Background: Anal squamous cell carcinoma (ASCC) is a rare cancer with increased occurrence of multiple cancers before and after the ASCC diagnosis. However, there is limited data on this aspect. This multi-institutional analysis aimed to define the occurrence of malignancies before and after ASCC, time trends, impact on survival, and identify prognostic factors.
Material and methods: Initial primary malignancy (IPM) was defined as a malignancy occurring before the ASCC. Second primary malignancy (SPM) was defined as a distinct primary cancer that developed after ASCC diagnosis. Retrospective multi-institutional chart review was done. Progression free survival (PFS), overall survival (OS) and prognostic factors were evaluated.
Results: 647 patients with ASCC treated with curative intent were analyzed. Median age was 61.23 years with 72% as females. 150 patients (23.3%) had multiple malignancies with IPM in 16% and SPM in 8%. Patients without prior cancer had better 5-year PFS (81.2% vs 67.2%, p = .011) and OS (81% vs 69%, p = .008) compared to those with prior cancer. SPMs had a significant adverse impact on PFS (HR 4.22) and OS (HR 3.56). Females had better 5-year PFS (82% vs 70%, p = .016) as compared to males. The median time interval for developing ASCC (as SPM) after IPM was 9.32 years.
Conclusions: ASCC patients have increased risk of multiple malignancies. Patients with prior cancer have inferior outcomes. SPM is a poor prognostic factor in patients without any prior cancer. SPM can develop years after treatment of primary ASCC.
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