Papillary cancer is, by far, the most common type of thyroid cancer and, overall, has a very good survival rate/prognosis. Those unusual cases of papillary thyroid cancer having guarded/relatively poor prognosis generally have spread to other body sites, such as the neck lymph nodes, the lungs and/or the bones. In general, appropriate management for papillary thyroid cancer requires surgery, followed in some cases by treatment with radioactive iodine therapy.
Recent studies aimed at predicting the behavior of papillary thyroid cancer have found that very small cancers (< 1 cm in diameter, called papillary micro-carcinomas) are unlikely to grow and spread and probably do not need to be removed surgically. Rather, such small cancers might simply be monitored for growth, with surgery only performed if such growth occurs. Unfortunately, however, a very small number of papillary micro-carcinomas will spread to distant body sites, without actually growing themselves. Because of this, an important area of research focuses on identifying which papillary micro-carcinomas will spread to distant body sites, so that these specific cancers can be removed surgically before they spread.
Cancer cells develop because of genetic changes in the normal cells from which they arise. Additional genetic changes can then occur within these cancer cells, giving them the ability to spread to other body sites. Because of this, one strategy for identifying which papillary microcarcinomas will spread out of the thyroid is to define which genetic changes allow this to occur and then to surgically remove only those papillary micro-carcinomas having these specific genetic changes.
The purpose of the study reviewed here was to compare the genetic changes in papillary micro-carcinomas that have spread out of the thyroid to the genetic changes in papillary micro-carcinomas that have remained within the thyroid.