Guidelines endorsing vegetable-enriched diets to improve outcomes for prostate cancer survivors are based on expert opinion, preclinical studies, and observational data.
To determine the effect of a behavioral intervention that increased vegetable intake on cancer progression in men with early-stage prostate cancer.
The Men's Eating and Living (MEAL) Study (CALGB 70807 [Alliance]) was a randomized clinical trial conducted at 91 US urology and medical oncology clinics that enrolled 478 men aged 50 to 80 years with biopsy-proven prostate adenocarcinoma (International Society of Urological Pathology grade group = 1 in those <70 years and ≤2 in those ≥70 years), stage cT2a or less, and serum prostate-specific antigen (PSA) level less than 10 ng/mL. Enrollment occurred from January 2011 to August 2015; 24-month follow-up occurred from January 2013 to August 2017.
Patients were randomized to a counseling behavioral intervention by telephone promoting consumption of 7 or more daily vegetable servings (MEAL intervention; n = 237) or a control group, which received written information about diet and prostate cancer (n = 241).
The primary outcome was time to progression; progression was defined as PSA level of 10 ng/mL or greater, PSA doubling time of less than 3 years, or upgrading (defined as increase in tumor volume or grade) on follow-up prostate biopsy.
Among 478 patients randomized (mean [SD] age, 64  years; mean [SD] PSA level, 4.9 [2.1] ng/mL), 443 eligible patients (93%) were included in the primary analysis. There were 245 progression events (intervention: 124; control: 121). There were no significant differences in time to progression (unadjusted hazards ratio, 0.96 [95% CI, 0.75 to 1.24]; adjusted hazard ratio, 0.97 [95% CI, 0.76 to 1.25]). The 24-month Kaplan-Meier progression-free percentages were 43.5% [95% CI, 36.5% to 50.6%] and 41.4% [95% CI, 34.3% to 48.7%] for the intervention and control groups, respectively (difference, 2.1% [95% CI, -8.1% to 12.2%]).
Among men with early-stage prostate cancer managed with active surveillance, a behavioral intervention that increased 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.
ClinicalTrials.gov Identifier: NCT01238172.
JAMA. 2020 Jan 14 [Epub]
J Kellogg Parsons, David Zahrieh, James L Mohler, Electra Paskett, Donna E Hansel, Adam S Kibel, Heshan Liu, Drew K Seisler, Loki Natarajan, Martha White, Olwen Hahn, John Taylor, Sheri J Hartman, Sean P Stroup, Peter Van Veldhuizen, Lannis Hall, Eric J Small, Michael J Morris, John P Pierce, James Marshall
Department of Urology, UC San Diego Moores Comprehensive Cancer Center and VA San Diego Healthcare System, La Jolla, California., Alliance Statistics and Data Center, Mayo Clinic, Rochester, Minnesota., Department of Urology, Roswell Park Comprehensive Cancer Center, Buffalo, New York., Comprehensive Cancer Center, Department of Medicine, The Ohio State University College of Medicine, Columbus., Department of Pathology, University of California, San Diego, La Jolla., Division of Urology, Dana-Farber/Brigham and Women's Cancer Center, Harvard Medical School, Boston, Massachusetts., Division of Biostatistics and Bioinformatics, Department of Family Medicine and Public Health and UC San Diego Moores Comprehensive Cancer Center, La Jolla, California., Alliance Central Protocol Operations, University of Chicago, Chicago, Illinois., Moores Cancer Center, Department of Family Medicine and Public Health, University of California, San Diego, La Jolla., Department of Urology, Naval Medical Center San Diego, San Diego, California., Menorah Medical Center, Midwest Oncology Associates, Overland Park, Kansas., Siteman Cancer Center, Department of Radiation Oncology, Washington University, St Peters, Missouri., UCSF Helen Diller Family Comprehensive Cancer Center, San Francisco, California., Memorial Sloan Kettering Cancer Center, New York, New York., Department of Prevention and Population Sciences, Roswell Park Comprehensive Cancer Center, Buffalo, New York.