Dietary interventions for adult cancer survivors

Background International dietary recommendations include guidance on healthy eating and weight management for people who have survived cancer; however dietary interventions are not provided routinely for people living beyond cancer. Objectives To assess the effects of dietary interventions for adult cancer survivors on morbidity and mortality, changes in dietary behaviour, body composition, health‐related quality of life, and clinical measurements. Search methods We ran searches on 18 September 2019 and searched the Cochrane Central Register of Controlled trials (CENTRAL), in the Cochrane Library; MEDLINE via Ovid; Embase via Ovid; the Allied and Complementary Medicine Database (AMED); the Cumulative Index to Nursing and Allied Health Literature (CINAHL); and the Database of s of Reviews of Effects (DARE). We searched other resources including reference lists of retrieved articles, other reviews on the topic, the International Trials Registry for ongoing trials, metaRegister, Physicians Data Query, and appropriate websites for ongoing trials. We searched conference s and WorldCat for dissertations. Selection criteria We included randomised controlled trials (RCTs) that recruited people following a cancer diagnosis. The intervention was any dietary advice provided by any method including group sessions, telephone instruction, written materials, or a web‐based approach. We included comparisons that could be usual care or written information, and outcomes measured included overall survival, morbidities, secondary malignancies, dietary changes, anthropometry, quality of life (QoL), and biochemistry. Data collection and analysis We used standard Cochrane methodological procedures. Two people independently assessed titles and full‐text articles, extracted data, and assessed risk of bias. For analysis, we used a random‐effects statistical model for all meta‐analyses, and the GRADE approach to rate the certainty of evidence, considering limitations, indirectness, inconsistencies, imprecision, and bias. Main results We included 25 RCTs involving 7259 participants including 977 (13.5%) men and 6282 (86.5%) women. Mean age reported ranged from 52.6 to 71 years, and range of age of included participants was 23 to 85 years. The trials reported 27 comparisons and included participants who had survived breast cancer (17 trials), colorectal cancer (2 trials), gynaecological cancer (1 trial), and cancer at mixed sites (5 trials). For overall survival, dietary intervention