LAUSR

Rationale: The efficiency and tolerance of long-term adjuvant imatinib treatment for patient who underwent complete resection of a localized recurrent gastrointestinal stromal tumor (GIST) was unknown. Patient concerns: A 45-year-old man underwent complete resection of an intestinal GIST in August 2001. Four years later, a giant (11 × 8 × 6 cm) recurrent GIST located in the retroperitoneum was detected. Diagnosis: The recurrent tumor was positive for CD117 by immunohistochemistry. Interventions: The recurrent tumor was completely resected after 4 months of effective imatinib treatment (400 mg/day), and the patient continued imatinib treatment postoperatively. In June 2011, imatinib treatment was stopped for 3 weeks because of hepatitis B infection, and resumed with a reduced dose level of 300 mg/day when liver function recovered. In March 2017, imatinib treatment was interrupted again for 12 days because the patient underwent cholecystectomy. Outcomes: In December 2017, a computed tomography scan showed no signs of tumor recurrence. To date, the patient has been under adjuvant imatinib treatment for >12 years without severe side effects. The plasma concentration of imatinib (detected in February 2018) was trough concentration (Cmin) 1015.7 ng/mL and peak concentration (Cmax) 1550.5 ng/mL. Lessons: This case report highlights the active role of long-term (>12 years) imatinib treatment after complete resection of localized recurrent GIST.