55000 'missing' cancer diagnoses: The pandemic effect researchers are still tracking

While the Covid-19 pandemic is often remembered for overwhelmed hospitals, lockdowns and vaccination drives, researchers are now drawing attention to another consequence that unfolded quietly in the background: thousands of cancer cases that may have gone undiagnosed during the crisis.

A major international study has found that disruptions to healthcare services during the early months of the pandemic resulted in a significant drop in cancer diagnoses across several high-income countries.

Experts say the findings highlight how delays in routine screening, medical appointments and diagnostic testing can have long-lasting effects on public health.

Nearly 55,000 cancer cases were 'missing' during the pandemic

According to a study published in the medical journal The Lancet Oncology, around 55,000 expected cancer diagnoses were not recorded across seven high-income countries during the first nine months of the Covid-19 pandemic.

Researchers analysed data from approximately 2.6 million patients across Australia, Canada, Denmark, Ireland, New Zealand, Norway and the UK. They found that between April and December 2020, cancer diagnoses were around 16 per cent lower than expected when compared with pre-pandemic trends.

In simple terms, thousands of people who would normally have been diagnosed during that period either experienced delays or never entered the healthcare system at all. This does not necessarily mean those cancers disappeared. Rather, many cases may have remained undetected because routine medical services were disrupted.

Which cancers saw the biggest decline?

The study found that some cancers were affected more than others.

Prostate cancer diagnoses experienced the sharpest fall, dropping 24 per cent below expected levels during the study period.

Female breast cancer diagnoses declined by 18 per cent, while melanoma diagnoses also fell by 18 per cent.

Researchers noted that lung cancer and ovarian cancer appeared to be less affected than some other cancer types.

Experts believe these differences may be linked to how cancers are typically detected. Cancers that rely heavily on routine screening programmes or non-urgent medical consultations were more likely to be impacted by lockdowns and healthcare disruptions.

Why did cancer diagnoses fall during Covid?

Researchers identified several factors that likely contributed to the decline.

During the pandemic, many countries temporarily suspended cancer screening programmes to reduce pressure on healthcare systems and minimise virus transmission.

Access to primary care services also became more difficult in many regions, with fewer in-person appointments available.

At the same time, many people avoided visiting clinics or hospitals because they were worried about contracting Covid-19. Symptoms that might normally have prompted a medical consultation were sometimes ignored or postponed.

Together, these factors created conditions where cancers that would usually have been detected early remained undiagnosed for longer periods.

Some countries recovered faster than others

One of the most notable findings from the study was the variation between countries.

Researchers found that Norway and New Zealand experienced smaller declines in cancer diagnoses and recovered more quickly than the UK and Ireland.

The difference suggests that healthcare systems with stronger continuity of screening and diagnostic services were better able to maintain cancer detection during the pandemic.

According to the researchers, understanding why certain health systems were more resilient could help governments prepare for future public health emergencies.

Study senior author Isabelle Soerjomataram, deputy head of the Cancer Surveillance Branch at the International Agency for Research on Cancer, said examining how some countries managed to maintain services could provide valuable lessons for future crisis planning.

What about long-term consequences?

One of the key questions surrounding pandemic-related healthcare disruptions is whether delayed diagnoses will lead to worse outcomes for patients.

The study found limited evidence that cancers diagnosed during 2020 were immediately being detected at more advanced stages. However, researchers caution that the longer-term impact is still not fully understood.

Cancer often develops over several years, and delays in diagnosis may only become apparent through future data and patient outcomes.

Previous research has already raised concerns about the potential consequences. A separate study published in JAMA Oncology earlier this year estimated that disruptions to cancer care in the United States during 2020 and 2021 were associated with roughly 17,390 excess cancer deaths within one year of diagnosis.

What lessons can healthcare systems learn?

The findings serve as a reminder that public health emergencies affect far more than the disease at the centre of the crisis.

Experts say maintaining access to cancer screening, diagnostic testing and routine medical care should remain a priority even during future outbreaks or emergencies.

The study suggests that healthcare resilience is not just about treating immediate threats but also ensuring that people continue receiving essential preventive and diagnostic services.