Prognostic utility of silver stained nucleolar organiser region counting in non Hodgkin's lymphoma.

Silver stained Nucleolar Organiser Region (AgNOR) counting is a well established method of estimating the proliferative activity of a tumour. Their utility in prognostication in Non Hodgkin's Lymphoma (NHL) has not been fully investigated. We analysed hundred cases of NHL, all of which had a minimum of two and a half years of follow up, using histology by International Working Formulation (IWF) and their AgNOR scores. We found the IWF grading to have a good correlation with the outcome. The two and a half year survival for low grade NHL was 90 percent, for intermediate grade NHL was 47 percent and for high grade NHL was 30 percent. AgNOR scores correlated well with IWF grading and classification, with average AgNOR score of 1.82 (SD 0.34) in low grade NHL; 4.47 (SD 2.25) in intermediate grade NHL and 7.07 (SD 4.40) in high grade NHL. Over histology, AgNOR counting yielded additional prognostic information only in the diffuse small cleaved cell NHL (DSC), where finely dispersed NORs were seen. Of the 22 case of DSC included, 11 cases with AgNOR scores less than three had a much better outcome with 75 percent survival at two and a half years. Cases of DSC with AgNOR scores greater than three had a significantly worse outcome with only 25 percent survival at two and a half years (p=0.0103). Such sub-stratification could not be done in any other catergory of NHL using AgNOR scores. Thus, counting of AgNORs in lymphomas with finely dispersed NORs as in DSC is of prognostic value.