April 2 2020
This is a second post in the series highlighting role of viruses (oncoviruses) in cancer development. See the first post on Human Papilloma Virus (HPV) and colorectal cancer (CRC).
Approximately 500,000 new cases of cervical cancer and 274,000 deaths are attributable to cervical cancer yearly, making cervical cancer the second most common cause of death from cancer in women. Fortunately, the incidence of cervical cancer has decreased by more than 50% in the past 30+ years, largely due to the increasing use of cervical cancer screening with cervical cytology - Papanicolaou smear (Pap-smear).
The test was invented by and named after the Greek-American doctor Georgios Papanikolaou, who started his research in 1923. It took 53 years to formulate hypothesis on the role of HPV in cervical cancer. Professor Harald zur Hausen from Heidelberg, Germany was awarded the 2008 Nobel Prize for this work.
HPV, with rare exceptions, must be present in order for cervical cancer to develop.
The American Cancer Society estimates about 13,240 new cases of invasive cervical cancer will be diagnosed and about 4170 women will die from cervical cancer in 2018 in the USA. Although worldwide cervical cancer rates have decreased dramatically with the increase in screening efforts, incidence and prevalence in developing countries remains high due to lack of screening programs, with approximately 80% of all cervical cancer deaths occurring in the developing world.
The good news: The first HPV vaccine became available in 2006. As of 2017, 71 countries include it in their routine vaccinations, at least for girls. It is on the World Health Organization's List of Essential Medicines, the safest and most effective medicines needed in a health system.
The wholesale cost in the developing world is about $47 a dose as of 2014. Naturally, in the United States, it costs more than $200. The cost makes vaccination cost effective in the developing world but not in the developed countries.
Gardasil-9 is the only vaccine in use in the USA. Gardasil-9 is effective against 9 high-risk types of HPV. As many as 97% of HPV-naive women (women who were never found to have HPV prior to vaccination) benefit from vaccination. The vaccination should start at 8-9 years olds, both for boys and girls. It is administered in two doses at least 5 months apart. It is now recommended for adults up to 45 years old
Dr. Why: in my opinion, there must be no upper age limit for HPV-naive people. There is a rationale for using this vaccine for everyone, regardless of age and HPV status, including patients who already had HPV-related cancer.
First, just as any vaccine, it “trains” immune system to respond to “intruders”.
Second, cancer is usually associated with one out of nine high-risk viruses, hence protection against 8 others should not hurt.
Third, it is logical to conclude, that it might protect from other HPV-associated cancers: anal, colorectal, nasopharyngeal, penile, and vulvar.