A MAMMOGRAM cleared them, as well as the conventional ultrasound scan which followed.
But when the 319 women were given an enhanced ultrasound scan, 13 were found to have breast cancer.
The scan, available only at Changi General Hospital (CGH) here, can pick up some breast cancers which otherwise might have been missed, the hospital found in a study. CGH has been using a machine since 2005, which comes with an extra function called ultrasound elastography, on top of the usual ultrasound. This enhanced scan gauges how hard a lump is.
Harder lumps are more likely to be cancerous, explained the author of the study, Dr Tan Su-Ming, head of CGH's Breast Service.
The gold standard for screening breast tumours is a mammogram X-ray, which is usually followed by an ultrasound scan.
If these detect an abnormality, a breast biopsy is carried out to determine if the cells are cancerous.
Conventional ultrasound scans provide important information about a lump. For example, they can tell if there is increased blood supply to the lump, a telltale sign of cancer, but cannot usually tell if the lump is hard or soft.
Ultrasound elastography gives the doctor more information to judge if the patient is in the clear or if a biopsy has to be done, said Dr Tan.
'It's like investigative detective work - the more information you gather, the more accurate the diagnosis,' she added.
'We don't want to miss a cancer.'
In the study, 550 suspected breast cancer patients were given both the usual and enhanced ultrasound scans and a breast biopsy.
About 4 per cent of 319 of them whose conventional ultrasound scan results had been normal, were found to actually have breast cancer.
After a breast biopsy, they were found to have breast cancer. The results of the study were published in a European journal, The Breast, in June.
Since it was completed, all women who have suspicious breast lumps have been offered both conventional and enhanced scans at CGH, at no additional cost.
An ultrasound scan for private patients at CGH costs $117.70. One patient, who is glad she got both scans, is insurance adviser Jessie Tan, 43, who was treated at CGH in 2006 after she felt discomfort in her breast.
Her mammogram and conventional ultrasound scan were clear.
Only ultrasound elastography detected two lumps, whose hardness hinted at them being probably cancerous.
A biopsy confirmed she had breast cancer, so surgery and chemotherapy followed.
She said: 'It was good that the doctor did the scan, which was more conclusive than the others. I was shocked to be told I had cancer, and just wanted to do whatever was needed to get it over and done with.'
This article was first published in The Straits Times on Oct 9, 2008.