The Occurrence of Gastrointestinal Stromal Tumors and Second Malignancies

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal malignancy of the gastrointestinal tract. GISTs may coexist with different types of cancer, either synchronous or metachronous. The frequency of this association and the spectrum of neoplasms involved have not been sufficiently analyzed; most of publications describe a single case report and rare case series. In the absence of definitive data, it could be interesting to compare the frequency of the occurrence of GIST and second malignancies in literature.

A review of all case series that reported the frequency of the occurrence of GIST and synchronous second malignancies were considered.

Six retrospective case series were considered, including 440 GIST patients; of these, there were 64 (14.5 %) patients with other synchronous second malignancies. Median age was 67 years, median GIST size was 3.91 cm (range 3.0-4.79 cm), and all cases (100.0 %) were CD117 and CD34 positive. According to the risk categories, 35.2 % of patients had a very low risk, 24.0 % a low risk, 27.6 % an intermediate risk, and 13.2 % a high risk.

Regarding the occurrence of GISTs and synchronous second malignancies, we can consider it as more common than it has been considered. Differently, concerning the topic of the incidence of second primary malignancies (SPMs) and metachronous second malignancies in pre-imatinib and after-imatinib era, we can consider it as a clinically relevant topic; according to the present knowledge, the main cause for the increased incidence of SPMs in the imatinib era is explained by the increased survival of patients with metastatic GISTs and therefore more time available to develop SPMs.