The MEAL Randomized Clinical Trial
By Natasha Crumby
Creating an environment of behavioral change can make an impact on the overall health of a patient. However, can a behavioral intervention to increase vegetable consumption really make an impact on the progression of prostate cancer? Well, this is a question investigated by the UC San Diego Moores Comprehensive Cancer Center research team lead by Dr. J. Kellogg Parson. Clinical guidelines circulated endorse a diet high in micronutrient- enriched vegetables by using different expert opinions and small preclinical experiments. Many of the recommendations published proposed vegetable intake has a direct correlation with decreased cancer progress ion and even death.
In early stage prostate cancer patients may choose to withhold from immediate treatment with radiation or surgical interventions and instead decide to monitor the prostate specific antigen (PSA). This a choice option for patients but according to the Journal of Clinical Oncology, at least 30% of active surveillance patients will progress or undergo definitive treatment within 2 years of follow-up. With the progression being at 30%, the UC San Diego Moores Comprehensive Cancer Center researchers decided to implement The Men’s Eating and Living (MEAL) Study (CALGB 70807 [Alliance]) intervention as a Phase 3 clinical trial.
The study was conducted from January 2011 to August 2015. Eligible patients were 50-80 years old and diagnosed with stage cT2a or less prostate adenocarcinoma which was determined by a biopsy. Patients were recruited from urology and medical oncology clinics. Patients who were deemed eligible were randomized to one of the two groups (telephone-based counseling intervention or control condition). Control patients received diet educational publication on diet instead of counseling.
A total of 443 participants were randomized at 91 study sites: 226 were in the intervention (counseling group) while 217 were in the control group. The intervention for patients randomized for counseling received encouragement to consume at least 7 daily fruit and vegetable servings. This was defined as half-cup of raw or cooked vegetables or fruits or 100% vegetable juice. For the counseling randomized group there were multiple phone calls providing feedback and monitoring.
In conclusion, a final biopsy was conducted to sample the tumor for comparison. The biopsy methodology was consistent with standard of care. Also, additional diet composition data was retrieved o compare the influence of vegetables. Ultimately, the study was able to determine among men with early-stage prostate cancer managed through surveillance, of a behavioral intervention to increase vegetable consumption did not significantly reduce the risk of prostate cancer progression. The findings do not support use of this intervention to decrease prostate cancer progression in this population, although the study may have been underpowered to identify a clinically important difference (J. Kellogg Parsons, 2020)