Clinical Edge Journal Scan

Commentary: Obesity, Pregnancy, and Adjuvant Chemotherapy in BC, December 2023

Dr. Roesch scans the journals so you don't have to!

Publish date: November 21, 2023
By
Erin Roesch, MD
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Clinical Edge Journal Scan: Breast Cancer November 2023 (1 of 11)


 

Erin Roesch, MD

Obesity and other metabolic comorbidities (including glucose intolerance, hypertension, and dyslipidemia) have been associated with poorer prognosis among breast cancer patients. 1 The underlying mechanisms for which obesity is linked to inferior breast cancer outcomes is complex and may also involve drug efficacy in these patients. Data from the ATAC trial showed that there was a higher risk for recurrence among patients with obesity who were receiving an aromatase inhibitor (AI) vs patients with a healthy body weight receiving an AI; however, patients receiving tamoxifen did not exhibit this difference. 2 A Danish Breast Cancer Group cohort study including 13,230 postmenopausal patients with stage I-III hormone receptor–positive (HR+) breast cancer treated with AI investigated the association of body mass index with recurrence ( Harborg et al ). There was a significantly increased risk for recurrence among those patients with obesity (adjusted hazard ratio 1.18; 95% CI 1.01-1.37) and severe obesity (adjusted hazard ratio 1.32; 95% CI 1.08-1.62) vs patients with healthy body weight. These results highlight the importance of lifestyle interventions targeting obesity and metabolic factors in breast cancer patients and support future studies investigating optimal drug selection based on body composition.

Breast cancer in young women presents a unique set of challenges owing to life-stage at the time of diagnosis and treatment. Oncofertility, family planning, and pregnancy are essential issues to address at the time of initial consultation and throughout the survivorship setting. Various studies have provided supportive evidence regarding the safety of pregnancy after breast cancer diagnosis and treatment. 3 HR+ breast cancer is associated with its own distinctive considerations related to pregnancy and its timing, including the use of endocrine therapy for 5-10 years, the role of female hormones during pregnancy, and late patterns of recurrence that characterize this subtype. A meta-analysis including eight eligible studies and 3805 women with HR+ early breast cancer investigated the prognostic impact of future pregnancy among these patients ( Arecco et al ). A total of 1285 women had a pregnancy after breast cancer diagnosis and treatment; there was no difference in disease-free survival (hazard ratio 0.96; 95% CI 0.75-1.24; P = .781) and better overall survival (OS; hazard ratio 0.46; 95% CI 0.27-0.77; P < .005) in those with vs those without subsequent pregnancy. Added to this body of data is the prospective POSITIVE trial, which showed that a temporary pause of endocrine therapy for an attempt at conceiving appears to be safe in young women with early HR+ breast cancer with short-term follow-up. 4 Future research efforts investigating outcomes after assisted reproductive technologies in this population, those with germline mutations, and extended follow-up of studies, such as POSITIVE, will continue to inform guidance for and management of young women with breast cancer.

Guidelines favor the use of adjuvant chemotherapy for small, node-negative, triple-negative breast cancer (TNBC), specifically T1b and T1c tumors. 5 However, high-quality data to inform this decision-making are sparse, and it is valuable to consider the magnitude of benefit weighed against possible risks and side effects of treatment, as well as patient comorbidities. A retrospective analysis of the Surveillance, Epidemiology, and End Results (SEER) database including 11,510 patients (3388 with T1b and 8122 with T1c TNBC) evaluated the impact of adjuvant chemotherapy on OS and breast cancer–specific survival (BCSS) ( Carbajal-Ochoa et al ). The use of adjuvant chemotherapy was associated with improved OS (hazard ratio 0.54; 95% CI 0.47-0.62; P < .001) and BCSS (hazard ratio 0.79; 95% CI 0.63-0.99; P = .043) among T1c TNBC. For those with T1b tumors, adjuvant chemotherapy improved OS (hazard ratio 0.52; 95% CI 0.41-0.68; P < .001) but did not improve BCSS (hazard ratio 0.70; 95% CI 0.45-1.07; P = .10). A better understanding of the molecular drivers implicated in this heterogeneous subtype, and predictors of response and resistance, will aid in identifying those patients who have greater benefit and those who can potentially be spared chemotherapy-related toxicities.

Additional References

  1. Anwar SL, Cahyono R, Prabowo D, et al. Metabolic comorbidities and the association with risks of recurrent metastatic disease in breast cancer survivors. BMC Cancer . 2021;21:590. doi: 10.1186/s12885-021-08343-0
  2. Sestak I, Distler W, Forbes JF, et al. Effect of body mass index on recurrences in tamoxifen and anastrozole treated women: An exploratory analysis from the ATAC trial. J Clin Oncol. 2010;28:3411-3415. doi: 10.1200/JCO.2009.27.2021
  3. Lambertini M, Blondeaux E, Bruzzone M, et al. Pregnancy after breast cancer: A systematic review and meta-analysis. J Clin Oncol . 2021;39:3293-3305. doi: 10.1200/JCO.21.00535
  4. Partridge AH, Niman SM, Ruggeri M, et al for the International Breast Cancer Study Group and POSITIVE Trial Collaborators. Interrupting endocrine therapy to attempt pregnancy after breast cancer. N Engl J Med. 2023;388:1645-1656. doi: 10.1056/NEJMoa2212856
  5. Curigliano G, Burstein HJ, Winer EP, et al. De-escalating and escalating treatments for early-stage breast cancer: The St. Gallen International Expert Consensus Conference on the Primary Therapy of Early Breast Cancer 2017. Ann Oncol. 2017;28:1700-1712. doi: 10.1093/annonc/mdx308

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Clinical Edge Journal Scan: Breast Cancer November 2023 (1 of 11)