Angiogenesis index (AI) as a predictor of tumor burden in lymph nodes in colon cancer (Cca) patients (pts) undergoing sentinel lymph node (SLN) mapping (M)

Abstract

14509 Background: Lymph Node (LN) status is the most important prognostic factor in colon cancer (Cca). Angiogenesis Index (AI) has been studied as a prognostic marker in various solid tumors with conflicting results. Hence, a retrospective analysis was done to evaluate the role of AI as a prognostic marker in Cca. Methods: Pts with Cca who underwent SLNM to determine LN status were included. A portion of tumor was sent for tumor marker analysis including p53, Thrombospondin-1 and CD31 by IHC. AI was derived for each specimen by summing the biomarker specific score for the three tumor markers. AI of -ve 6 was taken as cut off for significance based on previous studies on solid tumors. Metastatic foci in SLNs and non-SLNs were measured in greatest diameter by ocular micrometer; and were added for each pt to estimate overall tumor burden in SLNs and non-SLNs. Results: A total of 111 consecutive pts with Cca were included in the study. SLNM was successful in 100% pts. Pts with distant metastasis (mets) (n=18), Tis (n=1) and skip mets (n=9) were excluded from final analysis. Out of the remaining 83 pts, an AI of -6 or less was found in 22 pts (26.5%) while 61 pts (73.5%) had AI of more than (>) -6. Of the 61 pts with AI > -6, 37.7% pts were SLN +ve while 62.3% pts were SLN -ve (p=0.05)( Table 1A ). Of the 22 pts with AI less than or -6, 45.5% pts were SLN +ve and 54.5% pts were SLN -ve (p=0.65). Size of the metastatic tumor burden in lymph nodes was available in 69.7% of SLN +ve pts. Total average tumor burden for pts with AI > -6 (n=15) was 2.04cm as compared to 1.48cm in pts with AI of -6 or less (n=8)(p=0.66). Average SLN met size was 0.73cm in pts with AI > -6 and 0.63cm in pts with AI of -6 or less (p=0.66)( Table 1B ). Conclusions: AI did not correlate with nodal positivity or tumor burden in LNs in pts with Cca. LN status remains the most important prognostic marker in Cca. Further larger trials are required to determine the role of AI as a prognostic marker in Cca. [Table: see text] [Table: see text] No significant financial relationships to disclose.