Posted by July 13th, 2010
Some colon cancer patients don’t benefit from treatment with 5-FU based chemotherapy and may even have worse outcomes than if they no chemo at all.
Of every 100 people with colon cancer, about 15 will have cancers that arise when mistakes in DNA during cell division are not caught and fixed. Scientists call this defective mismatch repair or dMMR.
More often, colon cancer occurs when mutations in chromosomes accumulate but DNA repair pathways remain intact and mismatch repair is proficient (pMMR). This is true for about 85 percent of colon cancer.
Both prognosis and the potential benefit from FU-based chemotherapy appear to be very different for these two types of colon cancer. Knowing mismatch repair status of colon tumors can help patients and their doctors make better treatment decisions.
Patients with defective mismatch repair have better disease-free and overall survival and don’t seem to benefit from 5-FU at either stage II or stage III. Stage II patients with dMMR have significantly poorer overall survival if they get chemo after surgery.
Caution: These results come from studies of 5-FU plus levamisole or 5-FU plus leucovorin. They don’t include any information from the current standard treatments of FOLFOX or FLOX which contain oxaliplatin in addition to 5-FU and leucovorin.
Read the rest of this entry »