One crucial cause of death in patients with prostate cancer is second primary cancer (SPC), and an essential risk factor for SPCs is family history, a recent study has found.
A total of 6,396 men were diagnosed with SPC, of whom more than a third had first-degree family history of any cancer. Familial risk was 1.37 (95 percent CI, 1.271.40) vs 1.10 (1.08–1.16) for those without a family history.
By 83 years of age, cumulative incidence reached 21 percent for prostate cancer alone, 28 percent in patients with SPC and 35 percent in those with both SPC and family history. An association existed between family history and the risk of seven specific SPCs (colorectal, lung, kidney, bladder, melanoma and squamous cancers, and leukaemia).
Common SPCs included colorectal and lung cancers, and the risk of such SPCs doubled in patients with family history. SPC was the cause of half of deaths in patients with SPC, and only 12.77 percent were caused by prostate cancer. Lung and colorectal cancers were the most common causes of deaths in SPC.
“Prevention of SPC should be essential when prostate cancer survival rates are being improved, and this could start by conducting a thorough assessment of family history at the time of prostate cancer diagnosis,” researchers said.
A nationwide cohort study was conducted based on the Swedish Family-Cancer Database covering 4.4 million men and 80,449 prostate cancers diagnosed between 1990 and 2015. Researchers calculated relative risks and cumulative incidence for SPCs and for familial SPC for prostate cancer patients.