Johnson SB, et al. - In patients with cancer receiving conventional cancer treatment (CCT) with or without complementary medicine (CM), researchers compared overall survival and adherence to treatment and the characteristics of these patients. Refusal of additional CCT and a higher risk of death were more likely to be seen in patients who received CM. Also, the refusal of CCT was suggested to be the mediator of mortality risk associated with CM.

Methods

• In this retrospective observational study, researchers used data from the National Cancer Database on 1,901,815 patients from 1,500 Commission on Cancer–accredited centers across the United States who were diagnosed with nonmetastatic breast, prostate, lung, or colorectal cancer between January 1, 2004 and December 31, 2013.
• They matched patients on age, clinical group stage, Charlson-Deyo comorbidity score, insurance type, race/ethnicity, year of diagnosis, and cancer type.
• They carried out statistical analysis from November 8, 2017 to April 9, 2018.
• Use of CM was defined as “Other-Unproven: Cancer treatments administered by nonmedical personnel” in addition to at least 1 CCT modality, defined as surgery, radiotherapy, chemotherapy, and/or hormone therapy,
• Main outcomes and measures included overall survival, adherence to treatment, and patient characteristics.

Results

• A total of 1,901,815 patients with cancer were included (258 patients in the CM group and 1,901,557 patients in the control group).
• In the main analyses following matching, the CM group had 258 patients (199 women and 59 men; mean age, 56 years [interquartile range, 48-64 years]), and the control group had 1,032 patients (798 women and 234 men; mean age, 56 years [interquartile range, 48-64 years]).
• There was not a longer delay to initiation of CCT among patients who chose CM, but they had higher rates of surgery refusal (7.0% [18 of 258] vs 0.1% [1 of 1031]; P < .001), chemotherapy (34.1% [88 of 258] vs 3.2% [33 of 1032]; P < .001), radiotherapy (53.0% [106 of 200] vs 2.3% [16 of 711]; P < .001), and hormone therapy (33.7% [87 of 258] vs 2.8% [29 of 1032]; P < .001) in these subjects.
• In a multivariate model that did not include treatment delay or refusal, use of CM vs no CM was related to poorer 5-year overall survival (82.2% [95% CI, 76.0%-87.0%] vs 86.6% [95% CI, 84.0%-88.9%]; P=.001) and was independently related to greater risk of death (hazard ratio, 2.08; 95% CI, 1.50-2.90).
• However, once treatment delay or refusal was included in the model, no significant link was observed between CM and survival (hazard ratio, 1.39; 95% CI, 0.83-2.33).