Erin Roesch, MD
A total of 126 patients were included in the full analysis set; median progression-free survival (PFS) was 18.8 months, overall response rate was 64.3%, and the safety profile was similar to prior studies. The median PFS in this observational study was comparable to a median PFS of 16.9 months in the CLEOPTRA study among 88 patients with prior (neo)adjuvant trastuzumab. HELENA also demonstrated similar PFS results for the hormone receptor (HR)-negative and HR-positive (HR+) subgroups (19.4 months vs 18.2 months), as well as for patients with nonvisceral and visceral metastases (20.5 months vs 18.0 months). These findings provide further support for use of the THP regimen as first-line treatment in the real-world setting for patients with HER2+ MBC and prior receipt of trastuzumab.
Adjuvant endocrine therapy (ET) is associated with a survival benefit for early-stage HR+ breast cancer; however, the absolute degree of benefit depends on various clinicopathologic features.2 Although it generally has a manageable toxicity profile, some side effects carry more significant consequences (thromboembolism, endometrial carcinoma, osteoporosis), and some of the more common ones can affect routine quality of life (hot flashes, vaginal dryness, arthralgia).
A retrospective observational study including 5545 patients with pT1a-b estrogen receptor-positive (ER+) breast cancer demonstrated improvements in disease-free survival (DFS) and recurrence-free survival (RFS) among those who received ET vs those who did not receive ET after 5 and 7 years of follow-up (DFS: increases of 2.5% and 3.3%; RFS: increases of 1.9% and 4.3%) (Houvenaeghel et al). Among all patients, absence of ET was associated with decreased DFS (hazard ratio [HR] 1.275; P = .047) but no difference in RFS or OS. Patients with pT1a-b ER+ grade 2-3 tumors (n = 2363) experienced decreased DFS (HR 1.502, P = .049) without ET; however, those with pT1a-b ER+ grade 1 tumors did not experience a negative effect on DFS without ET.
These results provide further support for the survival improvements seen with adjuvant ET — although the relative benefit may be fairly modest — and that ET omission is a relevant consideration in patients with comorbidities or tolerance issues, particularly those with pT1a-b grade 1 tumors.
Advancements in breast cancer therapies have led to improvements in survival outcomes, and it is therefore increasingly essential to recognize risks for other cancer types in breast cancer survivors. Male breast cancer is rare, and although clinical management for the most part mirrors that of female breast cancer, it is important to be aware of potential differences in this population, including risks for subsequent non-breast primary cancers.3
A meta-analysis including eight retrospective cohort studies with male breast cancer survivors reported the standardized incidence ratio (SIR), which compares the incidence of non-breast second primary cancers (SPC) among men with first primary breast cancer vs the expected incidence of non-breast primary cancers in the general male population. The summary SIR estimate was 1.27 (95% CI 1.03-1.56), with increased risk for certain SPCs: colorectal (SIR 1.29; 95% CI 1.03-1.61), pancreatic (SIR 1.64; 95% CI 1.05-2.55), and thyroid (SIR 5.58; 95% CI 1.04-30.05) (Allen et al). Additionally, men diagnosed with breast cancer before 50 years of age were observed to have increased SPC risk compared with men who were older than 50 years at breast cancer onset (SIR 1.50 vs 1.14; P = .040).
This study highlights the importance of genetic assessment for men diagnosed with breast cancer, so they can be appropriately counseled on subsequent cancer risk. It also stimulates thinking regarding other potential contributing factors to the observed increased SPC risk among male breast cancer survivors, including the effect of various treatments, hormonal influences, and significant family history.
Studies have shown that older women derive a survival benefit with adjuvant chemotherapy; however, they may be at increased risk of experiencing toxicities owing to physical functioning and comorbidities.4 A comprehensive geriatric assessment is key, and it is also beneficial for identifying which patients have a higher likelihood of clinical decline after chemotherapy.
A prospective study including 295 robust women age ≥ 65 years with stage I-III breast cancer treated with chemotherapy showed that 26% had a chemotherapy-induced decline in frailty status; patients with high interleukin-6 (IL-6) and C-reactive protein (CRP) inflammatory markers before chemotherapy had a more than threefold odds of experiencing a chemotherapy-induced decline in frailty compared with those with low IL-6 and CRP (odds ratio 3.52; 95% CI 1.55-8.01; P = .003) (Ji et al).
These findings support the relationship between inflammation, aging, and chemotherapy-induced functional decline. Further research is warranted to identify whether there are specific drugs that are implicated, methods to enhance anti-inflammatory effects, and any downstream effect on breast cancer outcomes of these patients.
Additional References
- Swain SM, Miles D, Kim SB, et al; CLEOPATRA study group. Pertuzumab, trastuzumab, and docetaxel for HER2-positive metastatic breast cancer (CLEOPATRA): End-of-study results from a double-blind, randomised, placebo-controlled, phase 3 study. Lancet Oncol. 2020;21:519-530. Doi: 10.1016/S1470-2045(19)30863-0
- Ma SJ, Oladeru OT, Singh AK. Association of endocrine therapy with overall survival in women with small, hormone receptor-positive, ERBB2-negative breast cancer. JAMA Netw Open. 2020;3:e2013973. Doi: 10.1001/jamanetworkopen.2020.13973
- Pritzlaff M, Summerour P, McFarland R, et al. Male breast cancer in a multi-gene panel testing cohort: Insights and unexpected results. Breast Cancer Res Treat. 2017;161:575-586. Doi: 10.1007/s10549-016-4085-4
- Tamirisa N, Lin H, Shen Y, et al. Association of chemotherapy with survival in elderly patients with multiple comorbidities and estrogen receptor-positive, node-positive breast cancer. JAMA Oncol. 2020;6:1548-155 Doi: 10.1001/jamaoncol.2020.2388