Approximately a fifth of patients participating in phase III breast, lung, or colorectal cancer clinical trials conducted by the Canadian Cancer Trials Group (CCTG)also used complementary medicines (CMs). The use of CMs was associated with improved survival in patients with lung cancer, although patient baseline characteristics were more favourable in these cohorts. These findings were presented at the ESMO Congress 2019 in Barcelona, Spain.
Lead author John C. Wells, Internal Medicine, Queen's University, Kingston, Canada noted that CMs are often used concurrently with conventional medical treatment by patients with cancer, but the extent of their use by patients in phase III studies and patient’s outcomes have not yet been determined.
This analysis examined patient characteristics and outcomes of CM users enrolled in phase III clinical trials conducted by CCTG. This analysis included data from 3446 patients being treated for metastatic breast (17.7%), colorectal (44.4%), and non-small-cell lung cancers participating in six international phase III trials (MA.31 - NCT00667251; CO.17 - NCT00079066, CO.20 - NCT00640471, CO.23 - NCT01830621; BR.21- NCT00036647, BR.26- NCT01000025, respectively).
All medications used were independently reviewed by two of the authors to identify CM; any discrepancies were reviewed by a third author and the final list was approved by consensus. Chi-square and logistic regression were used to determine patient characteristics associated with CM use. Propensity score stratification was conducted to compare between CM users and non-users for overall survival (OS), grade ≥3 adverse events (AEs), and quality of life (QoL) scales (EORTC-QLQ-C30).
The investigators identified 651 (2.6%) medications that were considered as CM out of the 24908 medications used by the patients. In this study, CMs were defined as natural products and homeopathy.
Overall, CMs were used by 20.4% of patients. The CM use was associated with fewer AEs (p = 0.02, 61.5% versus 50.0%). The CM use also associated with worse subjective QoL ratings by patients for pain, constipation, and role. However, CM use did not affect time to global deterioration of QoL, hazard ratio (HR) 1.07; 95% confidence interval (CI) 0.94-1.21 (p = 0.22).
An analysis per cancer type revealed that CM use by patients with lung cancer was associated with ECOG performance status (PS) of 0-1 versus ≥2, weight loss <5%, non-smoker status, and Eastern Asian ethnicity (all p < 0.05).
In colorectal cancers, CM use was associated with age less than 65 years, PS 0-1 versus ≥2, fewer sites of metastases, and normal haemoglobin.
In patients with breast cancer, the use of CM associated only with age <50 years.
The OS in lung cancer favoured CM use, HR 0.80, 95% CI, 0.68-0.94 (p = 0.005). The hazard ratios for OS in colorectal and breast cancer were HR 0.87; 95% CI 0.75-1.02 (p = 0.08) and 0.85; 95%CI, 0.61-1.19 (p = 0.35), respectively.
The use of CM is relatively high amongst patients enrolled in phase III lung, breast, and colorectal cancer trials. The CM use tends to be highest in patients who are younger and those with better PS. CM users reported worse QoL, although time to deterioration and the incidence of AEs did not associate with CM use.
The HRs for OS in the lung cancer trials favoured CM users. However, the authors advise that this should be interpreted with caution given the retrospective/post-hoc nature of this study and the more favourable baseline characteristics of these patients.
No external funding was disclosed.
1758PD – Wells JC, Sidhu A, Ding K, et al. Complementary Medicine (CM) Use in Phase III Clinical Trials (P3T) Conducted by the Canadian Cancer Trials Group (CCTG).