Citations

1518 Background: Despite high interest among young women diagnosed with breast cancer (BC) in future fertility, prior research has been hampered by short follow-up and lack of prospective assessment of pregnancy attempts. We sought to describe fertility outcomes among young women participating in a prospective cohort who reported pregnancy attempt post-BC diagnosis. Methods: Women with stage 0-III BC in the Young Women's Breast Cancer Study (YWS, NCT01468246), a multicenter, prospective cohort of women diagnosed at age ≤40 from 2006-2016 who reported attempting pregnancy post-diagnosis were included. Those with prior hysterectomy, bilateral oophorectomy, or metastatic disease at diagnosis were excluded. Data on attempting pregnancy and fertility outcomes were obtained from serial surveys. Multivariable logistic regression with stepwise model selection was used to identify factors associated with pregnancy and live birth. Results: Among 1213 eligible participants, 197 reported any attempt of pregnancy (16%) over a median follow-up of 11 years (range: 3-17). Among attempters, median age at diagnosis was 32 years (range: 17-40); 74% were non-Hispanic White; 41% had stage I, 35% stage II, 10% stage III, and 14% stage 0 BC; 76% had HR+ disease; 68% received chemotherapy; 57% received endocrine therapy within one year post-diagnosis; 13% were BRCA1/2 pathogenic variant (PV) carriers; 51% reported financial comfort at baseline; 51% were nulligravida and 72% nulliparous at diagnosis; 28% had undergone fertility preservation consisting of egg/embryo freezing at diagnosis; 15% reported a history of infertility before BC diagnosis. Most (73%) reported ≥1 pregnancy after diagnosis and 65% reported ≥1 live birth. Median time from diagnosis to first pregnancy was 48 months (range: 6-125). In the multivariable model, greater age at diagnosis (odds ratio [OR] 0.82 per year increase, 95% CI 0.74-0.90, P<0.0001) was negatively associated with pregnancy, while financial comfort at baseline (OR 2.04, 95% CI 1.01-4.12, P=0.047) was predictive of pregnancy. For live births, greater age at diagnosis was negatively associated (OR 0.82 per year increase, CI 95% 0.76-0.90, P<0.0001) while having undergone fertility preservation at diagnosis was predictive (OR 2.78, 95% CI 1.29-6.00, P=0.009). History of infertility, nulliparity at diagnosis, tumor characteristics, cancer treatment, race, ethnicity, and BRCA1/2 PV status were not associated with either outcome. Conclusions: This is the first prospective study with greater than 10 years of follow-up to report fertility outcomes in young BC survivors accounting for attempting pregnancy. The majority achieved a pregnancy and most reported a live birth. Our findings can be incorporated into the counseling of young BC patients and survivors, and highlight the need for accessibility of fertility preservation services for this population. Clinical trial information: NCT01468246 .

12048 Background: Playing music has been an important part of human culture for millennia. Today more than half of American households have at least one person who plays music, and in the UK 43% of adults play an instrument. Despite the overlap between musicians and people diagnosed with cancer, the effect of cancer treatment on musicianship has not been well-studied. We previously reported that 26% of a musician breast cancer survivor cohort reported difficulty with musicianship after treatment, and here we conduct further analysis to identify treatment and disease factors associated with this difficulty, termed acute musical toxicity (AMT). Methods: The Musical Toxicity Questionnaire was distributed to participants who had previously enrolled in the Mayo Clinic Breast Cancer Registry. PROMIS (Patient-Reported Outcomes Measurement Information System) scores were available through the Registry and treatment details were collected retrospectively. Due to the inter-dependency and high correlation between treatment and disease-related variables, a classification tree analysis (CTA) was performed to identify the combination of variables that most accurately classified patients by AMT. Sixteen variables were analyzed by the algorithm. Logistic regression was utilized for examining associations between AMT and continuous variables. Results: Of the 4075 surveys distributed, 1871 were returned and 535 respondents identified as musicians. Median time from diagnosis was 5.2 years, respondents were mostly stage I or II (71%), and 32% were node positive (N+). Over a quarter (26% or 144 respondents) reported AMT. In the final CTA model, being N+ was strongly associated with AMT (42% of those N+ had AMT, 20% of those not N+ had AMT). For respondents who were N+, those who received endocrine therapy were more likely to have AMT than those who did not (46% vs 21% respectively). Subsequent leaves identified not undergoing axillary lymph node dissection (ALND) and receiving chemotherapy as associated with AMT. For respondents who did not receive chemotherapy, breast reconstruction was associated with AMT (60% vs 19%). Variables such as mastectomy, radiation volume, specific chemotherapies, and stage of disease were not selected by the algorithm. The odds of having AMT decreased by 9.7% and 17% with each additional point in the composite mental health (p=0.003) and physical health (p<0.001) PROMIS scores, respectively. The odds of having AMT increased by 3.5% with each lymph node removed (p=0.001). Conclusions: The final model suggests that the group with the largest proportion of AMT was N+, received endocrine therapy, did not have ALND, and received chemotherapy. Both physical and mental health PROMIS scores were associated with AMT, although the directionality of this relationship requires more study. Care teams should counsel patients on potential musical toxicity and engage in shared decision making with musical patients.

11059 Background: Some opioid stewardship policies could negatively affect patients with cancer pain. However, patients with cancer are also at risk for opioid related harms, especially with persistent use. We assessed opioid prescribing trends in the context of cancer treatment and patient reported pain in a large health system in Connecticut. Methods: We conducted a retrospective cohort study of opioid-naïve adult patients with solid tumor malignancies diagnosed from 2016 through 2020 within the Yale New Haven Health System. We identified new (≥1 opioid prescription in 0-6 months following diagnosis) and additional (0-6 and 6-9 months) opioid prescriptions. The analysis evaluated all eligible patients as well as two clinical cohorts: patients treated surgically and patients with metastatic cancer. For patients with metastatic cancer and a documented pain score in the electronic health record flowsheet data, we further stratified by any (any score≥1) or no (all scores=0) pain in the 6 months since diagnosis and prior to first opioid, if given. For these patients, we noted therapeutic class of the first opioid. We used a logistic model adjusted for patient demographics to calculate predicted probability of opioid prescription and change over time. Results: A total of 10,868 patients met study criteria. Overall, we observed a decline in new opioid prescribing from 69.0% to 62.7% (p<.001) (Table). Additional opioid use also declined from 23.4% to 20.2% (p=.02). In the surgery cohort, new opioid prescribing fell from 95.7% to 88.2% (p<.001), while additional opioid use was stable over time (approximately 12%). For patients with metastatic cancer with any documented pain, new opioid prescribing was stable over time (approximately 56%). For those with documented pain scores=0, new opioid prescribing declined from 59.7% to 34.2% (p<.001). In these patients, the class listed on the first opioid prescription was analgesia in 86.6% and cough in 13.4%. Conclusions: Overall, and in patients treated with oncological surgeries, our study in a single large US health system suggests a modest, gradual decline in opioid prescribing for patients with cancer over time. On the other hand, among patients with metastatic cancer, opioid prescribing remained stable for those with documented pain and declined steeply for those without documented pain. [Table: see text]

11145 Background: T-DXd is increasingly used in mBC. A T-DXd toxicity of special interest is interstitial lung disease/pneumonitis (ILD), occurring in 10-15% of pts in the DESTINY-Breast trials, and with potential lower incidence/severity in earlier line settings [Krop et al, ASCO 2023]. However, in routine practice, T-DXd may be used in pts with more heavily pre-treated mBC and previously exposed to other antibody-drug conjugates (ADC) [Premji et al SABCS 2023]. We evaluated the incidence/severity of T-DXd related ILD in mBC at Mayo Clinic. Methods: We retrospectively identified pts with mBC who received ≥1 dose of T-DXd at Mayo Clinic, Rochester, MN, between July 2022-December 2023. Demographic, mBC, and pulmonary clinical variables were abstracted from the clinical records. Data was summarized using descriptive statistics. Diagnosis of ILD was determined by treating clinicians, and severity to CTCAE V5 based on clinical documentation. Results: 77 pts with mBC received T-DXd during the study period. All were female, the majority (70, 91%) were Caucasian, and median age was 58. 53 (69%) had HER2-low mBC (37 HR+, 16 HR-) and 24 (31%) had HER2+ mBC (17 HR+, 7 HR-). 31 (40%) were active or former smokers. 11 (14%) had pulmonary comorbidities, including 6 (7.8%) with asthma, 2 (2.6%) with prior pneumonitis, and 3 (3.9%) with other pulmonary comorbidities. They had previously received a median of 1 line of endocrine therapy, and 4 lines of chemotherapy, with 20 (26%) having received another ADC. 17 (22%) developed any grade ILD [G1: 3 (4%), G2: 7 (9%), G3: 2 (3%), G4: 1 (1%), G5: 4 (5%)]. Among pts with ILD of any grade, 13 (76.5%) presented with at least 1 symptom (cough/SOB). The median number of T-DXd cycles prior to onset of any grade ILD was 6 (range 2-13), or 18 (range 6-39) weeks. 5 (29%) pts with any grade ILD received a prior ADC. Of pts with ≥G3 ILD (n=7), all were Caucasian, 2 (30%) were prior smokers, none had prior lung disease, and had received a median of 5 prior lines of chemo, with 4 (57%) having received a prior ADC. All grade ≥2 ILDs were treated with systemic steroids, and 1 also received IVIG. CT chest was used for diagnosis of all ILD. 7 pts (41%) required hospitalization, all of whom had bronchoscopy, with 5 (29%) requiring intubation. All pts with G1 ILD (3, 18%) restarted T-DXd without ILD recurrence. Conclusions: In this case series,22% of ps treated with T-DXd experienced ILD (5% G5), higher than the rate observed in the pivotal DESTINY-Breast trials, possibly due to real-world use of T-DXd in more heavily pre-treated pts and in pts with pulmonary comorbidities.

11108 Background: Advances in cancer treatment have led to a growing population of patients living with metastatic cancer. Symptom burden for these patients is understudied. Our objective is to report the prevalence and severity of SPPADE symptoms (sleep disturbance, pain, physical function impairment, anxiety, depression, and low energy /fatigue) in a large cohort of patients with metastatic cancer. Methods: These data are drawn from the Enhanced, EHR-facilitated Cancer Symptom Control (E2C2) stepped wedge pragmatic trial evaluating a symptom management intervention for cancer patients (NCT03892967). This analysis was limited to those identified with metastatic disease using ICD- codes and a natural language processing algorithm prior to or within 30 days of their baseline symptom survey. Symptom severity was measured on a 0-10 scale with scores of 1-3 categorized as “mild”, 4-6 as “moderate”, and ≥7 as “severe.” A SPPADE composite score was calculated by summing six individual symptom scores and is an indicator of total symptom burden. We report descriptive statistics for each symptom by severity category. We also test for differences in SPPADE composite score by race, disability status, employment status, education and cancer type using Kruskal-Wallis tests. Results: 12,824 patients with metastatic disease completed a survey between March 2019 and January 2023. Discretized score distributions for the SPPADE symptoms are reported in the Table. The SPPADE composite mean score for the cohort was 17.6 (SD +/- 12.0). Significant differences were found in total symptom burden by sociodemographic and clinical characteristics ( p<0.01): Higher total symptom burden (Mean [SD])was experienced by individuals who were American Indian/Alaska Native (AI/AN) (23.8[13.5]) or African American (AA) (20.5[14.7]), disabled (24.0[12.8]) or unemployed (21.1[13.0]), and had a high school education (20.0[13.3]) or less than high school education (18.5[12.4]). There were also statistically significant differences ( p<0.01) in symptom burden across cancer types, with patients with metastatic lung cancer reporting the highest symptom burden (20.0[12.2]) and those with metastatic melanoma reporting the lowest (14.7[11.4]). Conclusions: SPPADE symptoms are common in patients with metastatic cancer, especially fatigue, sleep disturbance, and physical function impairment. Symptom burden is especially high in AI/AN, AA, disabled/unemployed, and less educated patients. Further research is needed to tailor symptom interventions among those living with metastatic disease. [Table: see text]

PURPOSE We investigated time to pregnancy, efficacy and safety of fertility preservation, and assisted reproductive technologies (ARTs) in women with early hormone receptor–positive breast cancer (BC) desiring future pregnancy. PATIENTS AND METHODS POSITIVE is an international, single-arm, prospective trial, in which 518 women temporarily interrupted adjuvant endocrine therapy to attempt pregnancy. We evaluated menstruation recovery and factors associated with time to pregnancy and investigated if ART use was associated with achieving pregnancy. The cumulative incidence of BC-free interval (BCFI) events was estimated according to the use of ovarian stimulation at diagnosis. The median follow-up was 41 months. RESULTS Two hundred seventy-three patients (53%) reported amenorrhea at enrollment, of whom 94% resumed menses within 12 months. Among 497 patients evaluable for pregnancy, 368 (74%) reported at least one pregnancy. Young age was the main factor associated with shorter time to pregnancy with cumulative incidences of pregnancy by 1 year of 63.5%, 54.3%, and 37.7% for patients age <35, 35-39, and 40-42 years, respectively. One hundred and seventy-nine patients (36%) had embryo/oocyte cryopreservation at diagnosis, of whom 68 reported embryo transfer after enrollment. Cryopreserved embryo transfer was the only ART associated with higher chance of pregnancy (odds ratio, 2.41 [95% CI, 1.75 to 4.95]). The cumulative incidence of BCFI events at 3 years was similar for women who underwent ovarian stimulation for cryopreservation at diagnosis, 9.7% (95% CI, 6.0 to 15.4), compared with those who did not, 8.7% (95% CI, 6.0 to 12.5). CONCLUSION In POSITIVE, fertility preservation using ovarian stimulation was not associated with short-term detrimental impact on cancer prognosis. Pregnancy rates were highest among those who underwent embryo/oocyte cryopreservation followed by embryo transfer.

1597 Background: The impact of COVID19 pandemic on patient health beliefs and healthcare systems has adversely affected mammographic breast cancer screening (MBCS) during the initial stages of the pandemic. The aims of our study were to determine whether the initial decrease in MBCS rates persisted or if there was a rebound in later stages and to quantify the impact on urban and rural populations. Methods: This retrospective observational study analyzed data from March 2017 to March 2023 to assess whether eligible women received annual MBCS during this timeframe. We included women aged 40-75 years, drawn from the integrated Mayo Clinic system, encompassing nearly 60 primary care practices in Arizona, Florida, Iowa, Minnesota, and Wisconsin, representing a broad cross-section of the United States (US) population. US census data was utilized to classify a county as urban or rural. We divided the study period into 4 categories:1) pre-COVID-19 pandemic (March 1, 2017-March 10, 2020), 2) early pandemic (March 11, 2020-March 10, 2021; pre-vaccination period), 3) mid- pandemic (March 11, 2021-March 10, 2022; delta and omicron variant dominant period), and 4) late pandemic (March 11, 2022-March 1, 2023; recovery period). Utilizing the Poisson regression model, we compared the incidence rate ratio (IRR) for rates of MBCS across the 4 predefined time periods. Multivariable modeling was performed to assess the significance of MBCS rates with urbanicity while controlling for the year (2017-2022) and age. Results: By race and ethnicity, the women in this cohort were White (92%), Black (3.1%), Asian (3%) and other (1.9%). The median age was 57 years and the cohort included 239, 804 women aged 40-75 years. MBCS rates was 49.2% in 2017, 47.1% in 2018, 46.4% in 2019, and decreased to 42.1% in 2020 and improved to 44.7% in 2021 and 43.8% in 2022. Compared with the pre-COVID-19 pandemic period, there was a significant decrease in MBCS rate in the early pandemic (IRR= 0.886, 95% CI 0.879, 0.892, p<0.001). Though the MBCS rate improved in the mid-pandemic period, it remained below the pre-pandemic level (IRR=0.941, 95% CI 0.934, 0.948, p<0.001). Similarly, during the late stage of the pandemic, the MBCS rate remained lower than the pre-pandemic level (IRR=0.922, 95% CI 0.915, 0.928, p<0.001). Rural counties had a lower MBCS rate compared with urban counties (IRR = 0.936, 95% CI 0.931, 0.941, p<0.001). Conclusions: This study confirms the negative impact of the early COVID-19 pandemic on MBCS, and it revealed its persistent effect, as the current MBCS rate remains below the pre-pandemic rate. These findings were more evident in rural counties. Factors contributing to the long-lasting impact are being analyzed with the intent to develop and implement targeted solutions to improve the MBCS rate.

TPS632 Background: Male breast cancer is a rare disease, and most cases are hormone receptor-positive (HR+). Due to a lack of clinical trials, male breast cancer has historically been treated based on data extrapolated from women. However, there are substantial knowledge gaps in the comparative efficacy, safety, and patient-reported outcomes of endocrine therapies for male breast cancer. While tamoxifen is the current standard of care, additional data are warranted for aromatase inhibitors (AI), gonadal suppression, and cyclin-dependent kinase 4/6 (CDK4/6) inhibitors. Methods: This is an open-label, multicenter, randomized, phase II trial designed to evaluate different endocrine therapies in men with HR+ and human epidermal growth factor receptor 2 (HER2)-negative breast cancer. A total of 60 men will be enrolled across nine (9) sites within the Translational Breast Cancer Research Consortium (TBCRC). Key eligibility criteria include male sex and stage I, II, or III HR+/HER2- breast cancer before surgical resection of the primary tumor and axillary nodes. Key exclusion criteria include prior anti-cancer therapy for the current breast cancer or any other malignancy within the past 12 months, and inflammatory breast cancer. The trial has two phases. The first phase is a window of opportunity component in which newly diagnosed men are randomized 1:1:1 to either tamoxifen (Arm A), anastrozole (Arm B), or anastrozole plus degarelix (Arm C) given for three weeks. The primary endpoint for the window phase is Ki-67 reduction from the baseline diagnostic biopsy to the research biopsy at the end of the window phase. The second phase consists of neoadjuvant treatment, in which the tamoxifen group is randomized 1:1 to tamoxifen (Arm D) versus tamoxifen plus abemaciclib (Arm E), and the anastrozole alone (Arm B) and anastrozole plus degarelix (Arm C) groups are merged and then randomized 1:1 to anastrozole plus degarelix (Arm F) versus anastrozole plus degarelix plus abemaciclib (Arm G). The duration of the neoadjuvant phase is four (4) months, and the primary endpoint of this phase is residual cancer burden (RCB) index at time of surgery. The trial is powered for the RCB endpoint in a 2 x 2 factorial design to detect a 0.6 unit decrease in RCB index with 80% power and alpha=10%. For the Ki-67 endpoint, we assume an approximately 50% reduction in Arms A and B; Arm C will be of interest if it leads to ≥80% reduction in Ki-67. Secondary endpoints include: estradiol and testosterone levels at baseline, end of window, and during neoadjuvant phase; preoperative endocrine prognostic index (PEPI) score at surgery; adverse events; and patient-reported outcomes (including quality of life). Tumor tissue will be collected for correlative analyses. The study opened to enrollment at Dana-Farber in October 2023, and additional sites will open in 2024. Clinical trial information: NCT05501704 .

550 Background: Residual disease after neoadjuvant chemotherapy (NAC) in HER2-positive breast cancer (BC) confers poor outcomes. Despite additional trastuzumab emtansine (T-DM1) in the adjuvant setting, a significant number of patients with residual disease still develop recurrence. H2NVAC is a multi-epitope T helper cell-activating peptide vaccine that is composed of 4 degenerate HER2-derived HLA-DR epitopes admixed with GM-CSF. Our previous phase I trial showed that this vaccine was safe and generated robust, long-lasting T and B cell immune responses. Methods: Patients with stage II-III HER2+ BC with any amount of residual disease in the breast /axilla after NAC were enrolled in a safety run-in phase of H2NVAC in combination with T-DM1. Patients were treated with H2NVAC and T-DM1 for 6 cycles, followed by 2 boosters at 3 and 12 months. Dose-limiting toxicity (DLT) was defined as any grade (G) ≥ 3 adverse events (AE) occurring within 21 days after the first vaccination. Results: A total of20 patients were enrolled with a median age of 51 years (range 27-69), 80% were White and 15% were Black. Most patients had hormone receptor-positive disease (90%). 40% were premenopausal, 40% were postmenopausal, and 20% were unknown. 14 patients had ypT1, 3 patients ypT2, 3 patients ypT3, 1 patient ypT4, 8 patients ypN0, 9 patients yp N1, 1 patient ypN1mi, and 2 patients ypN2. H2NVAC, in combination with T-DM1, was well tolerated, with no DLT being observed. Only grades 1 and 2 AEs were observed during the DLT period, with fatigue being the most common (G1 60%, G2 5%), followed by peripheral sensory neuropathy (G1 55%, G2 5%) and injection site reaction (G1 50%). Across all treatment cycles, the top 10 most common AEs that were at least possibly related to treatment include injection site reaction (G1 85%, G2 15%), AST increase (G1 65%), ALT increase (G1 45%), fatigue (G1 35%, G2 10%), peripheral sensory neuropathy (G1 35%, G-tube 10%), alk-phos increase (40% G1), nausea (G1 35%, G2 5%), arthralgia (G1 35%), myalgia (G1 25%, G2 5%), and platelet count decrease (G1 30%). There were four patients with G3 AEs at least possibly related to the vaccine observed after the DLT period, including allergic reaction, myositis/skin infection, urticaria, and pruritus/maculopapular rash. Conclusions: H2NVAC, in combination with T-DM1, was safe without DLT observed. The side effect profile was favorable, with the most common AE being the G1 injection site reaction. A multicenter, randomized, placebo-controlled, phase II trial of H2NVAC vs. placebo in combination with trastuzumab emtansine is currently ongoing through the ACCRU consortium. Clinical trial information: NCT04197687 .

Abstract Purpose: We previously reported that postmenopausal women with estrogen receptor-α–positive breast cancer receiving adjuvant anastrozole 1 mg/day (ANA1) with estrone (E1) ≥1.3 pg/mL and estradiol (E2) ≥0.5 pg/mL [inadequate estrogen suppression (IES)] had a threefold increased risk of a breast cancer event. The objective of this study was to determine if increasing anastrozole to 10 mg/day (ANA10) could result in adequate estrogen suppression (AES: E1 &lt;1.3 pg/mL and/or E2 &lt;0.5 pg/mL) among those with IES on ANA1. Patients and Methods: Postmenopausal women with estrogen receptor-α–positive breast cancer planning to receive adjuvant ANA1 were eligible. E1 and E2 were assessed pre- and post-8 to 10 weeks of ANA1. Those with IES were switched to 8- to 10-week cycles of ANA10 followed by letrozole 2.5 mg/day. E1 and E2 were assessed after each cycle. Anastrozole concentrations were measured post-ANA1 and post-ANA10. Primary analyses included patients who documented taking at least 80% of the planned treatment (adherent cohort). Results: In total, 132 (84.6%) of 156 eligible patients were ANA1 adherent. IES occurred in 40 (30.3%) adherent patients. Twenty-five (78.1%) of 32 patients who began ANA10 were adherent, and AES was achieved in 19 (76.0%; 90% confidence interval, 58.1%–89.0%) patients. Anastrozole concentrations post-ANA1 and post-ANA10 did not differ by estrogen suppression status among adherent patients. AES was maintained/attained in 21 (91.3%) of 23 letrozole-adherent patients. Conclusions: Approximately 30% of ANA1-adherent patients had IES. Among those who switched to ANA10 and were adherent, 76% had AES. Further studies are required to validate emerging data that ANA1 results in IES for some patients and to determine the clinical benefit of switching to ANA10 or an alternative aromatase inhibitor.