Female breast cancer survivors living in the most deprived areas have a 35% higher risk of developing second, unrelated cancers compared to those from the most affluent areas, research show.
Breast cancer is the most commonly diagnosed cancer in the UK, with around 56,000 people being told they have it each year. Improved diagnosis and treatments mean this five year survival rates are now 86% in England.
Breast cancer survivors have a higher likelihood of second primary (unrelated) cancer, but until now the exact risk was not clear.
A team of researchers led by the University of Cambridge analyzed NHS data from nearly 600,000 patients in England and found that, compared with the general female population, women who had survived breast cancer had an increased risk of developing 12 other primary cancers.
They had double the risk of developing cancer in the unaffected (contralateral) breast, an 87% higher risk of endometrial cancer, a 58% increased likelihood of myeloid leukemia and a 25% higher risk of ovarian cancer.
The study, published in Lancet Regional Health – Europe, found that the risk of second primary cancers was higher in people living in areas of greater socioeconomic deprivation.
Compared to the most affluent, the least affluent female breast cancer survivors had a 166% greater chance of developing lung cancer, a 78% higher risk of stomach cancer, more than 50% increased risk of bladder and esophageal cancer, 48% higher risk of head and neck cancer and 43% increased risk of kidney cancer.
Overall, those from the most deprived areas had a 35% higher risk of a second non-breast cancer.
This may be because risk factors such as smoking, obesity and alcohol consumption are more common among more deprived groups. A 2023 study found this deprivation causes 33,000 extra cancer cases in the UK each year.
First author Isaac Allen, from the Department of Public Health and Primary Care at the University of Cambridge, said: “This is the largest study ever to investigate second cancers after breast cancer and the first to show that women with breast cancer diagnosed in deprived regions are more likely to get second cancers. Many cancers are caused by deprivation, but more research is clearly needed to identify the specific factors that drive the higher risks and how best to reduce these inequalities.”
In addition to data from more than 580,000 women, the authors examined the risk of second primary cancers for more than 3,500 male breast cancer survivors diagnosed between 1995 and 2019 using the National Cancer Registry dataset.
Male breast cancer survivors were 55 times more likely than the general male population to develop contralateral breast cancer, 58% more likely than the general male population to develop prostate cancer and had four times the risk of thyroid cancer, although the actual numbers of these cancers were low .
In response to the findings, Prof Pat Price, a leading oncologist and co-founder of the Catch Up With Cancer campaignsaid: “This highlights yet another case of worrying inequalities within cancer, highlighting the urgent need for a dedicated cancer plan. Where a person comes from or their socio-economic status should not determine the chances of developing cancer or to survive.”
Dr Simon Vincent, the director of research, support and advocacy at Bors Cancer Now, that said, while the higher risk of secondary cancer may occur due to genetic factors or the effects of initial breast cancer treatment, more research was needed into the causes of second primary cancers and how to follow up patients who complete primary breast cancer treatment.
