"Limited-Stage Follicular Lymphoma Might Be Curable: Presented at ICML"
By Chris Berrie
LUGANO, SWITZERLAND -- June 13, 2005 -- The absence of late relapses following moderate dose and volume radiotherapy argues that carefully selected patients with limited-stage follicular lymphoma can be cured using radiotherapy, according to results of a population-based study reported here June 10[th at the 9th International Conference on Malignant Lymphoma (ICML).
Although radiotherapy is a widely accepted treatment for limited-stage follicular lymphoma, it has not been determined whether patients can be cured with this therapy. It was generally believed that patients continue to relapse over many years after such treatment.
Principal investigator Nicholas Voss, MD, radiation oncologist, British Columbia Cancer Agency (BCCA), Vancouver, British Columbia, Canada, said, "We had long noticed that the long-term survival of localised low-grade lymphoma was suspected to fall off steadily, so we decided to look at this group, expecting to see a fall-off, and we were surprised when there were no late relapses."
They therefore decided to assess the long-term results of treatment with radiotherapy for limited-stage follicular lymphoma in this population-based group of patients in British Columbia (BC).
The BCCA has the exclusive responsibility for the delivery of radiation therapy over an area covering about 4 million residents of BC. Since 1986, the agency has a prospective database of all patients seen with malignant lymphoma, which allowed the researchers to review all the records of patients diagnosed with follicular lymphoma from then until 2004.
Of the 1455 patients identified with follicular lymphoma, 191 (median age, 63 years; range, 29-89 years; 46% male) had limited-stage disease that was treated with radiotherapy alone.
Over this period, the radiotherapy policy of the BCCA changed from involved region radiotherapy that encompassed the Anne Arbor nodal region (1986-1996), to involved field irradiation therapy that includes the involved nodes plus 5 cm above and below. For extranodal presentations, the regional nodes were not treated unless they were involved.
Dose applications were as follows: small fields, 30 Gy, 10 treatments; larger fields, 35 Gy, 20 treatments.
Inclusion criteria included patients who were 16 years old or older (no upper limit), who were treated with radiotherapy alone. The limited-stage definition for follicular lymphoma involved the clinical stages of IA or IIA, and a non-bulky lymphoma (< 10 cm) with fewer than 3 contiguous lymph node regions involved. All treatment with initial chemotherapy was excluded.
At presentation, these patients had follicular histologies of grades 1 (54%), 2 (33%), and 3 (13%), with Ann Arbor stages of IA (55%), IAE (17%), IIA (22%), and IIAE (6%). Forty-four patients (23%) showed a variety of extranodal sites.
With a median follow-up of 4.9 years, the collective progression-free survival rates (PFS) at 10, 15, and 18 years were 51%, 47%, and 47%, respectively, with a median of 10.75 years. Similarly, the overall survival rates were 64%, 45%, and 45%, respectively, with a median of 14.24 years.
When broken down into the individual datasets, there were no significant differences in the PFS between any of the follicular histology grades or Ann Arbor stages.
A further small subgroup of 36 patients who were treated with chemotherapy plus radiotherapy showed no late relapses and no additional benefits.
"If you carefully select [patients with] limited-stage follicular lymphomas and treat them, a proportion are likely to survive without showing relapse in the long term," Dr. Voss thus stressed.
He also put particular emphasis on the careful selection aspect, as limited stage, 3 or less areas of involvement, and non-bulky disease. Finally, for the clinic, he added, "Treat localised favourable follicular lymphoma with irradiation."
[Presentation title: Limited Stage Follicular Lymphoma. A Curable Disease? Abstract 243]
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