ORLANDO – Gastrointestinal stromal tumors of the duodenum can be managed safely with surgery, yielding good overall survival, an investigator reported at a symposium sponsored by the Society of Surgical Oncology.
In addition to surgery for duodenal gastrointestinal stromal tumors (GISTs), adjuvant treatment with imatinib (Gleevec) may reduce the risk of recurrence, and neoadjuvant imatinib may improve surgical outcomes, said Dr. Chiara Colombo, from the sarcoma service of the Fondazione Istituto Nazionale dei Tumori in Milan.
Dr. Chiara Colombo
"Imatinib in the neoadjuvant setting might facilitate the surgical resection and possibly help preserve the biliary and pancreatic anatomy," she said.
Only about 5% of GISTs originate in the duodenum, but tumors occurring in this section of the small intestine are anatomically challenging and there is considerable debate about the most appropriate surgical and therapeutic approaches, she added.
To gain a better understanding of the problem, Dr. Colombo and colleagues at her center, as well as the University of Mannheim (Germany), Massachusetts General Hospital in Boston, and the Maria Sklodowska-Curie Memorial Cancer Centre and Institute of Oncology in Gliwice (Poland), pooled data on patients with a primary duodenal GIST treated from February 2000 through August 2011 at their institutions.
There were a total of 39 men and 45 women, median age 58 years, treated with either pancreaticoduodenectomy (28 patients, 33%) or limited resection (56 patients, 67%). In all, 11 patients received preoperative imatinib for a median of 8 months, and 23 received it after surgery for a median of 17 months.
Surgical complication rates were higher among patients who underwent pancreaticoduodenectomy, compared with patients who had limited resection. The complications occurred in 5 patients who underwent limited resection (9%) and 10 who underwent pancreaticoduodenectomy (36%) and included evisceration/wound dehiscence (2 and 1, respectively), infections (1 in each group), gastric obstruction/delayed emptying (0 and 2), and pancreatic/biliary leakage (2 and 6 patients).
Among all patients, overall survival was 98% at 3 years and 89% at 5 years; the median follow-up was 42 months. Overall survival of patients at low or intermediate risk for recurrence was similar whether they received imatinib or did not. Among high-risk patients, however, imatinib was associated with significantly better 5-year overall survival, and the survival curves began to converge after imatinib was withdrawn, Dr. Colombo said.
She noted that the results echo those of a recent phase III study of adjuvant imatinib in patients with operable GISTs (ASCO 2011 Abstract LBA1).
In the intention-to-treat population of the randomized trial, the hazard ratio for overall survival for 36 months vs. 12 months of adjuvant imatinib was 0.45 (P = .019). The longer treatment schedule was also associated with better recurrence-free survival (hazard ratio 0.46, P less than .0001).
In the neoadjuvant setting, imatinib was associated with tumor regression, allowing for safer resection than might otherwise be possible, Dr. Colombo commented. This analysis on tumor regression was based on the combined clinical experience at all the centers.
The study was supported by the participating institutions. Dr. Colombo reported no relevant financial disclosures.