Journal of Surgical Oncology 2014;109:708–713

Treatment Strategy of Rectal Gastrointestinal Stromal Tumor (GIST) HELI LIU, MD,1 ZHONGSHU YAN, MD,1* GUOQING LIAO, MD,1 AND HONGLING YIN, 1

2 PhD

Department of Gastrointestinal Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, P.R. China 2 Department of Pathology, Xiangya Medical School, Central South University, Changsha, Hunan, P.R. China

Background: Rectal gastrointestinal stromal tumor (GIST) is a rare entity. A retrospective analysis of outcomes from a single institution to identify treatment strategies associated with improved outcomes. Methods: Records of patients with GIST of the rectum were retrospectively reviewed. Patient and tumor characteristics, treatment details, and outcome were evaluated. Results: Compared with the trans‐abdominal approach group, the local excision group patients had smaller size and lower location tumors (P < 0.05). Positive resection margin was an important hazard factor for DFS (OR, 7.63; P ¼ 0.015). Among the patients with the tumor size >5 cm, those with preoperative Imatinib therapy had higher rate of a negative resection margin than those without (100% vs. 20%, P ¼ 0.048). Among the patients with intermediate and high‐risk tumors, those who received peri‐operative Imatinib therapy had longer DFS compared with those without (61.3  6.1 months vs. 20.2  4.4 months, P ¼ 0.030). Conclusions: The location of rectal GIST impacts the choice of resection type. Most patients with tumors within 5 cm of the anal verge can be treated with local excision. Positive resection margin is the independent hazard factor for poorer survival. Peri‐operative Imatinib therapy is associated with a prolonged DFS in patients with intermediate and high‐risk tumors.

J. Surg. Oncol. 2014;109:708–713. ß 2014 Wiley Periodicals, Inc.

KEY WORDS: gastrointestinal stromal tumor; rectum; surgery; imatinib mesylate

INTRODUCTION

MATERIALS AND METHODS

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. GISTs were considered of smooth muscle origin or neurogenic tumors for many decades until 1983, when Mazur and Clark re‐evaluated the histogenesis [1]. In 1998, the molecular mechanism of the etiology of these tumors was elucidated by Hirota et al. [2]. The development of GISTs is largely driven by mutations in the KIT gene and, to a lesser extent, the PDGFRA gene. GIST may be found throughout the gastrointestinal tract, but the rectum is an uncommon site, representing approximately 5% of all GISTs [3]. Surgery is the mainstay of treatment for primary resectable GISTs. However, recurrence and/or metastasis develop frequently (in 40–60% of cases within 2 years), despite complete surgical resection [4]. To date, two tyrosine kinase inhibitors (TKIs) have been approved by the United States Food and Drug Administration for the treatment of advanced GIST: Imatinib mesylate (Gleevec) for first line and sunitinib malate (Sutent) for second line or Imatinib intolerance. The ACOSOG (American College of Surgeons Oncology Group)‐led randomized trial (Z9001) has showed significantly fewer recurrences of tumors in patients who received Imatinib for 1 year after complete surgical resection compared to patients receiving placebo (2% vs. 17%) [5]. Further clinical trial (NCT00116935) has demonstrated that compared with 12 months of adjuvant Imatinib, 36 months of Imatinib improved RFS and overall survival of GIST patients with a high risk of GIST recurrence [6]. Weighing the risk of loco‐regional recurrence versus the requirement of preserving anal sphincter function is a challenge for surgeons when treating patients with rectal GIST. Although there have been many reports regarding surgical treatment of GIST, there is no evidence‐based recommendation available for the treatment of rectal GIST because of its rarity [7,8]. A randomized control study is impracticable. The aim of this study was to explore the optimal treatment strategies for rectal GIST based on a retrospective review of 21 cases at a single institution in China.

Medical records of 21 patients with GIST of the rectum seen between January 2002 and December 2010 were retrospectively reviewed (Table I). Preoperative evaluation of the tumors was undertaken by digital rectal examination, colonoscopy, CT/MRI imaging, and/or trans‐ rectal sonography (Fig. 1). All pathology slides of the needle biopsy samples and surgical specimens stained with Hematoxylin–Eosin staining and immunohistochemical agents (Dako Cytomation, Carpinteria, CA) were reviewed by a senior pathologist. The surgical procedure included two approaches: local excision and trans‐abdominal approach (Table II). There were two comorbidities in the local excision group, one patient had diabetes mellitus and another had chronic obstructive pulmonary disease. There were three comorbidities in the trans‐abdominal group, one patient had renal insufficiency and two patients had coronary heart disease. Tumor risk grade was evaluated according to the National Institutes of Health Consensus Criteria (2001) for Assigning Risk to Gastrointestinal Stromal Tumors [9] that is tumors

Treatment strategy of rectal gastrointestinal stromal tumor (GIST).

Rectal gastrointestinal stromal tumor (GIST) is a rare entity. A retrospective analysis of outcomes from a single institution to identify treatment st...
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