Response to "Characteristic Analysis of Complementary and Alternative Medicine in Randomized Controlled Trials of Oncology: A Comparison of Published Studies".

Our team issued a study in 2018 providing a descriptive analysis of complementary and alternative medicine (CAM) randomized controlled trials (RCTs) in clinical oncology.[1] A total of 59 RCTs were involved, and we found that few CAM RCTs of oncology were published in higher impact journals in the most recent 10 years while the average number of citations of CAM RCTs was quite low. However, the study only focused on CAM RCTs and failed to give reasons for the few publications and citations. Based on this study, we made another analysis of CAM clinical studies of oncology, including retrospective and prospective studies.

The present analysis aimed to examine the characteristics of published studies in a sample of recently published CAM clinical studies of oncology in leading journals of 3 categories: general and internal medicine, clinical oncology, and CAM, and tried to find some reasons for the few publications and citations of CAM clinical studies.

Clinical studies published in the top 5 journals of the 3 categories from 2007 to 2016 were searched in PubMed. Detailed characteristics were identified and extracted from the included studies. Data were summarized by frequency, mean and median, and compared using χ2 test and Kruskal-Wallis H test.

Of the 34 181 articles retrieved from 2007 to 2016, a total of 94 CAM clinical studies of oncology were included in the analysis. Breast cancer was the most common cancer type to be studied (45.7%). For the type of study, RCTs accounted for the highest percentage (67.0%). For the type of the result, positive results took the highest percentage (83.0%). The mean sample size of the studies included was 334 while about three-fifths of the studies (59.6%) included were found with explicit calculation of sample size; the rate of calculation of sample size of articles in CAM journals was only 32.7%. For the type of study center, 45.7%, 53.2%, and 1.1% of the studies included were multicenter studies, single-center studies, and published in the name of a study group, respectively. Only 68 (72.3%) of the studies included were conducted by randomized grouping, meanwhile, a control group was set in 77 (81.9%) studies. The major type of blinding method in the involved trials was open (80.9%), followed by double-blind (14.9%) and single-blind (4.3%). Follow-up work was just done in 72 (76.6%) studies included, while safety evaluation was completed in just 71 (75.5%) of the studies included.

To better understand the reasons for few publications and citations of CAM clinical studies in oncology, we analyzed the above-mentioned factors of CAM clinical studies of oncology. Generally speaking, the factors we analyzed in this study such as sample size calculation and follow-up work were regarded as key for a standard and well-designed clinical study. For the results of the analysis, we found some faults with the factors of the design, and the relatively nonstandard design may explain at least some of the reasons for the few publications and citations. We hope that the above-mentioned analysis can provide some clarity to improve the design and quality of CAM clinical studies of oncology.