TOPLINE:
Women with estrogen receptor (ER)–positive, human epidermal growth factor receptor 2 (HER2)–negative invasive lobular carcinoma who are treated with endocrine therapy do not derive any additional survival benefit from neoadjuvant or adjuvant chemotherapy.
METHODOLOGY:
- Studies evaluating the long-term effects of chemotherapy in patients with invasive lobular carcinoma are limited and often "show inconclusive results," the authors explained.
- Female patients diagnosed with ER-positive, HER2-negative invasive lobular carcinoma who received endocrine therapy were identified from the breast cancer database at Erasmus Medical Center, Rotterdam, the Netherlands.
- Linked information on patient and tumor characteristics, vital status, and treatment were then obtained from the Netherlands Cancer Registry.
- Patients also had to have an indication for chemotherapy based on lymph node status, tumor size, histologic tumor grade, and hormone receptor status, in line with national guidelines.
- Among 716 patients with ER-positive, HER2-negative invasive lobular carcinoma, 520 who had an indication for chemotherapy were included. Of those, 379 received chemotherapy and 141 did not.
TAKEAWAY:
- Patients who received chemotherapy were younger at diagnosis than those who did not (51 vs 61 years), had an earlier average year of diagnosis (2010 vs 2015), and had longer follow-up (7.8 years vs 5.2 years).
- Chemotherapy recipients were more likely to have T3+ disease (33% vs 14%) and positive lymph node involvement (80% vs 49%), and less likely to undergo breast-conserving surgery (31% vs 43%).
- Researchers, however, found no difference between the chemotherapy and no-chemotherapy groups in terms of recurrence-free survival (hazard ratio [HR], 1.20; 95% CI, 0.63-2.31), breast cancer–specific survival (HR, 1.24; 95% CI, 0.60-2.58), and overall survival (HR, 0.97; 95% CI, 0.56-1.66) after adjustment for confounders.
IN PRACTICE:
The authors "observed no evidence for added value of chemotherapy" for ER-positive, HER2-negative invasive lobular carcinoma who received endocrine therapy. "In view of the adverse effects of chemotherapy, our study takes an important step in answering a valuable question from the patient's perspective," the researchers wrote.
SOURCE:
The study, conducted by Bernadette A.M. Heemskerk-Gerritsen, PhD, from Erasmus Medical Center Cancer Institute, Rotterdam, the Netherlands, was published in Cancer on November 20, 2023.
LIMITATIONS:
The retrospective design means that there is a risk for residual confounding from factors not recorded in the database. The researchers believe that some patients did not receive chemotherapy owing to having comorbidities or patient preference, which could have influenced the results. Moreover, the duration of endocrine therapy was not recorded.
DISCLOSURES:
No funding was declared. One author declares relationships with GlaxoSmithKline, Pfizer, Menarini Silicon Biosystems, and Novartis. No other relevant financial relationships were declared.
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