Cancer survivors age faster than those who haven’t had the disease

People who have had cancer naturally age faster than their peers who haven’t had the disease, finds a review of the available evidence, published in the online journal ESMO Open.

More research is therefore needed on how best to stave off the accelerated ageing process to lengthen their lifespan and improve the quality of their lives, suggest the researchers.

Thanks to more effective diagnosis and treatment, the number of cancer survivors is set to rise. Currently they number 30 million around the globe, but by 2025, around 19 million new diagnoses will be made every year, and most of these will produce long term survivors, they say.

Cancer survivors are more likely to develop long term conditions, and sooner than the general population. The list includes conditions, such as hormonal/gland disorders (endocrinopathies), heart problems, lower bone mineral density, lung scarring (pulmonary fibrosis), secondary cancers, and frailty.

This is most likely due to the damage caused by chemotherapy and radiotherapy to normal healthy tissues, which diminishes ‘physiological reserve’- the capacity in organs and biological body systems given to us at birth - and the body’s natural resilience to overcome internal and external biological stressors.

“While ageing prematurely is a better alternative to dying prematurely, a better understanding of what drives this process presents an opportunity for improvement,” state the researchers.

They therefore trawled databases for published evidence on the cellular processes involved in ageing and the potential impact of cancer treatments on these.

They found a wide range of side effects and late complications, which have implications not only for the individuals concerned, but also for health services. Among them:

• Childhood cancer survivors are between three and six times as likely to develop a second cancer.
• Childhood cancer survivors’ estimated life expectancy is 30% lower than that of the general population
• The risk of frailty among bone marrow transplant recipients is around eight times as high as that of their siblings.
• Long term steroid treatment, a component of many cancer treatment strategies, is associated with a higher risk of cataracts, osteoporosis, nerve damage, skin thinning, infection and impaired wound healing.
• Cancer treatment is associated with various aspects of biological ageing: telomere (the ‘shoelace caps’ on the end of DNA strands) shortening; cell death; stem cell abnormalities; primary DNA damage; and abnormal gene activity.
• Certain primary cancer drugs are associated with hearing loss, reduced thyroid gland activity, high blood pressure, congestive heart failure, muscular weakness, arthritis, kidney and liver diseases, chronic constipation, and infertility.
• Radiotherapy is associated with dementia, memory loss, carotid artery hardening, and secondary bone marrow cell and blood cancers.
• Tamoxifen (adjuvant treatment to stave off the return of cancer) is associated with cataracts

The researchers emphasise that despite these undesirable side effects, cancer treatments are worthwhile for scores of patients with the disease, and that ageing is part of life.

Accelerated ageing, experienced by many cancer survivors as a direct consequence of their treatment, is something that can, and should be, minimised, they insist. For one thing, cancer survivors deserve it, and for another, it’s a public health issue, they say.

“We believe that cancer survivors deserve long term follow up for the mitigation of the late effects,” they write.

“Future research to better understand mechanisms of accelerated ageing-like phenotypes is essential for the oncology community as well as from a public health and health policy perspective,” they add.

“The ultimate goal of these studies will be to prevent late complications using early interventions, including lifestyle changes and medications.”