BMC Cancer 2008, 8:213 http://www.biomedcentral.com/1471-2407/8/213 Table 2: Clinical and pathologic information for the 19 patients with a positive k-ras marker in the lavage fluid. Age Gender Otepcenriaqtuioen sStaamtupsle* Recurrent♣ peTrufomroatuiorn Metastatic T R N infSiletrroatsiaon Pecmareractteionnsoeo-al 69 M LAR primary yes yes no T3 R0 N0 no no 64 M APR primary no no no T3 R0 N2 no no 76 M APR primary no yes no T3 R0 N1 no no 71 K Hartmann local no no no unknown R0 Nx yes no recurrent 61 F APR recloucrraelnt no no no unknown R0 Nx no no 60 F LAR primary no no no T3 R0 N1 no no 77 M LAR primary no no no T3 R0 N0 no no 64 F LAR primary no no no T3 R0 N2 no no 49 F APR primary no no no T3 R0 N2 no no 60 M APR primary no no yes T2 R0 N1 no no 68 M LAR primary no no no T2 R0 N0 no no 71 M APR primary no no no T3 R0 N0 no no 61 M TumorRes recloucrraelnt yes yes yes unknown R1 Nx no no 82 M APR recloucrraelnt no no no T4 R1 Nx no no 59 F LAR primary no no no T3 R1 N0 possible unsertain 46 K Hartmann primary yes yes yes T4 R2 N0 no yes 66 M EksplLap primary yes unknown yes T4 R2 Nx unknown yes 69 M EksplLap recloucrraelnt yes no no unknown R2 unknown no no 78 M Hartmann recloucrraelnt yes yes no T4 R2 Nx no no APR: Abdominoperineal resection, LAR: Low anterior resection, EkspI. Lap: Explorative laparotomy * Sample status describes when the patient's tumour is classified either as a primary or a local recurrence. ♣ Recurrent describes whether or not the patients have developed a local recurrence after the surgery (when samples were retrieved). Time (months observed) 26 39 11 19 16 15 12 11 4 8 3 3 22 18 3 21 1 18 2 Status Dead Dead Dead Dead Dead Alive Alive Alive Alive Alive Alive Alive Dead Alive Alive Alive Dead Dead Dead Gross (R2) or microscopic (R1) positive surgical margins are well known indicators of recurrence and survival. However, our results showed that 12 of the 19 positive k- ras cases were R0 resections, which was an unpredicted result. Resection into the circumference of macroscopic (R2 resection) or microscopic tumour (R1 resection) or into the depth of the tumour can of course contribute to disseminated cells in the peritoneal cavity as well as is in cases with tumour penetration of serosa or in overt perito- neal carcinomatosis. As there were relatively more R0 stage resections in the k-ras negative group this is unlikely to explain our finding. Lymph node metastases might contribute by the shedding of cancer cells from a surgi- cally severed lymphatic vessel. Several groups have observed a relationship between the number of lymph nodes identified at pathological examination and survival Page 5 of 8 (page number not for citation purposes)