While women who are 40 years or younger and diagnosed with primary breast cancer experience a higher risk of locoregional recurrence (LRR) compared with older populations, the specific clinical and treatment-related drivers of this risk have remained unclear. To address these gaps, researchers from Dana-Farber Cancer Institute analyzed a modern cohort of 1058 patients treated between 2016 and 2023.
In an interview with CancerNetwork®, Kristen Brantley, PhD, instructor in medicine at Dana-Farber Cancer Institute, discussed findings from a poster presentation at the 2026 American Association for Cancer Research (AACR) Annual Meeting. The study found that at a median follow-up of 3.6 years, the 5-year cumulative incidence of LRR was 4.1%.
According to Brantley, several tumor and treatment factors were predictive of recurrence. Notably, patients with stage III disease had a significantly higher risk of LRR (sHR, 3.41; 95% CI, 1.07-10.9; P = .04). Regarding treatment, the use of mastectomy—with or without radiation—and adherence to endocrine therapy (ET) among those with hormone receptor–positive disease emerged as the strongest predictors for reducing recurrence risk.
Transcript:
When we looked at the factors individually, stage, grade, and tumor size came up as tumor factors that were predictive of LRR. The treatment factors included endocrine therapy, mastectomy vs lumpectomy, and radiation therapy, as well as adjuvant chemotherapy. When we looked at these factors together, what arose was the stage of the tumor [and] mastectomy plus radiation. We combined that as one variable because [patients are] often given mastectomy with or without radiation. The [patients with] lumpectomy in this cohort all had radiation. The other factor that came out was endocrine therapy. If you were eligible for endocrine therapy, and you had HR+ breast cancer, you tended to do better and not have LRR.
In terms of the subtype-specific findings, when we looked at individual subtypes, they didn’t independently come out as being significantly associated with LRR. However, if we look within the individual subtypes, we can see that the relative benefit of mastectomy plus radiation was not observed among those with triple-negative breast cancer. There does seem to be a subtype-specific leaning. Other studies have found that subtypes perhaps outweigh some of the other surgical and treatment benefits.
Reference
Brantley KD, Parker T, Vincuilla J, et al. Risk factors for early locoregional recurrence among young-onset breast cancer patients: findings from a single institutional prospective dataset. Presented at the 2026 American Association for Cancer Research Annual Meeting, San Diego, CA; April 17-22, 2026. Poster 5223.
