Synchronous Gastric and Rectal Adenocarcinoma With Complete Response After Total Neoadjuvant Therapy: A Case Report

Area of Science:

• Gastroenterology
• Oncology

Background:

• Synchronous gastric and colorectal cancers are rare, with colorectal cancer being the most common co-occurring malignancy.
• This case highlights a rare instance of synchronous gastric and rectal adenocarcinomas in a 76-year-old male.

Observation:

• The patient presented with symptoms leading to upper and lower endoscopies, diagnosing both gastric and rectal adenocarcinomas.
• Due to locally advanced disease, the patient received total neoadjuvant therapy (TNT) for rectal cancer, including radiotherapy and FOLFOX chemotherapy.

Findings:

• A complete clinical response of the rectal neoplasm was observed after seven cycles of TNT.
• Surgical resection revealed a complete pathological response in both the gastric and rectal tumors.

Implications:

• This case is among the first to report a complete pathological response in gastric cancer following TNT regimen primarily intended for rectal cancer.
• The findings suggest a potential benefit of neoadjuvant therapy in managing synchronous gastric and rectal cancers, warranting further investigation.