[Pharmaco-dynamic influence under ascites or laparotomy on intraperitoneal sequential MTX/5-FU therapy]

Area of Science:

• Oncology
• Pharmacology
• Gastroenterology

Context:

• Gastric cancer treatment often involves chemotherapy, with intraperitoneal administration being a key route.
• Malignant ascites can alter drug distribution and elimination in cancer patients.
• Understanding drug pharmacodynamics is crucial for optimizing treatment efficacy and managing toxicity.

Purpose:

• To investigate the pharmacokinetic and pharmacodynamic differences of intraperitoneal sequential methotrexate (MTX) and 5-fluorouracil (5-FU) in gastric cancer patients.
• To evaluate the impact of malignant ascites on MTX and 5-FU serum and ascites levels.
• To assess the influence of gastrectomy on the pharmacodynamics of this sequential therapy.

Summary:

• Intraperitoneal MTX clearance was significantly slower in gastric cancer patients with malignant ascites compared to those without.
• In patients with ascites, serum MTX peaked later (8 hours) and ascites MTX levels reduced to 1/10th within 2 days.
• Malignant ascites caused a minor prolongation of serum and ascites 5-FU levels, while gastrectomy did not impact MTX pharmacodynamics on post-operative days 1, 8, and 15.

Impact:

• Findings highlight the need to adjust MTX dosing or administration schedules in gastric cancer patients with malignant ascites.
• This study provides critical data for refining intraperitoneal chemotherapy protocols in complex patient populations.
• Understanding these pharmacodynamic alterations can lead to improved therapeutic outcomes and reduced side effects.