosis of 62 years (Range: 25 to 87 years) and a median follow-up duration of 35 months (Range: 13 to 134 months). 209 (29%) of these men underwent mammography within 13 months after surgery. The characteristics of patients who underwent mammography and those who did not are shown in Table 1. Mammography was more likely after lumpectomy than mastectomy (41% vs. 27%) and after radiation therapy (41% vs. 32% in those who did not receive radiation). In a multivariate logistic regression model, more recent diagnosis (2015+) was associated with lower odds of undergoing mammography, while receipt of radiation was associated with higher odds of undergoing mammography. In the subset of patients with two or more years of post-surgery coverage (n=527), the proportion who had at least one mammogram during that 24-month period was 49% after lumpectomy and 40% after mastectomy. Conclusions: In this insured cohort, 73% of men did not undergo mammography within a year after mastectomy, and 59% did not within a year after lumpectomy. Mammography was less likely in patients diagnosed more recently (perhaps due to acknowledgment of the unique aspects of male breast cancer including a relatively low risk of contralateral second primary tumors), and more likely in those who received radiation. These variations in practice likely result from the paucity of evidence-based guidelines for male breast cancer survivorship care. More research is needed pertaining to whether or not mammograms improve clinical outcomes after curative intent treatment for male breast cancer. Table 1: Patient characteristics associated with receipt of mammogram within first 13 months after male breast cancer surgeryUnivariate AnalysisMultivariate AnalysisNo Mammogram (N=521)Mammogram (N=209)P-value, chi-square testOdds Ratio (OR) and 95% CIP-value for ORAge Group:0.1225-4966 (12.7%)32 (15.3%)Reference50-64216 (41.5%)98 (46.9%)0.99 (0.60, 1.63)0.9665-74112 (21.5%)44 (21.1%)0.87 (0.48, 1.57)0.6575+127 (24.4%)35 (16.7%)0.57 (0.30, 1.07)0.08Census Region:0.52Midwest138 (26.5%)59 (28.2%)ReferenceNortheast97 (18.6%)47 (22.5%)1.10 (0.68, 1.78)0.69South223 (42.8%)79 (37.8%)0.74 (0.49, 1.11)0.15West63 (12.1%)24 (11.5%)0.83 (0.47, 1.47)0.51Year of diagnosis:0.072007-2010126 (24.2%)65 (31.1%)Reference2011-2014199 (38.2%)82 (39.2%)0.80 (0.54, 1.20)0.292015+196 (37.6%)62 (29.7%)0.63 (0.41, 0.96)0.03Elixhauser Category:0.250148 (28.4%)69 (33.0%)Reference1-2218 (41.8%)74 (35.4%)0.85 (0.56, 1.28)0.433+155 (29.8%)66 (31.6%)1.18 (0.75, 1.87)0.47Surgery Type:0.005Lumpectomy55 (10.6%)38 (18.2%)ReferenceMastectomy466 (89.4%)171 (81.8%)1.57 (0.97, 2.55)0.07Chemotherapy:0.79No301 (57.8%)123 (58.9%)ReferenceYes220 (42.2%)86 (41.1%)0.79 (0.54, 1.16)0.23Radiation:0.02No355 (68.1%)124 (59.3%)ReferenceYes166 (31.9%)85 (40.7%)1.51 (1.03, 2.20)0.03 Citation Format: Siddhartha Yadav, Lindsey Sangaralingham, Stephanie R. Payne, Karthik V. Giridhar, Tina J. Hieken, Judy C. Boughey, Robert W. Mutter, John R. Hawse, Rafael E. Jimenez, Rachel A. Freedman, Sadia Choudhery, Fergus J. Couch, Celine M. Vachon, Nilay Shah, Roberto A. Leon-Ferre, Kathryn J. Ruddy. Surveillance mammography after treatment for male breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P4-17-08.