Current status of biomarker testing in historically rare, high-unmet-need tumors: soft tissue sarcomas and thyroid cancers

Introduction: The development of precision medicine and targeted therapies have revolutionized cancer treatment. Historically, treatment was chosen based on the tumor-histology, but can now be tailored to patient-specific biomarkers. Investigations have shown up to 40% of cancer patients who undergo molecular testing have an actionable biomarker with a drug currently available, and that patients benefit from these drugs. In 2018, larotrectinib became the first drug developed and approved exclusively as a tumor-agnostic therapy. Because of advancement in precision medicine, biomarker testing has become a standard of care in a variety of tumors and its use is increasing.Areas covered: We discuss the landscape of biomarker testing in the context of soft tissue sarcomas and thyroid cancer, two rare diseases with historically high unmet needs in their subpopulations. We summarize historical data and contemporary applications.Expert opinion: The paradigm shift in oncology treatment toward precision medicine, including tumor-agnostic agents, is experiencing substantial momentum but still facing challenges. A gap exists between guideline recommendations for biomarker testing and clinical application, resulting in compromised access and suboptimal outcomes. Future progress will require routine access to testing and expanding treatment options coupled with awareness, predictability, and strategies to address resistance mechanisms.