Blood cancers

Haematological cancers linked to four-fold higher risk of COVID-19 death

Recent haematological malignancy is a clinical risk factor for death from COVID-19 disease identified in an analysis of data from patients in a UK database.

Patients with haematological malignancy up to five years from diagnosis had up to a four-fold increased risk of dying in hospital with COVID-19 compared to those without blood cancer history a large study from Oxford University found.

The preliminary findings, which are yet to be peer reviewed, are based on data drawn from NHS England’s primary care electronic health record system. This very large dataset was then linked to a registry of 5683 hospital inpatient COVID-19 death records.

In the study, most comorbidities were associated with higher risk of COVID-19 death, including diabetes, asthma (especially with recent use of an oral corticosteroid); respiratory disease; chronic heart disease; liver disease, neurological diseases, particularly stroke and dementia; reduced kidney function; and autoimmune diseases such as rheumatoid arthritis, lupus or psoriasis.

People with a recent diagnosis of haematological malignancy had an age and sex adjusted hazard ratio of 4.03 for COVID-19 death. For people with haematological malignancy diagnosed between one and five years previously the hazard ratio was 3.59, and for those diagnosed more than five years previously the hazard ratio for risk of death was 2.13.

For other cancers, considered separately to reflect the immunosuppression associated with them, the hazard ratio for recent diagnosis (less than one year) was 1.83 and for cancers diagnosed between one and five years previously the hazard ratio for COVID-19 death was 1.39.

The results also confirmed that factors such as  older age are strongly associated with risk of death, with the ≥80 years age group having more than 12-fold increased risk compared with those aged 50-59 years. Similarly the risk of COVID-19 death in men was double that of women.

Unanswered questions

However talking to the limbic about the study, Professor Miles Prince, Director of Molecular Oncology and Cancer Immunology, Epworth Healthcare and Haematologist at Peter MacCallum Cancer Centre, says key questions remain unanswered such as whether all patients with early-stage cancer should postpone their treatments, as well as whether immunotherapy may aggravate the severe outcomes experienced by patients with COVID-19 and cancer.

“Certainly the hazard ratio for haematological malignancy diagnosed at less than one year is high – above four – but it’s based on data from 27 people and you really want to know what the breakdown is for haematological type – acute myeloid leukaemia, versus lymphoma versus myeloma for instance, which this study doesn’t do.”

According to the study, some 210 patients with haematological malignancy of some kind died from COVID-19 during the study period.

Professor Prince says while it’s ‘tantalising’ to want to get that information about which haematological malignancies put patients at most risk of dying from COVID-19, the risk of drawing conclusions from such early, raw data means ‘statistical rigour’ is sacrificed, which could have devastating implications for patients with acute blood cancers.

He argues that, because of the study’s small haematology patient numbers, the only conclusions that can be drawn – at least at this stage – are that older age and renal function ‘trumps everything’ else in terms of risk factors.

“I think it would be fair to say in the Australian haematology community we are totally reliant on what’s happening overseas because there are just not enough patients here in Australia to draw our own conclusions,” he says.

Risk exposure

But another problem, according to Professor Miles, is that risk exposure overseas is very different to here in Australia.

“The environment is changing so quickly – exposure risk for patients in Italy compared to Spain, France or the UK: they’re all going to be different,” he said referring to COVID-19 testing rates as well the quality of primary health care in particular.

“Although we’ve got some learning of the people who are at risk I’d say the biggest thing that stands out is that it’s still those other patient characteristics [such as] age, renal disease, gender, that are key in defining what the patients’ risk are.”

For Professor Prince the findings indicate there is a concern but it’s not a ‘screaming signal’.

“Overall I would be saying that it’s reassuring that we’re not seeing large numbers but there is going to be a group in there that we have to be particularly careful about but we still don’t know which haematology patients are going to be at greatest risk and whether it’s their disease, their treatment or their other health issues.”

Advanced disease

For now, Professor Prince says advanced malignancy in older patients is a significant risk for mortality from COVID-19, and that every effort should be made to isolate these patients from those who are infected.

“I wouldn’t be making the vast majority of my patients feel anxious but I do worry about my patients who, for example have myeloma, are severely immunosuppressed who are 82 – what can they do? They have to self-isolate because they are at such high risk.”

As we approach the challenging winter months, Professor Prince admits he is anxious.

“Within six to eight weeks we’re potentially going to see hundreds of people diagnosed with COVID-19 per day. We have to reinforce the importance of social distancing with our patients, we have to remain super diligent because so far the numbers have been small enough for us to have escaped major issues. But the numbers are going to go up and we have to be as prepared as we were in March. We can’t afford to relax.

“I’m anxious that the next three months is going to see a resurgence but I think we’re as prepared as we can be. Haematology patients have to remain diligent around social distancing. It’s our only defence.”

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