S6209 Unmasking Hidden Threat of GI Tract: Duodenal Carcinoma

Introduction: Small bowel cancers are uncommon comprising only 2% of all gastrointestinal (GI) cancers. The majority of these are duodenal adenocarcinomas which account for <0.5% of all GI cancers. Risk factors are similar to that of colorectal cancer and diagnosis is usually delayed due to nonspecific presentations. Given the small number of cases described in the literature, there is very little information on treatment decisions. Case Description/Methods: A 60-yr old man with known prior medical history of hypertension, alcohol dependence presented with extreme fatigue, dyspnea on exertion and melena for 2 weeks. Initial workup revealed severe iron deficiency anemia, esophagogastroduodenoscopy (EGD) showed mild duodenitis with no source of active bleeding. He was started on Protonix and Carafate. He continued to have intermittent melena with low hemoglobin requiring readmission. Repeat EGD unmasked duodenal mass with central ulceration that was confirmed to be poorly differentiated adenocarcinoma of duodenum. Patient was referred to hematology and oncology. Positron emission tomography (PET) scan showed mass in duodenum with metastasis to liver. Patient started on systemic therapy with modified FOLFIRINOX regimen (5-FU, irinotecan, oxaliplatin, leucovorin calcium). Due to this metastatic nature, the clinical course is complicated with multiple hospitalizations secondary to gastrointestinal (GI) bleed and deep vein thrombosis. Attributed to severity within 6-8 months and complicity with cancer, the patient eventually opted for comfort care. Discussion: Duodenal adenocarcinoma accounts for <1% of GI cancer and most frequently occurs near the ampulla of Vater. Risk factors include family adenomatous polyposis, Peutz-Jeghers syndrome, crohn's disease, celiac disease, Lynch syndrome, diet and environmental factors also playing the role. Symptoms include abdominal pain, nausea, vomiting, GI bleed with anemia, weight loss and jaundice. Diagnostic studies include endoscopy with biopsy, computed tomography and magnetic resonance imaging for staging and PET scan for metastasis. Pathology usually shows gland-like structures in biopsy, and it is graded by TNM system. Pancreaticoduodenectomy is a treatment if the tumor is near the pancreas on segmental resection for more distal tumors is practiced. Chemotherapy regimens include 5-fluorouracil, capecitabine, oxaliplatin or gemcitabine with radiation therapy less commonly used. Targeted immunotherapy is still investigational, and the prognosis depends on the spread of the disease. Those without lymph node involvement have a 65% 5-year survival rate and those with lymph node involvement have a 21% 5-year survival rate.