Abstract 1542P
Background
To investigate, in a population-based study, the risk of developing second primary neoplasms (SPNs) after a diagnosis of primary Kaposi sarcoma.
Methods
Data on a cohort of patients with a diagnosis of primary Kaposi sarcoma as their first malignancy were extracted from the Surveillance, Epidemiology, and End Results US registry from 1975 to 2017. Observed-to-expected ratio of developing SPNs was calculated to estimate relative risk (RR) and associated 95% confidence interval (CI), which were compared to a reference population (RP) matched for age, sex, race, and calendar year.
Results
A total of 16,206 patients with primary Kaposi sarcoma were identified, 7.4% of whom developed SPNs (1,199/16,206). Mean age at Kaposi sarcoma diagnosis was 42 years old, while that at SPNs diagnosis was 52. There was a significant risk of SPNs development in Kaposi sarcoma patients compared to the RP (p < 0.05). Patients 2 to 11 months after Kaposi sarcoma diagnosis had the highest risk of developing SPNs [RR: 6.9 (95% CI: 6.15–7.8); p < 0.05], with Non-Hodgkin Lymphoma as the most common malignancy. Stratification by sex revealed an increased risk of cancer development in males [RR: 2.6 (95% CI: 2.4–2.7); p < 0.05]. Patients aged 25-29 years old experienced the greatest burden of SPNs with a significant risk compared to the RP [RR: 13.4 (95% CI: 10.4-17.0) p < 0.05].
Conclusions
Patients with primary Kaposi sarcoma experience a 7.4% increased risk of SPNs compared to the RP. Patients 25-29 years old at time of diagnosis display the highest risk of SPNs. Around 2 to 11 months after Kaposi sarcoma diagnosis mark an increased risk of Non-Hodgkin lymphoma development. Male Kaposi sarcoma patients tend to be more at risk to develop malignancies than the RP. Patients who are diagnosed with primary Kaposi sarcoma should be followed with these risks in mind.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.