SAN ANTONIO – , according to results from a new randomized trial.
In the UK study, researchers found similar recurrence rates and overall survival between patients who continued to undergo annual screening versus women who underwent screening every 2 years after breast-conserving surgery or every 3 years after a mastectomy.
Current US guidelines recommend annual screening with no stopping point, while UK guidelines recommend annual screening for 5 years, followed by every 3 years after that.
The study was commissioned by the UK government after a previously commissioned systematic review showed lack of evidence for the existing frequency and duration of mammograms in this patient population, and a survey showed wide-ranging clinical practices. In response, the UK government funded the new study to evaluate whether it would be safe to reduce screening, according to Janet Dunn, PhD, who presented the study at the San Antonio Breast Cancer Symposium.
“Ladies are going back for years and years and years [for mammograms], and it’s inappropriate, it’s not necessary,” Dr. Dunn, professor of clinical trials and head of cancer trials at University of Warwick in the UK, said in an interview.
The lower frequency schedule requires that the patient be cancer free at 3 years following curative treatment. “We know for anybody going through breast cancer there are a couple of peaks of recurrence. One peak is 2 to 3 years [after curative treatment] for high-risk patients. The other peak is when they start hormone therapy, so at 5 to 6 years you get the peak. But this particular set of patients are at low to moderate risk, so they’re not the high-risk patients going into treatment trials,” said Dr. Dunn.
When asked if the findings should change practice, Dr. Dunn suggested that they could. “We would say that this is providing clinical evidence and probably changing guidance for the management of these patients: Instead of giving annual mammograms for years and years and years, after three years post curative surgery, and having gone through treatment with a baseline mammogram that’s clear, in the UK we can manage these patients back within the screening program, certainly for the mastectomy patients,” said Dr. Dunn.
She emphasized the potential mental health impact. “Women who are going through mammograms waiting for the results are much more anxious if they’ve had breast cancer before than those who were who were just going through normal screening. So [deescalation] is reducing anxiety. It’s also reducing the cost. It’s just reducing the burden on the whole health care system,” said Dr. Dunn.
During the Q&A session after the talk, Bruce Mann, MBBS, PhD, asked if there were differences in the pathology of the cancers that occurred in the less frequent group than those that arose in the annual group. If more frequent screening leads to earlier diagnosis of a tumor, “you would expect that those who have less [frequent screening] may be diagnosed with more advanced recurrences or new cancers, and that would eventually lead to a difference in outcome,” Dr. Mann said in an interview. He is director of breast cancer services at the Royal Melbourne Hospital in Australia.
He acknowledged the need to reconsider screening frequency, and complimented the researchers. “This is a nice pragmatic study. It’s interesting. It’s provocative. I think it’s a bit too early [to change practice]. I think we do need to see more information,” he said.
The researchers randomized 5235 women aged 50 and older to annual or less frequent mammography. The disease type was invasive in 87% of women, while 13% had ductal carcinoma in situ.
Over a median follow-up of 8.7 years, 7% experienced a recurrence. At 5 years, breast cancer–specific survival was 98.1% and 98.3% in the annual and less frequent groups, respectively (hazard ratio [HR], 0.92; 95% CI, 0.64-1.32). There was also no difference in recurrence-free survival or overall survival.
Analyses showed noninferiority of less frequent mammograms at a 3% margin (P < .0001) and a 1% margin (P = .003).
The researchers found that 83% of women were compliant with the mammogram schedule in the annual group, versus 69% in the less frequent arm. The COVID-19 pandemic was responsible for 35% of missed mammograms overall.
Quality of life measures showed that levels of distress over mammograms was similar across time and between the two groups, with 24% of women reporting medium or high levels of distress.
Dr. Dunn and Dr. Mann have no relevant financial disclosures.
