Primary localized rectal/pararectal gastrointestinal stromal tumors: results of surgical and multimodal therapy from the French Sarcoma group.

Thanh-Khoa Huynh,Maria Rios,Florence Duffaud,Emmanuelle Bompas,Philippe Cassier,Pierre Meeus,Jean-Yves Blay,Michael Montemurro,Thierry André,Sophie Lardière-Deguelte,Nicolas Isambert,Olivier Bouché,Antoine Adenis,Didier Cupissol,Olivier Collard,Julien Mancini

doi:10.1186/1471-2407-14-156

Abstract

BackgroundRectal and pararectal gastrointestinal stromal tumors (GISTs) are rare. The optimal management strategy for primary localized GISTs remains poorly defined.MethodsWe conducted a retrospective analysis of 41 patients with localized rectal or pararectal GISTs treated between 1991 and 2011 in 13 French Sarcoma Group centers.ResultsOf 12 patients who received preoperative imatinib therapy for a median duration of 7 (2-12) months, 8 experienced a partial response, 3 had stable disease, and 1 had a complete response. Thirty and 11 patients underwent function-sparing conservative surgery and abdominoperineal resection, respectively. Tumor resections were mostly R0 and R1 in 35 patients. Tumor rupture occurred in 12 patients. Eleven patients received postoperative imatinib with a median follow-up of 59 (2.4-186) months. The median time to disease relapse was 36 (9.8-62) months. The 5-year overall survival rate was 86.5%. Twenty patients developed local recurrence after surgery alone, two developed recurrence after resection combined with preoperative and/or postoperative imatinib, and eight developed metastases. In univariate analysis, the mitotic index (≤5) and tumor size (≤5 cm) were associated with a significantly decreased risk of local relapse. Perioperative imatinib was associated with a significantly reduced risk of overall relapse and local relapse.ConclusionsPerioperative imatinib therapy was associated with improved disease-free survival. Preoperative imatinib was effective. Tumor shrinkage has a clear benefit for local excision in terms of feasibility and function preservation. Given the complexity of rectal GISTs, referral of patients with this rare disease to expert centers to undergo a multidisciplinary approach is recommended.

Highlights

Rectal and pararectal gastrointestinal stromal tumors (GISTs) are rare
During the period from November 1991 to March 2011, a total of 41 adult patients with localized rectal/ pararectal GISTs were included in this review, including 4 patients reported in a separate therapeutic trial known as the French Sarcoma Group BFR 14 study [20]
GISTs were mostly located in the middle third (9 patients, 24%) and lower third (22 patients, 50%) of the rectum

Summary

Introduction

Rectal and pararectal gastrointestinal stromal tumors (GISTs) are rare. The majority of GISTs arise in the stomach and small intestine [1], with an estimated annual incidence of 11 to 14.5 per million [2,3]. Few series of rectal GISTs have been reported in the literature, and the available reports are limited to a small number of cases [5,6,7]. Due to the rarity of rectal GISTs and the limited number of published studies, there is a paucity of data on how to optimally handle rectal GISTs. There is a tendency to treat rectal/pararectal GISTs as other GISTs, as gastric GISTs. Management typically involves en bloc resection of the tumor, which avoids tumor rupture and obtains clear margins; there is no need for lymphadenectomy because lymphatic metastases are exceedingly rare. Rectal/pararectal GISTs have a high risk of recurrence (local recurrence or metastasis), ranging from 55% for tumors of >5 cm with a mitotic index (MI) of ≤5/ 50 HPF to 85% for tumors with an MI of >5/50 HPF regardless of size [8]

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Conclusion