BMC Cancer Research article Molecular detection (k-ras) of exfoliated tumour cells in the pelvis is a prognostic factor after resection of rectal cancer? Annette Torgunrud Kristensen*1,2, Johan N Wiig1, Stein G Larsen1, Karl- Erik Giercksky1,2 and Per O Ekstrøm1 BioMed Central Open Access Address: 1Section for Surgical Oncology, Rikshospitalet-Radiumhospitalet Medical Center, Montebello, Oslo, Norway and 2The Faculty of Medicine, University of Oslo, Norway Email: Annette Torgunrud Kristensen* - a.t.kristensen@medisin.uio.no; Johan N Wiig - Johan.Wiig@radiumhospitalet.no; Stein G Larsen - Stein.Larsen@radiumhospitalet.no; Karl-Erik Giercksky - karl-erik.giercksky@radiumhospitalet.no; Per O Ekstrøm - peroe@radium.uio.no * Corresponding author Published: 27 July 2008 BMC Cancer 2008, 8:213 doi:10.1186/1471-2407-8-213 This article is available from: http://www.biomedcentral.com/1471-2407/8/213 Received: 9 January 2008 Accepted: 27 July 2008 © 2008 Kristensen et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract Background: After total mesorectal excision (TME) for rectal cancer around 10% of patients develops local recurrences within the pelvis. One reason for recurrence might be spillage of cancer cells during surgery. This pilot study was conducted to investigate the incidence of remnant cancer cells in pelvic lavage after resection of rectal cancer. DNA from cells obtained by lavage, were analysed by denaturing capillary electrophoresis with respect to mutations in hotspots of the k-ras gene, which are frequently mutated in colorectal cancer. Results: Of the 237 rectal cancer patients analyzed, 19 had positive lavage fluid. There was a significant survival difference (p = 0.006) between patients with k-ras positive and negative lavage fluid. Conclusion: Patients with k-ras mutated cells in the lavage immediately after surgery have a reduced life expectation. Detection of exfoliated cells in the abdominal cavity may be a useful diagnostic tool to improve the staging and eventually characterize patients who may benefit from aggressive multimodal treatment of rectal cancer. Background Cancer of the rectum is frequent in both genders and the incidence in Norway is still increasing, with a total of 1137 new cases in a population of 4.6 million citizens in 2004 [1]. Survival in cancer of rectum has continuously improved in the past ten year period [1,2]. The main rea- sons for this is the introduction of total mesorectal exci- sion (TME) [3] and better staging with adjuvant treatment for patient in high risk groups [4]. In spite of such improvement, local recurrence after potentially curative surgery is a major problem. There are several possible causes for local recurrences including: incomplete resec- tion of the primary carcinoma [4,5], insufficient removal of involved regional lymph nodes [6], development of a secondary tumour near the suture site and exfoliated can- cer cells released at the time of surgery [7]. Dissemination of tumour cells in the presacral space, as well as in tumour lymphatic drainage and in peripheral blood vessels after resection of the tumour, might play a role in the metasta- sis process, thus affecting the clinical course. Previous reports have indicated that tumours can release DNA into the circulation [8-10]. Hence, recovery of mutated cell by Page 1 of 8 (page number not for citation purposes)