Effect of a Behavioral Intervention to Increase Vegetable Consumption on Cancer Progression Among Men With Early-Stage Prostate Cancer: The MEAL Randomized Clinical Trial | Lifestyle Behaviors | JAMA | JAMA Network
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Original Investigation
January 14, 2020

Effect of a Behavioral Intervention to Increase Vegetable Consumption on Cancer Progression Among Men With Early-Stage Prostate Cancer: The MEAL Randomized Clinical Trial

Author Affiliations
  • 1Department of Urology, UC San Diego Moores Comprehensive Cancer Center and VA San Diego Healthcare System, La Jolla, California
  • 2Alliance Statistics and Data Center, Mayo Clinic, Rochester, Minnesota
  • 3Department of Urology, Roswell Park Comprehensive Cancer Center, Buffalo, New York
  • 4Comprehensive Cancer Center, Department of Medicine, The Ohio State University College of Medicine, Columbus
  • 5Department of Pathology, University of California, San Diego, La Jolla
  • 6Division of Urology, Dana-Farber/Brigham and Women’s Cancer Center, Harvard Medical School, Boston, Massachusetts
  • 7Division of Biostatistics and Bioinformatics, Department of Family Medicine and Public Health and UC San Diego Moores Comprehensive Cancer Center, La Jolla, California
  • 8Alliance Central Protocol Operations, University of Chicago, Chicago, Illinois
  • 9Moores Cancer Center, Department of Family Medicine and Public Health, University of California, San Diego, La Jolla
  • 10Department of Urology, Naval Medical Center San Diego, San Diego, California
  • 11Menorah Medical Center, Midwest Oncology Associates, Overland Park, Kansas
  • 12Siteman Cancer Center, Department of Radiation Oncology, Washington University, St Peters, Missouri
  • 13UCSF Helen Diller Family Comprehensive Cancer Center, San Francisco, California
  • 14Memorial Sloan Kettering Cancer Center, New York, New York
  • 15Department of Prevention and Population Sciences, Roswell Park Comprehensive Cancer Center, Buffalo, New York
JAMA. 2020;323(2):140-148. doi:10.1001/jama.2019.20207
Visual Abstract. Effect of a Behavioral Intervention to Increase Vegetable Consumption on Cancer Progression Among Men With Early-Stage Prostate Cancer
Effect of a Behavioral Intervention to Increase Vegetable Consumption on Cancer Progression Among Men With Early-Stage Prostate Cancer
Key Points

Question  Does a behavioral intervention promoting vegetable consumption decrease cancer progression in men with early-stage prostate cancer on active surveillance?

Findings  In this randomized clinical trial that included 478 patients, there was no significant difference in prostate cancer progression over 2 years among men who participated in a counseling program that encouraged consumption of leafy green, carotenoid, and cruciferous vegetables compared with controls (hazard ratio, 0.96).

Meaning  A behavioral intervention that increased vegetable consumption did not significantly reduce the risk of prostate cancer progression among men with early-stage disease.


Importance  Guidelines endorsing vegetable-enriched diets to improve outcomes for prostate cancer survivors are based on expert opinion, preclinical studies, and observational data.

Objective  To determine the effect of a behavioral intervention that increased vegetable intake on cancer progression in men with early-stage prostate cancer.

Design, Setting, and Participants  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.

Interventions  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).

Main Outcomes and Measures  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.

Results  Among 478 patients randomized (mean [SD] age, 64 [7] 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%]).

Conclusions and Relevance  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.

Trial Registration  ClinicalTrials.gov Identifier: NCT01238172