Breast Cancer Screening Guidelines Based on Defective Canadian Studies, New Paper States

In particular, Canadian National Breast Screening Study (CNBSS) was originally implemented in the 1980s, involving tens of thousands of women and eventually held in 15 different urban areas across the country.

A randomized trial initiated to determine if screening helped save a woman’s life. In the first study, women aged 40-49 years were randomly assigned to receive mammograms or were placed in a control group that underwent a single physical examination, and all participants were followed for several years.

During the course of the study, 38 people died of breast cancer in the mammography group and 28 people died of those who did not undergo mammography screening.

As a result, Canadian researchers concluded that annual screening of women aged 40 to 49 years at average risk did not reduce breast cancer mortality more than physical examination.

This research was continued to inform guidelines both here and around the world. NS Latest guidelines Published by the Canadian Task Force on Preventive Medicine does not yet recommend screening for women in that age group.

An important issue with previous screening is Risk of false positives and overdiagnosis. It is cancerous or not harmful to females and may be lumpy, but if found, a biopsy is required.

Experts warn that all types of breast cancer treatments, including radiation, chemotherapy, and surgery, can be harmful.

New evidence

However, according to Dr. Jean Seeley, co-author of the new paper, professor of radiology at the University of Ottawa, and head of breast imaging at the University of Ottawa, there were some problems with CNBSS.

She and her co-authors are seeking mammograms for women over the age of 40, if needed.

It is said that “conclusive confirmation” was made that CNBSS was conducted especially in some test sites for females who were not randomly assigned.

Interviews with 28 staff members who worked on the original study confirmed that there were multiple cases in which a female with a detectable lump pre-screened by a nurse was actually intentionally placed in a mammography group. She said it was done.

“I was surprised. I didn’t expect to find such clear and clear evidence of what was happening,” Sealy said. “Then I think my next reaction was anger. Why was this allowed?”

Paper add to Many years of discussion About the quality of research Since they were first published Whether women in their 40s need to be screened regularly.

Since the 90s, radiologists and researchers have been concerned about the inclusion of women with advanced cancer in their studies, the quality of screening, and the factors used to determine if mammography is beneficial to that age group. Has been expressed.

Experts primarily suspect the issue of randomization, but they distort the findings.

NS Investigation of these allegations was conducted by outside experts In the 1990s after the first results of CNBSS were announced.

The resulting paper stated that “it could not reveal credible evidence” that the randomization was somehow destroyed. The author further stated that even if there were vandalism, they were “small in number” and “the changes may have had a minor impact on the study results.”

Results will be different, experts insist

Still, some experts are not convinced. The new paper concludes that the results of the study would have changed in seven cases of lumpy females from the mammography group sent to the regular care group.

She hopes this new evidence will lead to change, Sealy said.

“I think the most personal and challenging moment I’m actually doing is when I see a woman in her 40s with advanced breast cancer,” she said.

In many cases, according to Sealy, these women should not be screened for their age by their doctor. “On a personal level, as an expert, I find this very, very difficult,” she said.

According to the Canadian Cancer SocietyWomen over the age of 50 have a higher diagnosis rate of breast cancer, but women aged 30-49 have a higher mortality rate.

Women in that age range account for 17 percent of all cancer deaths in Canada. This is compared to women aged 50-69, who account for only 8 percent of cancer deaths.

Principal Investigator Defends Research

Many other experts, including the CNBSS Principal Investigator, continue to defend the study.

Dr. Anthony Miller, Professor Emeritus of Dalla, said: The Lana School of Public Health at the University of Toronto, which led the study.

Miller, who saw a copy of the new newspaper, denies the possibility that the woman was not randomly placed in the trial. Extensive quality control measures were implemented to maintain the integrity of the study, he said.

The nurses were stationed only to inform participants about the study and to obtain their consent, he said, and any tests took place after the females were randomized.

At that point, except for a woman who might have had a palpable lump, Miller said, “It will certainly tamper with the results of the study.”

CNBSS is considered a gold standard

Miller isn’t the only defender of CBNSS. The author says their work has been under attack for decades, but CBNSS has endured years of skepticism and challenge.

This study is welcomed by many around the world as the gold standard for breast cancer screening studies. In 2019, the 25-year follow-up of this study was selected as one of the following: Top 5 research papers from the British Medical Journal over the last 10 years..

According to Dr. Karsten Jørgensen, Deputy Director of the Nordic Cochrane Center, it will be difficult to find one that is as documented and well-implemented as CNBSS compared to many other breast cancer screening trials. About breast cancer screening.

Canadian trial results are also consistent with other reputable studies around the world and show no benefit to early screening, Jørgensen said.

“There is always room for interpretation. There are always pitfalls. There are always limits to testing, which is why we are conducting a systematic review of these types of meta-analyses,” says Jørgensen.

“Most of this depends on interpretation, and which results should be trusted?”

New findings under consideration

Seely and her fellow researchers have raised concerns about CNBSS at the University of Toronto and the Canadian Medical Association Journal. Both were involved in the original study.

In the statement, the university offices responsible for research, oversight and compliance “emphasize research integrity” and “consider the concerns raised by a group of individuals and keep in touch with them.” Stated.

The university did not specify the scope or timeline of the review, only “return to them in the next step”.

“The CMAJ will fully cooperate with the university office process and wait for the office to report on the results of the review before deciding if more action is needed,” said Kirsten Patrick, Interim Editor-in-Chief of the Journal. The doctor writes. In her own statement.

She made no further comments.

Impossible guidelines change

The Canadian Task Force on Preventive Health says it is unlikely to consider changing the country’s current guidelines for breast cancer screening to include women in their 40s.

In a written response to the CBC, the Task Force upheld the guidelines by stating that they would “perform a rigorous and detailed evidence review” when developing the guidelines.

Dr. Brenda Wilson, Co-Chair of the Task Force, said:

Wilson wrote that “the best evidence available” is used to inform the guidelines. When there was a change in that evidence, she said the Task Force would “update the full review of the body of the evidence, including the new evidence.”

The Task Force will not comment on individual studies or opinion pieces without doing that review, she said.