Clinical, pathological, radiological characteristics, risk stratification and immunohistochemistry profile of gastrointestinal stromal tumors treated in a tertiary cancer centre located in Sub-Himalayan region: institutional experience of 20 patients and review of literature

Abstract

GIST (gastrointestinal stromal tumors) are the rare mesenchymal tumors. Treatment includes curative surgery along with targeted agents like TKI in neoadjuvant/adjuvant settings. A total of 20 patients of histology proven GIST who were registered between 2014 to 2020 were reviewed for clinico-pathological data, endoscopic and radiological investigations, sites, primary treatment received, histology, immunohistochemistry, stage, risk stratification and imatinib therapy. GIST was more common in males than females. Age group varied between 25 years to 76 years. Majority of patients consumed non vegetarian diet, half of them being smokers and consumed alcohol. Pain abdomen, abdominal lump, dysphagia, haematemesis, melena and blood in stools were presenting complaints. CECT revealed heterogeneously enhancing mass with necrosis as most common finding. Upper GI endoscopy/colonoscopy revealed extrinsic bulge, polypoidal growth or ulcers as main findings. Stomach was the most common site followed by jejunum. Few patients presented with metastatic disease to liver and lungs. HPE revealed spindle cell GIST as main histology (with one patient with mixed spindle and epithelioid cells) with all patients having immunoreactivity to CD117. Majority of patients belonged to stage III and high-risk category by NIH stratification criteria. In majority of patients treatment received was surgery followed by adjuvant imatinib. Few patients had unresectable disease at presentation and received imatinib as upfront therapy. Imatinib was well tolerated in majority of patients. Few experienced manageable side effects like headache, irritability, leukopenia, pain abdomen, vomiting. Duration of treatment was one to three years. GIST is a rare tumor with varied presentations. Surgery is the mainstay of treatment offering chances of cure and revolutionary adjuvant imatinib is well tolerated with mild and manageable side effects in our centre. Being a resource limited centre, affordability for special investigations like IHC (immunohistochemistry) for CD117 (which helps in further confirmation of the diagnosis), remains a challenge for the patient and so does the 2nd line agent like sunitinib in case of recurrence.