A new Stanford Medicine study has uncovered concerning patterns in breast cancer treatment adherence among young women who pause therapy for pregnancy, revealing significantly lower resumption rates than previously reported in clinical trials.
The retrospective analysis, examining 215 women diagnosed with stages 0-3 breast cancer between January 2000 and October 2024, found that only about one-third resumed their endocrine therapy after giving birth. This finding stands in stark contrast to earlier clinical trial results that showed approximately 75% of women returning to treatment.
Treatment Adherence Patterns
The study, utilizing Stanford Medicine's Oncoshare database, identified that among the cohort (median age 33.6 years), 161 women were eligible for hormone therapy. Of the 130 women eligible for breast imaging surveillance, only 87 (67%) resumed their regular screening after delivery.
"It's always important to understand how guidelines play out in a real-world setting," explains Dr. Allison Kurian, one of the study's leaders. "Clinical trial participants tend to be highly motivated and may be more likely to adhere to treatment recommendations. But we are interested in outcomes for all our patients — that's where the rubber really meets the road."
Clinical Implications and Recurrence Rates
Perhaps most concerning is the study's finding that nearly 20% of the women experienced breast cancer recurrence within the decade following pregnancy. This rate is notably higher than the 9% recurrence rate reported in previous clinical trials over a three-year period.
The research highlights the unique challenges faced by premenopausal women with hormone-responsive breast cancers who must temporarily discontinue endocrine therapy to start or expand their families. These medications, which either lower estrogen production or block its effects, are typically prescribed for five or more years but are contraindicated during pregnancy and breastfeeding.
Addressing Treatment Challenges
"It's common to think, 'Oh, I'm done with chemotherapy, now endocrine therapy and ongoing imaging is the easy part,'" notes Dr. Kurian. "But in reality, you've finished the sprint; you are not done with the treatment marathon."
The findings underscore the need for enhanced support systems and strategies to improve treatment adherence among young breast cancer survivors managing both their health and family planning. The research team is now planning larger studies to understand barriers to adherence across different demographics and geographic regions.
The researchers emphasize the importance of developing more comprehensive support systems for these patients. "These women are young, with young families, and we want to be particularly intensive in maintaining their wellness, even during the chaos and life changes of a growing family," Dr. Kurian adds.
Moving forward, the team plans to conduct a prospective study incorporating patient questionnaires about treatment expectations, challenges, and adherence patterns, aiming to better understand and address the barriers to consistent care in this vulnerable population.
