Backlogs in cancer treatment and diagnosis during COVID-19 may affect cancer survival

Unlike the COVID-19 pandemic, the cancer pandemic has been raging for centuries, although it equally afflicts people in every corner of the world. In 2020 alone, more than 19 million people were diagnosed with cancer worldwide and almost 10 million people die from cancer each year.

The COVID-19 pandemic has been devastating for people infected with the SARS-CoV-2 virus, with more than 481 million confirmed cases and 6.1 million deaths.

The number of people who have become ill or died due to unintended consequences of pandemic control measures has not yet been determined, although these invisible costs of COVID-19 control measures are likely to be substantial.

I am a cancer physician and health services researcher, and my team has found new evidence that will help count the invisible cost of the COVID-19 pandemic to the cancer pandemic.

Consequences for cancer

A pharmacy technician preparing chemotherapy drugs. Chemotherapy, radiation therapy and surgery – the three main cancer treatments – have been delayed during the COVID-19 pandemic.

For people with cancer, the direct consequences of the pandemic include a potentially higher risk of serious COVID-19 infection. Indirect consequences include late cancer diagnosis, delayed testing, and delayed treatment. For example, we saw a sevenfold decrease in biopsies required for the diagnosis of skin cancer in Ontario at the start of the pandemic, with a backlog of over 45,000 cases six months later.

Significant declines in cancer diagnoses and cancer surgeries have been observed in Canada and abroad. For example, in Ontario, we saw a 34% drop in cancer diagnoses and a 60% drop in cancer surgeries at the start of the pandemic in 2020. Most concerning is the slow recovery of cancer services after the lockdown , resulting in diagnosis and treatment delays for people with cancer.

These delays in diagnosis and treatment have many consequences. There are effects on quality of life and mental health while waiting for care. Waiting for cancer care can cause symptoms to worsen and progress to a more advanced stage in some cases. Treatments for more advanced cancer may have more side effects and not be as effective.

Treatment times and survival

To provide evidence to guide the health system response to cancer delays amid the pandemic, our unit conducted a high-quality evidence review of the impact of cancer treatment delays on survival.

We used information from over 1.2 million cancer patients from 34 high-quality studies of 17 conditions where surgery, radiation therapy or systemic therapy is commonly used. We studied seven types of cancer – bladder, breast, cervix, colon, rectum, lung and head and neck – which together account for 44% of all cancers diagnosed worldwide each year. We measured the impact on survival by four weeks.

A person lying down wearing a hospital gown with a mesh mask on their head, with red lines of light
Delaying cancer treatment by even four weeks could be associated with reduced survival.
(Unsplash/National Cancer Institute)

Our report published in BMJ found that in seven cancer types, a delay of even four weeks could be associated with reduced survival. For example, breast, colon, bladder, and head and neck cancer surgeries were associated with a six to eight percent increase in mortality for every four weeks delay. Gender, older age, and socioeconomic factors were often associated with disparities in wait times. As the delay increased, the impact on survival became even greater.

What does this mean concretely? A team from McGill University and the Canadian Partnership Against Cancer (CPCC) developed a model using information from our study on time to treatment and survival. They found that between 2020 and 2030, disruptions in cancer care during the COVID-19 pandemic could result in approximately 20,000 additional cancer deaths in Canada.

Given that the pandemic has affected global cancer care and that outside of Canada more than 19 million people are diagnosed with cancer each year, the additional deaths worldwide due to delays in cancer care cancer could be significant.

Implications for care

We now have standardized information covering seven cancers and the three main types of cancer treatment demonstrating a link between longer waits for cancer treatment and worse survival outcomes. If we had a new cancer drug that improved outcomes as much as rapid treatment did in our study, societal precedents suggest we would pay in the high fives per patient for it.

And now? More research needs to happen in this space. The impact of delayed cancer care on more conditions needs to be studied and methods need to be standardized. However, there are important implications for care now.

The entrance to a building with a revolving door and a sign in front stating COVID-19 protocols
Waiting for cancer treatment can cause symptoms to worsen and progress to a more advanced stage in some cases.

Given the massive backlog of health services due to the pandemic, investments are needed and happening at the federal level. It is welcome and important. For example, a 10% increase in treatment capacity could reduce the predicted mortality impact of the delayed pandemic in Canada by approximately 20,000 to 4,000.

As we face other health emergencies and possibly other waves of the COVID-19 pandemic, caution should be exercised when extending cancer wait times for reasons unrelated to a patient’s health care needs. The impact of these delays on cancer patients may take years to be felt, but they can be expected and should be factored into decisions about prioritizing and protecting limited healthcare resources.

During the pandemic, protecting hospitals, clinics and staff from COVID-19 infection can ensure optimal resources for timely cancer diagnosis and care. Centralized waiting lists and team-based care for surgery and other services can ensure fair wait times for treatment.

Finally, innovation in the delivery of care (e.g. learning about health systems) and in the care delivered (e.g. treatments requiring fewer hospital visits or less human resources) is very important .

It is crucial to treat pandemic cancer patients in time, during the COVID-19 pandemic and beyond.

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