Preoperative tattooing and improved lymph node retrieval rates from colectomy specimens in patients with colorectal cancers.

HYPOTHESIS India ink tattooing at the time of colonoscopy increases the yield of lymph nodes found in pathological analysis of colectomy specimens. DESIGN Retrospective study. SETTING Virginia Mason Medical Center, Seattle, Washington. PATIENTS Two hundred nine patients with colorectal cancers underwent surgical resections between April 5, 2006, and June 25, 2009, at one institution. MAIN OUTCOME MEASURES A retrospective review of a prospectively collected database was performed, with review of pathology reports for all cases. Adequate lymph node analysis was defined as evaluation of at least 12 lymph nodes. RESULTS Of 209 patients undergoing resections, 174 had colonic neoplasms, and 35 had rectal neoplasms. Sixty-two of 174 patients with colon cancer had India ink tattooing at the time of colonoscopy. The mean (range) numbers of lymph nodes examined in tattooed and nontattooed specimens were 23 (7-77) and 19 (2-74), respectively (P = .03). At least 12 lymph nodes were analyzed for 87.1% of the tattooed specimens compared with 72.3% of the nontattooed specimens (P = .02). Eight of 35 patients with rectal cancer had India ink tattooing at the time of colonoscopy. Fifty-four percent of patients with rectal cancer had undergone neoadjuvant chemoradiotherapy. The median numbers of lymph nodes examined in tattooed and nontattooed specimens were 19 and 16, respectively. CONCLUSIONS Tattooing of colonic lesions at the time of preoperative colonoscopy seems to increase the quality of lymph node analysis. We advocate routine tattooing of all suspicious neoplasms at the time of colonoscopy.