Body mass index and survival after breast cancer diagnosis in Japanese women

Abstract

BackgroundBody mass index (BMI) may be an important factor affecting breast cancer outcome. Studies conducted mainly in Western countries have reported a relationship between higher BMI and a higher risk of all-cause death or breast cancer-specific death among women with breast cancer, but only a few studies have been reported in Japan so far. In the present prospective study, we investigated the associations between BMI and the risk of all-cause and breast cancer-specific death among breast cancer patients overall and by menopausal status and hormone receptor status.MethodsThe study included 653 breast cancer patients admitted to a single hospital in Japan, between 1997 and 2005. BMI was assessed using a self-administered questionnaire. The patients were completely followed up until December, 2008. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated according to quartile points of BMI categories, respectively: <21.2, ≥21.2 to <23.3 (reference), ≥23.3 to <25.8 and ≥25.8 kg/m2.ResultsDuring the follow-up period, 136 all-cause and 108 breast cancer-specific deaths were observed. After adjustment for clinical and confounding factors, higher BMI was associated with an increased risk of all-cause death (HR = 2.61; 95% CI: 1.01–6.78 for BMI ≥25.8 vs. ≥21.2 to <23.3 kg/m2) among premenopausal patients. According to hormonal receptor status, BMI ≥25.8 kg/m2 was associated with breast cancer-specific death (HR = 4.95; 95% CI: 1.05–23.35) and BMI <21.2 kg/m2 was associated with all-cause (HR = 2.91; 95% CI: 1.09–7.77) and breast cancer-specific death (HR = 7.23; 95% CI: 1.57–33.34) among patients with ER + or PgR + tumors. Analysis by hormonal receptor status also showed a positive association between BMI and mortality risk among patients with ER + or PgR + tumors and with BMI ≥21.2 kg/m2 (p for trend: 0.020 and 0.031 for all-cause and breast cancer-specific death, respectively).ConclusionsOur results suggest that both higher BMI and lower BMI are associated with an increased risk of mortality, especially among premenopausal patients or among patients with hormonal receptor positive tumors. Breast cancer patients should be informed of the potential importance of maintaining an appropriate body weight after they have been diagnosed.

Post-diagnosis adiposity and survival among breast cancer patients: influence of breast cancer subtype

“…In our study and in previous literature, the effect of BMI on breast cancer-specific mortality has often been weaker than that for all-cause mortality [1], with several null findings [35, 38, 39]. These results indicate that non-cancer causes of death contribute to the less favorable outcomes noted for obese patients.…”

Progesterone receptor status modifies the association between body mass index and prognosis in women diagnosed with estrogen receptor positive breast cancer

“…On the other hand, the relation between underweight and worse prognosis has been less studied. The main mechanisms suggested include the presence of severe comorbidities like respiratory diseases and compromised immune system due to nutritional deficiency …”

Smoking and survival after breast cancer diagnosis in Japanese women: A prospective cohort study

“…The present study was performed within this survey. Details of the survey have already been described elsewhere . The questionnaire was distributed to patients on the day they made an appointment for their initial admission to the MCCH (i.e.…”

“…Details of the survey have already been described elsewhere. (16)(17)(18)(19)(20)(21)(22) The questionnaire was distributed to patients on the day they made an appointment for their initial admission to the MCCH (i.e. 10-15 days before admission) and collected by nurses on the actual admission day.…”