Other Cancers in Patients with Chronic Lymphocytic Leukemia Requiring Therapy: Association with Prognostic Factors and Impact On Survival

Abstract 3896

Chronic lymphocytic leukemia (CLL) is associated with an increased incidence of other cancers (OC). Potential risk factors for OC in CLL include immune disturbances, shared risk factors, genetic predisposition and chemotherapy. While reports on OC in patients with CLL have been typically descriptive in nature, detailed information regarding the clinical features of OC, relationship with the time of diagnosis of CLL, patient characteristics, prognostic factors and survival have been missing. We report an analysis of OC in pts with CLL requiring therapy, with a post therapy observation time of 5 years or longer. We reviewed our database and selected pts with CLL seen at our center who underwent treatment and who have a follow-up of at least 5 years after therapy. We studied pts with an OC either before or after the diagnosis and/or treatment of CLL and compared them with patients without OC. Richter's transformation of CLL was not considered an OC in this analysis. A total of 1,364 pts with CLL referred between 1963 and 2007 with a median follow up time of 8.2 years (range 5–28) were studied. Among these, we identified 324 pts (24%) with OC. Sixty-eight pts were diagnosed with >1 OC [2 OC (62 pts), 3 OC (4 pts) or 4 OC (2 pts)], for a total of 400 individual OC. Of the 324 pts with OC, OC preceded the diagnosis of CLL in 117 pts (36%), with a median time from OC to CLL of 80 (0–455) months, OC occurred after the diagnosis of CLL but before treatment in 49 pts (15%), with median time from CLL to OC of 22 (0–131) months. OC occurred after treatment of CLL in 158 pts (49%), with a median time from treatment to OC of 94 (0–304) months. The type, frequency and timing of OC are summarized in table 1. Clinical characteristics and traditional prognostic factors were not significantly different between pts with and without OC, with the exception of age, as pts with OC are older than pts without OC at the time of referral (median age: 60 vs 55 years, p<.0001). We next analyzed the distribution of the newer prognostic parameters in these two groups. Fifty-three % of pts with OC had unmutated IGHV genes, 65% were ZAP70+, 22% CD38+, 8% had del17p, 27% del11q, 22% +12, 20% negative FISH, and 23% del13q. Sixty-one % of pts without OC had unmutated IGHV genes, 58% were ZAP70+, 26% CD38+, 6% had del17p, 17% del11q, 22% +12, 26% negative FISH, and 29% del13q. A trend toward significance (p.07) for a higher incidence of del11q was observed in pts with OC. At the time of this analysis 536 (39%) pts have died and 828 (61%) are alive. One hundred seventy six/324 (54%) pts with OC are alive, vs 652/1040 (63%) pts without OC (p<.007). Median overall survival (OS) has not been reached in either pt group at a median follow up of 95 (61–284) months for pts with OC and 98 (61–340) months for pts without OC. Causes of death were: progression of CLL (99), CLL-related complications (121), OC (43), complications of stem cell transplant (16), events unrelated to CLL (39) and unknown causes (218). In pts with OC, the OC itself was the cause of death in 37%. Other causes of death were CLL/CLL-related complications in 44%, complications of stem cell transplant in 8%, and events unrelated to CLL in 11%. In contrast, in pts without OC CLL/CLL-related complications accounted for 83% of deaths, complications of stem cell transplant for 4%, and events unrelated to CLL for 13%. In conclusion, in pts with CLL requiring therapy and with post therapy follow up of >5 years, the incidence of OC is 24%. Among pts with OC, there is a trend for higher number of pts with del11q. In pts with OC, OC itself is a major cause of death, while the vast majority of deaths among pts without OC are caused by CLL or CLL-related complications.