Aggressive breast cancer needs better screening
CBC News
Posted: May 3, 2011 4:59 PM ET
Last Updated: May 4, 2011 12:13 PM ET
Related
External Links
(Note:CBC does not endorse and is not responsible for the content of external links.)
Better imaging technologies are needed to find some fast-growing breast cancer tumours. Eric Gaillard/ReutersBreast cancers in women over age 50 that are first found between mammogram screenings are more likely to act aggressively and grow quickly, a new Canadian study suggests.
There are two types of breast tumours that can be missed on mammograms — "true" interval cancers that were not actually detectable on a previous mammogram, and "missed" ones that weren't found because of observer error or misinterpretation.
In Tuesday's online issue of the Journal of the National Cancer, Anna Chiarelli of Cancer Care Ontario and her co-authors say true interval cancers were more likely to be aggressive with a poorer prognosis.
The researchers analyzed data for 288 women with true interval cancers and 87 women with missed interval cancers. Both kinds of interval tumours were compared with screen-detected tumours in 450 women who were similar in terms of age, location of the screening centre, and length of time since their last mammogram.
"We expected to find interval cancers to have a worse prognosis than screen-detected cancers," said Chiarelli. "However, very few studies have really looked at them by type of interval cancer. I think it was important to see those differences."
For women over 50, Chiarelli said the findings point to the importance of being "breast aware" to any breast symptoms that could occur between mammograms and getting those checked out by a doctor.
True interval cancers make up 75 per cent of missed tumours, Chiarelli noted.
Specifically, the researchers found true interval cancers were more likely to have:
- Grown rapidly in the time between mammograms.
- Tended to be estrogen receptor negative, which are less common but have a poorer prognosis.
- Have tumour cells that divide rapidly.
- Have a less common type and arrangement of cancer cells.
"The aggressive tumour features we observed for interval cancers are likely partly because of the rapid proliferative rate, the delay in diagnosis, and partly reduced tumor detection on mammograms," the study's authors concluded.
"This suggests a need for further advancement in imaging technologies to detect certain types of breast carcinomas and different approaches for early detection of fast-growing tumours."
Chiarelli is now analyzing data on breast cancer cases up to 2009 to look for any differences in detection after better technologies like digital mammography were introduced.
The research looked at mainly Caucasian women.
It was funded by the Canadian Breast Cancer Research Alliance.
With files from CBC's Amina ZafarShare Tools
Top News Headlines
- Tories line up to argue CP Railway strike hurting economy
- Conservative cabinet ministers say they're protecting the economy by moving to legislate Canadian Pacific Railway workers back to their jobs less than a week after the union went on strike, while the employees say their right to collective bargaining is under attack. more »
- Missing Winnipeg kids found in Mexico back with mom

- Two Winnipeg children who had been missing for nearly four years are back home, reunited with their mother, after they were located in Mexico late last week. more »
- Bullyproof: One classroom confession
- Chadia became physically scarred after incessant teasing. Her story is one of 150 gathered in a video confessional booth at a Quebec school. more »
- Quebec resumes talks with student leaders
- Negotiations between student leaders and Quebec's Liberal government resumed this afternoon in a third attempt to resolve the tuition crisis. more »
Latest Health News Headlines
- 5 ways to prevent kids from getting poisoned
- Poison centres across Canada field about 160,000 calls a year about children exposed to medications and other household chemicals more »
- Dementia patients may not imagine their future
- Our ability to imagine our future depends on a part of the brain used to store general knowledge, which is affected by some forms of dementia. more »
- Eastern Health to cut hundreds of jobs, Liberals say
- Health Minister Susan Sullivan says spending cuts at the province's largest health authority will not hurt programs and services, despite a claim by the Opposition Liberals. more »
- Ontario knocked for special-needs student support
- The province should conduct a review of how it serves special-needs students and improve a policy to support connections between schools and the community, a new report urges. more »
FEATURED HEALTH
- Missing Winnipeg kids found in Mexico back with mom
- Canadian Everest climber's body recovered
- Thunder Bay flooding causes state of emergency
- Vatican denies cardinal suspected in leaks scandal
- Evolution skeptics will soon be silenced by science: Richard Leakey
- Tories line up to argue CP Railway strike hurting economy
- Remains found in bag on Cape Breton river ID'd
- Justin Bieber wanted for questioning in L.A. scuffle
- Accused in blast that killed Alberta mom handled her funds

