A diagnosis of prostate cancer and pursuit of active surveillance is not followed by weight loss: potential for a teachable moment

A randomized controlled trial of a home-based exercise program on prognostic biomarkers in men with prostate cancer: A study protocol

Background

Herein, we propose a novel RCT study to collect preliminary data on the impact of a 24-week home-based exercise program that can improve prognosis, physical function, and quality of life (QoL) in men with prostate cancer (PCa). This study will provide data on the feasibility of conducting a home-based exercise study and pilot data on the impact of exercise on circulating concentrations of biomarkers reported in the literature to be beneficial for the prognostication of PCa.

Methods/design

Thirty male patients, clinically-diagnosed with prostate cancer under active surveillance, will be recruited to participate in a 2-arm, 24-week home-based program. Random allocation to each arm - intervention, and control – will be performed in a 1:1 ratio. Participants assigned to the intervention group will perform 30 min of light-to-moderate intensity walking five days a week (40–60% heart rate reserve) and three sets of 15 repetitions of light callisthenic exercises (bodyweight squats, incline push-ups, and hip thrusts) 3 days a week. Participants randomized to the control group will maintain normal activity throughout the 24 weeks. Four visits occurring at baseline, 12-, 18-, and 24-weeks will be used to assess QoL, body composition, prognostic biomarker concentrations, and overall physical function. Primary endpoints include significant changes in prognostic biomarkers. Secondary endpoints include changes in quality of life, physical function and body composition.

Discussion

This study should demonstrate preliminary evidence that a home-based exercise intervention can impact biomarkers of progression while improving quality of life, physical function and body composition. Results from this study have the potential to promote health and wellness while minimizing cancer progression in men with PCa.

mTOR inhibitors for treatment of low-risk prostate cancer

Prostate cancer incidence increases with age; along with many other cancers, it could be considered a disease of aging. Prostate cancer screening has led to a significant proportion of men diagnosed with low-grade, low-stage prostate cancer who are now more likely to choose an active surveillance strategy rather than definitive treatments. Definitive treatment, such as surgery and radiation therapy, is useful for high-grade disease; however, because of the low long-term risk of progression of a low-grade disease and side effects of surgery and radiation, these treatments are less commonly used for low-grade disease. While five alpha reductase inhibitors have been shown to reduce the risk of cancer detection on subsequent biopsies for men on active surveillance, no medications have been proven to prevent progression to high-grade disease. mTOR pathways have long been known to influence prostate cancer and are targets in various prostate cancer patient populations. Low-dose mTOR inhibition with rapamycin has shown promise in pre-clinical models of prostate cancer and appear to affect cellular senescence and immunomodulation in the aging population. We hypothesize that low-dose mTOR inhibition could reduce progression of low-grade prostate cancer patients, allowing them to remain on active surveillance.

Phase II prospective randomized trial of weight loss prior to radical prostatectomy

BACKGROUND

Obesity is associated with poorly differentiated and advanced prostate cancer and increased mortality. In preclinical models, caloric restriction delays prostate cancer progression and prolongs survival. We sought to determine if weight loss (WL) in men with prostate cancer prior to radical prostatectomy affects tumor apoptosis and proliferation, and if WL effects other metabolic biomarkers.

METHODS

In this Phase II prospective trial, overweight and obese men scheduled for radical prostatectomy were randomized to a 5–8 week WL program consisting of standard structured energy-restricted meal plans (1200–1500 Kcal/day) and physical activity or to a control group. The primary endpoint was apoptotic index in the radical prostatectomy malignant epithelium. Secondary endpoints were proliferation (Ki67) in the radical prostatectomy tissue, body weight, body mass index (BMI), waist to hip ratio, body composition, and serum PSA, insulin, triglyceride, cholesterol, testosterone, estradiol, leptin, adiponectin, interleukin 6, interleukin 8, insulin-like growth factor 1, and IGF binding protein 1.

RESULTS

Twenty-three patients were randomized to the WL intervention and twenty-one patients to the control group. Subjects in the intervention group had significantly more weight loss (WL:−3.7 ± 0.5 kg; Control:−1.6 ± 0.5 kg; p=0.007) than the control group and total fat mass was significantly reduced (WL:−2.1 ± 0.4; Control: 0.1 ± 0.3; p=0.015). There was no significant difference in apoptotic or proliferation index between the groups. Among the other biomarkers, triglyceride and insulin levels were significantly decreased in the WL compared to the control group.

CONCLUSIONS

In summary, this short-term WL program prior to radical prostatectomy resulted in significantly more WL in the intervention vs. the control group and was accompanied by significant reductions in body fat mass, circulating triglycerides, and insulin. However, no significant changes were observed in malignant epithelium apoptosis or proliferation. Future studies should consider a longer term or more intensive weight loss intervention.