THE INCIDENCE OF SECONDARY TUMORS IS NOT HIGHER IN PATIENTS TREATED FOR CLL COMPARED TO THE UNTREATED COHORT OF PATIENTS BUT IT IS HIGHER IN OLDER COMPARED WITH YOUNGER TREATED PATIENTS

Sborník

It is generally accepted that patients with CLL are in the higher risk of secondary tumors compared to the nonCLL population. Moreover, it has been demonstrated that some of the antileukemic treatments can be associated with secondary malignancies. There is however lack of data comparing treated and untreated populations.We have performed population based analysis of CLL patients diagnosed between 1977-2009 and recorded in the National Cancer Registry. Standard descriptive (median, percentile range) and epidemiological (crude incidence rate) statistics were used. The cumulative incidence of multiple malignancies developed over the time was estimated using standard KM estimates. Different cohorts were compared using Gray’s test.Altogether 14408 pts with median age 70 years were included into the analysis. The crude incidence of tumors in this population was 2137 pts (14.9%). Out of these pts 861 (6,0%)were diagnosed before or concurrently with the CLL diagnosis. Altogether 1276 were diagnosed after the CLL diagnosis. Out of tumors after CLL dg , most frequent secondary malignancies were: lung cancer (18.8%), colorectal cancer (16.0%), prostate cancer (9.1%), renal cancer (7.4%), urine bladder cancer (5.8%), melanoma (5.1%). The cumulative incidence of secondary tumors at 5, 10 and 15 years resp. was 10, 14 and 16% resp. There was no significant difference between treated and untreated population in all time points, 9 vs 11%, 13 vs 15% and 15 vs 17% resp (ns p=0.228). We analysed two cohorts of pts - younger and older than 60 from the time of CLL dg. We have demonstrated trend (however no significant and inverse) in difference of cumulative incidence of sec. tumors between the young pts treated vs untreated in all time points (12 vs 13% at 10y, p = 0,068,) as well as in the the older population (17% vs 13% at 10y, p = 0.059). We have analysed both cohorts with the landmark analysis for treated pts from the time of first treatment and the cumulative incidence of secondary tumors in the younger cohort vs older cohort was statistically significantly different (p = 0.013), at 5, 10 and 15 y respectively it was 9% vs 14%, 13 vs 17% and 16 vs 18% resp. Conclusions. We have demonstrated in this population-based analysis the cumulative incidence of secondary malignancies in treated CLL patients at 15 y 17%, which is not significantly higher compared with untreated patients. The incidence is however significantly higher in older compared to younger patients. The underlying CLL seems to be more important for the onset of secondary malignancies compared to the treatment itself.

Haematologica, 2012; 97(s1):  59