COMPUTED-TOMOGRAPHY ASSESSMENT OF SPLENIC SIZE AS A PREDICTOR OF SPLENIC WEIGHT AND DISEASE INVOLVEMENT IN LAPAROTOMY STAGED HODGKINS-DISEASE

Purpose: To evaluate how well splenic size predicts the risk of spleni c Hodgkin's disease and to assess how accurately splenic dimensions on computerized tomographic scans predict spleen size and involvement by Hodgkin's disease. Methods and Materials: Splenic weights were obtain ed from laparotomies performed on 897 patients who presented with Hodg kin's disease and were compared with histologic involvement using logi stic regression. Splenic dimensions were measured from preoperative co mputerized tomographic scans in 94 of these patients, and unidimension al splenic measurements [length (L), width (W), thickness (T)] and the ir products were compared with splenic weight at laparotomy using line ar regression. Results: Hodgkin's disease involved 42% of the spleens at laparotomy and 31% of those assessed by computerized tomography. Sp lenic weight averaged 198 +/- 5 g (range 40-2000 g). Weight and involv ement were greater with ''unfavorable'' histologies (mixed cellularity , lymphocyte depletion, and unclassified Hodgkin's disease: 229 +/- 12 g; 62.7% involved) than with ''favorable'' histologies (nodular scler osing, lymphocyte predominant, and interfollicular Hodgkin's disease: 191 +/- 5 g; 37.8% involved). Splenic weight was the strongest indepen dent risk factor correlated with Hodgkin's disease in univariate and m ultivariate analyses in all patients and the only identifiable univari ate risk factor among those with computerized tomographic scans. For m ost patients, however, splenic weight poorly predicted involvement: Th e probability of involvement never fell below 20% and exceeded 80% whe n splenic weight exceeded 270 g with unfavorable histologies or 685 g in favorable histologies. Spleens of average weight had a probability of involvement of 36% with favorable histologies, 70% with unfavorable histologies. Unidimensional measurements of the spleen on computed to mography correlated poorly with splenic weight, but their product corr elated well (Correlation coefficients: L: 0,73; W: 0.65; T: 0.78; [0.3 44485 x L x W x T]: 0.94). Conclusions: Splenic weight is the stronges t factor correlating with the risk of splenic involvement by Hodgkin's disease and can be accurately estimated from three-dimensional measur ements on computed tomographic scans, but not from unidimensional meas urements. However, splenic weight is not a sensitive predictor of invo lvement of the spleen by Hodgkin's disease. Therefore, treatment appro aches to Hodgkin's disease must be based upon intermediate risks of sp lenic involvement for most clinically staged patients.