Background: Evaluation of practical value of monitoring t(14:18) in peripheral blood in follicular lymphoma.
Methods and results: t(14;18) was tested in 115 follicular lymphoma patients by methods: FISH, nested and multiplex PCR of blood, bone marrow and lymph node specimens. We tested the patients with rearrangement MBR quantitatively by real-time PCR. Testing intervals of t(14;18) in peripheral blood were 1 month during treatment, 2-3 months during the first year after the end of treatment, then every 4 to 6 months. Patients were clinically examined in the same intervals and regular restaging was done by CT/PET. Each patient was evaluatee separately. Total detection of t(14;18) was 97% regardless tissue and methods of detection, FISH was superior to PCR (95% vs. 72%). The higher number of copies were observed in lymph nodes in comparison to bone marrow (p = 0.036) and peripheral blood (p = 0.016); 46/115 (40%) patients were positive for MBR, we followed up behaviour of t(14;18) in peripheral blood in 33 of them in long intervals (>6 months, med. 33 months). Molecular and clinical courses correlated in 20/33 (61%) patients, 7/33 (21%) clinically relapsed in lasting molecular remission. We found very short interval to clinical relaps in 7 cases of molecular relapses (0-5 months, median 3 months). We could not define "threshold quantity" of clinically important molecular relaps. Lasting molecular remission was associated with clinical in about 60% cases; lasting molecular activity corresponded with clinical relaps in 86% patients.
Conclusions: t(14;18) is highly associated with follicular lymphoma. In practice, monitoring of t(14;18) is feasible only in part of patients. Even if there is some correlation of clinical and molecular course, monitoring of t(14;18) in blood bears only limited prognostic value for the concrete patient. The treatment of patient can not be accomplished on the basis of these results only.