# Peritoneal-directed therapy for gastric cancer

Source: https://onco.cc/ideas/idea-peritoneal-directed-gastric/  
OnCo record `idea-peritoneal-directed-gastric` (Idea). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Stomach cancer usually comes back on the abdominal lining, where drugs barely reach. Deliver treatment directly into the abdomen.

## Summary

Gastric cancer most often recurs on the peritoneum, where systemic drugs barely reach, so this idea proposes delivering treatment directly into the abdomen. Candidates include intraperitoneal paclitaxel with systemic chemotherapy, which PHOENIX-GC narrowly missed and Japanese trials are pursuing, PIPAC, and regionally delivered CLDN18.2 CAR-T such as satricabtagene autoleucel. The rationale is the pharmacokinetic advantage of intraperitoneal delivery and the fact that peritoneal-only disease is a distinct, chemoresistant compartment that staging laparoscopy can identify early. The proposed test is a randomised phase 3 restricted to peritoneal-only disease, and at an early clinical stage it addresses the bottleneck that metastasis is understood least and studied last.

## Fields

- Kind: Idea
- Last checked: 2026-09-07
- Hypothesis: Adding intraperitoneal paclitaxel to systemic chemotherapy-immunotherapy improves OS in patients with peritoneal-only metastases.
- Rationale: Pharmacokinetic advantage of intraperitoneal delivery; peritoneal-only disease is a distinct, chemoresistant compartment.
- Proposed test: Randomised phase 3 restricted to peritoneal-only disease by laparoscopy; OS primary.
- Maturity: early-clinical

## Sources

- PHOENIX-GC: intraperitoneal plus intravenous paclitaxel with S-1 versus standard chemotherapy in gastric cancer with peritoneal metastasis (Journal of Clinical Oncology 2018): https://doi.org/10.1200/JCO.2018.77.8613

## Connected records

- cancers: [Gastric & gastro-oesophageal junction cancer](https://onco.cc/cancers/gastric/)
- technologies: [HIPEC / PIPAC (intraperitoneal chemotherapy)](https://onco.cc/technologies/hipec/)
- drugs: [Paclitaxel / nab-paclitaxel](https://onco.cc/drugs/paclitaxel/), [Satricabtagene autoleucel](https://onco.cc/drugs/satricabtagene-autoleucel/)
- terms: [Peritoneal metastasis](https://onco.cc/terms/peritoneal-metastasis/)
- key papers: [Phase III Trial Comparing Intraperitoneal and Intravenous Paclitaxel Plus S-1 Versus Cisplatin Plus S-1 in Patients With Gastric Cancer With Peritoneal Metastasis: PHOENIX-GC Trial](https://onco.cc/key-papers/paper-ishigami-j-clin-oncol/)
- bottlenecks: [Metastasis is understood least and studied last](https://onco.cc/bottlenecks/b-metastasis-biology/)

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