Large mediastinal tumor mass as a prognostic factor in Hodgkin's lymphoma. Is the definition on the basis of a chest radiograph in the era of CT obsolete?

PURPOSE: The risk factor "large mediastinal tumor mass" is an internationally accepted unfavorable prognostic factor in the staging of Hodgkin's lymphoma (HL). The definition of this risk factor varies considerably between large cooperative study groups. The purpose of the present analysis was to determine to which degree data obtained from chest radiograph (CRX) give the same results as those from CT scans (CT).

METHODS: A total of 145 de novo HL patients in early unfavorable and advanced stages were included in this study. A total of 94 patients had a large mediastinal tumor mass according to the guidelines of the German Hodgkin Study Group (GHSG), while 51 had mediastinal lymph node involvement only. The size of mediastinal involvement and the thoracic diameter were measured on CRX and CT. Agreement between CRX and CT was determined by sensitivity and specificity analysis as well as descriptive statistics and correlations.

RESULTS: The correlation of the diameters on CRX with those of CT was 0.95 for the tumor size and 0.77 for the thoracic diameter. The diagnostic decision-large mediastinal mass or not-correlated with 0.81 between CRX and CT and was identical in 90.3% of cases. The sensitivity was 0.87 and the specificity 0.96 for CRX, which is considered the current standard.

CONCLUSION: The results show that there is a high agreement between the measurements of CRX and CT. Diagnosis of a large mediastinal mass disagreed in 10% of patients. Since the correct diagnosis of this risk factor is decisive for the adequate multimodal treatment choice, CRX should not be omitted.