Vegetables fail to slow Prostate Cancer (2019 study - Parsons et al)

[James Morris-Lent]

Saw this reported in my local paper. Vegetables treating existing cancer struck me as pretty silly magical medical thinking but, hey, they put it to the test.

No need for anyone to think about this one too hard

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Effect of a Behavioral Intervention to Increase Vegetable Consumption on Cancer Progression Among Men With Early-Stage Prostate Cancer

The MEAL Randomized Clinical Trial
( )

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

sci-hub:
https://sci-hub.tw/https://jamanetwork.com/journals/jama/article-abstract/2758598
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Did patients in the intervention group actually eat more vegetables? Apparently (?)

At 12-month follow-up, intervention participants(n = 208) reported significant increases compared with con-trols (n = 199) in daily total vegetable servings (mean change,2.43 [95% CI, 2.17 to 2.69] vs 0.45 [95% CI, 0.19 to 0.70];P< .001)...

Plasma carotenoids, measured at 12-month follow-up in a sample of participants as a biomarker of vegetable intake,validated the self-reported dietary data. There were no sig-nificant baseline differences in mean levels of the log-transformed carotenoid values between groups: 0.41 log-μmol/L (95% CI, 0.34-0.47) in the intervention group(n = 152) vs 0.40 log-μmol/L (95% CI, 0.34-0.47) in the con-trol group (n = 142). At 12 months, the mean levels of the log-transformed carotenoid values between groups were 0.64(95% CI, 0.56-0.72) in the intervention group vs 0.52 (95% CI,0.45-0.60) in the control group, with a significant between-group difference in baseline to 12-month changes (interven-tion vs control difference in mean change scores, 0.1 [95% CI,0.02-0.18];P= .01)

 

[rvallee]

Button soup medicine. What is even the role of the "cognitive intervention" here? It's entirely superfluous.

At least we know "cognitive intervention", whatever it is, may increase vegetable consumption in people told increased vegetable consumption may improve their odds of survival from prostate cancer. Then again, maybe just having someone constantly nag them and saying "come oooooon, eat your veggies" works just as well. Actually, it probably would.

I am constantly amazed at how badly research funding is managed. This is not responsible use of limited resources and explains a lot about why medical research delivers so little for the money it consumes.

 

[Jonathan Edwards]

I did eat my greens, miss. (Oh, and I ate a ton of carrots before that blood test to make sure it looked OK.)

Since when did 'Hey, eat more greens' become a behavioural intervention that increased vegetable intake?

 

[Kitty]

Dunno, but can somebody tell me how to get a few hundred grand to test whether celery sticks dipped in mayonnaise or liquorice sticks dipped in rainbow kali work best for low back pain? It affects millions of people, and we need to find some solutions.

 

[Mithriel]

I think being told it would stop the progression of your cancer over the telephone every day might help you eat more! Though feeling rotten and ill makes it hard to get and prepare vegetables. I would eat lots more vegetables if they did not have to be peeled and cooked. Ready prepared stuff can taste horrible and salads don't keep well.

Maybe this is good research debunking a myth. Friends with MS are doing a (commercial) program which says you have to eat a plant based diet with no oils. They are finding it hard and I can see no justification for it. In fact the diet for MS used to be to include oils and walnuts to strengthen cell membranes.

 

[James Morris-Lent]

Since when did 'Hey, eat more greens' become a behavioural intervention that increased vegetable intake?

Right about when telling people to floss every day caused people to floss every day.

 

[Midnattsol]

I'd rather see a study on cancer in the gastrointestinal tract, where it is possible to get high enough concentrations of some of the anti-cancer or anti-inflammatory or other beneficial compound from the veggies*. It can't necessarily be absorbed and get to the cancer cells in the amount that's needed.

*I only remember this of quercetin and ulcerativ colitis, don't know about other compounds and what concentrations one can achieve in the gut from diet.

 

[Snow Leopard]

Guess we'll have to add this to the short list of "Vegetables, what can't they do?"

 

[Milo]

Cancer doesn’t care whether you eat fruits, veggies, meat, fat, french fries, Paleo, raw, vegan, nothing at all (fasting), donuts, and everything in between. Cancer cells have been programmed to take nutrition from healthy cells.