The suspension of breast screening services in 2020 to limit the risk of COVID-19 transmission does not appear to be resulting in a feared wave of more advanced breast cancers, according to a newly published analysis of NSW healthcare data.
Published today in Public Health Research & Practice, a peer-reviewed journal of the Sax Institute, the study used data from BreastScreen NSW and the NSW Cancer Registry to compare women aged 50-74 who were diagnosed with invasive breast cancer after attending a BreastScreen NSW clinic, in periods before and after a pandemic-related seven-week suspension of screening services in early 2020.
The researchers from Cancer Institute NSW compared the average tumour size detected in women who had had their mammography screening delayed by the pandemic and in those who had not, finding no significant difference between the two groups (16.2mm compared with 15.9mm respectively).
“Our retrospective analyses demonstrated no evidence of a substantial change in the size of tumours diagnosed by BreastScreen NSW in clients whose breast cancer screening was delayed by the suspension of service due to the COVID-19 pandemic,” the researchers wrote.
The study also looked at women who underwent surgery for both screen- and non-screen-detected breast cancers, using cancer surgery notification data to calculate the number of surgeries from 2018 to 2020. The researchers found the number of breast-conserving surgeries fell by roughly 50% during and shortly after the 2020 suspension of breast screening in NSW (March to May 2020). However, the number of mastectomies fell by only 7%. By September 2020, numbers for both surgery types had returned to normal, and there was no evidence of an increase in invasive breast surgeries following the suspension of services.
The researchers said their findings could reassure the public that the benefits of the suspension of screening in 2020 – including redeployment of BreastScreen staff to the pandemic response and reducing infection risk – were likely to outweigh any potential harms.
They noted their findings were in line with international research that has reported short-term interruptions to cancer screening may not result in cancers of a more advanced stage being diagnosed, particularly when screening services catch up with backlogs quickly.
But they said the findings may not reflect other Australian states and territories, due to variations in COVID restrictions and lockdowns.
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