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Are cancer patients more at risk for Covid-19?

Reports show a higher chance of infection and complications, but patients should not defer treatment to lessen the risk of infection as cancers likely pose a greater danger

"I just had the return of some semblance of calmness in my life," said Ms M. "And now this…"

This year did not begin well for Ms M. Barely a week into the new year, she received the shocking news that the lump she discovered in her right breast was cancerous in nature.

Ms M is only 32 years of age and had just delivered her second baby six months ago.

The frequent engorgement of her breast related to breastfeeding concealed the presence of the cancerous lump in her breast and the problem was picked up late.

Her breast surgeon recommended that she see me for chemotherapy with the aim of shrinking the huge cancerous lump substantially, so as to allow complete surgical removal of the cancer.

Ms M's condition responded very well to chemotherapy and three months into her treatment, the large breast lump shrank to a size that was hardly palpable.

Her usual optimism in life was restored; this was when - as she said - some semblance of calmness returned to her life.

But the sleepless nights returned of late.

In the midst of a worsening Covid-19 epidemic, a constant thought kept playing in her mind - my warning to her that during chemotherapy treatment, her immunity is lowered and she is more vulnerable to infections.

She thought: If healthy people not receiving chemotherapy had caught the coronavirus so easily, wouldn't she be certain to fall prey to the virus? Should she pause her treatment?

Indeed, are cancer patients undergoing treatment more likely to catch the coronavirus?


ST ILLUSTRATION: MANNY FRANCISCO

Much remains uncertain when it comes to the behaviour of the novel coronavirus, Sars-CoV-2, including the vulnerability of cancer patients to infection.

Nevertheless, borrowing from the past experience of a heightened risk of infection by the influenza virus for cancer patients, it would be fair to assume that this may also be true of the coronavirus.

Looking at early reports from China, the proportion of the population infected by the coronavirus was 0.3 per cent; among cancer patients, the proportion was threefold at 1 per cent.

Perhaps even more worrying was the high rate of severe complications requiring intensive care among cancer patients afflicted with the virus, as those reports showed.

The risk of such a downturn in condition was less than one in 10 for the general population, but shot to four in 10 among cancer patients. And the slide downhill was rapid.

The interval between the appearance of initial symptoms and the development of life-threatening complications was about a month for the general population, but less than two weeks on average for patients with cancer.

Part of the possible elevated risk of infection and of complications in cancer patients could be brought on by cancer treatment as certain chemotherapy or targeted therapy has depressive effects on patients' immune system.

Part of the risk may arise from the cancer itself as certain cancers, especially blood-related cancers, impair proper function of the immune system.

So, should cancer patients defer their cancer treatment to lessen the risk of infection by the coronavirus?

With the exception of very indolent and slow-growing cancers that are unlikely to trigger a life-threatening problem in the medium term, cancers, for the most part, probably pose a greater danger to patients' lives than the risk of coronavirus infection in patients not already infected.

Hence, with the maximum anti-infection precautions in place, it is often necessary to bite the bullet and start or continue anti-cancer treatment.

Should lightning strike twice at the same spot - an unfortunate patient simultaneously afflicted with cancer and the coronavirus - would it be sensible to continue the cancer treatment?

There is no straightforward answer for this conundrum. Where possible - if a few weeks' delay in the cancer treatment will not impact survival - it would be better to allow the coronavirus infection to blow over before continuing anti-cancer treatment.

However, in a situation where the cancer is immediately life-threatening and treatment is urgent, the oncologist may have to proceed, come hell or high water.

For Ms M, she is determined to see her cancer treatment through to the end. Hand washing: checked. Mask: checked. Staying home apart from clinic visits: checked.

• Dr Wong Seng Weng is the medical director and consultant medical oncologist at The Cancer Centre.

A version of this article appeared in the print edition of The Straits Times on May 18, 2020, with the headline 'Are cancer patients more at risk for Covid-19? '. Print Edition | Subscribe