Tumors of the gastric remnant

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Gastric cancer (GC) is the fifth most common cancer in the world. It is estimated that over one million new cases of GC occur annually.

Remnant gastric cancer, or gastric stump cancer, was defined as a tumor that develops in the gastric remnant more than 5 years after previous gastrectomy.

Its reported incidence in the literature varies between 2 to 6% of all patients with GC. It can occur in the remaining stomach either after previous resection for benign or malignant lesion. However, these tumors seem to have different behaviors and etiologies. Due to its rarity and diversity, the characteristics of remnant gastric cancer, prognostic factors and survival, remain uncertain.

Context

Gastric resection for benign disease was commonly performed until the late 1980s and created a large cohort of patients with gastric remnant at risk of developing tumors. The introduction of H2 receptor antagonists and proton pump inhibitors in the 1980s drastically reduced the number of gastric resections due to peptic disease. However, as the disease development period is long, the occurrence of remnant tumors is still part of the current reality due to the past use of gastric resection for peptic ulcer treatment. On the other hand, the improvement in the treatment results of GC has increased the survival of patients undergoing gastric resection, also increasing the population susceptible to the development of new neoplasia in the gastric remnant. Therefore, a change in this benign/malignant ratio related to previous indications of gastric resection is expected in the future.

Long-term endoscopic surveillance is recommended for early detection of lesions in patients who have undergone previous distal gastrectomy. Even with these recommendations, there is a common sense that remnant tumors usually present at a more advanced clinical stage and with a worse prognosis. The longer period of carcinogenic effect after resection, as well as the patients’ perception that they had benign disease, makes them less likely to continue monitoring the gastric remnant for early detection.

Carcinogenesis

The carcinogenesis of GC is a multi-step process that involves the interaction of several genetic, epigenetic and environmental factors. The risk factors commonly associated with the development of GC include chronic infection by H. pylori, low intake of fruits and vegetables, high salt intake, smoking and alcohol consumption.

• After previous gastric resection for malignant disease, this cumulative carcinogenic effect on the gastric mucosa is maintained. For this reason, patients with previous gastrectomy for cancer develop tumors in the remnant in a significantly shorter period than patients with previous benign lesions.
• After gastric resection for benign disease, environmental changes begin to induce chronic damage in a previously normal gastric mucosa of the remnant, initiating a de novo carcinogenic pathway with a longer period for the development of the tumor in the remnant. The reported time required to transform this remaining inflamed mucosa into a neoplastic epithelium is over 20 years.

Another factor contributing to remnant carcinogenesis is the vagotomy performed in the previous procedure, which causes denervation of the gastric mucosa leading to hypochlorhydria. On the other hand, the frequency of H. pylori infection decreases in the remnant mucosa, leading to a protective effect.

Whether these changes actually lead to a higher incidence of GC in the remnant mucosa, or just reflect the normal risk of GC in the general population, is still under discussion. This discrepancy in reports may result from the difference in GC incidence rates in the general population of different countries. Regions with low incidence of GC tend to have a higher proportion of remnant tumors compared to regions with high incidence of GC.

Type of reconstruction and risk of carcinogenesis

The relationship between type of reconstruction and risk of RGC remains uncertain.

• The Billroth I (BI) reconstruction maintains the flow of ingested food from the remaining stomach to the duodenum, but due to pyloric resection the duodeno-gastric bile reflux is increased.
• The Billroth II (BII) reconstruction allows the influx of bile from the afferent jejunal branch to the remaining stomach. This constant flow makes alkaline gastritis more common and severe after BII. This leads to inflammation and regeneration of the mucosa, which may be associated with a higher risk of remnant tumors. Despite some reports in the literature, this association is not yet a consensus.
• On the other hand, the Roux-en-Y reconstruction avoids bile reflux to the remaining stomach, but is rarely performed for benign resections.

Access the Gastropedia surgical video library to see the types of reconstruction

Characteristics and staging

In most cases the remnant tumor is located at the previous anastomosis (Figure 1). Patients usually have a more advanced age which reflects the long period of inflammatory gastritis necessary to induce carcinogenesis in the gastric mucosa. Although the TNM system is applied to all gastric tumors, the staging system for remnant tumors has not been established. For adequate final pathological staging, it is recommended to recover at least 15 lymph nodes to avoid stage migration due to underestimation.

Surgical treatment

Complete total gastrectomy with radical lymphadenectomy is the cornerstone of the treatment of remnant tumors. Adhesion to adjacent organs and displacement of anatomical structures are common difficulties during the procedure, making it longer and more prone to combine repair or resection of other organs. Normally, the surgical procedure is performed by conventional open approach, but recently minimally invasive laparoscopic and robotic approaches are increasing (access gastropedia surgical video library).

It has been suggested that the characteristics of lymph node metastasis in remnant tumors are different due to the interruption of the lymphatic pathway in the first procedure. The type of reconstruction and the previous indication of the first gastrectomy do not seem to influence the incidence of lymph node metastasis, but rather its location. This can lead to a greater involvement of the splenic artery, splenic hilum, lower mediastinum and jejunal mesentery. However, the standard extent of lymphadenectomy is not yet defined. Similar to GC, splenic hilum lymphadenectomy is indicated only if the tumor invades the greater curvature.

The presence of lymph node metastasis in the jejunal mesentery has a poor prognosis. It is known that extended lymphadenectomy in the area can severely affect postoperative quality of life. Therefore, the extent of lymphadenectomy in the mesentery should be determined based on the extent of lymph node involvement, considering a balance between risk and benefit.

References

1. Ramos MFKP, Pereira MA, Dias AR, Dantas ACB, Szor DJ, Ribeiro U Jr, Zilberstein B, Cecconello I. Remnant gastric cancer: An ordinary primary adenocarcinoma or a tumor with its own pattern? World J Gastrointest Surg. 2021 Apr 27;13(4):366-378. doi: 10.4240/wjgs.v13.i4.366.
2. Ramos MFKP, Pereira MCM, Oliveira YS, Pereira MA, Barchi LC, Dias AR, Zilberstein B, Ribeiro Junior U, Cecconello I. Surgical results of remnant gastric cancer treatment. Rev Col Bras Cir. 2020 Nov 30;47:e20202703. doi: 10.1590/0100-6991e-20202703.

How to cite this article

Ramos MFKP, Remnant gastric tumors. Gastropedia 2023 Vol 1. Available at: https://gastropedia.com.br/cirurgia/tumores-do-remanescente-gastrico/