Personalized cancer treatment based on tumor fluid testing

This trial is testing a new approach called PTC drug sensitivity testing, which analyzes fluid that builds up around advanced tumors to help doctors predict which chemotherapy drugs will work best for each patient. Researchers will collect a small sample of this fluid, test it in the lab to see which medications the cancer cells respond to, and then give participants two rounds of personalized treatment based on those results. The goal is to see if this testing method can help improve outcomes for people with advanced lung, breast, gastric, or colorectal cancer.

Many advanced cancer patients don't respond well to standard chemotherapy treatments, and doctors often have to try multiple drugs before finding one that works. This trial exists to see if testing tumor fluid in advance can help doctors predict which medications will be effective for each individual patient, potentially saving time and reducing side effects from ineffective drugs.