What is the role of conversion chemotherapy?

This study assessed the survival rates and characteristics of metastatic colorectal cancer (CRC) patients with liver-limited disease (LLD) who underwent conversion chemotherapy.

Colorectal cancer patients may develop metastases (spread of the cancer to other distant organs and tissues of the body) and the liver is one of the first organs affected by metastases. CRC that has spread to the liver only is called liver limited disease (LLD). Complete removal of the liver metastases is the only curative treatment. However, in some cases the metastases might be inoperable, either due to large tumor size or number of metastases, which makes surgery difficult without damaging the entire organ. In these cases, conversion chemotherapy may be applied. This technique involves use of cytotoxic drugs that shrink the tumor to a level that can allow surgery. This study analyzed the impact of conversion therapy on CRC patients with LLD.

The study involved 114 patients with LLD. All patients received chemotherapy. 47 Patients were initially diagnosed as having resectable (operable) LLD and underwent surgery to remove the metastases after chemotherapy (resected group). The other 67 patients were initially diagnosed as inoperable. Of these, 12 became operable after chemotherapy (conversion group), while the rest of 55 patients remained inoperable after chemotherapy (unresected group). Patients were followed up for an average time of 2 years and the main parameters evaluated were overall survival or OS and disease-free survival or DFS (the time patients survived without the cancer returning).

Results showed that surgery to remove liver metastases was more invasive in patients in the conversion group compared to the resected group. DFS was significantly higher in patients in the resected group (16.6 months) than in the conversion group (3.2 months) OS was also higher in the resected group compared to the conversion group, but the difference was not statistically significant. The average OS was 57.8 months for the resected group, 40.5 months for the conversion group and 24.3 months for the unresected group. Patients with abnormal cancer markers in the blood (such as the carcinoembryonic antigen or CAE) and long hospital stays (more than 30 days) had a poorer OS.

In summary, in patients with initially inoperable tumors, OS for conversion group was higher than in the unresected group. Therefore, conversion chemotherapy could contribute to longer OS in CRC patients with LLD.

The study had a small number of patients in the conversion group. Larger studies are needed to confirm these findings.