Investigators studying multiple measurements of tumor volume among patients undergoing active surveillance for small, low-risk papillary thyroid cancer (PTC) in the U.S. found that most cancers remained stable over several years of observation with the use of serial measurements defining the rate of growth for tumors. Further, the researchers found that tumor volume kinetics can inform the timing of surveillance imaging and therapeutic interventions for these patients while undergoing active surveillance. The research was published in August 2017 in JAMA Otolaryngolgy Head and Neck Surgery.
R. Michael Tuttle, MD, an endocronologist at Memorial Sloan Kettering Cancer Center in New York City, and colleagues examined tumor volume kinetics (probability, rate, and magnitude) in 291 patients undergoing active surveillance for low-risk PTCs (1.5 cm or smaller) in the U.S, with serial tumor measurements obtained via ultrasonography. During a median active surveillance of 25 months, growth in tumor diameter of 3 mm or more was observed in 11 of 291 (3.8%) patients, with a cumulative incidence of 2.5% (two years) and 12.1% (five years). No regional or distant metastases developed during active surveillance.
In all cases, 3-dimensional measurements of tumor volume allowed for earlier identification of growth. An increase in tumor size was more likely in younger patients. The kinetics of PTC volume growth followed classic exponential growth patterns, indicating that growth can be accurately modeled.