Patients with coronavirus disease 2019 (COVID-19) who have an underlying malignancy, have a higher mortality rate compared with those without cancer, although the magnitude of such excess risk is not clearly defined. A systematic review and pooled analysis of 52 studies by scientists from the USA, Italy and Belgium, involving 18,650 patients with both COVID-19 and cancer, revealed that 4,243 deaths were recorded among this population, equating a probability of death of 25,6%.1 Professor Evandro de Azambuja, MD, PhD, medical oncologist, was one of the authors of this study. He is Head of the Medical Support Team at the Institute Jules Bordet, Brussels, and specialises in breast cancer research. He discusses the outcomes of this study and explains why certain patients are more at risk of dying than others.
Cancer seems to have an independent adverse prognostic effect on COVID-19-related mortality.2 Why is that? Are there predictive factors for survival in cancer patients (for all cancer types in general) ? If so, which?
“Patients with cancer are more likely to have other co-morbidities which may increase mortality, such as liver or lung diseases. Also, they may be immunocompromised due to the current cancer therapies, for instance chemotherapy, immunotherapies or certain monoclonal antibodies. As a result, they are more likely to die from COVID-19.2”
Focusing on your own particular field of research and expertise, breast cancer patients seem to be relatively less at risk from a severe COVID-infection or mortality. Can you summarize these scientific findings, and perhaps explain what mechanism lies behind this?
“Indeed, breast cancer patients seem to have less mortality due to COVID-19, but this may well be explained by the fact that they are not so immunocompromised by their treatments as patients with other types of cancer. Typically, many breast cancer patients are treated with less aggressive therapies, such as endocrine therapy, instead of high-dose chemotherapy, immunotherapy or targeted therapy. Generally, breast cancer patients also have fewer co-morbidities. Also, they tend to be younger and have a better performance status compared to patients with other tumour types.”
Certain cancers are associated with a higher risk of mortality or severe COVID-infection (admission to ICU) than others. What cancer types have a higher risk and can you explain what may cause these discrepancies?
“Patients with cancer and lung diseases (often related to smoking) are more likely to have complications. This also applies to patients who are receiving high dose chemotherapies, immunotherapies or some monoclonal antibodies for haematological diseases, since these treatments compromise the immune system.”
What were the most important additional insights relevant for oncologists in Belgium following this systematic review of 52 studies concerning cancer patient management in general?
“In our pooled analysis with 18,650 patients with COVID-19 and cancer, the probability of death was 25,6%, which is quite high. Patients with cancer is a vulnerable population and therefore, ideal candidates for prioritization in vaccination campaigns. In Belgium, this was the case: cancer patients were among the first groups to be vaccinated along with healthcare professionals.”
While vaccinations are underway, the virus is mutating and several new strains have appeared across the world, raising concerns about efficacy of the vaccines and the associated risk for vulnerable populations, such as cancer patients. Do you expect a need for new treatment approaches in order to respond to these new variants?
“This is a good question, but at this moment little is known about the new variants and how they behave. Some variants seem to be more aggressive, with more ICU admissions and a higher mortality. I think it is still a question mark to everyone, and how to adequately manage them is yet unknown. Therefore, even after vaccination, we should keep social distance, wear masks, avoid crowds and clean our hands often. In my opinion, all the measures that the government has promoted since March last year remain relevant, while we are learning about the variants and about how effective the vaccines are against these variants. What also is yet to be established is: how long does immunity after vaccination lasts? We simply do not know yet.”
Looking closer at the relation between certain cancer treatments and COVID-19 we also see interesting differences. With regards to breast cancer, patients who receive targeted therapies seem to be at a greater risk for severe COVID than patients who are treated with hormone therapy or chemotherapy. Can you elaborate on this and explain why this is the case?
“Cancer treatments are very different. Endocrine therapy alone does not affect the immune system, while chemotherapy, immunotherapies and some targeted therapies do affect the immune system, rendering patients more susceptible to infections, including COVID. This is the subject of the Belgian Society for Medical Oncology (BSMO) COVID part II study, in which we are collecting retrospective data on patients with solid tumours who were in the hospital in Belgium. We have several large centres in Belgium who agreed to participate in this research. Also, we have received financial support from different pharmaceutical companies to collect this important data. Right now, we are studying the impact of COVID on cancer treatments. We created a database and participating sites are entering their data. We hope this data will help us to better understand what should be done with different cancer therapies and patients infected by COVID. We will also join forces with ESMO, they have a similar Europe-wide project and we have agreed on common data to be collected so we could merge both databases and have a larger patient population. Certain countries, like Italy, have already presented their findings. But we need a pan-European approach to cancer care in the setting of the COVID-19 pandemic.”
Are breast cancer patients and former breast cancer patients, who have a weakened immune system at a higher risk for more severe COVID, and if so, what can be done to diminish this risk?
“Any patient with cancer is more vulnerable for severe COVID-19, but those with active systemic therapies, such as chemotherapy, seem to be more at risk. Basically, any patient with cancer receiving systemic therapies that act on the immune system is at risk. So sometimes we need to adapt treatments to try to minimize the risk of immunosuppression in those patients. For example, using fewer myelotoxic therapies or three-weekly regimens chemotherapies with granulocyte colony-stimulating factor (GCSF).”