CHOP Alone Compared to CHOP Plus Radiotherapy for Early Stage Aggressive Non-Hodgkin's Lymphomas: Update of the Southwest Oncology Group (SWOG) Randomized Trial

Mary Kara Bucci, MD
The Abramson Cancer Center of the University of Pennsylvania
Last Modified: December 10, 2001

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Presenter: T.P. Miller
Presenter's Affiliation: Arizona Cancer Center, Tuscon, AZ
Type of Session: Scientific

Background
In 1998, SWOG study 87-36 reported the results of a randomized trial comparing 8 cycles of CHOP chemotherapy with 3 cycles of CHOP + involved field radiotherapy (IFRT). With a median follow up of 4.4 years, there was a significant benefit in overall survival, failure-free survival, and toxicity seen in the IFRT arm (NEJM 339:21-26, 1998). This is an update of that report, now with a median followup of 8.2 years.

Materials and Methods

  • 401 patients were randomly assigned to 3 cycles of CHOP chemotherapy followed by IFRT (40-55 Gy)or 8 cycles of CHOP.
  • All patient had biopsy-proven Stage I, IE, or non-bulky Stage II or IIE. Patients with lymphoblastic histology were excluded.

    Results

  • 5-year overall survival (OS) with 8.2 years of follow up is 82% for the IFRT arm and 74% for the chemo alone arm.
  • 5-year failure-free survival (FFS) with 8.2 years of follow up is 76% for the IFRT arm and 67% for the chemo only arm.
  • The OS curves cross at 9 years.
  • The FFS curves cross at 7 years.
  • There were 15 relapses and deaths due to lymphoma in the IFRT arm between 5 and 10 years.
  • There were 8 relapses and deaths due to lymphoma in the chemotherapy alone arm during 5 and 10 years.
  • The 5-year overall survival for stage-modified international prognostic index (IPI) (modified to Stage I vs. Stage II) favorable prognostic group (no adverse risk factors: Stage I, age <60, normal serum LDH, performance status 0-1) was 94%.
  • 5-year OS for patients with 1 adverse risk factor on the stage-modified IPI was 71%.
  • 5-year OS for patients wtih 3 adverse risk factors was 50%.

    Author's Conclusions

  • The five-year estimates reported in 1998 do not significantly change with longer follow-up; there continues to be a significant improvement in 5-year OS and FFS in the IFRT arm.
  • The curves cross at 9 and 7 years due to excess risk of relapse and death due to lymphoma in the IFRT arm.
  • Late relapses suggest that a different or more intense regimen of chemotherapy may be optimal.
  • A very favorable prognosic group with an excellent 5-year survival can be identified and should not receive more intensive therapy.
  • 3 cycles of CHOP + IFRT remains the best regimen for Stage I and non-bulky Stage II disease due to the increased survival in the first 9 years.

    Clinical/Scientific Implications
    While CHOP x 3 + IFRT remains the best regimen for the group of patients studies, the late failures (between 5 and 10 years) in this group demonstrate a need for improved systemic therapy.

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