Survival trends among patients diagnosed with both melanoma and chronic lymphocytic leukemia.

Abstract

e19527 Background: Patients previously diagnosed with melanoma have a higher risk of developing subsequent chronic lymphocytic leukemia (CLL). Similarly, melanoma risk has been observed to be elevated among patients with a history of CLL. However, previous studies have reported inconsistent results on whether being diagnosed with both cancers significantly reduces patient survival. Additional research is needed to assess the potential reduction in survival among this unique cohort of patients diagnosed with both melanoma and CLL. In addition, the timing of the cancer development needs to be assessed to further explore unique patient characteristics. Methods: A retrospective cohort study was conducted using data from adult patients who were diagnosed and/or treated for melanoma (n = 5,511) or chronic lymphocytic leukemia (CLL, n = 571) at Moffitt Cancer Center (MCC) in 2008-2020. Clinical characteristics and survival information were obtained from the MCC Cancer Registry including, date of diagnosis, vital status, time of death or last contact, and tumor stage at diagnosis. The Kaplan-Meier method was used to estimate survival for three patient groups: patients diagnosed with only melanoma, patients diagnosed with only CLL, and patients who were diagnosed with both cancers. The timing of the two cancer diagnoses were assessed among the 17 patients diagnosed with both melanoma and CLL. Results: The estimated 5-year survival was 78.5% and 82.9% among patients diagnosed with only melanoma and only CLL, respectively. Among patients who were diagnosed with both cancers, the 5-year survival since melanoma diagnosis was 61.4% whereas the 5-year survival since the CLL diagnosis further reduced to 60.2%. When analyzing the timing of the diagnoses of the two cancers, 13 out of 17 patients were diagnosed with melanoma prior to CLL. Further, among these 13 patients, 12 patients had CLL diagnosed within 100 days after the melanoma diagnosis. Conclusions: Patients diagnosed with both melanoma and CLL experienced poorer survival outcomes as compared to patients who were diagnosed with only one of these cancers. Among patients who were diagnosed with both cancers, more than 70% of the patients were diagnosed with CLL shortly after their melanoma diagnosis. Additional research using larger national cancer registry databases can help to advance the understanding of the underlying disease mechanism and confirm the observed timing of diagnoses is due to the CLL being diagnosed incidentally as result of node biopsies for melanoma.