Note: Some citations in the text of this section are followed by a level of evidence. The PDQ editorial boards use a formal ranking system to help the reader judge the strength of evidence linked to the reported results of a therapeutic strategy. (Refer to the PDQ summary on Levels of Evidence for more information.)
Stage IV colon cancer denotes distant metastatic disease. Treatment of recurrent colon cancer depends on the sites of recurrent disease demonstrable by physical examination and/or radiographic studies. In addition to standard radiographic procedures, radioimmunoscintography may add clinical information that may affect management. Such approaches have not led to improvements in long-term outcome measures such as survival.
The World Health Organization (WHO) classification of tumors of the colon and rectum include the following:
Intraepithelial neoplasia (dysplasia) associated with chronic inflammatory diseases
Low-grade glandular intraepithelial neoplasia.
High-grade glandular intraepithelial neoplasia.
Signet-ring cell carcinoma...
Surgical resection and anastomosis or bypass of obstructing or bleeding primary lesions in selected metastatic cases.
Resection of liver metastases in selected metastatic patients (5-year cure rate for resection of solitary or combination metastases exceeds 20%) or ablation in selected patients.[2,3,4,5,6,7,8,9,10,11]
Resection of isolated pulmonary or ovarian metastases in selected patients.
Clinical trials evaluating new drugs and biological therapy.
Clinical trials comparing various chemotherapy regimens or biological therapy, alone or in combination.
Approximately 50% of colon cancer patients will be diagnosed with hepatic metastases, either at the time of initial presentation or as a result of disease recurrence. Although only a small proportion of patients with hepatic metastases are candidates for surgical resection, advances in tumor ablation techniques and in both regional and systemic chemotherapy administration provide for a number of treatment options.
Hepatic metastasis may be considered to be resectable based on the following:[5,7,13,14,15,16]
Limited number of lesions.
Intrahepatic locations of lesions.
Lack of major vascular involvement.
Absent or limited extrahepatic disease.
Sufficient functional hepatic reserve.
For patients with hepatic metastasis considered to be resectable, a negative margin resection has resulted in 5-year survival rates of 25% to 40% in mostly nonrandomized studies, such as the NCCTG-934653 trial.[5,7,13,14,15,16] Improved surgical techniques and advances in preoperative imaging have allowed for better patient selection for resection.
Patients with hepatic metastases that are deemed unresectable will occasionally become candidates for resection if they have a good response to chemotherapy. These patients have 5-year survival rates similar to patients who initially had resectable disease. Radiofrequency ablation has emerged as a safe technique (2% major morbidity and <1% mortality rate) that may provide for long-term tumor control.[18,19,20,21,22,23,24] Radiofrequency ablation and cryosurgical ablation [25,26,27,28] remain options for patients with tumors that cannot be resected and for patients who are not candidates for liver resection.