Patients with newly diagnosed chronic lymphocytic leukemia should standardly undergo immunoglobulin heavy-chain variable region gene (IGHV) mutation status and interphase fluorescence in situ hybridization (FISH) tests, based on the results of a meta-analysis published in Blood.
“This change will help define the minimal standard initial prognostic evaluation for patients with CLL and help facilitate use of the powerful, recently developed, integrated prognostic indices, all of which are dependent on these 2 variables,” wrote Dr. Sameer A. Parikh of Mayo Clinic, Rochester, Minn., and associates.
By Gregor1976 via Wikimedia Commons
Human lymphocyte nucleus stained with DAPI with chromosome 13 (green) and 21 (red) centromere probes hybrydized (FISH).
IGHV and FISH have prognostic value independent of clinical stage in patients with newly diagnosed and previously untreated CLL, they said (Blood. 2016;127[14]:1752-60). Better understanding of the patient’s risk of disease progression at diagnosis can guide counseling and follow-up intervals, and could potentially influence the decision to treat high-risk patients on early intervention protocols.
IGHV and FISH also appear to provide additional information on progression-free and overall survival.
The researchers cautioned, however, that the results of these tests should not be used to initiate CLL-specific therapy. Only patients who meet indications for therapy based on the 2008 International Workshop on Chronic Lymphocytic Leukemia guidelines should receive treatment.
Further, they noted, the median age of patients included in studies that they analyzed was 64 years; the median age of patients with CLL is 72 years. The prognostic abilities of IGHV mutation and FISH may differ in these older individuals with CLL.
The researchers analyzed 31 studies that met the criteria for inclusion – full-length publications that included at least 200 patients and reported on the prognostic value of IGHV and/or FISH for predicting progression-free or overall survival in patients with newly diagnosed CLL.
They found that the median progression-free survival (range, about 1-5 years) was significantly shorter for patients with unmutated IGHV genes, than was the median progression-free survival (range, about 9-19 years) for those with mutated IGHV genes. Similarly, the median overall survival was significantly shorter for patients with unmutated IGHV (range, about 3-10 years) than for those with mutated IGHV (range, about 18-26 years).
For patients with high-risk FISH (including del17p13 and del11q23), the median progression-free survival was significantly shorter (range, about 0.1-5 years) than for those with low/intermediate-risk FISH (including del13q, normal, and trisomy 12; range, about 1.5-22 years). Median overall survival also significantly differed, ranging from about 3-10 years for patients with high-risk FISH and from about 7.5-20.5 years for those with low/intermediate-risk FISH.
In multivariable analyses, the hazard ratio for high-risk FISH ranged from 1.3 to 4.7 for progression-free survival and from 0.9 to 8.2 for overall survival. In studies reporting the results of multivariable analysis, high-risk FISH remained an independent predictor of progression-free survival in 8 of 17 studies and of overall survival in 10 of 14 studies, including in 10 of 13 studies adjusting for the prognostic impact of IGHV.
In multivariable analyses, IGHV remained an independent predictor of progression-free survival in 15 of 18 studies, including 12 of 15 studies adjusting for the prognostic impact of FISH. IGHV remained an independent predictor of overall survival in 11 of 15 studies reporting the results of multivariable analysis, including 10 of 14 studies adjusting for the prognostic impact of FISH.