Interesting article addressing this question is now available as "Full Free Text" from Clin Cancer Res Published OnlineFirst April 29, 2011.
Original summary on MDLinx:
Holdhoff M et al. –Mutant tumor-specific DNA can be detected beyond the visible tumor margin, but never beyond 4 mm, even in patients whose tumors were larger prior to chemotherapy. These data provide a rational basis for determining the extent of surgical excision required in patients undergoing resection of liver metastases.
- Evaluated 88 samples of tumor margins from 12 patients with metastatic colon cancer who each underwent partial hepatectomy of one to 6 liver metastases
- Punch biopsies of surrounding liver tissue obtained at 4, 8, 12 and 16 mm from the tumor border
- DNA from these biopsies analyzed by sensitive PCR-based technique, called BEAMing, for mutations of KRAS, PIK3CA, APC, or TP53 identified in corresponding tumor
- Mutations were identified in each patient's resected tumor and used to analyze the 88 samples circumscribing the tumor-normal border
- Tumor-specific mutant DNA was detectable in surrounding liver tissue in five of these 88 samples, all within 4 mm of the tumor border
- Biopsies 8, 12, and 16 mm from macroscopic visible margin were devoid of detectable mutant tumor DNA as well as of microscopically visible cancer cells
- Tumors with significant radiologic response to chemotherapy were not associated with any increase in mutant tumor DNA in beyond 4 mm of main tumor
Read the full article here