# Optimal upfront surgery for gastric adenocarcinoma. Real life situation in Brazil. Results comparable to neoadjuvant treatment

## TL;DR

This study shows that upfront surgery for gastric cancer in Brazil can be as effective as neoadjuvant treatment, especially when combined with adjuvant therapy and D2 dissection.

## Contribution

The study demonstrates that optimal upfront surgery achieves similar survival outcomes to neoadjuvant treatment in gastric cancer patients.

## Key findings

- Optimal upfront surgery resulted in similar overall survival to neoadjuvant treatment (56.6% vs. 52.4%).
- Preoperative chemotherapy, D2 lymphadenectomy, and complication rates were independent factors influencing survival.
- Optimal surgery was achieved in 68.6% of the neoadjuvant group and 51.9% of the upfront group.

## Abstract

Complete neoadjuvant treatment for gastric cancer is not always tolerated due to nutritional and clinical reasons, such as gastric outlet obstruction. In this context, upfront surgery becomes an alternative.

The aim of the study was to compare upfront resection with neoadjuvant systemic therapy followed by surgery and identify factors influencing their outcomes.

Retrospective study of 410 patients with locally advanced gastric adenocarcinoma followed between 2012 and 2020, comparing upfront surgery and perioperative treatment. Patients with early tumor (cT1N0), metastasis, and stump cancer were excluded. The comparison was stratified by stage without the influence of systemic treatment (primary stage). Resections with D2 dissection, no residual tumor (no R2), and no complications were considered optimal surgery.

Upfront resection was performed in 216 patients (85% of upfront surgeries). Gastrectomy after neoadjuvant treatment was performed in 47 cases (76% of indications), and another four were resected among 39 previous unsuccessful surgeries (10%). In total, there were 51 resections after chemotherapy. Independent factors associated with overall survival at 60 months were: preoperative chemotherapy (57.3% vs. 40.7%, p=0.029); complication rate; D2 lymphadenectomy; and primary stage. Initial cases showed a better outcome in the neoadjuvant group without statistical significance (p=0.447), but it was present in more advanced tumors (p=0.027). Optimal surgery was achieved in 68.6% of the neoadjuvant group and 51.9% of the upfront group (p=0.030) and resulted in similar overall survival (56.6% vs. 52.4%, p=0.904).

Optimal upfront surgery followed by adjuvant therapy, particularly with D2 dissection, is effective and was not statistically inferior to neoadjuvant treatment.

Preoperative systemic treatment is indicated for locally advanced gastric cancer in Western countries.

However, especially in obstructive tumors, it is not tolerated.

Optimal upfront surgery — radical and without complications — has demonstrated similar results to perioperative treatment.

The distal stomach remains an important site of gastric adenocarcinoma. Due to the high rate of late diagnoses, patients’ nutritional status is commonly affected, sometimes with gastric outlet obstruction, which often requires intervention before systemic treatment. Patient morbidity, costs, side effects, and variable response rates also hinder the decision for neoadjuvant treatment. In this context, upfront surgery becomes an alternative.

The higher incidence of distal tumors and subtotal gastrectomies in the UPF group, within a context of more advanced stages, might suggest a higher proportion of obstructive tumors and patients with poorer baseline status. However, even in this context, the outcomes of optimal upfront surgery were similar to those of neoadjuvant treatment. Optimal upfront surgery followed by adjuvant therapy, particularly with D2 dissection, is effective and was not statistically inferior to neoadjuvant treatment.