Pilot study on the occurrence of multiple cancers following cancer-related therapy at the University of Florida, Jacksonville (2011-2016).

New primary cancers can occur in patients with a previous cancer. Among the risk factors, therapies such as chemotherapy, radiotherapy, and hormonal therapy have been associated with the development of neoplasms. Second cancers most commonly develop 5-10 years after the initial tumor. We observe the implications of cancer-related therapy in the development of a new tumor. We looked at 602 patients who had their first cancer diagnosed in 2011 and calculated the number of different primary cancers between 2011 and 2016 for each patient. Twenty-four patients had a second cancer within 5 years from the first diagnosis and there were no patients with a third cancer. There was no statically significant difference in the rates of second cancers after exposure to chemotherapy, radiotherapy, hormonal therapy, or any combination of these (p=0.738). Of the second cancers reported after 2011, renal, uterine, cervical, and lung cancers were the most frequently reported. Additionally, there was no statically significant difference among the rates of second cancers in men versus women (p=0.467), as well as among whites versus blacks (p=0.318). We conclude that while new primaries can occur after one cancer, there was no increased risk after exposure to different cancer-related therapies. With increased focus on the primary disease, there is a higher likelihood of missing another primary lesion. This is important as the practical implications of managing multiple primaries are rarely discussed.