BMC Cancer 2008, 8:213 http://www.biomedcentral.com/1471-2407/8/213 mab) therapy and are associated with a an impaired prognosis [41]. In this study we found the frequency of k-ras mutations in tumour to be 30% and one-third of these showed k-ras mutations in the lavage fluid. Thus in 70% of these patients a k-ras mutant is absent. Therefore other gene mutations need to be investigated to obtain increased sen- sitivity. To date as mention earlier there is no general genetic marker that gives accurate information on the prognostic impact for patients with rectal cancer. New analyses of mutations or combinations of genes that are specific for rectal carcinoma might lead to better candi- dates. Detection of cancer specific markers in an abdomen without visible tumour deposits and with a proven increased risk of recurrence obviously imposes the ques- tion of additional therapy either as intraoperative hyper- thermic chemotherapy or systemic chemotherapy or any combination of these. It should be remembered that this is a pilot study that needs to be confirmed in an appropri- ate multicenter study before therapeutic considerations are carried out. Conclusion The overall clinical value of this molecular approach needs further elucidation. The k-ras gene seems to be a good genetic marker for detecting circulating tumour cells from rectal cancer patients. However, studies with gene markers covering a larger number of tumours are impor- tant. Examination of lavage fluids before and after surgery will further elucidate the mechanism of inducing exfoli- ated tumour cells. If our results are confirmed, in the future detection of disseminated cancer cells might enable the selection of high-risk patients with poorer prognosis, who would benefit from adjuvant treatment. Competing interests The authors declare they have no competing interests. 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