Use of Complementary and Alternative Medicine in Cancer and Its Impact on Survival: A Systematic Review

Abstract

The use of complementary and alternative medicines (CAMs) among cancer patients has increased steadily over the years in response to the search for a more comprehensive method for the relief and care of these patients. The incorporation of traditional Chinese medicines (TCM), herbs, and naturopathic medicines within the field of oncology still has an unclear effect on the survival rate. This systematic review integrates available evidence from empirical studies exploring the interface between the usage of CAM and survival benefits in relation to overall survival (OS), progression-free survival (PFS), or quality of life (QOL) in patients with cancer. In this study, eleven peer-reviewed articles, which include randomized controlled trials, cohorts, and case series, were analyzed according to the PRISMA 2020 guidelines. Data were extracted from the PubMed, Scopus, Web of Science, and Embase database, ranging from 2000-2025. They were assessed for their quality using the RoB 2, which is the Cochrane RoB. The results showed variable findings. Studies like Johnson et al. (2018) and others, such as Ma et al. (2011), indicated a poorer outcome in patients substituting CAM for Western medication, owing largely to drug refusal. Meanwhile, the outcome showed improved OS and PFS for combined CAM strategies, starting from 30% up to 70%, as seen in studies conducted by Li et al. (2019), Xu et al. (2021), and Zhao et al. (2024). The quality of life, as well as decreased toxicity, was likewise documented. CAM, when used adjunctively, may enhance survival and well-being; however, substitution for standard care is associated with reduced survival. Integrative, patient-centered oncology models emphasizing safe, evidence-informed CAM use are recommended.