There have been an increasing number of patients diagnosed with cancer each year. Certain malignancies have been a major cause of death in some populations. People who have been diagnosed with cancer want to do everything they can to combat the disease, manage its symptoms and cope with the side effects of radio/chemotherapy. Many turn to complementary and alternative medicine. G. lucidum extract is a medication that has been widely used by traditional Chinese medicine (TCM) practitioners for this regard. It is usually recommended as an immune system support supplement in cancer treatment. Latest laboratory research and preclinical trials of G. lucidum have shown promising results of its antitumour activity. However, clinical evidence of its efficacy is sparse and a systematic review is in need to provide collective information for health-care consumers.
Our review identified and subsequently included five relevant randomised controlled trials. A total of 373 subjects were analysed. A meta-analysis was performed to pool available data from individual trials. Our results found that patients with G. lucidum extract in their anticancer regimen were 1.27 times more likely to respond to chemotherapy or radiotherapy than those without. However, the data failed to demonstrate significant effect on tumour shrinkage when it was used alone. In addition, G. lucidum could stimulate host immune functions by considerably increasing CD3, CD4 and CD8 lymphocyte percentages. Nevertheless, natural killer (NK)-cell activity, which has been suggested to be an indicator of self-defence against tumour cell, was marginally elevated. Patients in the G. lucidum group were found to have a relatively better quality of life after treatment than those in the control group. A few cases of minor side effect associated with G. lucidum treatment including nausea and insomnia were reported.
There are limitations of the results from this systematic review. First, most included studies were small and there were concerns on the methodological quality of individual trials. Second, all participants in the individual trials were recruited from the Chinese population. Together, the robustness and applicability of the results were largely affected.