Long-term breast cancer survival continues to rise among women from all backgrounds but a worrying survival gap between poor and affluent women still remains – say leading statisticians.
One year after diagnosis survival was worse for deprived breast cancer patients than affluent. And this “deprivation gap” between the two social groups doubled five years after diagnosis.
The study looked at more than 380,000 women who were diagnosed with breast cancer in England and Wales between 1986-1999. Even after adjusting for other causes of death, the five-year survival of women with breast cancer who lived in the most affluent areas was consistently about six per cent higher than for women who lived in deprived areas.
The survival figures are part of a detailed analysis of cancer survival published today in the British Journal of Cancer (BJC)*.
For the first time each article in the survival supplement is twinned with an expert commentary from a leading UK specialist who treats the particular cancer under discussion. In several cases researchers and clinicians disagree about the reasons for survival inequalities.
Such a debate should lead to better understanding of the persistent inequalities in cancer survival between rich and poor patients – according to Professor Michel Coleman, Cancer Research UK epidemiologist and senior author of the survival articles in the supplement.
The research comes just a week ahead of Breast Cancer Awareness Month which provides an opportunity to raise awareness of the disease as well as an annual fund-raising platform for breast cancer throughout October.
While overall survival continues to improve for the majority of adult cancers there is a notable difference between those from affluent backgrounds and those from deprived backgrounds.
Researchers have found that this deprivation gap in survival exists for most cancers but the gap does not generally widen between one-year survival and 5-10 year survival. Breast cancer is a notable exception.
The study looked at survival for the 20 most common cancers diagnosed in England and Wales over a 14 year period from 1986 to 1999 and patients were followed up to the end of 2001. Results were based on data for 2.2 million cancer patients.
Professor Coleman said: “Deprived women have lower breast cancer survival than affluent women in the period soon after diagnosis. But we have seen this actually double between one and five-year survival.”
Prof Coleman suggests that some of the reasons why the deprivation gap in survival becomes wider with time since diagnosis may include lower take-up of radiotherapy, which leads to a higher risk of late recurrence of breast cancer, and problems with access to chemotherapy or hormone therapy. Differences, between affluent and deprived women in access to the life-prolonging drug, tamoxifen, may also have been a contributory factor for women diagnosed in the late 1980s and early 1990s.
For most cancers survival up to 10 years has improved significantly between those diagnosed in the mid 1980s and the late 1990s. But there was almost no change in survival for lung, pancreatic, cervical and bladder cancer.
Expert clinicians commenting on the results suggested that greater public awareness, early detection, better treatment and multi-disciplinary teams were all reasons for improved survival in many cancers.
Clinicians also suggested that the continuing deprivation gap in survival between the more affluent and more deprived patients could be due to patients living in deprived areas having other life-threatening diseases.
In contrast the other researchers ascribed the reasons to later diagnosis and, for some cancers, poor access to adequate treatment.
Regarding improved survival in both testicular and malignant melanoma, clinicians praised public awareness campaigns, such as Cancer Research UK’s SunSmart campaign, which had helped to make people more aware of the signs and symptoms of cancer leading to earlier presentation, earlier diagnosis and improved survival.
Professor Mike Richards, National Cancer Director, highlighted differences of opinion between clinicians and epidemiologists in finding reasons for the survival deprivation gap.
He said: “In general clinicians were likely to attribute the deprivation gap in survival mainly to the fact that people from poorer backgrounds had other diseases as well as cancer. By contrast statisticians put more emphasis on late diagnosis in deprived groups as a cause for poorer survival.
“These differences of opinion highlight the need for high quality information on the details of cancer staging and additional diseases to be collected by clinical teams and made available to the cancer registries.”
For media enquiries please contact the Cancer Research UK press office on 020 7061 8300 or, out of hours, the duty press officer on 07050 264059.
* The BJC is owned by the charity Cancer Research UK and its mission is to encourage communication of the very best cancer research from laboratories and clinics in all countries. Broad coverage, its editorial independence and consistent high standards have made BJC one of the world’s premier general cancer journals. Visit www.nature.com/bjc
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