6. Avrupa Meme Kanseri Konferansın'ndan;(Medscape News)
Mammograms Should Continue Up to Age 75 Years, and 3-Year Intervals Are Sufficient "From 6th European Breast Cancer Conference (EBCC)
April 21, 2008 — Two very large studies of mammography screening for breast cancer have concluded that such screening is beneficial in women 70 to 75 years of age and that a 3-year interval between mammograms is sufficient. The new data were reported here at the 6th European Breast Cancer Conference (EBCC) in Berlin, Germany, and highlighted at an official press briefing during the meeting.
Many countries that run breast cancer screening programs offer regular mammography to women between the ages of 50 and 70 years, but the new study shows that there are benefits to extending the upper age limit to 75 years. The study comes from the Netherlands, which extended the upper age limit from 69 to 75 years in 1998.
It usually takes about 5 years for the effect of screening to have an impact, so the researchers analyzed data from 2003 on. They found a steady decline in breast cancer deaths among women aged 75 to 79 years. During the period from 1986 to 1997 (ie, before screening for the older age group had been introduced), the average rate for death from breast cancer in this age group was 166 per 100,000 women. In 2006, after such screening had been in place for 8 years, this rate had dropped 29.5%, to 117 per 100,000 women.
"This reduction in breast cancer mortality shows that the screening has started to have a statistically significant effect," said lead researcher Jacques Fracheboud, MD, an epidemiologist and senior researcher at the Erasmus Medical Center, Rotterdam, the Netherlands.
Breast Cancer Easier to Detect in Elderly Women
Between 1998 and 2006, a total of 7.37 million mammograms were carried out, of which 862,655 were in women 70 to 75 years of age. The participation rate was 81.2% for women aged 50 to 69 years and 71.9% for women aged 70 to 75 years (but the proportion increased from 62.5% in 1998 to 77.6% in 2006). The screening led to a referral for diagnostic assessment in 12.8% of women 50 to 69 years of age and in 16.4% of women 70 to 75 years of age.
Breast cancer was detected in 4.5 per 1000 women screened in the 50- to 69-year age group, giving a positive predictive value (PPV) of 36% and in 7.8 per 1000 women screened in the 70- to 75-year age group, with a PPV of 47%.
"This difference shows that it is easier to find breast cancer in older women because their breast tissue is less dense," Dr. Fracheboud commented. "But it is not necessarily an argument for continuing screening beyond 75 years, because many tumors found at this stage are slow growing and may never reach the stage of causing a problem."
"The results of our study suggest that screening women aged 70 to 75 has a strong impact on breast cancer mortality and that it is effective and appropriate up to 75 years," Dr. Fracheboud concluded.
"I agree that mammography should be continued up to the age of 75, because a very fit woman of this age still has a life expectancy of about 15 years," commented Emiel Rutgers, MD, PhD, from the Netherlands Cancer Institute and Antoni van Leeuwenhoek Hospital in Amsterdam. Dr. Rutgers was chairman of the EBCC meeting and was also moderator at the press briefing. However, he was less in agreement with the conclusion from the second study, which suggested that a 3-year interval between mammograms is sufficient. This might be the case in the general population, he told Medscape Oncology, but for women who are at higher risk for breast cancer because of a family history or because of their exposure to estrogen, screening may need to be more frequent.
Screening at 3-year intervals was compared with screening at 1-year intervals in the United Kingdom Breast Screening Frequency Trial, which began in 1989 and involved nearly 100,000 women. After an average follow-up of 13 years, there were 373 breast cancer deaths in the 1-year-interval group and 374 in the 3-year-interval group (relative risk [RR], 1.02; P = 0.
.
When the researchers considered only the women who turned up for screening, rather than the study groups as a whole (which included the nonattenders), they found that 209 women in the 1-year-interval group and 231 women in the 3-year-interval group had died from breast cancer (RR, 0.89; P = .2).
No Evidence for Shortening Current 3-Year Intervals
The absolute risk of dying from breast cancer was statistically insignificant between the 2 groups, the researchers explained at the meeting.
"There was a lot of criticism of the UK for having a 3-year interval when breast screening was set up," one of the study's authors, Roger Blamey, MD, a breast surgeon at Nottingham City Hospital, commented to journalists. "Screeners and advocacy groups said, without evidence, that it was too long an interval." But the results of the current study vindicate the decision that was made. "There is no evidence in favor of shortening the current 3-year screening interval," he said.
6th European Breast Cancer Conference (EBCC): Abstracts 4LB and 5LB. Presented April 18, 2008.
Pearls for Practice
Mammography screening in women aged 75 to 79 years is associated with a 29.5% lower mortality rate vs no mammography, and the PPV for mammography in women aged 70 to 75 years is 47% vs a PPV of 36% in women aged 50 to 69 years.
A mammography screening interval of 3 years vs 1 year is not associated with worse outcomes of breast cancer mortality rate in women who are followed up to 13 years. "
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