By Hae-ri Lim
HealthKoreaNews

SEOUL, South Korea, July 29 — A Korean Phase 2 study found that combining intraperitoneal paclitaxel with systemic FOLFOX chemotherapy enabled 40.9% of patients with gastric cancer and peritoneal metastasis to undergo conversion surgery, while producing a one-year overall survival rate of 86.4%.

The study was conducted by a research team led by Professor So-hyun Kang of the Department of Surgery and Professor Jin-won Kim of the Department of Hematology and Medical Oncology at Seoul National University Bundang Hospital.

Peritoneal metastasis occurs when gastric cancer cells spread across the lining of the abdominal cavity. Because the cancer is distributed over a broad surface, it is often difficult to remove surgically.

Systemic chemotherapy also has difficulty reaching cancer cells in the peritoneal cavity at sufficient concentrations because of the barrier between the bloodstream and the peritoneum. Patients treated with conventional systemic chemotherapy have historically had a median overall survival of about nine to 11 months, according to the researchers.

To address this limitation, the team implanted a port beneath the abdominal skin and used it to deliver paclitaxel directly into the peritoneal cavity. Patients simultaneously received intravenous FOLFOX chemotherapy to treat cancer cells both within the abdominal cavity and elsewhere in the body.

The investigator-initiated IPLUS Phase 2 trial enrolled 22 patients with gastric cancer and peritoneal metastasis between 2021 and 2022. The participants received intraperitoneal paclitaxel diluted in saline every two weeks in combination with systemic FOLFOX chemotherapy.

At one year after treatment initiation, the overall survival rate was 86.4%, while the progression-free survival rate was 63.6%. Median overall survival was 20.2 months.

Nine patients, or 40.9% of the study population, showed no visible peritoneal lesions after treatment and became eligible for conversion surgery. They subsequently underwent gastrectomy and lymph-node dissection, achieving complete removal of all macroscopically detectable disease.

Median overall survival among patients who underwent conversion surgery was 32.9 months.

The researchers said the findings demonstrate the potential of combining intraperitoneal and systemic chemotherapy to reduce peritoneal disease sufficiently for selected patients with stage 4 gastric cancer to undergo surgery.

"Systemic chemotherapy alone has difficulty delivering a sufficient concentration of anticancer drugs to cancer cells in the peritoneal cavity," Kang said. "Intraperitoneal chemotherapy is designed to overcome this limitation by delivering the drug directly to peritoneal lesions, and we will continue to evaluate its potential to improve survival."

The team is now conducting a multicenter Phase 3 trial involving 321 patients at six hospitals across South Korea. The study will further assess whether the combination therapy can improve survival and become a key treatment option for patients with gastric cancer and peritoneal metastasis.

The Phase 2 results were published in the international journal Gastric Cancer.