Long-Term Dietary Changes and Mortality among Participants of a Whole Food Plant-Based Pilot Study for Metastatic...

There are limited data on dietary interventions among women with metastatic breast cancer. We previously conducted a feasibility trial of a whole food, plant-based (WFPB) diet in 32 women with metastatic breast cancer randomly divided 2:1 to WFPB (n = 21) or control (n = 11). The 8-wk intervention provided meals and weekly visits and resulted in beneficial changes but was not designed to support long-term behavior change.

Given impressive short-term benefits, we wanted to know whether any dietary changes persisted even in the absence of support.

We attempted to contact and re-consent survivors for a descriptive follow-up consisting of a 3-d food diary and quality-of-life questionnaires; medical records were reviewed to ascertain survival status. Two participants (1 control, 1 intervention) were withdrawn shortly after randomization in the pilot and were not included in this follow-up.

Overall, 2 of 20 (10%) participants originally assigned to the intervention and 5 of 10 (50%) assigned to control had died by the time of chart review. Among surviving participants, 11 of 18 intervention and 2 of 5 control participants completed the follow-up assessment, which occurred, on average, 5 y after their last study visit. Among intervention participants who completed dietary follow-up, mean energy intake remained lower. Although the intake of most food groups returned toward baseline, intake of refined grains and added fats remained lower at follow-up.

In this small, exploratory, long-term follow-up, research participants maintained selective dietary changes 5 y after completing an 8-wk intervention. Although mortality differences require cautious interpretation, these descriptive findings suggest that longer, adequately powered studies are warranted.This trial was registered at clinicaltrials.gov as NCT03045289 on 7 February 2017.