Comparing combined versus sequential chemotherapy for patients with advanced colorectal cancer

This trial compared the effect on disease progression and survival of different chemotherapy combinations used in the treatment of patients with metastatic colorectal cancer. 

Metastatic colorectal cancer (mCRC) is cancer that has spread from the large intestine to other organs and tissues. Chemotherapy (treatment with toxic anticancer drugs) is so far the best treatment option for delaying the advance of the disease in these patients. Fluorouracil, irinotecan and oxaliplatin are some of the chemotherapies commonly used. They work by attacking cells that multiply rapidly (such as cancer cells), thus stopping them from multiplying, and killing them. Therefore, chemotherapy can stop the cancer from growing or advancing. These drugs can be administered by themselves or together, in several combinations. This trial compared the use of several chemotherapy drugs combined and given together versus the use of individual drugs given sequentially (one after the other) in patients with mCRC.

This trial included 410 patients with mCRC. Patients were divided into two groups. 205 patients were treated with sequential chemotherapy. They were first treated with fluorouracil alone and when the cancer advanced, they received a second treatment with fluorouracil and oxaliplatin (a combination called FOLFOX6). If the cancer still advanced, the last treatment included FOLFOX6 and irinotecan (a combination called FOLFIRI). The remaining 205 patients were treated from the beginning with the combination FOLFOX6 as first therapy and FOLFIRI as second therapy.

Results showed that, although the cancer showed better response to initial treatment in the combined therapy group, progression free survival (defined as the time without the cancer progressing) was not different between the two groups. Overall survival (defined as the time patients survived after treatment) was also similar in the two groups. However, patients treated with sequential therapy had significantly less toxic side effects.

In summary, this study showed that combination therapy was associated with more toxic side effects than sequential therapy, but was not more effective in terms of disease progression and survival of patients with mCRC.

This study only included patients with very progressive cancers, such as those that could not be surgically treated at all. This might explain why survival rates in this trial were significantly lower than other similar trials.

Consult with your doctor regarding the best chemotherapy regimen for your condition.