N61: Physical Activity And The Risk Of Colorectal Cancer In Lynch Syndrome

S. Ghazaleh Dashti1, A. K. Win1, 2, S. S. Hardikar3, S. Glombicki4, S. Mallenahalli4, S. Thirumurthi4, S. K. Peterson5, Y. N. You6, D. D. Buchanan1, 2, 7, J. C. Figueiredo8, 9, P. T. Campbell10, S. Gallinger11, P. A. Newcomb3, 12, J. D. Potter3, N. M. Lindor13, L. Le Marchand14, R. W. Haile15, J. L. Hopper1, M. A. Jenkins1, K. M. Basen-Engquist5, P. M. Lynch4, M. Pande4

1 – Center for Epidemiology and Biostatistics, The University of Melbourne School of Population and Global Health. 2 – Genetic Medicine and Family Cancer Clinic, The Royal Melbourne Hospital. 3 – Division of Public Health Sciences, Fred Hutchinson Cancer Research Center. 4 – Department of Gastroenterology, Hepatology and Nutrition, The University of Texas MD Anderson Cancer Center. 5 – Department of Behavioral Science, The University of Texas MD Anderson Cancer Center. 6 – Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center. 7 – Colorectal Oncogenomics Group, Genetic Epidemiology Laboratory, Department of Pathology, The University of Melbourne. 8 – Keck School of Medicine, Norris Comprehensive Cancer Center, The University of Southern California. 9 – Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center. 10 – Epidemiology Research Program, American Cancer Society. 11 – Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Department of Molecular Genetics, University of Toronto. 12 – School of Public Health, University of Washington, Seattle. 13 – Department of Health Sciences Research, Mayo Clinic. 14 – Cancer Epidemiology Program, The University of Hawaii Cancer Center. 15 – Cedars Sinai Health System.

 

Aim: The association between physical activity and colorectal cancer risk for DNA mismatch repair (MMR) gene mutation carriers is not well understood. We investigated this relationship in a cohort of 2,042 MMR gene mutation carriers (807 diagnosed with colorectal cancer) from the Colon Cancer Family Registry.

Method: Physical activity was self-reported in three age periods (20-29, 30-49, and ≥50 years). This information was used to calculate the average metabolic equivalent of task hours per week (MET-h/week) during the age-period of cancer diagnosis or censoring (near-term exposure), and across all age-periods preceding cancer diagnosis or censoring (long-term exposure). Hazard ratio (HR) and 95% confidence intervals (CI) for the association were estimated using a weighted Cox regression approach.

Results: A small reduction in colorectal cancer risk was observed in relation to the near-term physical activity (HR ≥35 vs. <3.5 MET-h/week, 0.71; 95% CI, 0.53 – 0.96). For long-term physical activity, the strength of direction of the association was similar, but the association was not nominally significant.

Conclusion: Our results suggest that physical activity may reduce colorectal cancer risk in MMR gene mutation carriers. If replicated, this information could be useful for risk prediction and counselling advice for lifestyle modification in this high-risk population.

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