Nanogirl Michelle Dickinson: Should breast cancer screening start at 35?

In a study, early-age breast screening was able to detect 80 per cent of small invasive tumours Photo / Getty Images

About 3300 Kiwi women are diagnosed with breast cancer each year.

Currently, most women are only entitled to regular, free mammogram screening when they reach the age of 45. New research this week suggests that reducing the breast cancer screening age to 35 from 45 could help to save the lives of women who already have close family members with the disease.

Breast cancer can affect men and women and occurs when the cells in the breast develop abnormally and form a malignant tumour. These cells can spread from the breast to other parts of the body through the lymphatic system resulting in what are known as metastasised or secondary cancers.

Although breast cancer isn't as common in women under the age of 50, the risk is significantly increased when there is a history of close family members such as a mother or sister having the disease. The younger the family member was when they developed their breast cancer the greater the risk of developing the disease is.

Mammograms have been successful in detecting early signs of breast cancer in hundreds of thousands of women, many of whom have gone on to be successfully treated. Mammography is life-saving as it can often find a lump before it can be felt by the hand during self-examination or a clinical breast examination.

Currently, the Ministry of Health funds free mammograms for women aged 45-69 and since it was introduced in 1998 this programme has been very successful in helping to detect breast cancer.

If the cancer is detected early there is a very high survival rate with 92 per cent of women whose breast cancer is detected early by a mammogram surviving 10 years or more after diagnosis.

However, new research published this week in the Lancet's online journal EClinicalMedicine shows that this age bracket may be too high for women who have a history of close family members with the disease.

The large-scale study screened almost 3000 women aged between 35 and 39 who were considered to be at a higher risk of breast cancer by having at least one first degree relative affected by the disease.

In these early screened women, the scientists detected 50 breast cancers across 49 patients of which 35 were invasive tumours meaning they had spread into the surrounding healthy tissue.

Of these 35 invasive tumours, the early-age mammography screening was able to detect 80 per cent of them when the tumour was 2cm in size or smaller. Tumours that are 2cm or smaller are much less likely to have spread to the lymph nodes resulting in a much higher success rate for treatment.

In comparison, at-risk women of the same age who were not screened early only had a 45 per cent chance of having their tumours detected before they reached 2cm and of the tumours detected 54 per cent of them had already spread to the lymph nodes.

In New Zealand, a recent report from the Breast Cancer Foundation found that the average survival length for a woman whose cancer has spread beyond the breast and lymph nodes is only 16 months.

With one in nine New Zealand women at risk of developing breast cancer at some stage in life the new findings suggest that targeting the breast screening process to start at the age of 35 in women who already have a family history of the disease could help to detect tumours that are significantly smaller in size and therefore less likely to have spread to the lymph nodes giving these women a much higher chance of survival.

Dr Michelle Dickinson, creator of Nanogirl, is a nanotechnologist who is passionate about getting Kiwis hooked on science and engineering. Tweet her your science questions @medickinson