Cancer
Impact of Time Since Recent Childbirth on Survival in Young Women Diagnosed with Ductal Carcinoma in Situ (DCIS) in the Breast Zhenzhen Zhang* Zhenzhen Zhang Solange Bassale Ken R Smith Emily Guinto Alison Fraser Pepper Schedin
Background: Postpartum breast cancer (PPBC), diagnosed within 5-10 years after childbirth, is associated with increased metastasis, but its impact on mortality among women with Ductal Carcinoma in Situ (DCIS) remains unclear. This study examined the associations between time since recent childbirth and mortality outcomes in young women (≤45 years) diagnosed with DCIS.
Methods: Using the Utah Population Database (UPDB) and SEER Utah Cancer Registry data, we conducted a retrospective cohort study of 597 young women diagnosed with DCIS (stage 0) from 1996 to 2017, with a median follow-up of 12.5 years. Women were classified as nulliparous (n=183) or parous, with parous women grouped by time since recent childbirth and DCIS diagnosis: <5 years (n=87), 5–<10 years (n=131), or ≥10 years (n=196). Cox proportional hazards models assessed associations between time since recent childbirth and mortality, adjusting for diagnosis year, age at diagnosis, tumor stage, and estrogen receptor (ER) status. Published UPDB data on invasive breast cancer (BC) were used to compare frequency with DCIS. Chi-square tests evaluated distributions of BC type (DCIS vs invasive).
Results: Of 597 women, 23 deaths occurred during follow-up, with only 2 BC-related deaths total, both in the <5 year postpartum group. DCIS was less frequent in the <5-year postpartum group (12.4%) compared to nulliparous (17.6%) and 5–<10 years group (17.6%), and invasive BC was more frequent in the <5-year group. ER-negative DCIS was higher in the <5-year group (18%) compared to other groups (7%, 6%, 9%). All-cause mortality for postpartum women diagnosed <10 years after childbirth was comparable to nulliparous women [HR=0.97 (95% CI: 0.33–2.90), P=0.96], with no significant differences for those diagnosed <5 years [HR=2.28 (95% CI: 0.68–7.66), P=0.18] or 5–<10 years [HR=0.40 (95% CI: 0.08–1.98), P=0.26], and for those diagnosed ≥10 years [HR=1.15 (95% CI: 0.40–3.26), P=0.80].
Conclusion: BC-specific mortality was very low during the follow-up, implicating standard care as largely curative. All-cause mortality showed no significant differences by time since recent childbirth. The lower frequency of DCIS and higher ER-negative % in the <5-year postpartum group suggest potential progression of DCIS to invasive carcinoma during the early postpartum period.