Effects of COVID-19 on Cancer Patients

Introduction:

The novel coronavirus is an RNA (ribonucleic acid) virus affecting humans and animals. It mainly affects the human respiratory systems, gastrointestinal systems, and central nervous systems. The severe acute respiratory syndrome coronavirus (SARS‐CoV) and the Middle Eastern respiratory syndrome coronavirus (MERS‐CoV) are considered the two most pathogenic coronaviruses.The coronavirus 2019 is caused by the SARS‐CoV‐2, which has rapidly spread all over the world, responsible for thousands of deaths. This outbreak made WHO (World Health Organization) declare public health emergency globally, as there is no specific treatment for COVID-19, and this infectious spread can only be prevented by:

• Early detection.

• Isolation.

• Immediate treatment.

• Vaccination.

As this virus transmission from human to human is asymptomatic for two to ten days, there is an increase in spread day by day worldwide with a history of dry cough, fever, diarrhea, vomiting, and myalgia. Also, individuals with comorbidities (diabetes, hypertension, cancer diseases, or heart diseases) may experience severe kidney damage and acute respiratory distress syndrome.

Cancer is the most common disease worldwide, and people with cancer are more likely to get COVID-19 than a normal person. The aggressive cancer treatments and the failure to control the growth of tumor cells weaken the immune system in people with cancer, making them more susceptible to acquiring infections.

What Are the Clinical Aspects of People with Cancer?

Cancer is distinguished by unstable cell growth, where the cells can invade and spread other organs. There are more than 100 different types of cancer cells, which result in abnormal proliferation in the body, varying in behavior and response to treatment. These cells compromise the patient's immune system by affecting the cellular regulatory mechanisms in the body.

Cancer cells start penetrating the bone marrow to get sufficient space and nutrients. This leads to the destruction of normal bone marrow cells and reduces the production of white blood cells responsible for fighting against various infections. The immune system becomes compromised when cancer or cancer treatment, such as chemotherapy or radiation therapy, affects the bone marrow by reducing blood cell production.

Further mechanisms of the immune system can also be affected by cancer, for example:

• Skin Tumors - They break the natural barriers and allow germs to enter the body.

• Large Tumors - Reduces the blood flow of tissues.

• Lung Tumors - Blocks the normal mucus drainage, which leads to infections.

Why People with Cancer Are at an Increased Risk of Severe COVID-19 Infection?

The understanding of SARS-CoV-2 has greatly improved when compared to the time of discovery. Also, there are various risk factors for susceptibility to the virus. They are:

• Chronic obstructive pulmonary disorder (COPD), is a lung disease that makes it difficult to breathe.

• Hypertension (high blood pressure).

• Obesity.

• Cardiac diseases.

• Cancer.

Cancer being the risk factor, is more vulnerable to SARS-CoV-2 infection due to its immunocompromised state. But COVID-19 does not affect all people with cancer the same because a certain subtype of cancer is at greater risk of getting severely ill following infection by SARS-CoV-2, they are:

• Patients with hematologic malignancies (cancer of blood-forming tissue, such as bone marrow).

• Patients with metastatic malignancies (cancer that spreads rapidly from where it started to a different body part).

• Patients with lung malignancies (lung cancer).

• People who had previously undergone surgical resection procedures.

People with non-metastatic cancer also experience severe effects of COVID-19 as the general population. Age is considered to increase the risk of COVID-19, as the fatality rate for people with cancer and COVID-19 is greater as the patient’s age increases.

Who Are at a Higher Risk of Getting COVID-19?

The following patients are considered to be at higher risk of COVID-19:

1. Patients who took chemotherapy or surgery in the past month are at higher risk when compared to patients who did not receive recent treatment.

2. Patients with more than one chronic medical condition.

3. Patients who are undergoing active treatment for cancer are at higher risk than those who are in remission.

4. Patients who are in the first year after stem cell transplantation or CAR (chimeric antigen receptor) T-cell therapy.

5. Patients who received transplantation beyond 1 year are still considered to be immunocompromised.

What Is the Impact of Chemotherapy on the Immune System of People With Cancer?

Chemotherapy targets cancer cells and results in rapid cell division. Antineoplastic chemotherapy affects the normal cells in the blood, bone marrow, mouth, intestinal tract, nose, nails, vagina, and hair and shows rapid cell division because they do not specifically act on cancer cells.

Chemotherapeutic agents affect the immune system, and the damage intensity depends on chemotherapeutics' usage and their combinations. Chemotherapeutic agents damage depends on:

• Patients age.

• Duration of time.

• General health.

• Frequency of treatment.

Some of the chemotherapeutic agent's damages-

• Bone marrow cells.

• Red blood cells.

• White blood cells.

• Platelets.

The greatest impact is on white blood cells, so the patients are more susceptible to infections.

Patients who are under systemic treatment (chemotherapy or immunotherapy) are considered to be at higher risk of COVID-19. This condition is at even more risk when in older patients and patients without cancer. Therefore, in order to reduce the effects of chemotherapy on the immune system, we should know which chemotherapy drugs will have less impact to use. In addition, to minimize the damage of chemotherapy to the immune system, they should have:

• Healthy diet.

• Exercise.

• Reduce stress.

• Maintain rest.

In people with cancer, SARS‐CoV‐2‐related damage is mediated mainly by inflammation, and those inflammation mechanisms are:

• Increased interleukin‐6 (IL‐6) - Related to most severe cases of COVID-19.

• Lymphopenia development - Related to most severe cases of COVID-19.

• Longer prothrombin time.

• D‐dimer plus high.

• Lower albumin.

• Higher neutrophil count.

What Are the Risks to People with Cancer Due to COVID-19 Infection?

COVID‐19 is an opportunistic disease taking advantage of a patient with a weakened immune response. Undertreatment or not, people with cancer have a weakened immune system and are more susceptible to infections caused by COVID‐19. SARS‐CoV‐2 changes the immune system after entering the body. It results in cytolytic immune responses, mainly through:

• Type I interferons.

• Natural killer cells.

Meanwhile, adaptive immunity is produced by T cells and B cells, where antibodies act against the virus. Conversely, patients seriously ill with COVID‐19 show a reduction in some defense cells such as:

• CD4+ T cells.

• CD8+ T cells.

• Natural killer cells.

• Pro‐inflammatory cells.

The reduction in the defense cells weakens the immunity, and if the same immune response persists, it can cause high production of inflammatory cytokines, causing COVID‐19 progression.

People who have weakened immune systems cannot fight infections and are more likely to be:

• Hospitalized.

• Put on mechanical ventilators.

• Even die.

If patients develop COVID-19 when undergoing chemotherapy or have lung cancer or lung metastases are more likely to be contaminated, in addition to being able to compromise their lung problems.

People with cancer presents rapid disease progression and requires therapeutic action to prevent complications from irreversible diseases. People with cancer cannot drop their immediate treatments suddenly, but considering the risks of COVID-19, they need some protective measures. There are about 19.4 % of deaths by COVID‐19 in people with cancer. Thus, people with cancer are considered a highly vulnerable group to COVID‐19.

How to Care for People with Cancer Amid a Pandemic?

People with cancer also need to be concerned about their respiratory conditions. People treated with intensive therapy and who receive bone marrow transplants are more likely to get pneumonia and this is because of:

• Compromised immune systems.

• Due to tumors.

• Due to the treatments, they receive.

Patients with lung cancer are at increased risk due to the increased affinity of the virus to the respiratory tract, and when infected, present severe lung damage, such as

• Edema (swelling).

• Protein exudate.

• Focal reactive pneumocyte hyperplasia.

People with cancer undergoing radiotherapy and chemotherapy are exposed to SARS‐CoV‐2 due to:

• Cytotoxic action of cancer treatment on the hematopoietic and immunological system.

• Due to the reduction in the number of neutrophils.

• Due to the decrease in immunological capacity.

Sometimes, these people with cancer cannot get vaccines and should follow only the COVID-19 safety protocols. As of now, many hospitals postpone non-urgent procedures like elective surgeries and examinations, and these decisions are made based on the case to protect them from infection. However, careful monitoring of exposed patients is necessary to limit the risk of infection to all patients and should allow the lesser spread of COVID-19 infection without compromising cancer treatment.

Conclusion:

The COVID‐19 pandemic infects thousands of people every day and has a high mortality rate. As people with cancer have weakened immune responses, it makes them more prone to infections, where COVID‐19 worsens their clinical condition, and often, people die. It is important to take protective measures for people with cancer by restricting their visits to hospital environments and making them visit only in cases of extreme need. Also, the best way to prevent COVID-19 is to social distance and follow hygiene measures with hand washing.