Significantly improved survival after making liver metastases operable

The authors evaluated the effectiveness of chemotherapy and targeted therapy for patients with initially unresectable (inoperable) colorectal liver metastases.

Liver resection (surgical removal of cancerous tissue from the liver) with chemotherapy is the standard procedure as well as the only curative treatment for colorectal liver metastases (spread of colorectal cancer to the liver). Patients may be categorized depending on whether the metastases are initially resectable, marginally resectable or unresectable. The percentage of patients with initially resectable metastases is estimated to be less than 25%.

When marked tumor shrinkage results after induction chemotherapy (chemotherapy administered before usual surgery and chemotherapy), colorectal liver metastases that were initially unresectable may become resectable. This is called conversion therapy, and is associated with a more favorable long-term prognosis (outlook).

This study evaluated the effectiveness of a chemo and targeted therapy regimen in converting unresectable liver metastases to resectable metastases, and the associated long-term survival.

199 patients with liver metastases were treated. Initial therapy included straightforward hepatic resection (24% of patients), induction chemotherapy followed by surgery (74%) and radiofrequency ablation (2%). 

In 56 of 137 patients (40.9%) with initially unresectable liver metastases, tumors were downsized and converted to resectable tumors. 

In the patients with resectable liver metastases, the 5-year overall survival rate was 54.6% and the average survival time was 77.3 months. In the patients with unresectable liver metastases the 5-year overall survival rate was 5.3% and the average survival time was 21.3 months.

Conversion hepatectomy (removal of cancer tissue from the liver following change from nonresectable to resectable liver metastases) was associated with an 81% decreased risk of mortality while response to chemo and targeted therapy was associated with a 54% decreased risk.

Cancer originating from the left side of the colon or the rectum was associated with 8.4 times the odds of conversion. The absence of metastases outside the liver was associated with 52.6 times the odds of conversion while response to chemo and targeted therapy was associated with 6.1 times the odds.

The authors concluded that chemo and targeted therapy can facilitate downsizing of liver metastases, sometimes allowing surgical removal. This approach is likely to significantly improve survival.