# Ten-Year Follow-Up After Chemotherapy and Conversion Surgery for Human Epidermal Growth Factor Receptor 2-Positive Stage IV Esophagogastric Junction Cancer With a Pathological Complete Response: A Case Report

## TL;DR

A patient with advanced esophagogastric junction cancer achieved long-term remission after chemotherapy and conversion surgery.

## Contribution

This case report demonstrates a rare long-term recurrence-free outcome after conversion surgery for stage IV HER2-positive cancer.

## Key findings

- The patient achieved a pathological complete response after chemotherapy and conversion surgery.
- No metastasis or recurrence was observed for nine years post-surgery.
- Conversion surgery may offer long-term benefits for select stage IV GC patients.

## Abstract

Recent reports have focused on the usefulness of conversion surgery, in which chemotherapy is given to patients with unresectable advanced gastric cancer (GC), and radical surgery is subsequently performed if resection becomes possible; however, no consensus has been reached regarding the usefulness of this strategy. We report on a 74-year-old man who was diagnosed with esophagogastric junction cancer (T3N3M1 (LYM): stage IV). Chemotherapy was chosen and seven courses of S1 + cisplatin (SP) + trastuzumab (HCN) and two courses of S1 + HCN were administered. Approximately 10 months after the start of chemotherapy, the tumor had almost disappeared and we therefore decided to perform conversion surgery. Pathologic examination of the specimen and dissected lymph nodes showed no cancer. Postoperatively, the patient underwent chemotherapy until the second postoperative year, and no metastasis or recurrence was observed for nine years after surgery. Conversion surgery after chemotherapy resulted in recurrence-free survival in this case; however, further studies are needed to elucidate the effect of surgery after chemotherapy for patients with stage IV GC, as chemotherapy continues to evolve.