Anew vaccine to be available worldwide soon promises to reduce the incidence of cervical cancer, but women should still have regular tests to protect their health, gynaecologists say.

With more than half a million new cases of cervical cancer reported annually, the disease is Thailand's most common cancer, killing nine women every day.

The danger is more serious than most realise. Of the more than 6,000 Thais diagnosed with cervical cancer each year, half do not survive.

The rest suffer through painful operations and the side effects of radiation and chemotherapy treatments.

A German researcher tracked cervical cancer to the human papilloma virus, HPV, which is the most common sexually transmitted infection in Thailand.

There are more than 100 types of the virus, but only a few are considered serious threats. These are divided into two categories.

"The high-risk category contains HPV types 16 and 18, which are the main causes of cervical cancer," explains Assoc Prof Wichai Termrungruanglert of Chulalongkorn University's faculty of medicine.

"The low-risk group contains HPV 6 and 11, the causes of genital warts, which aren't cancer but they're not easily cured."

HPV, Dr Wichai says, alters the cells around the cervix, enabling them to divide to malignant cells that can grow uncontrollably.

No symptoms appear in the first stage. In fact, the metamorphosis of the cells takes five to 10 years.

By the time an afflicted person brings clear symptoms to a gynaecologist - vaginal bleeding, especially after sex, other abnormal discharges, pain during sex - treatment is difficult, the chance of a cure dubious.

"The cancer can be cured only if diagnosed at the beginning stage through internal examination - the pap smear test," Wichai says.

"In that case the patient can be temporarily cured, but unfortunately, the main problem here in Thailand is that most women are too shy or afraid of seeing a doctor and getting a pap smear, quite unlike the situation in the West."

Any woman who has sex should have regular pap smears, he stresses, and virgins should have their first sometime between ages 25 and 30.

Less than 10 per cent of Thai women bother with the test, he laments, despite it being a cheap way to prevent deadly cancer.

"A smear test isn't painful, and the doctor doesn't even need to see your face," he says.

"Lubricant is applied to the vagina and an instrument called a speculum is inserted. A spatula is then dabbed over the surface of the cervix to collect some cells for laboratory analysis. The patient knows the result in just a few days."

The new cervical cancer vaccine, due on the market in the next few months, is expected to be a boon to future generations, but it's not a cure for people who have already contracted the disease.

Youngsters aged 10 to 15 will be given shots - boys as well, both as protection and to prevent them from becoming carriers once they become sexually active.

Dr Wichai says the vaccine will completely protect women from HPV 16 and 18, the primary cancer threats.

But these two types represent only 70 per cent of the cancer's causes, so there's still a 30-per-cent chance of contracting it.

That potentially lethal difference must be countered with common sense, he says.

One can avoid sex altogether, remain faithful to a single partner, or always use condoms.

Better still is the pap smear - the most cost-effective way of preventing cervical cancer.

The new vaccine is being produced by Merck Sharp and Dohme and GlaxoSmithKline.

Both stop HPV 16 and 18, but the former company's also blocks HPV 6 and 11, the causes of genital warts.

Assoc Prof Chitsanu Pancharoen, a paediatrician in the same faculty as Dr Wichai, notes that the vaccine is only the second one in the world introduced to battle cancer.

Its dosage is the same as the Hepatitis B vaccine now on the market, which prevents liver cancer: shots on Day 1, Month 2 and Month 6.

Data on the cervical-cancer vaccine isnow being reviewed by the US Food and Drug Administration and its counterparts around world, including that of Thailand.

Juthamas Cholthavornpong

 The Nation