Risk Factors for Gastrointestinal Stromal Tumors: A 10-Year Retrospective Review from a Tertiary Care Facility

Abstract

Introduction: With age-adjusted annual incidence of 6.8 per million (from 1992 to 2000), gastrointestinal stromal tumors (GIST) are still the most common non-epithelial tumors of gastrointestinal tract (GIT). GISTs are mostly sporadic, occur in older adults with equal distribution among all ethnic, demographic & gender groups and generally have a favorable prognosis (5-year survival of 54% who undergo complete resection). The main aim of this study was to identify and analyze the different variables associated with the development of this rare and poorly-understood mesenchymal tumor. Methods: A retrospective chart review was conducted over the past 10 years to devise a case-control study (n=465) among cases (n=36) and their age-, sex- and race-matched controls (n=429) for evaluation of a variety of patient characteristics which included smoking, alcoholism, history of another malignancy (either before or after the diagnosis of GIST) and the presence of a family history of malignancy in first degree relatives. Results: Cases had a mean age of 61.7 ± 11.5 with blacks representing 86% of cases. Patients with GIST were more likely to be smokers (OR 3.47, 95% CI 1.64-7.35, p 0.002) and alcoholics (OR 3.48, 95% CI 1.22-9.95, p 0.03) when compared with controls. Cases had a statistically significant family history of malignancy [odds ratio (OR) 4.52, 95% CI 2.18-9.36, p < 0.001], especially in father (OR 4.32, 95% CI 1.60-11.61, p 0.008) and mother (p < 0.001). Patients with GISTs were more likely to have a history of another malignancy when compared with controls (OR 5.52, 95% CI 2.26-13.66, p < 0.001), with the other malignancy being detected either before or after the diagnosis of GIST. Histologic grade 1, stage 4, stomach (75%) as the primary site and liver as site of metastasis were the most common among their respective categories. Multivariate regression model to identify independent predictors showed that patients with GISTs are more likely to have another malignancy (OR 3.48, 95% CI 1.47, 8.20) when controlled for alcoholism, smoking and family history of malignancy. Conclusion: This study concludes that smoking, alcoholism, family or personal history of malignancy can add greatly to the risk of having GIST. We should conduct more sophisticated studies on a larger scale in order to obtain a better understanding of the factors involved in the carcinogenesis of this arcane pathology.