Breast screening and your own risk

What breast screening is

A mammogram is a low dose X-ray of the breast. Usually two images are taken of each breast, each lasting a few seconds while the machine holds the breast firmly in place, which some women find uncomfortable for a short time [1].

Our mammography is digital with 3D tomosynthesis, reported by a sub-specialist breast radiologist, with breast ultrasound available alongside when it is needed [2].

Why it is done and who it is for

In England, breast screening is offered to women from 50 up to their 71st birthday, every 3 years, and women over 71 can still ask for it [3] [1]. In the US, the Preventive Services Task Force recommends a mammogram every 2 years from 40 to 74 [4]. Countries draw the line differently because the balance of benefit and harm shifts gradually with age.

If cancer runs in your family, NICE sets out a plan by risk. Women at moderate risk are offered yearly mammograms from 40 to 49, and women with a known BRCA1 or BRCA2 variant are offered yearly MRI from 30 to 49 and yearly mammograms from 40 to 69 [5]. A doctor works out which group you are in from your family history.

Dense breasts

Dense breasts have more glandular and fibrous tissue and less fat. Nearly half of women have dense breasts, which raises the risk of breast cancer a little and makes cancers harder to see on a mammogram [4].

Whether extra ultrasound or MRI helps is not yet settled. The US task force found the evidence insufficient to recommend for or against it, and the UK National Screening Committee is reviewing changes for women at higher risk, including risk from dense tissue [4] [6]. If you have been told your breasts are dense, a doctor can talk through your options.

Benefits

Screening finds cancers early, when treatment may be simpler and more likely to work [1]. An independent UK review estimated that being invited to screening lowers the risk of dying from breast cancer by about 20%, and the UK programme is thought to prevent around 1,300 deaths each year [7] [6].

Most women have a clear result. For every 100 women screened, 96 need no further tests, and 4 are called back, of whom 1 is found to have cancer [1].

Limitations and risks

The main harm is overdiagnosis, finding a cancer that would never have caused harm and treating it. The same review estimated about 3 women overdiagnosed for every death prevented [7].

Call backs that turn out to be nothing are common over many years. In US data, about 38.1% of women screened every 2 years with digital mammography had at least one false positive over 10 years [4]. Mammograms involve a small dose of radiation, and the benefits are judged to outweigh that risk [1]. A cancer can also develop between screens, so it still matters to know your breasts and report changes.

Who screening is not for

Screening is for women without symptoms. A new lump, a change in shape, skin changes, or nipple discharge or inversion needs a doctor rather than a screening appointment, and NICE advises urgent assessment for an unexplained lump at 30 or over [8].

Mammograms are not used to screen young women. Even with a family history, NICE advises against mammographic surveillance at 29 and under, and for women at moderate risk it starts at 40 [5].

How you prepare and what to expect

On the day, avoid deodorant and talcum powder, because they can show on the images, and wear a top with trousers or a skirt, since you undress to the waist [1]. Tell the clinic beforehand if you have breast implants, a pacemaker or another implanted device, or if you are pregnant or breastfeeding [1].

The mammogram itself takes 20 to 30 minutes, and you can ask to stop at any point if it becomes too uncomfortable. The report is usually ready in 24 to 48 hours, and if a closer look is needed, the next step is often further images or an ultrasound [2] [1].

Questions to ask your doctor

These questions help you and your doctor agree a plan for your own risk.

• Given my family history, what is my level of risk?
• Should I start screening earlier, or have it more often?
• Are my breasts dense, and would ultrasound or MRI add anything for me?
• Would a genetic assessment be useful for my family?
• What changes should I look out for between screens?

How The Wellness can help

A GP appointment gives you time with a GMC registered doctor to go through your family history and decide on screening that matches your own risk. When a mammogram is right, it is carried out through registered partner clinics, reported by a sub-specialist breast radiologist, with ultrasound available alongside [2].

The doctor goes through the report with you and, if anything needs a closer look, arranges the next step and a specialist where needed. Our clinics are on Baker Street in Marylebone and Eccleston Street in Belgravia.