The Auxiliary Effects of Low-Molecular-Weight Fucoidan in Locally Advanced Rectal Cancer Patients Receiving Neoadjuvant Concurrent Chemoradiotherapy Before Surgery: A Double-Blind, Randomized, Placebo-Controlled Study.

Patients with cancer use low-molecular-weight fucoidan (LMF) as a supplement to therapy. However, most studies of LMF are in vitro or conducted using animals. Concurrent chemoradiotherapy (CCRT) is the gold standard for locally advanced rectal cancer (LARC). This study investigated the quality of life (QoL) and clinical outcomes of patients with LARC taking LMF as a supplement to neoadjuvant CCRT. This was a double-blind, randomized, placebo-controlled study. The sample comprised 87 patients, of whom 44 were included in a fucoidan group and 43 were included in a placebo group. We compared their QoL scores and clinical outcomes before treatment, and at 1 month, 2 months, and 3 months posttreatment. Pretreatment and posttreatment gut microbiota differences were also compared. Although enhanced physical well-being (PWB) at 2 months and 3 months posttreatment in the fucoidan group were observed (both P  < .0125), the improvements of the Functional Assessment of Cancer Therapy for Patients with Colorectal Cancer (FACT-C) were nonsignificant (all P  > .0125). Skin rash and itching and fatigue were less common in the fucoidan group (both P  < .05). Posttreatment, the genus Parabacteroides was significantly more common in the gut microbiota of the fucoidan group. LMF administration improved the QoL, skin rash and itching, fatigue, and gut microbiota composition of the patients with LARC receiving CCRT. Clinical Trial Registration: NCT04342949.