Thames Valley Cytology Society

TruScan

Report by Jocelyn Hakim, Northwick Park Hospital

TVCS scientific meeting and AGM, 15 February 2001, at University College, London

Dr. Carl Chow gave an update talk about TruScan (previously named as Polar Probe) at the Thames Valley Cytology Society meeting held at University College London. This was in fact the third time a member of Prof. Singer's team had kindly presented their findings to the TVCS and it was extremely interesting to see what further refinements or developments had been made to the device.

Dr Chow began his talk by giving an overview of the incidence of cervical cancer or pre-invasive disease and pointed out that cervical cancer is the second most frequent cancer in women and the leading cause of cancer mortality in women worldwide. But in the developed countries regular cervical smears have dramatically reduced its incidence. In England and Wales alone, the mortality rate is now estimated to about 1100 deaths a year.

But the cervical smear test is not the only method that can be employed and others include

• HPV DNA testing
• Speculoscopy
• Cerviscopy
• Colposcopy
• Fluorescence spectroscopy
• Real - time technology (i.e. TruScan)

Many people have looked at the possibility of using one or more of these methods with varying degrees of success and it is more likely the greater degrees of success will be achieved by using two or more methods in conjunction with each other.

Koss suggests that "the screening error based on a single adequate smear is likely to be at least 50%". Thus, the concerns about screening methods for cervical cancer and the need for an adjunct method to the Papanicolau smear has led the researchers from Australia for the TruScan project. This emerging real-time technology for cervical smear screening is a computerised diagnostic instrument specifically developed to detect early stages of cancer.

Dr Chow then went onto explain the technology involved with TruScan, which involves:
- the probe body which contains the tissue stimulation and sensor elements
- electrical property which controls and assembles detector signals
- computer software which interprets the tissue response signals

( schematic diagram below)

TruScan, Dr Chow pointed out, detects the early stages of cancer and results from the study show has a 90 - 95% specificity and sensitivity, which compares favourably with the results using the cervical smear test.

The potential applications of this screening method are

• decrease false-negative rates
• triage of women with borderline changes and mild dyskaryosis
• stand-alone screening device in developing countries where existing cervical screening programme is poor

The researchers from Australia have concluded that TruScan

• provides an instantaneous result allowing immediate patient management
• accuracy of TruScan compares with that of an in-study Papanicolaou smear
• relatively low patient assessment cost which will, in turn, enhance the community benefit of screening programmes

During his talk Dr Chow pointed out that it did not appear that TruScan would replace the cervical smear but could be used in conjunction with to help reduce further the incidence of and detection of cervical cancer. Greater impact may be made if it were used in some of the developing countries where there is no real provision for the taking regular cervical smears. So thankfully, it doesn't appear TruScan will be replacing the cervical smears and we will have a job to do for the foreseeable future!

Schematic diagram of TruScan (previously named as Polar Probe)