EULALEE THOMPSON
THE BIG story in health is, of course, that the next generation of women will not have to suffer the ravages of cervical cancer like their mothers did.
A vaccine, Gardasil, that targets the germ associated with this form of cancer, in clinical trials, completely prevented early-stage cervical cancer and precancerous lesions, pharmaceutical giants Merck & Co. Inc. announced last Thursday. The vaccine maker is planning to seek U.S. Food and Drug Administration (FDA) approval for Gardasil before year end.
Merck, licensed the vaccine technology from Australian blood products and vaccine developer CSL Ltd. In phase III trials, involving over 12,000 women in 13 countries, half the women in the group received three doses of Gardasil over a six-month period and the other half received placebos. The women were followed for an average of 17 months.
Gardasil is expected to compete with GlaxoSmithKline Plc's experimental, Cervarix cervical cancer vaccine, but the latter is expected to receive a later FDA approval.
VACCINE TECHNOLOGY
So, it seems like it's immunisation to the rescue ... again. And, like smallpox, poliomyelitis and other infectious diseases, cervical cancer will soon become history as a result of vaccine technology.
If you were not following the trials over the years, you may be wondering, how can a vaccine work against cancer? The breakthrough is linked to the long-time discovery that cancer in the cervix (the neck of the womb that projects into the vagina), is associated with a germ, the human papillomavirus (HPV). The HPV is believed to be passed on during sexual intercourse.
There are about 100 subtypes of this virus, that causes warts including genital warts. Most of the subtypes are low-risk germs and health experts say that most people who acquire HPV will resist its effect anyway but in about one per cent of women the cells become malignant. HPV subtypes 16 and 18 have been found to be widely associated with cervical cancer (99.7 per cent of the cancers in the clinical trials were linked to these subtypes). The current Merck vaccine acts against these two subtypes of the virus.
However, Professor Horace Fletcher, head, University of the West Indies, Department of Obstetrics, Gynaecology and Childhealth points out that local studies by Rattray et al have also identified a subtype 45 as being linked with as many as 12 per cent of women in Jamaica with cervical cancer.
"It (subtype 45) is a recognised high-risk type. If we have a vaccine against subtypes 16 and 18, it won't protect the woman against subtype 45...but if you can supply the manufacturers with the subtype, they could perhaps manufacture a specific vaccine," he said. " But even with the vaccine against subtypes 16 and 18, that would considerably reduce cervical cancer rates."
KILLS WOMEN
Cervical cancer is the second leading form of cancer (after breast cancer) among women in Jamaica. Currently, women are advised to do regular screening tests, Pap smears, to pick up early, precancerous changes in their cervix. Applying aggressive, time-consuming and expensive treatment, if the malignancy is detected in the precancerous stage, can actual see women recovering from this cancer.
However, most women do not do their Pap smears regularly or none at all. Dr. Wendel Guthrie, consultant obstetrician/gynaecologist and a Jamaica representative to Pan American Health Organisation (PAHO) technical group, said that in one year about 168 women die here from cervical cancer; the incidence is about 30 per 100,000 and the mortality rate is about 17 per 100,000. This cancer is estimated to kill about 300, 000 women worldwide each year.
Dr. Guthrie said that the logistics regarding when to give the vaccine to girls (more than likely during adolescent, before the first sexual act), the cost and duration of immunity still need to be spelt out.
You can send your comments to eulalee.thompson@gleanerjm.com.
