Increased Incidence of Melanoma, Prostate, Lung, Bladder, Renal and Thyroid Cancer after Diagnosis of Primary Cutaneous B-Cell Lymphoma: A SEER Database Analysis
Authors: Banner Lauren , Rohan Thomas Z , Zachian Rachel , Gross Tyler , Joffe Daniel , Porcu Pierluigi , Nikbakht Neda 
Published: December 2023

Background: Primary cutaneous B-cell lymphomas (PCBCLs) are a subset of non-Hodgkin lymphomas originating in the skin. The risk of developing other malignancies in PCBCL patients is not known. We evaluated the risk of developing a second primary malignancy after a PCBCL diagnosis.
Methods: We utilized the surveillance, epidemiology, and end results (SEER-17) data registry of 9,208,295 patients from 2000-2020 to generate a cohort of 5,435 patients with PCBCL to identify patients at risk for a second primary malignancy. Relative risk was calculated by using the Standardized Incidence Ratio (SIR), defined as the ratio between observed cases (O) and expected cases (E) of malignancies (SIR = O/E). Statistical significance was established based on 95% confidence intervals (CI).
Results: Of the 5,435 patients with PCBCL, 847 (16%) received diagnoses of a second malignancy, identifying a higher risk than the general population (SIR, 1.54; 95% CI, 1.43-1.64). Males had a higher chance of developing prostate cancer (SIR, 1.29; 95% CI, 1.07-1.54), melanoma (SIR, 1.49; 95% CI, 1.03-2.09), and bladder cancer (SIR, 1.42; 95% CI, 1.01-1.94). Females were more predisposed to cancers of the lung (SIR, 1.69; 95% CI, 1.25-2.24), thyroid (SIR, 3.06; 95% CI, 1.63-5.23), and kidney (SIR, 2.13; 95% CI 1.06-3.81). For males with PCBCL, there was an increased risk of prostate cancer in patients 60-69 (SIR, 1.53; 95% CI, 1.14-2.02). For females, there was an increased risk of lung cancer in patients over 70, especially in the age group of 70-79 (SIR, 1.84; 95% CI, 1.12-2.84). For cutaneous melanoma, bladder, renal, and thyroid cancer, there was no age group identified to be at a significantly greater risk. Prostate cancer risk was increased within the first year (SIR, 2.09; 95% CI, (1.28 - 3.23) and between 5-10 years after PCBCL diagnosis (SIR, 1.45; 95% CI, 1.04-1.97) .For males, melanoma and bladder cancer were associated with an increased risk between 1-5 years after PCBCL (SIR, 1.91; 95% CI, 1.09-3.11 and SIR, 1.7; 95% CI, 1.01-2.68). Females were at the highest risk of developing thyroid cancer within the first year of PCBCL diagnosis (SIR, 21.11; 95% CI, 10.12-38.83) and lung cancer 1-5 years after PCBCL diagnosis (SIR, 1.7; 95% CI, 1.04-2.62). For renal cancer, there was no latency identified carrying an increased risk.
Conclusion: These data, should inform screening strategies for melanoma, prostate, bladder, lung, renal, and thyroid cancer in patients with PCBCL. Males 60-69 within 10 years of PCBCL can benefit from prostate screening. Males within 1-5 years of PCBCL diagnosis can benefit from screening for melanoma and bladder cancer. Females can benefit from thyroid, lung, and renal cancer surveillance. Specifically for females over 70, screening for lung cancer should be considered, and for females within the first year of PCBCL diagnosis, thyroid cancer screening should be considered.