In Brief

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Increased risk of second primary cancer among cancer survivors

By Nicole MacKee
Cancer survivors are at increased risk of developing and dying from a second primary cancer, US researchers have reported in JAMA.

In a retrospective cohort study of more than 1.5 million people (aged 20 to 84 years) who had survived at least five years after a first primary cancer diagnosis, the researchers identified 88,818 deaths from second primary cancers during a follow-up period (average seven years).

The researchers found that, among men, the risk of developing or dying from a second primary cancer was significantly higher than the general population for 18 and 27, respectively, of the 30 first primary cancer types included in the study.

For women, the risk of developing or dying from a second primary cancer was greater for 21 and 28, respectively, of the 31 first primary cancer types.

Participants who had survived a first primary cancer associated with smoking or obesity were shown to have the greatest risk of developing and dying from a second primary cancer.

‘Although some of the higher-risk [second primary cancers] among survivors may reflect genetic predisposition and treatment exposures, most of this excess risk is likely due to host factors (e.g. ageing, immunity) and to lifestyle risk factors (e.g. smoking, obesity, alcohol, infection) shared by the first and subsequent cancers,’ the researchers wrote.

Professor Jon Emery, Herman Professor of Primary Care Cancer Research at the University of Melbourne, and the Victorian Comprehensive Cancer Centre Primary Care Research and Education Lead, said the study showed that cancer survivors had about a 10% increased risk of developing a second cancer, and even greater risk of dying from that cancer (by 45% in men and 33% in women).

Professor Emery said the study highlighted a key role for primary care in cancer survivorship.

‘Cancer survivorship care continues to focus on detection of recurrence and management of treatment side effects,’ he told Medicine Today. ‘Primary care can play a key role in lifestyle management of cancer survivors to reduce their risk of a second cancer. Specifically, this includes smoking cessation interventions, promoting healthier eating, regular exercise and reducing alcohol consumption.’

Professor Emery said primary care physicians could also ensure cancer survivors were up to date with recommended cancer screening tests and encourage early investigation of cancer symptoms.
JAMA 2020; 324: 2521-2535.