Best tests December 2009
QUIZ FEEDBACK: Cervical screening
Full colour PDF of the pages as they appeared in ‘best tests’.
This quiz provides an opportunity to revisit the recent bpac “best tests” that had a key focus on the adoption of liquid based cytology (LBC) and the subsequent introduction of human papillomavirus (HPV) testing.
This document provides a reminder of the advantages of using LBC, as well as the situations in which HPV will aid management. It is worth remembering that although LBC provides some distinct advantages over conventional cytology, the biggest health gains will still be achieved by ensuring all eligible women have regular cervical smears.
The quiz feedback includes the aggregated responses from GPs that completed the quiz, comments from the GP review group and specialist commentary from Dr Peter Fitzgerald.
All general practitioners who responded to this quiz, will receive personalised feedback online and CME points. This quiz can still be completed online. Currently, there are over 30 interactive quizzes available which provide an ongoing opportunity for the accumulation of points.
|1.||Your peers||GP Panel|
|HPV testing is not indicated in women under 30 years||91%|
|Not indicated for post menopausual women||5%|
|All LBC specimens will now also be automatically tested for HPV||9%|
|Is indicated for all women older than 30 years||17%|
The correct answer is that routine HPV testing is not indicated in women under 30 because of the high prevalence of HPV in this age group. However, regardless of age it may be required for the ongoing management of women who have been treated for a high-grade lesion, and for women with discordant cytology and colposcopy results. There is no indication to test all women over 30 years.
A number of respondents thought that all LBC specimens would automatically be tested for HPV. This only occurs when a woman older than 30 years is identified by the laboratory to have low grade changes in her cervical cytology.
|2.||Your peers||GP Panel|
|Reduction in number of unsatisfactory smears||99%|
|Quicker laboratory turnaround time||81%|
|Ability to use same sample for HPV||91%|
|Collection devices cause less trauma to the cervix||4%|
The main advantages of moving to LBC are:
- A reduction in number of unsatisfactory smears
- Quicker lab turnaround time
- The ability to use same sample for HPV
The panel felt the main practical benefit to general practice of laboratories adopting LBC, was the ability to use the same specimen for HPV testing if required. However, it was noted that the change to LBC in itself is unlikely to reduce the incidence of or mortality from cervical cancer in New Zealand. The most important factor in the short to medium term is improving screening coverage. In the long term, vaccination against HPV infection should reduce cervical cancer incidence and mortality.
|3.||Your peers||GP Panel|
|Wooden spatula + cytobrush (in combination)||4%|
|Plastic spatula + cytobrush (in combination)||91%|
|Cytobrush (on its own)||11%|
|Cervibroom (on its own)||92%|
The plastic spatula + cytobrush (in combination) or cervibroom (on its own) are the collection devices recommended for use with LBC. Neither the cytobrush nor plastic spatula on their own are recommended and wooden spatulas are unsuitable for use with LBC. On a practical note the panel said they tended to use just the cervibroom, since it meant only one sample had to be collected.
|4.||Your peers||GP Panel|
HPV is one of the most common sexually transmitted infections in the world with 15-20% of all young sexually active women acquiring the infection per year.
LBC is at least as sensitive as conventional cervical cytology and more sensitive for women with recurrent inflammatory smears. LBC can reduce the amount of obscuring blood and inflammation in cervical samples compared to conventional smears, however routine screening smears should still be avoided at the time of menses.
Note: Collection devices are not interchangeable between the Surepath and Thinprep systems.
There was some concern expressed at the high proportion of respondents who answered this question incorrectly. All cervical smears should contain some endocervical cells to indicate that the squamocolumnar junction has been sampled. Squamous cell carcinoma begins as cervical intraepithelial neoplasia (CIN) at the squamocolumnar junction which is why it is important to sample this site to detect early changes. If a previous smear is reported as containing no endocervical cells, a cytobrush is recommended for the repeat smear.
It is important that if the cervix looks abnormal or there are abnormal symptoms, the women should be referred for colposcopy, irrespective of the cytology report. If the cervix looks abnormal due to known benign changes (eg nabothian cysts) referral for colposcopy may not be required.
|7.||Your peers||GP Panel|
|HPV testing is indicated||94%|
|Should be referred automatically for colpolscopy||13%|
|Watchful waiting and retest cervical cytology in 12 months||29%|
|Confirm with conventional Pap smear||<1%|
Almost all respondents correctly answered that HPV testing is indicated for all women > 30 years with low grade abnormalities. This is generally initiated by the laboratory. Referral for colposcopy should be made following a positive HPV result and watchful waiting would be appropriate following a negative HPV result, with repeat HPV testing at 12 months.
HPV results will be of benefit when managing women who:
- Are 30 years and over with low grade changes
- have been treated for a high-grade lesion
- have discordant colposcopy and cervical cytology results
HPV testing will hopefully reduce the number of patients who receive unnecessary specialist referral and colposcopy. HPV testing is not indicated for women less than 30 years with low grade changes. Follow-up will depend on previous patient history.
Other comments on cervical screening
Some additional questions arose out the panel discussion and these were put to pathologist Peter Fitzgerald for his comment.
- Who is responsible for requesting HPV testing?
- The laboratory is responsible for performing HPV testing in women over the age of 30 years with ASCUS/LSIL cytology. When HPV testing is used as proof of cure, the smear taker is responsible for gaining patient consent and requesting the test. And when there is discordance between laboratory results and colposcopy, the colposcopists are responsible for requesting HPV testing.
- How long is the LBC sample stored for, and can HPV testing be requested at a later date?
- The vials may be used for HPV testing for several months after the sample is taken. However for most laboratories storage beyond about 4 weeks is not practical.
- Do the laboratories perform HPV testing if it is requested as part of an STI screen?
- HPV is not an appropriate test for STI screening, as it is only indicated for triage in conjunction with cervical cytology. Current HPV testing in New Zealand is only designed for use within an organised cervical screening program.
GP Review Panel:
- Dr Janine Bailey, Motueka
- Dr Suzie Lawless, Dunedin
- Dr Neil Whittaker, Nelson
- Dr Marie Neylon, Dunedin
bpacnz would like to thank the GP review panel and Dr Peter Fitzgerald for their expertise and guidance on the development of this quiz feedback.
|Page 1 | 2 | 3||Page 3|