The major health news today is that the FDA has approved a new vaccine which will prevent many cases of cervical cancer.
The vaccine, called Gardisil and developed by Merck, has been approved for administration to girls ages 9 through 26 who have not begun sexual activity.
In my opinion, this development is transformational for medicine and medical practice, and will have a substantial impact on the health of women in this country and elsewhere.
9710 women expected to be diagnosed with cervical cancer in this country in 2006, and it is expected that 3700 women will die from this disease.
What is truly remarkable is that there are going to be over 1.5 million women in the United States who will be diagnosed with pre-cancerous lesions of the cervix that require the follow-up and possible treatments I mentioned above.
The cost of treating cervical disease each year in this country is approximately $3.5 billion dollars, not to mention the loss of productivity and anxiety associated with these diagnoses and treatments.
Gardisil has the potential to reduce deaths from cervical cancer throughout the world, which is critically important since cervical cancer kills about 288,000 women worldwide every year. It is the second leading cause of cancer death in women outside of the United States, especially in underdeveloped countries who cannot afford extensive cervical cancer screening programs.
This vaccine also has the potential, over the next several decades, to substantially change the way we provide healthcare to women.
Much of women’s gynecologic healthcare is focused on cervical cancer screening, and dealing with the results of what are effective tests (for example, the PAP smear) which can produce confusing results.
Aside from the anxiety associated with those abnormal results, there are the real issues of the follow-up and procedures that are done to find out whether or not the test was significantly abnormal or whether more extensive treatments including surgery are required to prevent a pre-cancerous lesion in the cervix from progressing to a frank cervical cancer.
Over the past several years, researchers were able to demonstrate that HPV causes cervical cancer, and they have been able to identify which viruses are closely associated with the development of cervical cancer
There are many types of HPV viruses, and they are transmitted by sexual contact. Almost everyone who is sexually active gets these viruses—both men and women—but it is only a very few who develop any problem as a result of the virus.
For most of us, it goes away and doesn’t cause a problem. But, for some, the problems can be serious and include cervical cancer and genital warts.
The current vaccine includes 4 types of HPV viruses. Two of these virus types are related to cervical cancer, and the other 2 to genital warts.
We know that another vaccine is in testing which contains just the two HPV viruses that cause cervical cancer, but it wouldn’t be unexpected to see additional viruses added to both vaccines over time.
Right now, the estimates are that Gardisil will be able to prevent about 70% of cervical cancers, and about 90% of genital warts. But to be most effective, based on current evidence, it has to be given before women become sexually active. There are ongoing studies to determine whether booster doses will be necessary at some time after the primary series of 3 shots within 1 year is completed.
Not to be ignored were research results presented this week at the American Society of Clinical Oncology meeting where Gardisil was also demonstrated to decrease the incidence of vulvar and vaginal cancers in women. Although these cancers are much less frequent, they can be devastating for women who are diagnosed with them.
Interestingly, this is not the first vaccine that is known to prevent cancer although it is the first vaccine specifically designed for that purpose.
Hepatitis B vaccine has been shown to reduce the risk not only of hepatitis, but also primary liver cancer (called hepatoma). In some parts of the world, primarily Asia, where the incidence of hepatitis B and liver cancer are high, there have been dramatic reductions in liver cancer as a result of widespread immunization programs in young people.
I can recall years ago having discussions with my colleagues about what we called the “viral theory of cancer.”
After all, we reasoned, if cats could be vaccinated and protected against feline leukemia virus, why would it such a stretch of the imagination to think that the same thing could be done for humans?
We were a bit premature in our optimism, although there has been and will continue to be considerable research into the question of whether viruses (and bacteria, for that matter) cause other cancers besides liver cancer and cervical cancer.
Although there was some circumstantial evidence in the past that cervical cancer may have had an infectious cause, or could be transmitted by some other agent related to sexual activity, it was still a pleasant surprise when research honed in on HPV as the cause of cervical cancer.
That gave researchers the opportunity to target the virus and begin work on the vaccine which has culminated in its approval today.
It was not without a considerable amount of hard work, research support (including funds from the American Cancer Society) and financial investment that enabled us to reach this goal.
Our hope is that over time further research will not only expand our knowledge regarding HPV and cervical cancer, but also provide insights into the etiologies of other cancers where a vaccine “strategy” may prove effective in preventing disease.
The vaccine may not be related to an infection, but could also be the result of expanding knowledge into what targets on the cancer cell could be detected and “killed” by an antibody our bodies could produce in response to a vaccine.
Just this week an article was published in the prestigious Proceedings of the National Academy of Sciences describing a vaccine which targeted angiogenesis (growth of new blood vessels in tumors) and slowed tumor growth in mice. It did this through targeting a receptor on the surface of a cancer cell that is involved in angiogenesis.
Granted that mice are not men, and that it is a long way from basic research into developing a concept that actually works in treating patients.
But just imagine the impact if we were able to make a vaccine that would target similar proteins and receptors on cancer cells before they become visible?
That may sound like the stuff of dreams, but I’m not certain that such a goal cannot be achieved.
So what we have today is a definitive major step forward in our efforts to reduce the burden and suffering from one form of cancer.
Our hope is that this is just the beginning, and that the future will bring many more such advances.
Time will tell.
