Breast awareness: Benefits and harms of breast screening
BREAST physician Dr Deborah Pfeiffer, who deals with screening every day of her work as a relieving senior medical officer with Breastscreen Queensland, looks at the issues around the current screening program.
The main breast cancer risk factors are being female and aged over 50. Added to that, we are living much longer which means we more likely to get breast cancer. "However, the older you are, the less likely you are to die from breast cancer, particularly if it is found early," Dr Pfeiffer said. This goes to the heart of the discussion around the benefits and harms of screening.
The benefit of screening is finding the signs of the disease before we notice any symptoms. If the disease is found early, there is more opportunity for a person to live a normal life span due to better treatment options.
In the past, saving a life was seen as the ultimate outcome. But times have changed as many cancer treatments have become often more effective. Specialists are now able to use the early detection screening results to help minimise the amount of necessary treatment.
However, there are downsides to screening.
- No screening test is perfect therefore not all cancers are detected through screening. "Depending on the method used, there is a five to 50 per cent chance of missing the cancer depending upon what screening test is used," Dr Pfeiffer said.
- Digital mammography has a detection rate of between 50 to 90 per cent, depending on breast density.
- When a cancer is found that may not progress, it can lead to a person receiving unnecessary treatment and experiencing harmful side-effects. Not all cancers are killers, Dr Pfeiffer explains. Some are invasive and may kill in time. Others can be non-invasive but can still progress. "The difficulty is knowing which of them will progress and possibly threaten life," she said.
- Finding an abnormality that is not cancer, but which may lead to a biopsy and cause anxiety, until it is proved not to be cancerous.
- Finding a cancer for which the treatment is worse than the disease. "We are beginning to question the value of excessive treatment such as mastectomy, chemotherapy and radiation therapy in women over 80 with small cancers," Dr Pfeiffer said. "It may be worse than doing nothing. Whereas, if she hadn't been screened, she may never have been aware of it."
Between the ages of 50 to 74 free government screening is available every two years to all women throughout Australia with the BreastScreen Australia program. However, there are some women who should be screened more often Dr Pfeiffer said. Some should be screened yearly and some should have more than just mammography.
She adds, "Putting all our faith in mammography is inadequate for those who have extremely dense breasts". It may be only 50 per cent effective.
The following people should have personalised screening which may include ultrasound, clinical breast examination and MRI, and possibly genetic testing -
- Family breast and ovarian cancer history. Where you have one or more first-degree relatives who have had breast or ovarian cancer while aged under 50, or two or more first or second-degree relatives on the same side, this increases your risk. A strong family history of melanoma or bowel cancer can also increase risk. You can use the Cancer Australia website to assess your risk of familial breast cancer. Go to www.canceraustralia.gov.au/clinical-best-practice/gynaecological-cancers/familial-risk-assessment-fra-boc
- Breast cancer diagnosis. You should also be screened every year, for life.
- Multiple benign lumps or have had multiple biopsies.
- Tested positive to the BRCA1 and BRCA2 test, or other rare genes.
- Ashkenazy Jewish heritage.
What should women do?
Dr Pfeiffer says all women should be breast aware. They should know what their breasts normally look and feel like.
From age 40 women, with no symptoms and no significant risk factors, should have a screening mammogram every two years and understand that a call-back does not necessarily mean they have breast cancer.
After age 74 women should discuss with their GP whether to continue screening. Dr Pfeiffer says she favours the continued screening of women in good health who have a further life expectancy of at least 10 years.
"Those women with a known family history of breast cancer should request a risk assessment from their GP, or at least perform the online FRA-BOC themselves," Dr Pfeiffer said. "Any woman with an increased risk or any new breast symptom should see their GP for further advice regarding personalised screening or investigation."