Obesity at breast cancer (BC) diagnosis has been associated with poor outcome, although the magnitude of effect in different BC subtypes is uncertain. We report on the association of obesity or overweight at diagnosis of nonmetastatic BC with disease-free (DFS) and overall survival (OS) in the following defined subtypes: hormone receptor positive/HER2 negative (HR+HER2−), HER2 positive (HER2+), and triple negative (TNBC). We searched MEDLINE, EMBASE, and COCHRANE databases up to January 1, 2019. Study eligibility was performed independently by 2 authors. Studies reporting hazard ratios (HRs) of OS and/or DFS for obesity or overweight in BC subtypes were included. The pooled hazard ratio was computed and weighted using generic inverse variance and random effects models. Twenty-seven studies were included. Obese compared with nonobese women had worse DFS in all subtypes: the hazard ratios were 1.26 (95% confidence interval [CI] = 1.13 to 1.41, P < .001) for HR+HER2− BC, 1.16 (95% CI = 1.06 to 1.26, P < .001) for HER2+ BC, and 1.17 (95% CI = 1.06 to 1.29, P = .001) for TNBC. OS was also worse in obese vs nonobese women (HR+HER2− BC HR = 1.39, 95% CI = 1.20 to 1.62, P < .001; HER2+ BC HR = 1.18, 95% CI = 1.05 to 1.33, P = .006; and TNBC HR = 1.32, 95% CI = 1.13 to 1.53, P < .001). As opposed to obesity, overweight was not associated with either DFS or OS in HER2+ BC (HR = 1.02, 95% CI = 0.81 to 1.28, P = .85; and HR = 0.96, 95% CI = 0.76 to 1.21, P = .99, respectively) or TNBC (HR = 1.04, 95% CI = 0.93 to 1.18, P = .49; and HR = 1.08, 95% CI = 0.81 to 1.44, P = .17), respectively. In HR+HER2− BC, being overweight was associated with worse OS (HR = 1.14, 95% CI = 1.07 to 1.22, P < .001). Obesity was associated with modestly worse DFS and OS in all BC subtypes.

Metformin has been associated with lower breast cancer (BC) risk and improved outcomes in observational studies. Multiple biologic mechanisms have been proposed, including a recent report of altered sex hormones. We evaluated the effect of metformin on sex hormones in MA.32, a phase III trial of nondiabetic BC subjects who were randomly assigned to metformin or placebo. We studied the subgroup of postmenopausal hormone receptor-negative BC subjects not receiving endocrine treatment who provided fasting blood at baseline and at 6 months after being randomly assigned. Sex hormone-binding globulin, bioavailable testosterone, and estradiol levels were assayed using electrochemiluminescence immunoassay. Change from baseline to 6 months between study arms was compared using Wilcoxon sum rank tests and regression models. 312 women were eligible (141 metformin vs 171 placebo); the majority of subjects in each arm had T1/2, N0, HER2-negative BC and had received (neo)adjuvant chemotherapy. Mean age was 58.1 (SD=6.9) vs 57.5 (SD=7.9) years, mean body mass index (BMI) was 27.3 (SD=5.5) vs 28.9 (SD=6.4) kg/m² for metformin vs placebo, respectively. Median estradiol decreased between baseline and 6 months on metformin vs placebo (−5.7 vs 0 pmol/L; P < .001) in univariable analysis and after controlling for baseline BMI and BMI change (P < .001). There was no change in sex hormone-binding globulin or bioavailable testosterone. Metformin lowered estradiol levels, independent of BMI. This observation suggests a new metformin effect that has potential relevance to estrogen sensitive cancers.

Obesity is a known risk factor for developing endometrial cancer. However, the association of obesity with endometrial cancer (EC) outcomes has not been clearly established. This study examined how outcomes in women with early stage EC vary with body composition measured via computed tomography (CT). In this retrospective study, patients diagnosed with EC international Federation of Gynecology and Obstetrics stages I-III and available CT scans were included. Automatica software was used to assess the areas of visceral adipose tissue, subcutaneous adipose tissue (SAT), and intermuscular adipose tissue (IMAT) and skeletal muscle area. Of 293 patient charts assessed, 199 met eligibility criteria. Median body mass index (BMI) was 32.8 kg/m² (interquartile range [IQ] = 26.8-38.9); 61.8% had histologic subtype endometrioid carcinoma. Adjusted for age, international Federation of Gynecology and Obstetrics stage, and histologic subtype, a BMI of at least 30 vs less than 30 kg/m² was associated with lower endometrial cancer–specific survival (ECSS) (hazard ratio [HR] = 2.32, 95% confidence interval [CI] = 1.27 to 4.25) and overall survival (OS) (HR = 2.7, 95% CI = 1.35 to 5.39). Higher IMAT 75th vs 25th percentile and SAT of at least 225.6 vs less than 225.6 cm² were associated with lower ECSS (HR = 1.53, 95% CI = 1.1 to 2.13, and HR = 2.57, 95% CI = 1.13 to 5.88) and OS (HR = 1.50, 95% CI = 1.11 to 2.02, and HR = 2.46, 95% CI = 1.2 to 5.01), respectively. The association of visceral adipose tissue (75th vs 25th percentile) with ECSS and OS was not statistically significant (HR = 1.42, 95% CI = 0.91 to 2.22, and HR = 1.24, 95% CI = 0.81 to 1.89). Higher BMI, IMAT, and SAT were associated with higher mortality from EC and lower OS. A better understanding of the mechanisms underlying these relationships could inform strategies to improve patient outcomes.

PURPOSE Although representing the majority of newly diagnosed cancers, patients with breast cancer appear less vulnerable to COVID-19 mortality compared with other malignancies. In the absence of patients on active cancer therapy included in vaccination trials, a contemporary real-world evaluation of outcomes during the various pandemic phases, as well as of the impact of vaccination, is needed to better inform clinical practice. METHODS We compared COVID-19 morbidity and mortality among patients with breast cancer across prevaccination (February 27, 2020-November 30, 2020), Alpha-Delta (December 1, 2020-December 14, 2021), and Omicron (December 15, 2021-January 31, 2022) phases using OnCovid registry participants (ClinicalTrials.gov identifier: NCT04393974). Twenty-eight-day case fatality rate (CFR28) and COVID-19 severity were compared in unvaccinated versus double-dosed/boosted patients (vaccinated) with inverse probability of treatment weighting models adjusted for country of origin, age, number of comorbidities, tumor stage, and receipt of systemic anticancer therapy within 1 month of COVID-19 diagnosis. RESULTS By the data lock of February 4, 2022, the registry counted 613 eligible patients with breast cancer: 60.1% (n = 312) hormone receptor-positive, 25.2% (n = 131) human epidermal growth factor receptor 2-positive, and 14.6% (n = 76) triple-negative. The majority (61%; n = 374) had localized/locally advanced disease. Median age was 62 years (interquartile range, 51-74 years). A total of 193 patients (31.5%) presented >= 2 comorbidities and 69% (n = 330) were never smokers. In total, 392 (63.9%), 164 (26.8%), and 57 (9.3%) were diagnosed during the prevaccination, Alpha-Delta, and Omicron phases, respectively. Analysis of CFR28 demonstrates comparable estimates of mortality across the three pandemic phases (13.9%, 12.2%, 5.3%, respectively; P = .182). Nevertheless, a significant improvement in outcome measures of COVID-19 severity across the three pandemic time periods was observed. Importantly, when reported separately, unvaccinated patients from the Alpha-Delta and Omicron phases achieved comparable outcomes to those from the prevaccination phase. Of 566 patients eligible for the vaccination analysis, 72 (12.7%) were fully vaccinated and 494 (87.3%) were unvaccinated. We confirmed with inverse probability of treatment weighting multivariable analysis and following a clustered robust correction for participating center that vaccinated patients achieved improved CFR28 (odds ratio [OR], 0.19; 95% CI, 0.09 to 0.40), hospitalization (OR, 0.28; 95% CI, 0.11 to 0.69), COVID-19 complications (OR, 0.16; 95% CI, 0.06 to 0.45), and reduced requirement of COVID-19-specific therapy (OR, 0.24; 95% CI, 0.09 to 0.63) and oxygen therapy (OR, 0.24; 95% CI, 0.09 to 0.67) compared with unvaccinated controls. CONCLUSION Our findings highlight a consistent reduction of COVID-19 severity in patients with breast cancer during the Omicron outbreak in Europe. We also demonstrate that even in this population, a complete severe acute respiratory syndrome coronavirus 2 vaccination course is a strong determinant of improved morbidity and mortality from COVID-19.

Purpose: Previous data suggest synergy between PARP inhibition and immune checkpoint blockade in different genetic settings. The estrogen receptor (ER) pathway remains a key target in metastatic breast cancer regardless of genomic context. This study assesses the activity of the combination of PARP, ER, and PD-L1 inhibition among patients with metastatic breast cancer and relevant genomic alterations. Patients and Methods: In this multicenter, single-arm, phase II clinical trial, we used a Simon two-stage design to evaluate the activity and safety of a combination of durvalumab, olaparib, and fulvestrant as second or third line in patients with ER+/HER2− metastatic breast cancer. Patients with either somatic or germline mutations of a homologous recombination repair gene, a microsatellite instability status, or an endocrine resistance–related mutation were eligible. Primary endpoint was 24-week progression-free survival rate. Results: The 172 (100%) patients included received prior endocrine therapy for metastatic breast cancer and 86% received a CDK4/6 inhibitor, and 67 (39%) had a previously documented germline BRCA1/2 mutation (gBRCA1/2m). The 24-week progression-free survival rate was 66.7% [95% confidence interval (CI), 58.6–74.1] in the evaluable population and 76.3% (95% CI, 63.4–86.4) in gBRCA1/2m patients. The median progression-free survival was 9.3 months (95% CI, 7.5–12.7) and 12.6 months (95% CI, 8.2–16.7) in the intention-to-treat and gBRCA1/2m populations, respectively. The median overall survival was 30 months (95% CI, 26.6–not reached). Most common adverse events of any grade were nausea (59%) and asthenia (43%). No new toxicity warning was detected. Conclusions: In patients with ER+/HER2− metastatic breast cancer and selected genomic alterations, this triplet combination was active and had an acceptable toxicity profile (NCT04053322).