Management of liver metastases: New horizons for biologically based therapy

Currently, the only chance for cure in patients with colorectal liver metastases is surgical resection. Despite these encouraging results, only patients who have intrinsically favorable biology that limits spread of the disease are able to benefit from this therapy. In clinical practice, fewer than 10% of patients present with resectable disease, and only a third of resected patients enjoy long-term survival. These poor outcomes underscore the need for novel treatment strategies to manage this disease. Our knowledge of the histological and biochemical mechanisms of the processes of tumor progression and metastasis is increasing dramatically. Each step in the metastatic process can be manipulated with increasing precision. Anti-angiogenic factors are being developed to block the angiogenesis that allows tumors to grow in their new host tissue, while metalloproteinase inhibitors are being tested for their ability to block tumor cell digestion of the basement membrane. Gene therapy efforts continue to be frustrated by the low efficiency and specificity of transduction using current vectors, while a wide array of novel cancer cell vaccines are being tested in clinical trails. Despite the challenges ahead, the horizon for biologically based therapy holds the promise of new efficacious treatments.