Non-resection approaches for colorectal liver metastases

Ablative therapies for colorectal liver metastases: a systematic review

AIM

The standard treatment for colorectal liver metastases (CRLM) is surgical resection. Only 20-30% of patients are deemed suitable for surgery. Recently, much attention has focused on ablative therapies either to treat unresectable CRLM or to extend the margins of resectability. This review aims to assess the long-term outcome and complication rates of various ablative therapies used in the management of CRLM.

METHOD

A literature search was performed of electronic databases including Medline, Cochrane Collaboration Library and the National Library of Medicine's ClinicalTrials.gov. Inclusion criteria were ablation for CRLM with minimum 1 year follow-up and >10 patients, published between January 1994 and January 2010.

RESULTS

In all, 226 potentially relevant studies were identified, of which 75 met the inclusion criteria. Cryotherapy (26 studies) had local recurrence rates of 12-39%, with mean 1-, 3- and 5-year survival rates of 84%, 37% and 17%. The major complication rate ranged from 7% to 66%. Microwave ablation (13 studies) had a local recurrence rate of 5-13%, with a mean 1-, 3- and 5-year survival of 73%, 30% and 16%, and a major complication rate ranging from 3% to 16%. Radiofrequency ablation (36 studies) had a local recurrence rate of 10-31%, with a mean 1-, 3- and 5-year survival of 85%, 36% and 24%, with major complication rate ranging from 0% to 33%.

CONCLUSION

Ablative therapies offer significantly improved survival compared with palliative chemotherapy alone with 5-year survival rates of 17-24%. Complication rates amongst commonly used techniques are low.

Liver ablation techniques: a review

BACKGROUND

Ablation techniques for unresectable liver carcinomas have evolved immensely since their introduction. Results of studies involving these techniques are restricted to reports of patient case series, which are often not presented in a standardised manner. This review aims to summarise the major studies in ablation technologies and present them in a way that may make comparison between the major modalities easier.

METHODS

All major databases (Medline, Cochrane, Embase and Pubmed) were searched for studies using microwave, radiofrequency or cryoablation to treat unresectable liver tumours. Only studies with at least 30 patients and 3-year follow-up were included. Complication, recurrence and survival rates of all studies are summarised and presented.

RESULTS AND CONCLUSION

It is difficult to compare ablation modalities, as probe design and energy sources have evolved rapidly over the last decade. Ablation offers an invaluable palliative option and in some cases it may offer rates of cure approaching that of surgical resection with lower morbidity and mortality. Perhaps the time has come, therefore, for prospective large-scale randomised control trials to take place comparing ablation modalities to each other and surgical resection.

Laparoscopy for metastatic colorectal cancer

Patients with metastatic disease from colorectal cancer are now living twice as long as they were one decade ago. With this increasing life expectancy, we are beginning to see these patients strive for an acceptable and improved quality of life. Medical advances have led to unanswered questions regarding the role of surgery in metastatic colorectal cancer. Despite the increasing application of laparoscopy for primary treatment of colorectal cancer, the appropriate role for laparoscopy in patients with stage IV disease has yet to be defined. This review addresses this topic and suggests treatment algorithms for patients with metastatic colorectal cancer. While unresectable, metastatic colorectal cancer remains incurable at the current time, continued advances will inevitably challenge this presumption and it is crucial to outline the role of laparoscopy in this patient population.

Modern multimodality approach to hepatic colorectal metastases: solutions and controversies

Hepatic resection for colorectal metastases, limited to the liver, has become the standard of care, and currently remains the only potentially curative therapy. Numerous single institutional reports have demonstrated long-term survival and there are no other treatment options that have shown a survival plateau. However, curative resection is possible in less than 25% of those patients with disease limited to the liver, which translates into only 5-10% of the original group developing colorectal cancer. To increase the number of patients who could benefit from hepatic resection, the last decade has seen considerable effort being directed towards novel approaches to permit curative hepatic resection such as: neoadjuvant systemic and regional chemotherapy, pre-operative portal vein embolization for hypertrophy of future liver remnant, staged hepatic resection and radio frequency ablation combined with resection for addressing multiple bilobar metastases. This article reviews development of these innovative multidisciplinary modalities and the aggressive surgical approach that has been adopted to extend the frontiers of surgical therapy for colorectal hepatic metastases.

H19 expression in hepatic metastases from a range of human carcinomas

AIMS

To investigate the expression of the imprinted oncofetal H19 gene in hepatic metastases derived from a range of human carcinomas and assess its prognostic value with the view of developing a DNA based treatment for such metastases.

METHODS

Non-radioactive in situ hybridisation for H19 RNA was performed on paraffin wax embedded sections of liver biopsies or partial hepatectomy specimens, taken from 80 patients with hepatic metastases derived from carcinomas from several medical centres in Israel. The degree of expression was graded qualitatively according to the number of cells expressing H19 and the intensity of staining. The medical files were searched for demographic data and survival times before and after diagnosis of hepatic metastases.

RESULTS

H19 expression was found in the hepatic metastases of 64 of 80 patients. High expression (higher staining grades) of H19 in the metastases was found in 43 of 80 patients. However, H19 expression status in the hepatic metastases did not correlate with either the length of time to development of metastasis or overall survival.

CONCLUSIONS

H19 is highly expressed in more than half of hepatic metastases derived from a range of carcinomas. Thus, these metastases may be suitable candidates for H19 DNA based treatment. Further studies are needed to determine whether H19 expression has prognostic value in metastatic liver disease using larger numbers of specific subtypes of primary carcinomas.