MADRID, 20 Ago. (EUROPA PRESS) –
Breast cancer survivors have a significantly increased risk of developing second cancers, including endometrial and ovarian cancer in women and prostate cancer in men, according to new research studying data from nearly 600,000 patients in England.
For the first time, research has shown that this risk is higher in people living in areas of greater socioeconomic deprivation. The results of this analysis, led by the University of Cambridge (United Kingdom), were published a few months ago in ‘Lancet Regional Health – Europe’.
People who survive breast cancer are at risk of developing a second primary cancer, but the exact risk is unclear. Previously published research suggested that women and men who survive breast cancer have a 24% and 27% higher risk of developing a second non-breast primary cancer than the general population, respectively. It has also been suggested that the risks of a second primary cancer differ depending on the age at diagnosis of breast cancer.
To provide more accurate estimates, a team led by researchers at the University of Cambridge analyzed data from more than 580,000 female and more than 3,500 male breast cancer survivors diagnosed between 1995 and 2019 using the National Cancer Registry Dataset.
First author Isaac Allen, from the Department of Public Health and Primary Care at the University of Cambridge, said: “It’s important for us to understand how much having one type of cancer puts you at risk of getting a second cancer at a different site. The female and male breast cancer survivors whose data we studied were at increased risk of multiple second cancers. Knowing this can help inform conversations with their care teams to look for signs of possible new cancers.”
Researchers found significantly increased risks of cancer in the contralateral (i.e., unaffected) breast and of endometrial and prostate cancer in women and men, respectively. Women who survived breast cancer had twice the risk of contralateral breast cancer compared with the general population and an 87% increased risk of endometrial cancer, a 58% increased risk of myeloid leukemia, and a 25% increased risk of ovarian cancer.
Age at diagnosis was also important: Women diagnosed with breast cancer before age 50 were 86% more likely to develop a second primary cancer compared with the general population of the same age, while women diagnosed after age 50 had a 17% increased risk. One possible explanation is that more younger breast cancer survivors may have inherited genetic alterations that increase their risk of multiple cancers. For example, women with inherited changes in the BRCA1 and BRCA2 genes have a higher risk of contralateral breast, ovarian, and pancreatic cancers.
Women from the most socioeconomically deprived backgrounds had a 35% higher risk of developing a second primary cancer compared with women from the least deprived backgrounds. These differences were mainly due to risks unrelated to breast cancer, particularly lung, kidney, head and neck, bladder, oesophagus and stomach cancers. This may be because smoking, obesity and alcohol consumption (established risk factors for these cancers) are more common among the most deprived groups.
Allen, a PhD student at Clare Hall, added: “This is further evidence of the health inequalities experienced by people from more deprived backgrounds. We need to fully understand why they are at higher risk of second cancers so that we can intervene to reduce this risk.”
Male breast cancer survivors were 55 times more likely than the general male population to develop contralateral breast cancer, although the researchers stress that an individual’s risk was still very low. For example, for every 100 men diagnosed with breast cancer at age 50 or older, about three developed contralateral breast cancer over a 25-year period. Male breast cancer survivors were also 58% more likely than the general male population to develop prostate cancer.
Professor Antonis Antoniou from the Department of Public Health and Primary Care at the University of Cambridge, lead author of the study, concludes: “This is the largest study to date looking at the risk of breast cancer survivors developing a second cancer. We were able to carry this out and calculate more accurate estimates thanks to the excellent datasets available to researchers through the NHS.”
