Secondary solid tumors in patients younger than 55 with chronic lymphocytic leukemia (CLL).

Abstract

10083 Background: Patients with CLL are at an increased risk of secondary solid tumors. Few studies have looked at this risk in patients < 55, despite research suggesting that this is a distinct cohort with a longer overall survival. What data does exist has yielded variable results in limited populations. In light of this, our study utilized the SEER registry to look at secondary solid tumors in patients < 55 with CLL. Methods: 4559 patients 15-54 years old with CLL were identified in the SEER registry between 1973 and 2013. Cancer risk was assessed using standardized incidence ratios (SIR) of observed (O) and expected (E) cancers. 95% confidence intervals (CI) were calculated assuming a Poisson distribution. Results where the CI = 1 were excluded. Results: 498 patients (O/E = 1.4) developed a secondary solid tumor after CLL with a mean age at diagnosis of 48.8 and 59.9 years for CLL and a second tumor, respectively. Higher than expected risk was seen in lip (O/E = 7.5), non-epithelial skin (O/E = 5.4), salivary (O/E = 4.8), mesothelioma (O/E = 4.4), melanoma (O/E = 3.1), lung (O/E = 2.4), and kidney (O/E = 1.7) cancers. Uterine cancer had a lower risk (O/E = 0.4). Stratifying the cohort by gender and race found that lip cancer in whites (O/E = 7.6) and men (O/E = 7.3), descending colon cancer (O/E = 13.3) in blacks and ureter cancer (O/E = 19.8) in women posed the highest risks. Lung cancer was the most prevalent among all groups. Secondary tumor risk was elevated in the < 1, 1-5, 5-10, and 10-15 years after diagnosis with CLL (O/E = 2.3, 1.4, 1.5, and 1.4, respectively). The cancers with the highest SIR in each period were thyroid ( < 1 year, O/E = 9.2), lung (1-5 years, O/E = 3.1), nose/ear (5-10 years, O/E = 11.8), and lip (10-15 years, O/E = 15.6). In 4459 patients > 55 (O/E = 1.1), Kaposi sarcoma (O/E = 4.9), non-epithelial skin (O/E = 3.6), salivary (O/E = 2.8), melanoma (O/E = 2.1), nose/ear (O/E = 2.0), lip (O/E = 1.7), soft tissue (O/E = 1.6), lung (O/E = 1.4), kidney (O/E = 1.3), and colon cancers (O/E = 1.2) were significant. Conclusions: Patients < 55 have a unique tumor profile and greater risk of secondary solid tumors compared to patients > 55. This risk differs on the basis of gender, race, and survival time. Further research may help influence screening guidelines.