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

Sep 21, 2026

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Synchronous gastric cancer paired with another neoplasm is uncommon, with colorectal cancer the most frequent associated malignancy. This case report describes a 76-year-old male with synchronous gastric and rectal adenocarcinomas who achieved complete remission after adjuvant therapy. Symptoms prompted upper and lower endoscopies, confirming both cancers. Staging showed locally advanced disease, leading to total neoadjuvant therapy (TNT) for rectal cancer using radiotherapy and FOLFOX-based chemotherapy, followed by simultaneous surgery.

LanguageEnglish

CategoryHealthcare

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Pages5

Reading Time13 min

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Abstract

Introduction

Case Presentation

Open Access Case Report DOI: 10.7759/cureus.60787 Review began 05/16/2024 Review ended 05/19/2024 Published 05/21/2024 © Copyright 2024 Martins et al. This is an open access article distributed under the terms of the Creative Commons Attribution License CC-BY 4.0. , which permits unrestricted use , distribution , and reproduction in any medium , provided the original author and source are credited. Synchronous Gastric and Rectal Adenocarcinoma With Complete Response After Total Neoadjuvant Therapy: A Case Report Daniela Martins 1, 2, Rita Marques 1, 2 , Diana Martins 3, 4, Ana Melo 1, 2, João Pinto-de-Sousa 1, 2 1. General Surgery, Unidade Local de Saúde de Trás-Os-Montes e Alto Douro, Vila Real, PRT 2. General Surgery, Clinical Academic Centre Trás-Os-Montes e Alto Douro, Vila Real, PRT 3. Oncology, Unidade Local de Saúde de TrásOs-Montes e Alto Douro, Vila Real, PRT 4. Oncology, Clinical Academic Centre Trás-Os-Montes e Alto Douro, Vila Real, PRT Corresponding author: Daniela Martins, [daniela.cor.martins@gmail.com](daniela.cor.martins@gmail.com) Abstract Synchronous gastric cancer with another neoplasm is a rare condition, with colorectal cancer being the most frequently associated neoplasm. This article presents a case of a 76-year-old male diagnosed with synchronous gastric and rectal cancer with complete remission of gastric and rectal neoplasms after adjuvant therapy. The patient exhibited symptoms prompting upper and lower endoscopies, revealing gastric and rectal adenocarcinomas, respectively. Staging was performed, and due to the locally advanced nature of both malignancies, the patient underwent total neoadjuvant therapy (TNT) for rectal cancer. The treatment consisted of external radiotherapy and neoadjuvant chemotherapy with oxaliplatin, leucovorin, folinic acid, and fluorouracil (FOLFOX) . Remarkably, after seven cycles, a complete clinical response of the rectal neoplasm was achieved. Subsequent surgical resection included simultaneous subtotal gastrectomy and rectal anterior resection, resulting in a complete pathological response for both tumors. To the best of our knowledge, it is among the first cases to report a full pathological response in gastric cancer following TNT intended for rectal cancer. Categories: General Surgery, Oncology Keywords: neoadjuvant chemoradiotherapy, complete response, synchronous cancers, rectal cancer, gastric cancer Introduction Colorectal cancer ranks third, and gastric cancer ranks fifth in the global incidence of solid tumors, according to data from Global Cancer Statistics 2022 (GLOBOCAN 2022) . As we delve into the complexities of malignancies, the occurrence of multiple primary malignancies (MPMs) adds another layer to the intricate landscape of cancer [1] . MPMs may be classified as synchronous or metachronous. Synchronous tumors are defined as MPMs that manifest within six months of the appearance of another tumor. On the other hand, a metachronous tumor will develop six months after another primary tumor [2-4]. Synchronous gastric cancer coexisting with another solid tumor is a rare condition, with an estimated incidence of 3 .4% . The most frequently observed synchronous neoplasm is colorectal cancer, with a prevalence ranging from 20. 1% to 37.2%, followed by lung cancer (12%) and liver cancer (11%) [2,5,6]. With the release of data from recent pivotal randomized controlled trials such as “Short-course radiotherapy followed by chemotherapy before total mesorectal excision (TME) versus preoperative chemoradiotherapy, TME, and optional adjuvant chemotherapy in locally advanced rectal cancer (RAPIDO) : a randomised, openlabel, phase 3 trial”(RAPIDO) and “Neoadjuvant chemotherapy with FOLFIRINOX and preoperative chemoradiotherapy for patients with locally advanced rectal cancer (UNICANCER-PRODIGE 23): amulticentre, randomised, open-label, phase 3 trial”(PRODIGE-23), total neoadjuvant therapy (TNT) has emerged as a leading approach in

FAQs

What makes synchronous gastric and rectal cancer a rare condition?

Synchronous gastric cancer together with another solid tumor is uncommon, and colorectal cancer is the most frequently associated malignancy.

How was the patient diagnosed in this case?

Symptoms such as anemia and gastrointestinal bleeding led to upper and lower endoscopies, which identified gastric and rectal adenocarcinomas.

What treatment approach led to complete response?

Because both malignancies were locally advanced, the patient received total neoadjuvant therapy (radiotherapy plus neoadjuvant chemotherapy with a FOLFOX regimen) and achieved complete clinical response, followed by surgical resection.

Sep 21, 2026

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