The impact of prior malignancies on the development of second malignancies and survival in follicular lymphoma: A population‐based study

We assessed the impact of a prior malignancy diagnosis (PMD) – as a potential proxy for genetic cancer susceptibility – on the development of a second primary malignancy (SPM) and mortality in follicular lymphoma (FL) patients. From the nationwide Netherlands Cancer Registry, we selected all adult FL patients diagnosed in 1994‐2012 (n = 8028) and PMDs and SPMs relative to FL, with follow‐up until 2017. We constructed two Fine and Gray models – with death as a competing risk – to assess the association between a PMD and SPM incidence. A PMD was associated with an increased incidence of SPMs (subdistribution hazard ratio [SHR], 1.30; 95% confidence interval [CI], 1.03‐1.64) – especially carcinomas of the respiratory tract (SHR, 1.83; 95% CI, 1.10‐3.05) and cutaneous squamous cell carcinomas (SHR, 1.58; 95% CI, 1.01‐2.45) – and a higher risk of mortality in a multivariable model (HR, 1.43; 95% CI, 1.19‐1.71). However, when additionally adjusted for the receipt of systemic therapy and/or radiotherapy before FL diagnosis, only patients who received such therapies had an increased incidence of SPMs (SHR, 1.40; 95% CI, 1.02‐1.93). In conclusion, patients with a PMD had a higher rate of SPMs and mortality than those without a PMD, which might have resulted from therapy‐related carcinogenesis.