Prognostic significance of mediastinal mass in adult Hodgkin's disease.
The authors analyzed the prognostic significance of mediastinal involvement with Hodgkin's disease in 169 pathologically stage adults (greater than or equal to 17 years) treated at the Mayo Clinic between 1974 and 1978. Sixty percent of the patients presented with mediastinal disease, evenly divided between those with a mediastinal to thoracic ratio (MTR) less than 0.33 and greater than or equal to 0.33. They were of younger average age and were more likely to have nodular sclerosis histologic subtype than those patients without a mediastinal mass. The median follow-up from diagnosis was 4.1 years with 90% of the patients being followed for 2 or more years. The 5-year disease-free survival (DFS) for the radiation only group was 70% in patients without mediastinal disease, 53% in the less than 0.33 MTR group and 44% in the greater than or equal 0.33 MTR group (P = 0.25). The 5-year survival was 92% in the patients without mediastinal disease, 88% in the less than 0.33 MTR group and 90% in the greater than or equal to 0.33 MTR group (P = 0.70). This lack of significant difference both in the 5-year DFS and survival between the three groups was also seen in the patients taken in toto (169) and in those receiving combined modality treatment (36). However, in early stage (I and II) patients, treated with radiation only, those with a large mediastinal mass had a 5-year DFS (33%) that was significantly worse than both the small mass patients (71%) and those with no mediastinal mass (87%) P less than 0.005). The pattern of relapse in the 40 patients who failed following treatment by radiation only was not affected by an increasing size of mediastinal involvement. At the time of this analysis 27 of the 40 patients who had relapsed following treatment by radiation only (all stages) had remained free from second relapse. The authors do not believe that the current data either support or negate the use of a combined modality approach in the initial treatment of Hodgkin's disease patients presenting with a large mediastinal mass. Only further follow-up will establish whether the treatment of patients, who have relapsed following radiation only, is durable and results in an overall survival comparable to that obtained by using combined modality initially.