Obesity and breast cancer outcomes in chemotherapy patients in New Zealand – a population-based cohort study
Abstract Background Obesity has been reported as an adverse prognostic factor in breast cancer, but inconsistently, and under-treatment with chemotherapy may occur. We provide the first assessment of obesity and breast cancer outcomes in a population-based, multi-ethnic cohort of New Zealand patient...
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doaj-deff88c5dd3b427ea995096246bd00602020-11-25T00:14:43ZengBMCBMC Cancer1471-24072018-01-0118111310.1186/s12885-017-3971-4Obesity and breast cancer outcomes in chemotherapy patients in New Zealand – a population-based cohort studyJ. Mark Elwood0Sandar Tin Tin1Marion Kuper-Hommel2Ross Lawrenson3Ian Campbell4Epidemiology and Biostatistics, School of Population Health, University of AucklandEpidemiology and Biostatistics, School of Population Health, University of AucklandWaikato Clinical School, University of AucklandWaikato Clinical School, University of AucklandWaikato Clinical School, University of AucklandAbstract Background Obesity has been reported as an adverse prognostic factor in breast cancer, but inconsistently, and under-treatment with chemotherapy may occur. We provide the first assessment of obesity and breast cancer outcomes in a population-based, multi-ethnic cohort of New Zealand patients treated with chemotherapy. Methods All 3536 women diagnosed with invasive breast cancer in the Waikato region of New Zealand from 2000-2014 were registered and followed until last follow-up in specialist or primary care, death or Dec 2014; median follow-up 4.1 years. For the 1049 patients receiving chemotherapy, mortality from breast cancer, other causes, and all causes, and rates of loco-regional and of distant recurrence, were assessed by body mass index (BMI), recorded after diagnosis, adjusting for other clinico-pathological and demographic factors by Cox regression. Results BMI was known for 98% (n=1049); 33% were overweight (BMI 25-29.9), 21% were obese (BMI 30-34.9), and 14% were very obese (BMI 35+). There were no significant associations between obesity and survival, after adjustment for demographic and clinical factors (hazard ratios, HR, for very obese compared to BMI 21-24, for breast cancer deaths 0.96 (0.56-1.67), and for all deaths 1.03 (0.63-1.67), respectively, and only small non-significant associations for loco-regional or metastatic recurrence rates (HR 1.17 and 1.33 respectively). Subgroup analyses by age, menopausal status, ethnicity, stage, post-surgical radiotherapy, mode of diagnosis, type of surgery, and receptor status, showed no associations. No associations were seen with BMI as a continuous variable. The results in all patients irrespective of treatment but with recorded BMI data (n=2296) showed similar results. Conclusions In this population, obesity assessed post-diagnosis had no effect on survival or recurrence, based on 1049 patients with chemotherapy treatment with follow-up up to 14 years.http://link.springer.com/article/10.1186/s12885-017-3971-4Breast cancerObesityBody-mass indexSurvivalRecurrence |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
J. Mark Elwood Sandar Tin Tin Marion Kuper-Hommel Ross Lawrenson Ian Campbell |
spellingShingle |
J. Mark Elwood Sandar Tin Tin Marion Kuper-Hommel Ross Lawrenson Ian Campbell Obesity and breast cancer outcomes in chemotherapy patients in New Zealand – a population-based cohort study BMC Cancer Breast cancer Obesity Body-mass index Survival Recurrence |
author_facet |
J. Mark Elwood Sandar Tin Tin Marion Kuper-Hommel Ross Lawrenson Ian Campbell |
author_sort |
J. Mark Elwood |
title |
Obesity and breast cancer outcomes in chemotherapy patients in New Zealand – a population-based cohort study |
title_short |
Obesity and breast cancer outcomes in chemotherapy patients in New Zealand – a population-based cohort study |
title_full |
Obesity and breast cancer outcomes in chemotherapy patients in New Zealand – a population-based cohort study |
title_fullStr |
Obesity and breast cancer outcomes in chemotherapy patients in New Zealand – a population-based cohort study |
title_full_unstemmed |
Obesity and breast cancer outcomes in chemotherapy patients in New Zealand – a population-based cohort study |
title_sort |
obesity and breast cancer outcomes in chemotherapy patients in new zealand – a population-based cohort study |
publisher |
BMC |
series |
BMC Cancer |
issn |
1471-2407 |
publishDate |
2018-01-01 |
description |
Abstract Background Obesity has been reported as an adverse prognostic factor in breast cancer, but inconsistently, and under-treatment with chemotherapy may occur. We provide the first assessment of obesity and breast cancer outcomes in a population-based, multi-ethnic cohort of New Zealand patients treated with chemotherapy. Methods All 3536 women diagnosed with invasive breast cancer in the Waikato region of New Zealand from 2000-2014 were registered and followed until last follow-up in specialist or primary care, death or Dec 2014; median follow-up 4.1 years. For the 1049 patients receiving chemotherapy, mortality from breast cancer, other causes, and all causes, and rates of loco-regional and of distant recurrence, were assessed by body mass index (BMI), recorded after diagnosis, adjusting for other clinico-pathological and demographic factors by Cox regression. Results BMI was known for 98% (n=1049); 33% were overweight (BMI 25-29.9), 21% were obese (BMI 30-34.9), and 14% were very obese (BMI 35+). There were no significant associations between obesity and survival, after adjustment for demographic and clinical factors (hazard ratios, HR, for very obese compared to BMI 21-24, for breast cancer deaths 0.96 (0.56-1.67), and for all deaths 1.03 (0.63-1.67), respectively, and only small non-significant associations for loco-regional or metastatic recurrence rates (HR 1.17 and 1.33 respectively). Subgroup analyses by age, menopausal status, ethnicity, stage, post-surgical radiotherapy, mode of diagnosis, type of surgery, and receptor status, showed no associations. No associations were seen with BMI as a continuous variable. The results in all patients irrespective of treatment but with recorded BMI data (n=2296) showed similar results. Conclusions In this population, obesity assessed post-diagnosis had no effect on survival or recurrence, based on 1049 patients with chemotherapy treatment with follow-up up to 14 years. |
topic |
Breast cancer Obesity Body-mass index Survival Recurrence |
url |
http://link.springer.com/article/10.1186/s12885-017-3971-4 |
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