Post-diagnostic weight change and all-cause mortality of postmenopausal breast cancer patients

Introduction:

Weight gain is common in breast cancer survivors, but the evidence is inconclusive among studies examining associations between changes in post-diagnostic weight with breast cancer survival in postmenopausal women. The aim of this analysis was to examine the impact of post-diagnostic weight change on all-cause mortality (ACM) in postmenopausal BC patients.

Methodology:

We used data from a patient cohort study, MARIE study, in Germany that included 2110 incident postmenopausal breast cancer patients. Patients were diagnosed aged 50 – 74 years, recruited during 2002 – 2005, and followed prospectively. Current weight was obtained by interviews conducted at recruitment and at first follow-up in 2009. Cox proportional hazards models adjusted for established prognostic and lifestyle factors at baseline were used to examine the associations between percent weight change ([(follow-up weight – recruitment weight)/recruitment weight] * 100) with ACM. Person-time was calculated from first follow-up (˜5.1 years after recruitment) until death or 30 June 2015.

Results:

Two hundred thirty-five deaths occurred over a median follow-up time of 6.0 years from 1st follow-up until end of follow-up. Women overweight and obese at baseline were combined to achieve sufficient power. Preliminary analyses revealed that for women who had normal BMI at baseline, both modest (> 5%-< 10%) and large weight loss (≥10%) were associated with significant increase in ACM ((HR 3.45 (95%I 1.83 – 6.51) and HR 4.90 (95%CI 1.70 – 14.12), respectively) but not modest (> 5%-< 10%) or large gains (≥10%) compared to weight stable (within 5% change). In overweight/obese women, ACM was significantly increased for large gain (≥10%) and large loss (≥10%) ((HR 2.31 (95%CI 1.19 – 4.50) and HR 3.91 (95%CI 2.29 – 6.68), respectively) but not for modest changes compared to weight stable.

Conclusions:

Post-diagnostic weight gain and loss seems to increase risk of ACM compared to those who were able to maintain their weight.