ASCO20: Update on RAS-Mutated Sporadic Medullary Thyroid Cancer
Posted: Monday, June 29, 2020
According to the experience of a tertiary cancer center, presented during the ASCO20 Virtual Scientific Program (Abstract 6584), patients with RAS-mutated sporadic medullary thyroid cancer are at intermediate risk for aggressive disease, an observation in line with previous studies. Spandana Brown, MD, of Houston Methodist Hospital, and colleagues reported a 10-year overall survival rate of 73% in this patient population, with worse rates in those with HRAS and KRAS mutations other than HRAS Q61R.
“Future research comparing outcomes between various RAS mutations and in comparison to RET-positive and RAS-negative/RET-negative patients is needed, especially as systemic therapy use in RAS-mutated sporadic medullary thyroid cancer evolves,” the authors concluded.
In this retrospective trial, the authors focused on 218 patients with sporadic medullary thyroid cancer, with 42 exhibiting RAS mutations. Of the patients with RAS mutations, 26 had stage IV disease at the time of diagnosis, 14 also had KRAS mutations, and 28 also had HRAS mutations (HRAS Q61R in 19 patients).
The median overall survival for all patients was 16.2 years, with 5- and 10-year overall survival rates of 88% and 73%, respectively. For the 20 patients who received systemic therapy, 79% exhibited stage IV disease and skewed older, with a median age of 54. The median time from diagnosis to the initiation of systemic therapy was 33 months.
The authors identified several factors associated with worse overall survival, including distant metastases at diagnosis, shorter time intervals between diagnosis and treatment, and calcitonin and carcinoembryonic antigen doubling times of less than 6 months. Patients with HRAS Q61R mutations had a 10-year overall survival rate of 100%, and a better prognosis than those with HRAS and KRAS mutations (10-year overall survival rate of 39% and 51%, respectively).
Disclosure: For full disclosures of the study authors, visit coi.asco.org.