Prognostic factors of recurrence and survival of gastrointestinal stromal tumors: First multicentric study of Mexico.

Abstract

11045 Background: Gastrointestinal stromal tumors are mesenchymal lesions arising from the interstitial cells of Cajal. In GIST the location, size, number of mitosis and risk group are accepted as prognostic factors; some factors in which there are still controversies about their value as prognostic factors include male gender, tumor cellularity, the margins of resection, the presence or absence of p16 or intraperitoneal tumor breakdown. Methods: Observational, retrospective and longitudinal study. Patients admitted to the Oncology Hospital, CMN Siglo XXI of January 1, 1991 to April 30, 2012. Results: We identified 384 patients, the mean follow-up time was 55.86 months, the mean age was 58 years, 80.3% had symptoms and only 4.54% the finding was incidental. The most common site was the stomach (66.6%), followed by small intestine (28.7%) and colon (1.54%). The 7.57% had metastases at diagnosis, 4.54% in liver and 3.03% in the peritoneum. Were expressed by abdominal pain (39.39%) and gastrointestinal bleeding (30.30%), intestinal obstruction in 1.5%. The most common site was the stomach (66.6%), followed by small intestine (28.7%) and colon (1.54%). The 7.57% had metastases at diagnosis. The average tumor size was 10.84 cm (2.2 to 38 cm). Immunohistochemical markers were studied: 94.28% positive for CD117, CD34 74.28%, 11.42% S100 protein, desmin 5.71% and 51.72% for smooth muscle actin (AML). Overall rate at 5 years and 82% rate of recurrence-free survival at 5 years and 61% survival. The location of the tumor (p = 0.0002), size (p = 0.03145), the number of mitosis (p = 0.008), risk group (p = 0.020) and adjuvant treatment with Imatinib showed a statistically significant difference for Survival Recurrence-free. For overall survival, lesion location was the only factor that showed statistical significance with p = 0.0054. Conclusions: The tumor location, size, number of mitosis, the risk group and adjuvant treatment with Imatinib were statistically significant prognostic factors for disease recurrence. The location of the lesion was the only factor that showed statistical significance as a predictor of overall survival.