A randomised clinical trial to improve healthy lifestyle adherence in prostate cancer patients undergoing radiotherapy (Microstyle study).

5105 Background: The standard non-surgical approach for localized Prostate Cancer (PCa) is radiotherapy (RT) but PCa patients may experience worsening of bowel disorders affecting quality of life and attributable to RT. The main aim of the study was to examine whether personalized dietary and physical activity counselling, provided at the start of RT, improves adherence to a healthy lifestyle, according to the standardised WCRF/AICR score 1 that assists clinicians in providing evidence-based recommendations to reduce risk of morbidity and improve quality of life in cancer patients. Methods: We designed a randomized controlled cross-over trial with two arms – MicroStyle 2 : an intervention (IG) and a control (CG) group, which were enrolled at the start of RT and followed for six months (T6) and 12 months (T12) respectively. Clinical data, questionnaires and circulating biomarkers were collected at two Italian Cancer Centres (Milan and Naples) on different time points. Linear regression models and logistic models were applied to estimate differences by arms in the WCRF/AICR score and its association with toxicity and circulating biomarkers. Results: Of the 308 patients enrolled, 299 completed the baseline evaluation, and 286 completed the six-month follow-up. The intervention showed at T6 a greater WCRF adherence compared to the CG: change from baseline 0.2 95%CI: 0.03, 0.36, p =0.02 IG vs CG) adjusting for baseline. The proportion of adherent subjects significantly increase at T6 with IG (26% vs 19%, P=0.04) and at T12 (28% vs 13%, P=0.01) more than CG. A high WCRF score at T6 was found to be associated with a significantly reduced rectal toxicity (P=0.03). IG at T12 was associated with lower Testosterone (P=0.04) and lower Estradiol (P=0.02) adjusting for hormonal therapy and baseline values. Patients with WCRF improvement were associated with lower IL6 and higher adiponectin Improvement of WCRF adherence is significantly associated with improvement in quality of life (P=0.04, IPSS) and prostate symptom (p=0.05, IPSS), sexual function (P=0.01, IIEF) and in particular erectile dysfunction (P=0.03, IIEF) and functional assessment of cancer therapy (P=0.01, FACT-P), adjusting for baseline values. Conclusions: This innovative trial showed that that a personalized dietary and physical activity counselling during RT significantly improves adherence to a healthy lifestyle, influencing rectal toxicity and circulating biomarkers. Future analyses will explore the toxicity associated with RT, changes in microbiome and its potential interactions with lifestyle factors. Funding: This study is funded by Italian Ministry of Health, Ricerca Finalizzata 2019 (RF-2019-12368771). ClincalTrial.gov registration number: NCT05155618. 1) https://epi.grants.cancer.gov/wcrf-aicr-score/details.html. 2) Gnagnarella, BMC Cancer (2022) doi s12885-022-09521-4 . Clinical trial information: NCT05155618 .