A combination of two tests prove to be better than the routine Pap smear done annually as recommended by physicians as part of a routine medical check up.

On its own, the HPV test screens for the viruses, but does not indicate whether these viruses cause cervical cancer.

Promising findings in Singapore

A study was conducted by the Singapore General Hospital (SGH) on 1,900 women above 25 who underwent this co-testing of a regular Pap Smear with DNA testing for HPV.

This dual screening method has found to increase the rate of those diagnosed from 70% when only a Pap smear was done, to 100% when done in combination.

With over 200 cases reported annually, cervical cancer marks the tenth most common cancer among females in Singapore. In Singapore, eight out of every 100,000 women are diagnosed with cervical cancer each year which is substantially lower than the global average of 25.

With the increased accuracy of this method, women need to go for co-testing only once every five years, instead of the recommended once every three years for a Pap smear, said Professor Tay Sun Kuie, a senior obstetrician and gynaecologist at SGH.

However, since co-testing costs about $200 - four times the cost of a Pap smear - Singapore has adopted a subsidised cervical cancer screening programme, which began in January 2004 whereby women aged 25 years and above only pay $15 for a pap smear should be exemplified by countries in the region as a leader in preventive medicine.

Typically takes about 10 years for precancerous cells to become cancerous

New and advanced cases are able to be kept at bay due to the pathogenesis of the disease which if detected early at a precancerous stage is preventable.

Cervical Intraepithelial Neoplasia (CIN), the pre-invasive stage of cervical cancer often occurs in women in their late twenties to thirties. These pre-cancerous lesions are what the screening tests hope to detect and given that HPV causes over 99% of cervical cancer cases, hence the rationale behind combining the confirmatory DNA tests.

This is a critical stage to be identified accurately as a simple treatment could hinder it from turning into full blown malignancy.

Early changes of the deadly cancer can be discovered through a Pap smear. But this test is not foolproof even if it is done regularly every three years as recommended, said Professor Tay.

The limitations lie in that most lesions being localised may easily be missed during a Pap smear. Also to serve as a reminder that the precancerous stage is for a large part asymptomatic and the excessive bleeding presented is more of an exception than the norm.

What the study results translates into in practical terms of management

With this recent confirmation of dual testing being significantly better than what was previously thought to be the standard of care, doctors will be able to better assess the risk of patients developing cervical cancer in future.

Subsequently, this knowledge will also give them the edge to recommend necessary treatments at an earlier junction to prevent it from worsening. Patients who undergo the procedures would be reassured with a peace of mind as the sensitivity and specificity being close to 100% if tested negative. MIMS

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