Back to Authors

Come, Steven E.

https://orcid.org/0000-0001-8136-2908

Mayo Clinic

Beth Israel Deaconess Medical Center

Citations 67

Association of Breast Cancer Surgery With Quality of Life and Psychosocial Well-being in Young Breast Cancer Survivors
Rosenberg, Shoshana M. , Dominici, Laura S. , Gelber, Shari , Poorvu, Philip D. , Ruddy, Kathryn J. , Wong, Julia S., Schapira, Lidia , Come, Steven E. , Peppercorn, Jeffrey , Tamimi, Rulla M. , Borges, Virginia F. , Partridge, Ann H.

JAMA Surgery | September 16, 2020 | Volume: 155 | Issue: 11 | Pages: 1035

10.1001/jamasurg.2020.3325 Get It

Posttraumatic stress in breast cancer survivors diagnosed at a young age
Vazquez, Danny, Rosenberg, Shoshana M. , Gelber, Shari , Ruddy, Kathryn J. , Morgan, Evan , Recklitis, Christopher J. , Come, Steven E. , Schapira, Lidia , Partridge, Ann H. , Rosenberg, Shoshana , Recklitis, Christopher , Partridge, Ann H

Psycho-Oncology | June 9, 2020 | Volume: 29 | Issue: 8 | Pages: 1312-1320

10.1002/pon.5438 Get It

AbstractObjectiveYoung breast cancer patients experience greater psychosocial distress compared with older patients, which raises concern for their risk of posttraumatic stress disorder (PTSD). We sought to characterize the prevalence of clinically significant symptoms of PTSD and associated factors among breast cancer survivors diagnosed at a young age.MethodsThe Young Women's Breast Cancer Study, an ongoing prospective cohort study, enrolled 1302 women diagnosed with breast cancer at age ≤ 40 between 2006 and 2016. Participants complete serial surveys, and we obtained additional information from medical record review. Socio‐demographics, anxiety and depression, social support, and psychiatric co‐morbidities and medications were assessed at study baseline (median, 5 months post‐diagnosis). We defined a participant as having clinically significant posttraumatic stress symptoms (PTSS) by scoring ≥50 on the PTSD Checklist‐Specific Version, administered on the 30‐month survey.ResultsAmong 700 women with stage 1‐3 disease, the prevalence of PTSS was 6.3% (95%CI = 4.5‐8.1). In multivariable analyses, PTSS was significantly associated with anxiety (OR 12.43, 95%CI = 5.81‐26.59, P < .0001) and stage 2 vs 1 disease (OR 2.26, 95%CI = 1.04‐4.93, P = .04). PTSS was inversely associated with having a college degree (OR 0.29, 95%CI = 0.13‐0.62, P = .002) and greater social support (OR 0.44, 95%CI = 0.21‐0.94, P = .03).ConclusionsWe found similar rates of cancer‐related PTSS in breast cancer survivors diagnosed at a young age compared with the general breast cancer population despite their well‐documented increased risk of overall distress. Nevertheless, factors associated with posttraumatic stress should be considered at diagnosis and in survivorship to identify young patients who may benefit from psychosocial resources.
Response to neoadjuvant chemotherapy and the 21-gene breast recurrence score in young women with estrogen receptor-positive early breast cancer.
Sella, Tal , Gelber, Shari , Poorvu, Philip D. , Kim, Hee Jeong , Arocho, Yaileen D Guzman, Collins, Laura C. , Ruddy, Kathryn J. , Peppercorn, Jeffrey , Schapira, Lidia , Come, Steven E. , Russell, Christy , Rosenberg, Shoshana M. , Tamimi, Rulla M. , Borges, Virginia F. , Warner, Ellen , Snow, Craig , Jakubowski, Debbie , Winer, Eric P. , Partridge, Ann H.

Journal of Clinical Oncology | May 25, 2020 | Volume: 38 | Issue: 15_suppl | Pages: 514-514

10.1200/jco.2020.38.15_suppl.514 Get It

514 Background: The 21- gene Breast Recurrence Score predicts benefit from adjuvant chemotherapy in estrogen receptor positive (ER+), HER-2 negative (-) breast cancer (BC). We aimed to examine whether the 21-gene assay predicts response to neoadjuvant chemotherapy (NAC). Methods: We identified patients with stage I-III ER+/HER2− BC treated with NAC from the Young Women's Breast Cancer Study, a prospective cohort of women diagnosed with BC at age ≤ 40 years. The 21-gene assay was performed on tumor specimens removed prior to NAC either as part of clinical care or retrospectively for research. Pathologic complete response (pCR) was defined as no residual invasive tumor (ypT0/is ypN0). The relationship between Recurrence Score result (RS) and pCR was evaluated using logistic regression modeling. Results: 76 women in the cohort had undergone NAC for ER+, HER2- BC and were eligible for this analysis: 5 had undergone clinical 21-gene assay testing, 71 had banked specimens retrospectively tested. Median age at diagnosis was 36.7 (24.3-40). Most tumors were of ductal histology (78%), high grade (51%), progesterone receptor (PgR) positive (86%), ≥T2 (88%), clinically node positive (74%), and anthracycline and taxane containing protocols were administered in 86% of cases. RS ranged between 5-75 with 50% > 25 and only 4 < 11. Mean RS was significantly higher among tumors achieving pCR vs. non-pCR response (51.9 vs. 26.6, pwilcoxon= 0.0005). pCR rate in patients with RS > 25 was 21% (8/38) vs. 5% in patients with RS < 25 (2/38), with both pCRs in the <25 group in patients with RS 21-25. In univariable analysis, PgR negativity (odds ratio (OR) 5.62, 95% confidence interval (CI) 1.27-24.89, p = 0.02), high grade (OR 9.03, 95%CI 1.07-76.32, p = 0.04) and higher RS as a continuous variable (OR 1.08, 95%CI 1.04-1.13, p = 0.0003) were associated with a greater likelihood of pCR. In multivariable analysis only RS remained significantly associated with pCR (OR: 1.07, 95%CI 1.01-1.12, p = 0.01): a 7% increase in the odds of pCR for every 1-point increase in RS. Conclusions: In young women with ER+, HER2- BC who received NAC, higher pretreatment RS was associated with an increased likelihood of pCR. Genomic expression profiling assays may have a role in decision-making in young women in need of neoadjuvant therapy. For women with low likelihood of benefiting from NAC, alternative approaches are clearly warranted. Given the demonstrated efficacy of neoadjuvant endocrine therapy in post-menopausal women, further evaluation in young women should be pursued.
Abstract P4-07-02: Clinicopathological features and BRCA 1/2 status in a large prospective cohort of young women with breast cancer
Rosenberg, Shoshana M. , Poorvu, Philip D. , Ruddy, Kathryn J. , Kirkner, Greg, Peppercorn, Jeffrey , Schapira, Lidia , Come, Steven E. , Brachtel, Elena F. , Collins, Laura C. , Guzmán‐Arocho, Yaileen D. , Snow, Craig , Tamimi, Rulla M. , Borges, Virginia F. , Warner, Ellen , Partridge, Ann H.

Cancer Research | March 26, 2020 | Volume: 80 | Issue: 4_Supplement | Pages: P4-07-02-P4-07-02

10.1158/1538-7445.sabcs19-p4-07-02 Get It

Abstract Background: Breast cancer arising in young women is more likely to have higher risk features than in older women and more likely to be associated with germline BRCA1 or BRCA2 mutations. We previously reported a higher distribution of luminal B-like tumors among young women. Here we present the clinical and pathologic features of invasive disease in a large prospective cohort of young women with breast cancer, and associations between surrogate molecular subtype and BRCA 1/2 mutation status. Methods: Among 1,297 young women (aged ≤40 years) with breast cancer enrolled from 2006-2016, tumor histopathological features were examined by central review, and biomarker status was extracted from pathology reports. Based on histologic grade and biomarker expression, invasive tumors were categorized as luminal A-like (LA=ER/PR+ and HER2-, histologic grade 1 or 2), luminal B-like (LB=ER/PR+ and HER2+, or ER/PR+, HER2-, and grade 3), HER2 enriched (E) (ER/PR- and HER2+) or triple negative (TN=ER-, PR- and HER2-). Tumor stage, clinical characteristics, and BRCA status were retrieved by medical record review (and patient survey for BRCA status if not in medical record). Results: The majority of women presented with early stage invasive disease (8% stage 0, 32% stage 1, 40% stage 2, 15% stage 3; 5% stage 4). Among invasive tumors with evaluable molecular phenotype (n=1,136), 57% were high grade and the distribution of subtypes was: 33% LA, 42% LB, 8% HER2E, and 16% TN (Table 1). Among different age groups (≤ 30, 31-35, and 36-40 years), there were no significant differences in molecular phenotype, tumor stage, tumor grade or histopathological features including presence of tumor necrosis, lymphocytic infiltration, and central fibrotic focus. 96% of women were tested for BRCA1 and BRCA2 germline mutations, and 127 (11%) tested positive: 65% were BRCA1+, and 35% were BRCA2+ (table 2). Among BRCA1+ patients, 2% of cancers were LA, 30% LB, 5% HER2E, and 62% TN; among BRCA2+, 29% were LA, 56% LB, 2% HER2E, and 13% TN. These proportions were relatively consistent across age groups. BRCA1+ patients’ tumors were proportionately more TN and BRCA2+ patients’ tumors more likely to be LB/HER2 negative (p&lt;0.0001), irrespective of age category. Conclusion: In a large cohort of women diagnosed with breast cancer at age ≤40, there was no association between age group (≤ 30, 31-35, vs. 36-40 years) and tumor stage, grade, or tumor molecular phenotype among women with invasive disease. As in older women, tumor molecular phenotype does vary by BRCA1 or BRCA2 mutation status, which has implications for prevention and treatment. Table 1. Subtype by age groupTotal (n=1136)≤30 yrs (n=144)31-35 yrs (n=314)36-40 yrs (n=678)p=0.42Luminal A-like377 (33%)48 (33%)99 (32%)230 (34%)Luminal B-like477 (42%)59 (41%)137 (44%)281 (41%)• ER/PR+, HER2-, grade 3245 (22%)27 (19%)68 (22%)150 (22%)• ER/PR+, HER2+232 (20%)32 (22%)69 (22%)131 (19%)HER2E95 (8%)13 (9%)34 (11%)48 (7%)Triple Negative187 (16%)24 (17%)44 (14%)119 (18%) Table 2. Subtype by BRCA statusTotal(n=1136)BRCA1+(n=82)BRCA2+(n=45)No mutation/not tested(n=1009)p&lt;0.0001Luminal A-like377 (33%)2 (2%)13 (29%)362 (36%)Luminal B-like477 (42%)25 (30%)25 (56%)427 (42%)• ER/PR+, HER2-, grade 3245 (22%)21 (26%)18 (40%)206 (20%)• ER/PR+, HER2+232 (20%)4 (5%)7 (16%)221 (22%)HER2E95 (8%)4 (5%)1 (2%)90 (9%)Triple Negative187 (16%)51 (62%)6 (13%)130 (13%) Citation Format: Yaileen D Guzman-Arocho, Shoshana M. Rosenberg, Philip Poorvu, Kathryn J. Ruddy, Greg Kirkner, Craig Snow, Rulla M. Tamimi, Jeffrey Peppercorn, Lidia Schapira, Virginia F. Borges, Steven E. Come, Elena F. Brachtel, Ellen Warner, Ann H. Partridge, Laura C. Collins. Clinicopathological features and BRCA 1/2 status in a large prospective cohort of young women with 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 P4-07-02.
Body weight changes in young breast cancer survivors and associated predictors.
Sella, Tal , Tan‐Wasielewski, Zhenying, Rosenberg, Shoshana M. , Poorvu, Philip D. , Ruddy, Kathryn J. , Gelber, Shari , Schapira, Lidia , Come, Steven E. , Peppercorn, Jeffrey , Ligibel, Jennifer A. , Tamimi, Rulla M. , Borges, Virginia F. , Partridge, Ann H.

Journal of Clinical Oncology | March 12, 2020 | Volume: 37 | Issue: 15_suppl | Pages: 11574-11574

10.1200/jco.2019.37.15_suppl.11574 Get It

11574 Background: Weight gain after cancer diagnosis is common in cancer survivors and has been linked to increased treatment toxicity, poor quality of life, and increased risk of second cancers and overall mortality. Young breast cancer (BC) survivors may be especially susceptible to weight changes given the impact of treatments such as chemotherapy and hormonal therapy on menopausal status. Methods: We identified women with Stage 0-III breast cancer diagnosed at ≤40 years (y) between 2006-2016 from a multi-center prospective cohort study. Clinical data including self-reported pre-diagnosis and follow-up weights were obtained using baseline and follow-up patient surveys. Participants missing baseline weight, pregnant at diagnosis/within 1y of diagnosis or with BC recurrence within 1y were excluded; those pregnant or with BC recurrence between 1-3y from diagnosis were excluded from the 3y analysis. Menopausal status at baseline and treatment-related amenorrhea (TRA) in follow-up were defined by self-reported last menstrual period. Factors associated with weight gain (>5%) were evaluated using univariate two-sided Fisher's exact test. Results: At baseline, 1y and 3y post diagnosis, 956, 899 and 687 women were eligible for analysis respectively. Median age at diagnosis was 37y (17 - 40), 65% received endocrine therapy and 74% chemotherapy. Premenopausal status was verified in 94% at baseline. Mean BMI at baseline was 24.4 (SD 5.3) kg/m2; 20% (187/956) were overweight and 12% (116/956) obese. At 1y and 3y, mean BMI increased modestly to 24.7 (SD 5.6) and 24.9 (SD 5.2), respectively with weight gain (>5%) observed in 18% (164/899) and 13% (87/687) respectively. 37% (300/804) and 32% (196/615) of eligible premenopausal subjects experienced TRA at 1y and 3y, respectively. Receipt of chemotherapy, receipt of endocrine therapy and TRA were not associated with weight gain at any timepoint. Conclusions: In this large prospective cohort of young BC survivors, mean BMI increased only modestly over time. Self-reported weight gain was not associated with treatment and not exacerbated by TRA. Further analysis to understand the effects of physical activity and other predictors of weight gain in this population are ongoing.
Prognostic Impact of the 21-Gene Recurrence Score Assay Among Young Women With Node-Negative and Node-Positive ER-Positive/HER2-Negative Breast Cancer
Poorvu, Philip D. , Gelber, Shari , Rosenberg, Shoshana M. , Ruddy, Kathryn J. , Collins, Laura C. , Peppercorn, Jeffrey , Schapira, Lidia , Come, Steven E. , Russell, Christy , Tamimi, Rulla M. , Borges, Virginia F. , Warner, Ellen , Jakubowski, Debbie , Winer, Eric P. , Partridge, Ann H.

Journal of Clinical Oncology | December 6, 2019 | Volume: 38 | Issue: 7 | Pages: 725-733

10.1200/jco.19.01959 Get It

PURPOSE The 21-gene recurrence score (RS) assay is prognostic among women with early-stage estrogen receptor–positive (ER+) and human epidermal growth factor receptor 2–negative (HER2−) breast cancer and is used to inform recommendations for chemotherapy. Women ≤ 40 years of age represent a minority of patients studied using gene expression profiles. METHODS The Young Women's Breast Cancer Study is a prospective cohort of women diagnosed with breast cancer at age ≤ 40 years and enrolled patients between 2006 and 2016 (N = 1,302). We identified patients with stage I-III ER+/HER2− breast cancer. The RS assay was performed on banked specimens for patients who had not been tested clinically. Distant recurrence-free survival (DRFS) was assessed by TAILORx and traditional RS risk groups among patients with axillary node–negative (N0) and limited node–positive (N1) breast cancer. RESULTS Among eligible women (N = 577), 189 (33%) had undergone RS testing, and 320 (56%) had banked specimens sufficient for testing. Median follow-up was 6.0 years. Median age at diagnosis was 37.2 years; 300 of 509 patients (59%) had N0 breast cancer, of whom 195 (65%) had an RS of 11-25 and fewer than half (86 of 195; 44%) received chemotherapy. Six-year DRFS rates were 94.4% and 92.3% (RS < 11), 96.9% and 85.2% (RS 11-25), and 85.1% and 71.3% (RS ≥ 26) among women with N0 and N1 disease, respectively. CONCLUSION The RS assay is prognostic among young women with node-negative and limited node-positive breast cancer, representing a valuable tool for risk stratification. Disease outcomes with a median follow-up of 6 years among young women with N0 disease and an RS of 0-25, a minority of whom received chemotherapy, and node-positive disease with an RS < 11 were very good, whereas those with N0 disease and an RS ≥ 26 or N1 disease with an RS ≥ 11 experienced substantial risk of early distant recurrence.
Diagnostic and treatment delays in young women with breast cancer.
Poorvu, Philip D. , Sella, Tal , Rosenberg, Shoshana M. , Ruddy, Kathryn J. , Gelber, Shari , Peppercorn, Jeffrey , Schapira, Lidia , Come, Steven E. , Zheng, Yue , Tamimi, Rulla M. , Borges, Virginia F. , Warner, Ellen , Partridge, Ann H.

Journal of Clinical Oncology | May 27, 2019 | Volume: 37 | Issue: 15_suppl | Pages: 6575-6575

10.1200/jco.2019.37.15_suppl.6575 Get It

6575 Background: Delays in diagnosis (dx) and treatment (tx) affect breast cancer (BC) outcomes. We sought to identify factors associated with delays among young women, who do not undergo routine screening and often have pregnancy or breastfeeding-related breast changes that may mask a BC. Methods: The Young Women’s Breast Cancer Study is a multicenter, prospective cohort that enrolled 1302 women with newly dx BC age ≤40 between 2006-2016. Women reported the method and timing of cancer detection on the baseline survey. 231 were ineligible or excluded due to missing information. Among those reporting self-detected cancers, using multivariable regression we evaluated factors associated with delays ≥90 days (d) from symptom to presentation (self delay) and presentation to dx (care delay); in stage 0-III BC we evaluated delays ≥60d from dx to tx (tx delay). Results: 1071 eligible women had median age at dx of 37 yrs (17-40) and 74% reported self-detected cancers. Self delay or care delay ≥90d was reported in 17% and 13%, respectively. Factors inversely associated with self delay included pregnancy at dx (vs nulliparous, OR 0.10, CI 0.01-0.78) and perceived financial comfort (vs not, OR 0.62, CI 0.41-0.93). Women dx ≤1 year post-partum who breastfed (vs nulliparous, OR 2.60, CI 1.14-5.93) and those with a family history of breast/ovarian cancer (vs none, OR 1.79, CI 1.00-3.19) were more likely to have a care delay. Age was inversely associated with care delays (OR 0.94, CI 0.89-0.99). Tx delay was reported by 10% (105/1015), and associated with being single (vs partnered, OR 1.61, CI 1.02-2.56 ), non-white (vs white, OR 1.85, CI 1.09-3.13) and having Stage 0 BC (vs stage 1, OR: 3.08, CI 1.65-5.77); women with stage 3 BC (vs stage 1, OR 0.13, CI 0.03-0.56) were less likely to have a tx delay. Conclusions: In this cohort, most young women with BC underwent timely dx and tx initiation. Women dx ≤1 year post-partum who breastfed were more likely to experience a care delay, likely because lactational changes may mask BC signs and symptoms. The associations of perceived financial status with self delay and non-white race with tx delay underscore the need for additional support to ensure timely care for underserved populations with the goal of eliminating disparities in outcomes.
Genomics of HER2+ breast cancer in young women before and after exposure to chemotherapy (chemo) plus trastuzumab (H).
Waks, Adrienne G. , Jain, Esha , Collins, Laura C. , Rosenberg, Shoshana M. , Ruddy, Kathryn J. , Schapira, Lidia , Come, Steven E. , Peppercorn, Jeffrey , Wagle, Nikhil , Tamimi, Rulla M. , Borges, Virginia F. , Warner, Ellen , Snow, Craig , Partridge, Ann H. , Jain, Esha

Journal of Clinical Oncology | May 27, 2019 | Volume: 37 | Issue: 15_suppl | Pages: 554-554

10.1200/jco.2019.37.15_suppl.554 Get It

554 Background: HER2+ breast cancer (BC) is particularly common in young women. Genomic features of HER2+ tumors before and after H-based therapy have not been described in a population of young women and may point to clinically targetable mechanisms of resistance. Methods: From a large prospective cohort of women diagnosed with BC age ≤40 years, we identified those with HER2+ BC and tumor tissue available for sequencing before and after chemo+H. Whole exome sequencing (WES) was performed on each tumor and on germline DNA from blood. Tumor-normal pairs were analyzed for mutations and copy number (CN) changes. Evolutionary analysis was performed for patients with both pre- and post-treatment (tx) samples. Results: 22 women had successful WES samples from at least one timepoint; 13 of these had paired sequencing results both before and after chemo+H. For the majority of women, post-tx sample was following neoadjuvant chemo + H, though post-tx timepoint for other women represented locoregional or distant metastasis (Table). TP53 was the only gene that was significantly recurrently mutated in both pre- and post-tx samples. Comparison of matched pre-tx and post-tx samples demonstrated that large changes in HER2 CN over the course of tx were uncommon, only 2/13 pts had > 2-fold change in HER2 CN. Other clonal and subclonal genomic alterations were found to be acquired in the post-tx sample compared to the pre-tx sample. One patient acquired a putative activating mutation in ERBB2. Another patient acquired a clonal hotpsot mutation in TP53. MYC gene amplification was observed in 4 post-tx tumors. NOTCH2 alterations were found in post-tx biopsies from 2 different patients, and mutations in STIL were also found in post-tx biopsies from 2 patients, though the function of these mutations is not known. Conclusions: HER2+ breast tumors in young women display genomic evolution following tx with chemo+H. HER2 CN changes are uncommon, but we identified several genes that warrant exploration as potential mechanisms of resistance to therapy in this population.[Table: see text]
Nonadherent behaviors among young women on adjuvant endocrine therapy for breast cancer
Wassermann, Johanna , Gelber, Shari , Rosenberg, Shoshana M. , Ruddy, Kathryn J. , Schapira, Lidia , Come, Steven E. , Meyer, Meghan E., Partridge, Ann H. , Partridge, Ann H , Tamimi, Rulla M. , Borges, Virginia F.

Cancer | May 23, 2019 | Volume: 125 | Issue: 18 | Pages: 3266-3274

10.1002/cncr.32192 Get It

Background Young age is a known factor associated with suboptimal adherence to endocrine therapy (ET) for adjuvant breast cancer (BC) treatment. This study was aimed at assessing nonadherent behaviors and associated factors among young women with early‐stage hormone receptor–positive BC. Methods As part of a multicenter, prospective cohort of women with a diagnosis of BC at or under the age of 40 years, participants were surveyed 30 months after their diagnosis about adherent behaviors. Among those who reported taking ET, adherence was measured with a 3‐item Likert‐type scale: Do you ever forget to take your ET? If you feel worse when you take your ET, do you stop taking it? Did you take your ET exactly as directed by your doctor over the last 3 months? Women reporting at least 1 nonadherent behavior were classified as nonadherers. Variables with a P value <.20 were included in a multivariable logistic model. Results Among 384 women, 194 (51%) were classified as nonadherers. Univariate factors that retained significance in the multivariable model included educational level (odds ratio [OR], 0.50 for high vs low; P = .04), level of social support according to the Medical Outcome Study Social Support Survey (OR, 0.98 per 1 point; P = .01), and confidence with the decision regarding ET measured on a 0 to 10 numerical scale (OR, 0.63 for high vs low; P = .04). Conclusions Findings from this study could help to identify young patients at higher risk for nonadherence. Interventions adapted to the level of education and aimed at reinforcing support and patients' confidence in their decision to take ET could improve adherence and associated outcomes in this population.
Abstract GS6-01: Surgical treatment after neoadjuvant systemic therapy in young women with breast cancer: Results from a prospective cohort study
Kim, HJ, Dominici, Laura S. , Rosenberg, S, Pak, LM, Poorvu, PD, Ruddy, KJ, Schapira, Lidia , Come, Steven E. , Peppercorn, Jeffrey , Vardeh, Hilde, Collins, Laura C. , King, Tari A. , Tamimi, Rulla M. , Borges, Virginia F. , Warner, Ellen , Partridge, Ann H.

Cancer Research | May 11, 2019 | Volume: 79 | Issue: 4_Supplement | Pages: GS6-01-GS6-01

10.1158/1538-7445.sabcs18-gs6-01 Get It

Abstract Background Young women are more likely than older women to present with higher stage breast cancer (BC) and may benefit to a greater extent from downstaging with neoadjuvant systemic treatment (NST). Young age is also associated with greater likelihood of pathologic complete response (pCR). Using a large prospective cohort of young women with BC, we investigated response to neoadjuvant therapy, eligibility for breast conserving surgery (BCS) pre- and post-NST, and surgical treatment. Methods The Young Women's Breast Cancer Study (YWS) is a multi-center cohort of women diagnosed with BC at age ≤40, that enrolled 1302 patients from 2006 to 2016. Disease characteristics and treatment information were obtained through medical record and central pathology review. Surgical recommendation before and after NST, conversion from BCS borderline/ineligible to BCS eligible, surgery, documented reasons for choosing mastectomy (MTX) among BCS eligible women, and final pathologic response were independently reviewed. Results Among 1302 women enrolled in YWS, 801 (62%) presented with unilateral stage I-III breast cancer and 317(40%) received NST. Median age was 36 years old (22-40). Pre-NST, 85/317 (27%) were BCS eligible, 49 (15%) were borderline, and 169 (53%) were not eligible (16 inflammatory breast cancer (IBC), 88 large tumor size /cosmetic, 48 diffuse calcifications, and 83 multicentricity). Among the 218 patients who were BCS ineligible/borderline pre-NST, 82 (38%) became eligible for BCS after NST. 4 patients who were BCS eligible pre-NST became ineligible. Of all patients eligible for BCS post-NST (n=163), 80 (49%) attempted BCS, 74 (93%) of whom were successful, and 83 (51%) chose MTX. Reasons for choosing MTX included: patient preference (38/83 (46%)), BRCA or TP53 mutation (31 (37%)), family history (3 (4%)), unknown (11 (13%)). On final pathology, 75 (24%) patients had pCR. Among patients who achieved a pCR, 48 (64%) underwent MTX, fewer than half (21/48 (44%)) were for anatomic indications (IBC, large tumor at diagnosis, diffuse calcifications, multicentric disease). Conclusion While NST doubled the proportion of young women eligible for BCS, nearly half chose MTX regardless of response to NST, mostly for personal preference or high-risk preventative reasons. These data highlight that surgical decision making among young women with breast cancer is often driven by factors beyond extent of disease and clinical response to therapy. Table 1.Clinical-pathologic characteristicsCharacteristicsNumber%Pre NST surgical recommendation BCS eligible8526.8Borderline4915.5BCS ineligible16953.3Unknown144.4Clinical Response Complete20263.7Partial9229.0Stable30.9Progressing72.2Unknown134.1Pathologic Response pCR (No invasive or DCIS)7524No pCR24276Post NST Surgical recommendation BCS eligible16351.4BCS ineligible14445.4Unknown103.2Attempted surgery BCS8025.2MTX23674.1Unknown20.6Final Surgery BCS7423.3MTX24176unknown20.6 Citation Format: Kim HJ, Dominici L, Rosenberg S, Pak LM, Poorvu PD, Ruddy K, Tamimi R, Schapira L, Come S, Peppercorn J, Borges V, Warner E, Vardeh H, Collins L, King T, Partridge A. Surgical treatment after neoadjuvant systemic therapy in young women with breast cancer: Results from a prospective cohort study [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr GS6-01.