These days, many of my cancer patients are working on soliloquy like Shakespeare’s Hamlet.
In their case, they ask: jab or not?
Cancer patients are wondering whether to get the Covid-19 vaccine.
These patients are particularly vulnerable to deadly viruses.
Multiple reports in the medical literature document the higher risk of infection as well as the likelihood of developing complications and mortality in such patients.
Mortality rates for cancer patients who went down with Covid-19 ranged from 5% to 60%, with a median hovering at around 25%, depending on which particular report they were looking at.
In comparison, the general population infected with Covid-19 has a mortality rate of 2% to 3%.
Not only are cancer patients particularly vulnerable to the virus, but when infected with the virus, anticancer treatment may be suspended, permanently stopped, or never started, resulting in a high future cancer mortality rate. Become.
Therefore, there is a strong incentive to protect cancer patients by vaccination.
However, concerns about such vaccination strategies arise from potentially immunocompromised cancer patients.
Cancer patients have an immune system that can be affected by their cancer status or cancer-related treatments.
Therefore, given the balance of risks and benefits associated with vaccination, they are often considered “different varieties”.
A well-functioning immune system is a prerequisite for successful vaccination (which is essential in Latin).
Immune cells need to respond appropriately by producing the antibodies needed to neutralize the problematic virus that invades the body in response to vaccine stimulation.
Cancer is a group of rapidly growing cells that is a major depletion of the body’s nutrient and energy stores. Therefore, normal cells (including immune cells) are relatively undernourished and often fail to reproduce.
Cancers that result from malignant transformation of white blood cells (these are the immune cells of the system) are particularly damaging to the normal immune response because the immune cells themselves are ill-formed. Leukemia and lymphoma are such cancers.
Many cancer-related therapies, such as radiation therapy and traditional cytotoxic chemotherapy, inadvertently block the normal growth of white blood cells while suppressing the growth of cancer cells, placing the immune system on the hind legs.
Therefore, cancer patients rely on doctors and scientists to help answer three important questions specific to them when receiving Covid-19 vaccination: does it work? Is it safe? Are all cancer patients the same?
When trying to answer the question of whether cancer patients would benefit from Covid-19 vaccination both on and off treatment, doctors generally did not participate in clinical trials, so scientific data. Suffering from the problem of lack of. This will lead to the approval of these vaccines.
However, indirect evidence can be gathered from decades of experience with influenza vaccination in cancer patients.
Cancer patients initiate an immune response in response to influenza vaccination, producing protective antibodies (a process known as seroconversion).
Sufficient clinical evidence shows that with the help of influenza vaccines, influenza mortality in cancer patients can be significantly reduced.
The experience of direct clinical trials of Covid-19 vaccination in cancer patients is unlikely to come soon and is estimated from influenza vaccination data given the increasing threat that such patients face the virus. It’s not easy to come to a conclusion. Vaccination may give them protection.
Chemotherapy will probably lead to some attenuation of seroconversion, and thus protection, by causing an incomplete immune response.
Cancer immunotherapy and endocrine therapy (also known as endocrine therapy) probably do not have such problems.
Perhaps severe immunosuppressive therapies, such as stem cell transplantation (bone marrow transplantation) and treatment of antibody-producing immune cells (known as B cells), have the most severe effects and significantly reduce vaccine protection.
With the exception of patients receiving such treatment, other cancer patients will probably initiate a fairly efficient immune response to vaccination.
If so, is there the best time for cancer patients to choose to get vaccinated? The immune system is fairly robust, but it’s probably best to do it before starting chemotherapy.
The next question is: Is it safe?
Thankfully, the Covid-19 vaccine currently being developed is not a live vaccine from the perspective of cancer patients.
In general, it is not recommended to use live vaccines for cancer patients with a damaged immune system.
The use of the BCG (Bacillus Calmette-Guerin) vaccine against tuberculosis in this vulnerable group has caused some serious infectious complications in the past. The current Covid-19 vaccines used worldwide are either mRNA-based or non-replicating vaccines and are unable to produce new viral particles.
Cancer doctors have been experimenting with mRNA-based anticancer vaccines for over a decade.
Although therapeutic success for cancer has yet to be achieved, oncologists have at least gathered from experiments that allow mRNA-based vaccines to be safely administered to cancer patients.
Is there a specific vaccine that is more suitable for cancer patients? From a safety point of view, no. Both mRNA-based and non-replicating vaccines that use inactivated viral particles or vectors should be fairly safe.
Finally, we face the question of whether all cancer patients should be treated the same or stratified.
Broadly speaking, cancer patients can be divided into active groups undergoing treatment, chronic groups in remission during treatment leave, and survival groups in which the cancer may be cured.
Singapore has a chronic group (provided it has not been treated for at least 3 months and does not plan to start further treatment within another 2 months) and a surviving group (untreated or treated). We are adopting the approach of vaccination. Hormone therapy only).
Active groups are currently excluded from Singapore’s vaccination program.
This decision may be made with great care, concerned about the ability and safety issues of these patients to initiate an immune response to the vaccine.
The international trend is towards vaccination of most, if not all, cancer patients.
The European Society for Medical Oncology is calling for action to vaccinate all cancer patients.
The American Cancer Society has written an open letter appealing to the governors of all US states to prioritize vaccination of cancer patients.
Once the local healthcare community has a sufficient level of peace of mind about potential benefits that far outweigh the risks of vaccination, Singapore will prioritize, not just include all cancer patients in its vaccination program. You need to move quickly in the direction.
About the writer
Dr. Wong Seng Weng is a medical director and consultant medical oncologist at the Cancer Center of the Singapore Medical Group. His areas of expertise include breast, lung and gastrointestinal cancers.