Wernli, Karen J.

1564 Background: Adolescent and young adult (AYA) females with early-stage ER-negative and/or HER2-positive breast cancer commonly receive chemotherapy to reduce risk of recurrence. Fertility concerns, counseling, and preservation may influence chemotherapy decisions and time to chemotherapy (TTC) initiation. Methods: We surveyed AYA survivors of stage I–III premenopausal ER-negative and/or HER2-positive breast cancer treated at Kaiser Permanente Northern and Southern California (2013-2022). Fertility concerns were defined as not having completed desired family size or being unsure about having completed desired family size at diagnosis. We summarized receipt of fertility counseling, receipt of chemotherapy, and use of oocyte/embryo cryopreservation for fertility preservation (FP). Among fertility-concerned patients who received chemotherapy, TTC (days from diagnosis) was assessed separately for neoadjuvant chemotherapy (NAC) vs for adjuvant chemotherapy (AdjC). Time to NAC was natural log–transformed and modeled with multivariable log-linear regression to estimate relative differences in TTC, adjusting for stage, study site, ER, HER2, age, and diagnosis year. Results: Of 363 respondents, 197 (54%) had fertility concerns at diagnosis; 183/197 (93%) received chemotherapy, similar to 153/166 (92%) among those without concerns (p=0.7). Of the concerned chemotherapy recipients, 45 (25%) saw a fertility specialist but did not pursue FP while 55 (30%) underwent FP. For the 112 fertility-concerned NAC recipients, FP was associated with longer TTC than no fertility specialist counseling (mean=41 vs. 30 days; adjusted ratio=1.39; 95% CI 1.15–1.69), whereas fertility specialist counseling without FP was not (mean= 31 vs. 30 days, adjusted ratio=1.04; 95% CI 0.86–1.25). For the 71 fertility-concerned AdjC recipients, TTC was similar for patients who did not see a fertility specialist (mean=63 days), those who froze oocytes/embryos (mean=65 days), and those who saw a fertility specialist but did not pursue FP (mean=69 days). Conclusions: In this AYA breast cancer cohort, there was no evidence that fertility concerns led patients to decline chemotherapy. FP was associated with a modest delay in NAC initiation (<2 weeks on average). Time to chemotherapy (TTC) among 183 AYA patients with ER− and/or HER2+ breast cancer and fertility concerns. Fertility-focused care N (n=183) Neoadjuvant chemotherapy (n=112) Mean TTC, days Relative difference in TTC, adjusted ratio (95%CI) Adjuvant chemotherapy (n=71) Mean TTC, days No fertility counseling from a specialist 83 (45%) 55 (49%) 29.6 Reference 28 (39%) 62.6 Received fertility counseling from a specialist No fertility preservation 45 (25%) 28 (25%) 30.7 1.04 (0.86,1.25) 17 (24%) 68.6 Fertility preservation 55 (30%) 29 (26%) 41.2 1.39 (1.15,1.69) 26 (37%) 64.6

PURPOSE Survivors of adolescent and young adult (AYA)-onset cancers require comprehensive cancer surveillance care. Guidelines recommend 1-4 clinician visits annually for 5 years depending on stage and disease. The goal of this study was to identify factors associated with patterns of post-treatment primary and oncology care in a large cohort of survivors of AYA-onset cancers diagnosed within an integrated health care system. METHODS Patients diagnosed with cancer between 2006 and 2020 age 15-39 years were included. Surveillance visits were identified from electronic medical records 2-5 years after diagnosis. Multivariable logistic regression was used to assess associations with zero oncology specialty visits. RESULTS Of 7,925 survivors, 46% were Hispanic, 6% non-Hispanic Black, 11% non-Hispanic Asian, 35% non-Hispanic White, and 65% female. One-quarter had no oncology specialty visits in the first surveillance year rising to 38% in year 5; 31% had 3+ visits in the first year, declining to 13% in year 5. Over the surveillance period, 17% did not have any oncology specialty visits and 6% had no primary care or oncology visits. Those who were male (odds ratio [OR], 1.21 [95% CI, 1.02 to 1.45]), 20-24 years at diagnosis (OR, 1.58, 95% CI, 1.27 to 1.9; v 35 to 39), or non-Hispanic Black (OR, 1.38, 95% CI, 1.05 to 1.82; v non-Hispanic White) or had high-deductible commercial or Medicaid insurance (OR, 1.35, 95% CI, 1.15 to 1.59; OR, 1.42, 95% CI, 1.11 to 1.82, respectively; v no or low deductible commercial) were more likely to be in the 0-visit group for oncology specialty care. CONCLUSION Although the majority of this cohort received either primary or oncology specialty care, our study identifies those who may need tailored outreach for follow-up care. Continued research into development and testing of interventions to improve uptake of appropriate health care for survivors of AYA-onset cancers is critical.