Patterns of Biomarker Use in Cancer Treatment Among Medical Oncologists in the Philippines

Several factors affect how medical oncologists in the Philippines use biomarkers in real-world practice. This study describes patterns of biomarker testing for the management of breast, colorectal, and lung cancers among medical oncologists in the Philippines.

A cross-sectional survey was performed among practicing medical oncologists in the Philippines from November to December 2019. The questionnaire determined the ideal and practical use of biomarkers as perceived by the respondents. Responses were summarized. Associations between biomarker use across select conditions were determined.

A total of 127 respondents (38% of medical oncologists in the Philippines) participated in this study. In actual practice, 97% of the respondents requested estrogen receptor/progesterone receptor testing, and 93% requested human epidermal growth factor receptor 2 testing. For colorectal cancer, the respondents would use KRAS and mismatch repair/microsatellite instability, but 59.84% had never used BRAF. For lung cancer, 97.64% of respondents would test for epidermal growth factor receptor (EGFR), 88.19% would test for PD-L1, 80.31% for anaplastic lymphoma kinase, 58.27% for ROS1, and 33.07% for BRAF. In actual practice, EGFR was the most frequently ordered test (67.72%), while 44.80% of medical oncologists had never used ROS1. The most common reason for testing was adherence to international guidelines (96%). The most commonly cited barrier to biomarker use was patients' financial constraints (94.49%). Overall, the respondents' use of biomarkers was not significantly associated with institutional affiliation, the number of patients they saw monthly, and the availability of biomarker tests in their areas of practice.

Medical oncologists in the Philippines would use biomarkers in treating breast, colorectal, and lung cancers if these were clinically indicated and if cost were not a factor. Financial difficulty experienced by patients was the most commonly cited barrier to biomarker use.