The number of Queensland women undergoing mastectomies has decreased by a third since the introduction of breast cancer screening programs, according to a University of Queensland study.
Surgery Department Clinical Associate Professor Ian Bennett was part of a team which analysed the patterns of detection of 9862 breast cancer cases recorded between 1984 and 1994 in Queensland.
"The study showed that breast cancer is being detected earlier and can therefore be treated with less radical surgical procedures than techniques such as mastectomies," Dr Bennett said.
"Most of the trend towards earlier detection has taken place since the more extensive development of the screening programs in the early 1990s."
Funded by a $27,000 grant from Queensland Health, the study's aim was to measure the impact of the Queensland Breast Screening Program introduced in 1985 and widened into the Breast Screen Queensland Program in 1992.
Both programs encouraged women, especially those in the high-risk age group of between 50 and 69, to attend clinics throughout the State for mammograms. It has been estimated breast cancer affects one in 13 women at some stage.
The research team consisted of Dr Bennett, Queensland Health statistician Catherine James, Queensland Medical Laboratories pathologist Dr Gordon Wright and the director of the Royal Brisbane Hospital's Brisbane North region Dr Christine Baker.
For each breast cancer case, the team examined the tumour type and size at the time of detection, whether the cancer had spread to the lymph nodes and what operative procedure had been required.
Dr Bennett said when breast cancer was detected early enough, a surgical procedure known as pre-operative wire localisation was necessary to remove the tumour, indicative of the very early nature of the cancer.
The proportion of women having localisation biopsies increased during the period from two percent in 1984 to 22 percent in 1994. Quite significantly, the proportion of women requiring mastectomies fell from 71 percent in 1984 to 46 percent in 1994, Dr Bennett said.
During the 10-year period, Dr Bennett said there had been a significant reduction in tumour size and a significant increase in the proportion of intraduct cancers - the early growth phase of tumours - reported at the time of detection. He said this suggested breast cancer was being detected far earlier in recent years.
He said the study also showed a significant reduction in cases in which the cancer had spread to the lymph nodes, again suggesting it had been diagnosed a lot earlier than previously.
"There was also an increase in the proportion of special tumour subtypes detected. These have a much better prognosis and are classified as a less aggressive cancer type," Dr Bennett said.
These trends in early diagnosis of breast cancer had been consistent throughout the State suggesting rural areas were also well-serviced by screening clinics and programs, Dr Bennett said.
For more information, contact Dr Bennett (telephone 07 3839 0006).
