Computed tomography assessment of splenic size as a predictor of splenic weight and disease involvement in laparotomy staged Hodgkin's disease

Purpose: To evaluate how well splenic size predicts the risk of splenic 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 obtained from laparotomies performed on 897 patients who presented with Hodgkin's disease and were compared with histologic involvement using logistic regression. Splenic dimensions were measured from preoperative computerized tomographic scans in 94 of these patients, and unidimensional splenic measurements [length (L), width (W), thickness (T)] and their products were compared with splenic weight at laparotomy using linear regression. Results: Hodgkin's disease involved 42% of the spleens at laparotomy and 31% of those assessed by computerized tomography. Splenic weight averaged 198 ± 5 g (range 40-2000 g). Weight and involvement 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 sclerosing, lymphocyte predominant, and interfollicular Hodgkin's disease: 191 ± 5 g; 37.8% involved). Splenic weight was the strongest independent risk factor correlated with Hodgkin's disease in univariate and multivariate analyses in all patients and the only identifiable univariate risk factor among those with computerized tomographic scans. For most patients, however, splenic weight poorly predicted involvement: The probability of involvement never fell below 20% and exceeded 80% when 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 tomography correlated poorly with splenic weight, but their product correlated well (Correlation coefficients: L: 0,73; W: 0.65; T: 0.78; [0.344485 × L × W × T]: 0.94). Conclusions: Splenic weight is the strongest factor correlating with the risk of splenic involvement by Hodgkin's disease and can be accurately estimated from three-dimensional measurements on computed tomographic scans, but not from unidimensional measurements. However, splenic weight is not a sensitive predictor of involvement of the spleen by Hodgkin's disease. Therefore, treatment approaches to Hodgkin's disease must be based upon intermediate risks of splenic involvement for most clinically staged patients.