Multimodality therapy of rectal gastrointestinal stromal tumors in the era of imatinib-an Indian series

Primary objective was to determine if sphincter preservation is possible with the use of neoadjuvant imatinib in cases of rectal gastrointestinal stromal tumor (GIST). Secondary objectives were to determine clinicopathological characteristics and intermediate term oncological outcomes of the cases of rectal GIST. This is a retrospective review of 13 cases of GIST of the rectum diagnosed between January 1, 2010 and June 30, 2015 at Tata Memorial Centre, Mumbai, India. Clinical parameters that were assessed were duration of the neoadjuvant imatinib therapy, type of surgery performed as well as perioperative morbidity. Pathological parameters that were assessed included the size of the tumor, completeness of resection, mitotic count and mutational analysis. Of the 13 patients included, 11 were nonmetastatic at the time of presentation. All the patients received neoadjuvant imatinib in view of locally advanced nature of the tumors. Median distance from anal verge was 2 cm. Median duration of imatinib was 9 months. Of the 9 patients who underwent surgery, three had sphincter preserving surgery (33%) whereas the rest had abdomino-perineal resection. Two patients had perineal wound infections. All the operated patients received adjuvant imatinib therapy for 3 years. Median follow up period was 34 months. One patient developed distant metastasis; otherwise rest had no local or distant recurrence. In cases of rectal GIST, sphincter preservation may not be possible in spite of neoadjuvant therapy with imatinib.