Cancer Incidence in Sickle Cell Disease. Howard University, 1996–2004.

There are no prospectively collected data on cancer incidence and mortality in patients with sickle cell disease. This information would be a useful baseline for cancer surveillance, particularly in sickle patients exposed to potentially carcinogenic interventions such as hydroxurea administration and stem cell transplantation. A review of cancer cases among 696 adult sickle cell patients (mean age 28.8 y) at Howard University for the years 1986–1995 (2,684 patient-years, pt. yrs.) estimated the cancer incidence and mortality at 1.74 and 1.04 per 1000 pt. yrs, respectively (

Because sickle cell patients are now surviving longer, we examined again the cancer incidence and mortality at our institution for the years 1996 – 2004. In determining the patient-years of observation we assumed that if a patient was seen at least once during a given calendar year, the patient had been observed for that whole year. A total of 677 adult sickle cell patients (mean age 35.1 ± 12.5 y) were followed from 1996 through 2004 (2,317 pt.yrs.). There were 54.5 % females and 45.5 % males; the Hb genotype distribution was SS=70.5%, SC=19.2%, S-Thal=9.7%, and other=1%. The table shows the characteristics of 7 sickle cell patients who developed cancer during the study period. Their ages ranged between 38 and 64 years. All but one (Pt. 7) were female and all but one (Pt. 2) had Hb SS. Patients 1 and 3 had been treated with hydroxyurea.

Based on these cases, the estimated cancer incidence was 3.02 per 1000 patient years, still below the upper 95% confidence limit in the 1986–1995 estimate (4.3 per 1000 patient years). Two additional cancer patients were seen at our institution, one with prostate cancer and the other with metastatic breast cancer. They were not included in the incidence estimate since they were specifically referred to our institution because of the cancer diagnosis. The current incidence of cancer in adult sickle cell patients at our institution is not increasing appreciably even though they are getting older and some are taking hydroxyurea.