Long-term results of CCG 5942: a randomized comparison of chemotherapy with and without radiotherapy for children with Hodgkin's lymphoma--a report from the Children's Oncology Group

Abstract

Purpose: In 1995, the Children's Cancer Group (CCG) opened a trial for patients with Hodgkin's lymphoma evaluating whether low-dose involved-field radiation therapy (IFRT) improved event-free survival (EFS) for patients achieving a complete response after chemotherapy. We present the long-term study outcome using final data through March 2007.

Patients and methods: Between January 1995 and December 1998, 826 eligible patients were enrolled onto CCG 5942. Four hundred ninety-eight patients achieving an initial complete response to chemotherapy were randomly assigned to receive IFRT or no further therapy. EFS and overall survival (OS) were assessed from the date of study entry or random assignment, as appropriate.

Results: Ten-year EFS and OS rates for the entire cohort were 83.5% and 92.5%, respectively. In an as-treated analysis for randomly assigned patients, the 10-year EFS and OS rates were 91.2% and 97.1%, respectively, for IFRT and 82.9% and 95.9%, respectively, for no further therapy. For EFS and OS comparisons, P = .004 and P = .50, respectively. Bulk disease, "B" symptoms, and nodular sclerosis histology were risk factors for inferior EFS.

Conclusion: With a median follow-up of 7.7 years, IFRT produced a statistically significant improvement in EFS but no improvement in OS. For individual patients, the relative risks of relapse versus late effects of IFRT must be considered. Patient and disease characteristics and early response assessment will aid in deciding which patients are most likely to benefit from IFRT.

Fig 1.

CONSORT diagram.

Fig 2.

Study schema. COPP/ABV, cyclophosphamide, vincristine, procarbazine, and prednisone/doxorubicin, bleomycin, and vinblastine; CR, complete response; LD-IFRT, low-dose involved-field radiation therapy; PR, partial response. Data adapted.

Fig 3.

Event-free survival (EFS) and overall survival (OS) from the time of study entry for all patients. Ten-year EFS is 83.5% (SE, 1.3%), and 10-year OS is 92.5% (SE, 1.0%).

Fig 4.

As-treated event-free survival analysis for randomly assigned patients. Ten-year event-free survival rates with involved-field radiation therapy (IFRT) and no radiation therapy (RT) are 91.2% (SE, 2.0%) and 82.9% (SE, 2.4%), respectively (P = .004).

Fig 5.

As-treated overall survival analysis for randomly assigned patients. Ten-year overall survival rates with involved-field radiation therapy (IFRT) and no radiation therapy (RT) are 97.1% (SE, 1.2%) and 95.9% (SE, 1.3%), respectively (P = .50).