A Case of Simultaneous Overlapping Cancer of the Pancreatic Head and Gastric Body Managed With Pancreaticoduodenectomy and Total Gastrectomy in Two Stages.

Simultaneous overlapping cancers are defined as two or more primary malignancies diagnosed within six months of each other. The treatment strategy is highly individualized and depends on the localization and progression of each cancer. Although radical surgery is sometimes performed at the first instance, patients might be hesitant to undergo extensive resection due to the risk of surgical complications, depending on their condition. Herein, we describe the case of an 80-year-old male patient, diagnosed with concurrent pancreatic head and upper gastric cancer. He underwent a two-stage surgical treatment with favorable results. The patient was initially diagnosed with gastric cancer (cT1b, cN0, cM0, cStage1) and pancreatic head cancer (cT1, cN0, cM0, cStage1A) based on gastrointestinal endoscopy and computed tomography findings. Due to the highly invasive nature of simultaneous surgical resection, the patient opted to avoid a one-stage surgical resection. Furthermore, the treatment plan prioritized surgery for pancreatic cancer, which included subtotal stomach-preserving pancreaticoduodenectomy, m-Child reconstruction, and the Blumgart method. Postoperative pathology showed a pT3 (with duodenal invasion), pN0, cM0, and pStage2A pancreatic cancer. The patient received S-1 (tegafur/gimeracil/oteracil potassium) as an adjuvant chemotherapy for pancreatic cancer. This treatment resulted in a significant shrinkage of the gastric cancer after three months. However, one year after the surgery, the gastric cancer progressed, spreading from the upper gastric body to the middle. Despite administering two courses of S-1, it did not shrink. A total gastrectomy with Roux-en-Y reconstruction was performed, and the pathological findings indicated ypT1b, ypN0, ycM0, and ypStage1A gastric cancer. The patient remained alive even 31 months after the surgery, without recurrence. Our patient was an older adult, raising concerns about the complications with one-stage surgical resection. We successfully managed the patient by adopting a two-stage surgical approach with adjuvant chemotherapy in between. It resulted in recurrence-free survival at 31 months after the operation.