Physical activity, insulin-like growth factor 1, insulin-like growth factor binding protein 3, and survival from colorectal cancer
- 1Department of Epidemiology and Preventive Medicine, Monash Medical School, Alfred Hospital, Melbourne, Australia
- 2Cancer Epidemiology Centre, The Cancer Council Victoria, Melbourne, Australia, and School of Population Health Melbourne University, Melbourne, Australia
- 3Department of Epidemiology and Preventive Medicine, Monash Medical School, Alfred Hospital, Melbourne, Australia, and Cancer Epidemiology Centre, the Cancer Council Victoria, Melbourne, Australia, and School of Population Health Melbourne University, Melbourne, Australia
- 4Hanson Institute, Adelaide, Australia
- Correspondence to:
Dr A Haydon
Department of Epidemiology and Preventive Medicine, Monash Medical School, Alfred Hospital, Melbourne 3004, Australia;
- Accepted 25 October 2005
- Revised 13 October 2005
- Published Online First 18 November 2005
Background: Recent reports have shown that physical activity improves the outcome of patients with colorectal cancer as well as breast and prostate cancer. However, the mechanisms whereby physical activity reduces cancer mortality are not well established.
Methods: Incident cases of colorectal cancer were identified among participants of the Melbourne Collaborative Cohort Study, a prospective cohort study of 41 528 Australians recruited from 1990 to 1994. Information on tumour site and stage, treatments given, recurrences, and deaths were obtained from systematic review of the medical records. Baseline assessments of physical activity and body size were made, and cases with available plasma had pre-diagnosis insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 3 (IGFBP-3) levels measured. We assessed associations between these hormones and colorectal cancer specific deaths with respect to physical activity.
Results: A total of 526 cases of colorectal cancer were identified, of which 443 had IGF-1/IGFBP-3 levels measured. Median follow up among survivors was 5.6 years. For the physically active, increasing IGFBP-3 by 26.2 nmol/l was associated with a 48% reduction in colorectal cancer specific deaths (adjusted hazard ratio (HR) 0.52 (0.33–0.83); p = 0.006). No association was seen for IGF-1 (adjusted HR 0.90 (0.55–1.45); p = 0.65). For the physically inactive, neither IGF-1 nor IGFBP-3 was associated with disease specific survival.
Conclusions: This study supports the hypothesis that the beneficial effects of physical activity in reducing colorectal cancer mortality may occur through interactions with the insulin-like growth factor axis and in particular IGFBP-3.
- CRC, colorectal cancer
- BMI, body mass index
- AJCC, American Joint Committee on Cancer
- IGF-1, insulin-like growth factor 1
- IGFBP-3, insulin-like growth factor binding protein 3
- MCCS, Melbourne Collaborative Cohort Study
- ELISA, enzyme linked immunosorbent assay
- ICC, intraclass correlation
- colorectal cancer
- physical activity
- insulin-like growth factor 1
- insulin-like growth factor binding protein 3
Cohort recruitment was funded by VicHealth and the Cancer Council Victoria. This study was funded by a grant from the National Health and Medical Research Council (209057) and was further supported by infrastructure provided by the Cancer Council Victoria.
Conflict of interest: None declared.