Effect Of Exercise Intervention On Insulin, Igfs And Igfbps In Cancer Patients

Abstract

PURPOSE: Increased level of insulin and insulin like growth factor (IGF) have not only been associated with increased risk of different cancers but also with poor prognosis after cancer diagnosis. Aerobic exercise training lowers the levels of insulin and IGF in healthy people. Research looking at the effects of different exercise interventions on insulin, IGF and Insulin Growth Factor Binding Protein (IGFBP) is newly emerging. The purpose of this study is to systematically review the effects of exercise on insulin, IGF and IGFBPs in cancer patients. METHODS: An electronic literature search was conducted using PubMed database up to July 2019, with search terms: cancer, exercise, insulin-like growth factor, IGF, and IGFBP. Eligible studies included peer-reviewed, randomized clinical trials (RCTs) that utilized either exercise or physical activity as their intervention for cancer survivors. All study design, participant characteristics, intervention, IGF related outcomes, and key findings were evaluated systematically and summarized. RESULTS: Eight articles were deemed eligible for the systematic review. Cancer types included breast cancer, colorectal cancer, prostate cancer, non-small cell lung cancer, and endometrial cancer. Mean age of the sample population included in our study was 60.3± 6.9 years (n, intervention group= 184; n, control group= 160). Mode of exercise consisted of either aerobic, strength training, combination of aerobic and strength training, endurance exercise, or Tai chi. All but one study showed that exercise resulted in significant reduction or no change in circulating levels of IGF-1 and IGF-2. Results were inconsistent with exercise on IGFBP-3 levels. CONCLUSIONS: The literature is inconsistent of the impact of exercise to lower IGF levels and that could be because of the different duration and type of exercise intervention in different studies. Because of the inconsistency, meta-analysis could not be performed. Large randomized control trials with different exercise interventions are required in this area to reach a firm conclusion. A greater understanding of the impact of exercise and dosing of exercise can empower physical therapists to play a greater role in cancer survivorship programming.