Gastrointestinal stromal tumors in the imatinib era: 15 years' experience of a tertiary center.

Gastrointestinal stromal tumors (GISTs) were associated with a disease free survival rate of disease of 50% at 5 years, but the actual natural history since the advent of imatinib is poorly described. Our objective was to evaluate the evolution in the treatment and prognosis of patients with GISTs since the start of imatinib. Retrospective analysis of GISTs diagnosed between January 2000 and June 2015 in a Portuguese large volume center. We included 131 patients, 55% female, with a mean age of 64±14 years, followed for a median of 30 months; 64% of cases had gastric involvement; 92% of the tumors were c-Kit positive; 95% of patients were operated. Imatinib was initiated in 25% of patients, as adjuvant therapy in 69%; 75% reported adverse effects, and 16% developed resistance. The recurrence rate was 4%, and was associated with age at diagnosis (P=0.037), tumor size (P=0.028), presence of metastases (P=0.019) and high-risk lesions (P=0.036). Survival at 1, 3 and 5 years was 87%, 71% and 61%, respectively. One year's mortality was significantly associated with tumor size (P=0.021), stage IV at diagnosis (P=0.003), non-complete resection (P=0.002) and palliation with imatinib (P=0.035). Similar associations were observed at the 3 and 5 years. In the imatinib era there is an increased long-term survival in comparison with previous epidemiological data, and reduced recurrence rates. In more advanced cases survival remains limited in the short term.