New fronts in the adjuvant treatment of GIST

To review the prognostic factors and stratification systems used to determine the need for adjuvant therapy in the treatment of gastrointestinal stromal tumors (GIST), and to review recent clinical advances in investigation of the efficacy and safety of adjuvant imatinib mesylate treatment.

Recent data from clinical trials of various durations of adjuvant imatinib in GIST are reviewed, with emphasis on key results from the Phase III American College of Surgeons Oncology Group (ACOSOG) Z9001 trial and the Scandinavian Sarcoma Group XVIII/Arbeitsgemeinschaft Internistische Onkologie (SSGXVIII/AIO) trial.

Complete surgical resection remains the standard of treatment for localized GISTs; however, disease recurrence occurs in up to 50 % of patients who undergo complete resection. The ACOSOG Z9001 trial established that 1 year of adjuvant imatinib reduces the risk of recurrence in patients with resected GIST. The SSGXVIII/AIO trial further demonstrated that 3-year adjuvant imatinib improves both recurrence-free survival and overall survival compared with 1-year therapy in patients at high risk of recurrence after surgery. Considering risk factors associated with tumor recurrence is essential for identifying the patients who are most likely to benefit from adjuvant imatinib.

Although the optimal duration of adjuvant therapy remains to be determined, results from these pivotal trials provide firm evidence that adjuvant imatinib improves recurrence-free survival and improved overall survival of patients in the SSGXVIII/AIO trial. Ongoing studies may shed further light on the benefits and harms of adjuvant therapy, as well as the most appropriate patient candidates for adjuvant imatinib treatment.