Vaccines stimulate the immune system to locate and eliminate cancer cells. (Image: DC)
Vaccines boost the immune system in order to combat a target — typically a virus. Vaccines for infectious diseases including the flu, measles, mumps and COVID are common and well-known now. But less known is the fact that there are similar vaccines against cancer. These are not often prescribed by doctors, either as a preventive or for treatment, for various reasons. Currently, the majority of cancer vaccines are therapeutic — that is, they are used to treat patients in an advanced stage of the disease, frequently in conjunction with other treatments like chemotherapy, surgery or radiation.
The development of cancer-specific vaccinations constitutes a watershed in oncology. They are intended to stimulate the body’s immune system to recognise and target cancer cells, making them an effective tool for both cancer prevention and treatment. These vaccinations show enormous promise for avoiding particular types of cancer." — Dr D Nageshwar Reddy, chairman and founder, Asian Institute of Gastroenterology & AIG Hospitals.
There has been a significant rise in the overall burden of all types of cancers in India; therefore, the importance of cancer-specific vaccines cannot be over-emphasised in the fight against this formidable disease. "The development of cancer-specific vaccinations constitutes a watershed in oncology. They are intended to stimulate the body’s immune system to recognise and target cancer cells, making them an effective tool for both cancer prevention and treatment. These vaccinations show enormous promise for avoiding particular types of cancer, such as cervical and liver cancer, which disproportionately affect people in developing countries like ours, where access to regular cancer screenings and treatments is limited," says Dr D Nageshwar Reddy, chairman and founder, Asian Institute of Gastroenterology & AIG Hospitals.
Comprehensive cancer screening and early detection programmes are difficult to implement in countries with limited healthcare infrastructure and resources. "Cancer-specific vaccinations can fill this void by providing a low-cost and easily accessible method of cancer prevention. We can dramatically reduce the chance of getting linked cancers by immunising people against cancer-associated viruses such as the human papillomavirus (HPV) and Hepatitis B virus (HBV)," says Dr Nageshwar Reddy.
Hairspray star Marissa Jaret Winokur is now cancer-free and wants to spread the word about the importance of obtaining the HPV vaccine to avoid cancer.
ROLE OF VACCINES
"Vaccines stimulate the immune system to fight a specific target, which is usually a virus. If the antibodies are not in the desired range, a booster dosage might be taken," says Dr A Ravi Chandran, Consultant Medical Oncologist at AINU.
Challenges and limitations
Why do some doctors refuse to provide cancer-prevention or cancer-treatment vaccines to their patients? Dr. Prashant Mehta, Senior Consultant, Department of Medical Oncology and BMT, Amrita Hospital, cites several reasons:
A — High price
B — People in India are currently less motivated towards preventative health, but this is changing.
C —Vaccination programmes
"Cancer cells have well-developed escape mechanisms to resist immunity, making it much more difficult to create vaccines for cancer than for infectious diseases. In addition, cancer patients have decreased immunity, making immunisations less effective," notes Dr Mehta.
Vaccines are currently available for treating only a few types of cancer, including prostate cancer, melanoma and sarcoma. Even for these conditions, vaccines are not currently the most effective options.
"Even for diseases such as melanoma, immunotherapy (checkpoint inhibitors) and targeted therapies such as BRAF + MEK inhibitors play a significantly larger role in treatment.
BCG, a well-known tuberculosis vaccination, has a significant role in the treatment and prevention of recurrence of early stage urinary bladder cancer," says Dr. Mehta.
Prevention is better than cure
There are 4 types of prevention programmes, says Dr A Ravi Chandran, Consultant Medical Oncologist at AINU.
1 Primordial prevention: IEC (information, education and communication) activities
2 Primary prevention: Vaccination
3 Secondary prevention: Screening
4 Tertiary prevention: Rehabilitation
HPV and HBV induced cancers are more prevalent than others
Cervical cancer is the second most common cancer in Indian wome
Almost all cervical cancers are caused by HPV infection
Apart from cervical cancer, HPV can also play a role in oropharyngeal vaginal, vulval anal penile cancers
Ideal age for HPV vaccination is 9-14 years
It can be given up to the age of 45
Vaccine against the Hepatitis B virus can decrease the incidence of Hepatocellular carcinoma (HCC), is the most common type of primary liver cancer.