Surgical treatment of patients with initially inoperable and/or metastatic gastrointestinal stromal tumors (GIST) during therapy with imatinib mesylate.

BACKGROUND: The aim of the study was to analyze the surgical possibilities of unresectable and/or metastatic GIST CD117(+) patients during imatinib treatment.

METHODS: We analyzed the results of surgery in 141 patients treated with imatinib for initially inoperable and/or metastatic GIST CD117(+). Median follow-up time was 12 months (range: 3-26).

RESULTS: Surgery was performed as subsequent treatment in 24 patients (Group I, 17%) for resection of residual disease after complete/partial response and lack of further response to imatinib and as salvage therapy in eight patients (Group II, 6%), who progressed on initially successful imatinib therapy. In Group I, the viable GIST cells were not detected histologically in only three resection specimens. The first five patients in Group I did not receive imatinib further and we observed four recurrences. In next 19 patients, continuing imatinib after surgery, we observed only one relapse. In Group II, we continued imatinib therapy after high-risk surgical procedures, but in five patients we observed subsequent progression.

CONCLUSIONS: Surgical removal of residual disease during imatinib treatment may allow for complete remission in selected GIST patients after response to therapy, theoretically prolonging durable remission, but it is necessary to continue imatinib for its maintenance.