This month I have interviewed consultant gynaecologist at the University Hospitals of North Midlands NHS Trust, on behalf of a healthcare magazine, about his experience of using ZedScanTM.
Mr Charles Redman said he had implemented ZedScan at the gynaecology departments at both the Royal Stoke University Hospital and County Hospital Stafford, with the aim of offering a more accurate diagnosis for women who are at risk of cervical cancer.
He said: “At Stoke our aim is to manage an effective patient-centred service – dealing with patients quickly, in a safe, individualised and optimal way. These goals are only achieved by the optimal use of clinical resources, which involves accurate diagnosis and appropriate management – ZedScan can support us with this.”
Colposcopy – an important procedure, after an abnormal smear test, relies on the presence of visible indicators to detect atypical cells on the cervix. Unfortunately, these indicators are not specific which means that interpretation is subjective. Colposcopy as a clinical examination has remained mainly unchanged for 90 years with efforts to improve performance to date targeted at enhancing the optics.
The ZedScan system takes a different approach utilising Electrical Impedance Spectroscopy to perform a quantitative assessment of the cervix, This permits the different tissue types to be identified and differentiated according to their electrical properties.
These properties are known to change during the development of neoplasia, with more abnormal cells exhibiting a reduced resistance to the flow of current as a result of structural changes.
Mr Redman explains: “The attraction of EIS is that this comprises an assessment of tissues in a completely different way; using electrical impedance rather than reflected light. Our formal evaluation of EIS has demonstrated a performance that is at least as good and significantly better than high-quality but conventional colposcopy.”
“ZedScan is very easy to use and does not get in the way of what a colposcopist normally does,” continued Mr Redman. “The other benefit is that it doesn’t significantly prolong the colposcopic examination.
Recently published case study data shows that the use of ZedScan helped achieve significant assurance for treatment at first visit, recording a high positive predictive value of 95.4%. ZedScan with its single point mode also helps direct the best position for a biopsy.
Mr Redman added that without ZedScan as a support to colposcopy, many clinicians would often take a biopsy to confirm the presence of disease before offering treatment. This can take up to 2 weeks to receive the histology results, leaving many women with an anxious wait of knowing they may have to come back for treatment. He also reported that it can be difficult to know the best place to take the biopsy, resulting in clinicians often taking more than one biopsy sample, again adding to patient discomfort.
He said “As a diagnostic test, colposcopy is reasonably accurate. It performs best when the likelihood of High Grade disease is high, such as in patients with high-grade smears or with high-grade findings. However, colposcopy performs poorly when the likelihood or prevalence of disease is low, such as in patients with negative or low-grade cytology.”
“With the advent of primary HPV screening, especially in a vaccinated population, there will be an increase in the number of referrals, and of patients with low-grade cytology in particular. On the one hand, those patients with high-grade disease may be missed because colposcopy may have a sensitivity as low as 50%, or on the other hand, patients with low-grade may undergo unnecessary biopsies or treatment.”
Mr Redman continued “We are currently in the process of conducting our own evaluations, but what I can confirm is that it feels particularly relevant in those patients with either low-grade cytology presentations or in whom there are colposcopic low-grade findings.
“One group to note especially, is those patients with recently confirmed CIN2+ disease on a punch biopsy, yet have minimal post-biopsy findings – many of these patients are young and wishing to have more children and are keen to consider conservative management if possible – ZedScan facilitates this.”
The full article can be found in this month’s Clinical Services Journal p54 – 57 – http://clinicalservicesjournal.com/ –