Yara Abdou, MD
Among the patients treated with trastuzumab deruxtecan, median progression-free survival was significantly prolonged compared with the physician's choice treatment group (17.8 vs 6.9 months; hazard ratio 0.36; P < .0001). There were no new safety signals reported for trastuzumab deruxtecan. Of interest, drug-related interstitial lung disease occurred in 10% of patients treated with trastuzumab deruxtecan (including two grade 5 death events) compared with < 1% in the physician's-choice treatment group.
Overall, trastuzumab deruxtecan demonstrated a favorable benefit-risk profile in patients with HER2+ BC previously treated with trastuzumab emtansine. This is the first randomized study to show efficacy with an antibody-drug conjugate after a previous antibody-drug conjugate.
Breast density is a known independent risk factor for BC, furthermore, dense breast tissue can make identifying BC on screening mammograms more challenging. The nested case-control cohort study by Jiang and colleagues observed women with no history of any cancer for 10 years, with screening mammograms every 1-2 years. Subsequently, 289 women who developed BC were identified and analyzed along with 658 matched control individuals. BC risk factors were also collected via questionnaires at the time of enrollment. Of note, the BC cases cohort had an overall higher mean body mass index, a higher percentage of Black women, and of women with a family history of BC. The results showed that though women's breast density decreased over time in both cases and controls, the rate of change in breast density was significantly slower in the breast that later developed cancer compared with the cancer-free breast in control individuals (estimate 0.027; P = .04). Enhancing screening modalities to enable assessing for longitudinal changes in breast density may provide an additional tool for evaluating the risk for BC.
Reducing the late BC recurrence risk beyond 5 years is a significant issue in patients with hormone receptor–positive (HR+) BC. This prospective, randomized, phase 3, AERAS trial included 1593 postmenopausal women with HR+ early-stage invasive BC who were disease-free at 5 years after postoperative endocrine therapy. Patients were randomly assigned 1:1 to stop or continue receiving anastrozole for an additional 5 years. Results showed that continuation of anastrozole treatment for an additional 5 years significantly improved 5-year disease-free survival (DFS) (hazard ratio 0.61; 95% CI 0.46-0.82; P < .0010). Furthermore, extended anastrozole treatment reduced the incidence of local recurrence and second primary cancers. However, there was no significant difference in distant DFS. The incidence of grade 3 or higher adverse events was < 1% in both groups, although menopausal or bone-related all-grade adverse events were more frequent among patients in the group that continued with anastrozole, as expected. Results from this study help inform the risks and benefits of extending hormone therapy beyond 5 years.
The RxPONDER trial comparing endocrine therapy (ET) alone to chemotherapy plus endocrine therapy (CET) in patients with one to three positive axillary lymph nodes and recurrence score (RS) ≤ 25 showed that CET did not improve survival outcomes compared with ET alone in postmenopausal women with HR+/HER2- BC. This retrospective cohort study of real-world data from the National Cancer Database included 28,427 women with stage I-III HR+/HER2- BC and one to three positive axillary lymph nodes, of which 26.3% and 73.7% of patients received CET and ET, respectively. Results showed that in patients with RS of 20-25, CET was associated with a significant improvement in overall survival compared with ET alone, in both premenopausal (age ≤ 50 years: hazard ratio 0.334, P = .002) and postmenopausal patients (age > 50 years: hazard ratio 0.521, P = .019). Though these results are inconsistent with the RxPONDER trial results regarding the postmenopausal cohort, they do raise an important finding that is supported by prior published data.1 More studies are needed to validate these findings. At this time, guidelines recommend omitting chemotherapy in patients with HR+/HER2- BC, one to three positive axillary lymph nodes, and an RS of 20-25 per RxPONDER.
Additional Reference
- Early Breast Cancer Trialists' Collaborative Group (EBCTCG). Comparisons between different polychemotherapy regimens for early breast cancer: Meta-analyses of long-term outcome among 100,000 women in 123 randomised trials. Lancet. 2012;379:432-444. doi: 10.1016/S0140-6736(11)61625-5