Recurrence after treatment (LLETZ) for cervical intraepithelial neoplasia (CIN): impact of human papillomavirus (HPV) test

  • Protocol
  • Intervention

Authors


Abstract

This is the protocol for a review and there is no abstract. The objectives are as follows:

  • To evaluate the risk of developing recurrent cervical intraepithelial neoplasia 2+ (CIN2+) in women with a positive high risk human papilloma virus (HPV) test after large loop excision of the transformation zone (LLETZ) treatment

  • To determine the optimal follow-up strategies for women following LLETZ treatment according to high risk HPV status

Background

Description of the condition

The development of cancer of the cervix is a multi-step process; before cervical cancer develops cervical cells undergo changes and become abnormal. These abnormalities are called cervical intraepithelial neoplasia (CIN) and are associated with an increased risk of subsequent invasive cancer of the cervix (Pinto 2000). Cervical cancer is the second most common cancer among women up to 65 years of age and is the most frequent cause of death from gynaecological cancers worldwide. A woman's risk of developing cervical cancer by age 65 years ranges from 0.69% in developed countries to 1.38% in developing countries (GLOBOCAN 2008). In Europe, about 60% of women with cervical cancer are alive five years after diagnosis (EUROCARE 2003). It is widely accepted that infection with human papilloma virus (HPV) is associated with the development of CIN and cancer (Galaal 2011; McCredie 2008; Pinto 2000). There is strong epidemiologic evidence demonstrating that the major risk factor for the development of pre-invasive or invasive carcinoma of the cervix is HPV infection (Brisson 1994). This risk factor outweighs other known risk factors including high parity, increasing number of sexual partners, young age at first intercourse, low socioeconomic status, and smoking history (Brisson 1994; Schiffman 1993).

Description of the intervention

Large loop excision of the transformation zone (LLETZ) is highly effective treatment of CIN and early invasive disease, FIGO stage 1A1. However, following LLETZ, 4% to 17% of women have CIN2 or more due to either residual or recurrent disease (Alvarez 1994; Bollen 1999; Jain 2001; Mitchell 1998). Previous studies have shown that the risk of residual or recurrent disease is consistently associated with large lesion size before LLETZ, endocervical extension of the disease, and incomplete excision of the lesion (Brockmeyer AD 2003; Costa 2003; Houfflin Debarge 2003). However, even women with clear margins following excision are at risk for disease recurrence (Paraskevaidis E 2000).

How the intervention might work

Carcinogenic human papillomavirus (HPV), the causative agent of cervical cancer and its precursor lesions, is present in up to one third of women following LLETZ and is associated with increased risk of disease recurrence (Costa 2003; Paraskevaidis E 2000). Therefore, HPV testing may serve as a surveillance tool for identifying women at high risk of recurrence. HPV persistence after high-grade CIN removal may be associated with residual lesions or risk of disease recurrence (Sarian 2004). High risk HPV testing will enable us to identify women at increased risk of recurrent CIN, and therefore will enable us to offer closer surveillance and early treatment where indicated.

Why it is important to do this review

Following the excision of CIN using LLETZ, post-treatment CIN rates of 4% to 17% have been reported (Alvarez 1994; Bollen 1999; Jain 2001; Mitchell 1998). Long-term follow-up after local treatment of CIN is mandatory due to the late occurrence of cervical cancer over a period of 20 years (Ghaem-Maghami 2007; Soutter 1997). Therefore, early detection of treatment failure is important. It has been suggested that persistence of high risk HPV represents an independent risk factor for developing relapsing disease and constitutes the basis to introduce HPV testing even in the follow-up of patients treated for high-grade CIN (Fallani 2008; Nam 2009). In addition, post-treatment HPV testing could be useful in the follow-up of patients after conization. In the case of negative post-treatment HPV testing the frequency of follow-up could be reduced, particularly in those patients with free margins (Houfflin Debarge 2003). Some other studies have suggested that persistence is associated with age greater than 35 years and smoking in addition to HPV positivity (Sarian 2004).

Objectives

  • To evaluate the risk of developing recurrent cervical intraepithelial neoplasia 2+ (CIN2+) in women with a positive high risk human papilloma virus (HPV) test after large loop excision of the transformation zone (LLETZ) treatment

  • To determine the optimal follow-up strategies for women following LLETZ treatment according to high risk HPV status

Methods

Criteria for considering studies for this review

Types of studies

Randomised clinical trials (RCTs)

Types of participants

Adult women (aged 18 years or older) undergoing LLETZ for the treatment of CIN

Types of interventions

Intervention

Post-treatment HPV testing

Control

Conventional cervical screening with a Papanicolaou test (Pap smear)

Types of outcome measures

Primary outcomes
  1. Persistence or recurrence, or both, of CIN2 or higher lesion

Secondary outcomes
  1. Anxiety, measured using a validated scale

  2. Psychosexual scores, measured using a validated scale

Search methods for identification of studies

Papers in all languages will be sought and we will carry out translations if necessary.

Electronic searches

See: Cochrane Gynaecological Cancer Group methods used in reviews.

We will search the following electronic databases:

  • Cochrane Gynaecological Cancer Review Group Trials Register;

  • Cochrane Central Register of Controlled Trials (CENTRAL);

  • MEDLINE;

  • EMBASE;

  • CINAHL;

  • PsycINFO.

The MEDLINE search strategy based on terms related to the review topic is presented in Appendix 1. The strategy will be adapted for other databases accordingly.

We will search the databases from 1946 until the present.

All relevant articles that are found will be identified on PubMed and, using the 'related articles' feature, we will further search for newly published articles.

Searching other resources

Unpublished and grey literature

We will search Metaregister (http://www.controlled-trials.com/rct), Physicians Data Query (http://www.nci.nih.gov), http://www.clinicaltrials.gov, and http://www.cancer.gov/clinicaltrials for ongoing trials. We will approach the principal investigators to double check for missed relevant data if ongoing trials which have not been published are missed through these searches.

We will search conference proceedings and abstracts through Zetoc (http://zetoc.mimas.ac.uk) and WorldCat Dissertations.  

Handsearching

We will handsearch the citation lists of included studies, key textbooks and previous systematic reviews, and we will contact experts in the field to identify further reports of trials. We will handsearch reports of conferences in the following sources:

  • Gynecologic Oncology (Annual Meetings of the American Society of Gynecologic Oncologists);

  • International Journal of Gynecological Cancer (Annual Meetings of the International Gynecologic Cancer Society);

  • British Journal of Cancer;

  • British Cancer Research Meetings;

  • Annual Meetings of European Society of Medical Oncology (ESMO);

  • Annual Meetings of the American Society of Clinical Oncology (ASCO);

  • Cervical screening, colposcopy and HPV meetings:

    • British Society for Colposcopy and Cervical Pathology (BSCCP),

    • European Federation for Colposcopy (EFC),

    • International Federation for Cervical Pathology and Colposcopy (IFCPC),

    • American Society for Colposcopy and Cervical Pathology (ASCCP),

    • International Papillomavirus (IPV).

We will also search the following websites:

  • British Gynaecological Cancer Society (www.bgcs.org.uk);

  • European Society of Gynaecological Oncology (www.esgo.org);

  • Society of Gynaecological Oncologists (www.sgo.org).

Data collection and analysis

Selection of studies

We will download all titles and abstracts retrieved by the electronic searching to the reference management database Endnote. We will remove duplicates and the remaining references will be examined by two review authors (EH, KG) independently. These two authors will screen the references by the title and abstract and eliminate references which are clearly not related to the research question. When both authors agree on exclusion of a reference, no further action will be taken. When one or both of the authors determine that the article may be eligible for inclusion, we will obtain the full text article. Each author will decide independently if these studies are eligible and then we will reconcile any differences. We will resolve disagreements about inclusion by discussion. We will contact study authors if required information to decide if a study is eligible is missing. We will not be blinded to article title, authors or journal title.

Data extraction and management

We will abstract the data for the included studies as recommended in chapter 7 of theCochrane Handbook for Systematic Reviews of Interventions, Version 5.1 (Higgins 2011). Two authors will extract the data independently and these will include the following.

  • Author, year of publication and journal citation (including language).

  • Country.

  • Setting.

  • Inclusion and exclusion criteria.

  • Study design, methodology.

  • Study population:

    • total number enrolled;

    • patient characteristics;

    • age;

    • race;

    • co-morbidities;

    • previous treatment.

  • CIN details at diagnosis:

    • CIN2, CIN3 details.

  • Intervention details:

    • post-treatment HPV testing in combination with cytology testing ± HPV typing;

    • criteria for referral to colposcopy.

  • Comparison details:

    • conventional cervical screening with a Pap smear;

    • criteria for referral to colposcopy.

  • Risk of bias in study (see below).

  • Duration of follow-up and follow-up intervals.

  • Outcomes (see above):

    • for each outcome, outcome definition (with diagnostic criteria if relevant);

    • for scales, upper and lower limits, and whether high or low score is good;

    • results, number of participants allocated to each intervention group;

    • for each outcome of interest, sample size, missing participants and reasons for losses to follow-up.

We will extract data on outcomes as below.

  • For time to event (developing recurrent CIN2 or higher lesion) data, we will extract the log of the hazard ratio (HR), (log(HR)), and its standard error from the trial reports (if these are not reported, we will attempt to estimate them from other reported statistics using the methods of Parmar 1998). 

  • For dichotomous outcomes (e.g. developing recurrent CIN2 or higher lesion, if not expressed as time to event data), we will extract the number of patients in each treatment arm who experience the outcome of interest and the number of patients assessed at the endpoint, in order to estimate a risk ratio (RR).

  • For continuous outcomes (e.g. anxiety, psychosexual scores), we will extract the final value and standard deviation of the outcome of interest and the number of patients assessed at the endpoint in each treatment arm, at the end of follow-up, in order to estimate the mean difference (if trials measure outcomes on the same scale) or standardised mean difference (if trials measure outcomes on different scales) between the treatment arms and its standard error.

Where possible, all data that are extracted will be those relevant to an intention-to-treat analysis, in which participants are analysed in the groups to which they were assigned. We will note the time points at which outcomes are collected and reported.

Data will be abstracted independently by two review authors (EH, KG) onto a data abstraction form specially designed for the review. We will resolve differences between the review authors by discussion or by appeal to a third review author (AB).

Assessment of risk of bias in included studies

We will assess the risk of bias in the included RCTs in accordance with the guidance in the Cochrane Handbook for Systematic Reviews of Interventions, using the Cochrane Collaboration's tool and the criteria specified in chapter 8 (Higgins 2011). This will include assessment of:

  • sequence generation;

  • allocation concealment;

  • blinding (restricted to blinding of outcome assessors as it is not possible to blind participants and healthcare providers to the interventions);

  • incomplete outcome data:

    • we will record the proportion of participants whose outcomes are not reported at the end of the study. We will code the satisfactory level of losses to follow-up for each outcome as

      • 'Yes', if fewer than 20% of patients are lost to follow-up and reasons for loss to follow-up are similar in both treatment arms,

      • 'No', if more than 20% of patients are lost to follow-up or reasons for loss to follow-up are different between treatment arms,

      • 'Unclear', if loss to follow-up is not reported;

  • selective reporting of outcomes;

  • other possible sources of bias.

Two review authors (EH, KG) will independently apply the risk of bias tool, and differences will be resolved by discussion or by appeal to a third review author (AL). Results will be summarised in both a risk of bias graph and a risk of bias summary. Results of meta-analyses will be interpreted in light of the findings with respect to risk of bias.

Measures of treatment effect

We will use the following measures of the effect of treatment.

  • For time to event data, we will use the HR, if possible.

  • For dichotomous outcomes, we will use the RR.

  • For continuous outcomes, we will use the mean difference (MD) between treatment arms.

Dealing with missing data

We will not impute missing outcome data for the primary outcome. If data are missing, or only imputed data are reported, we will contact the trial authors to request data on the outcomes only among the participants who were assessed.

Assessment of heterogeneity

We will assess heterogeneity between studies by visual inspection of the forest plots, estimation of the percentage heterogeneity between trials which cannot be ascribed to sampling variation (Higgins 2003), a formal statistical test of the significance of the heterogeneity (Deeks 2001) and, if possible, by subgroup analyses (Subgroup analysis and investigation of heterogeneity). If there is evidence of substantial heterogeneity, we will investigate and report the possible reasons for this.

Assessment of reporting biases

We will examine funnel plots corresponding to the meta-analysis of the primary outcome to assess the potential for small study effects.

Data synthesis

If sufficient, clinically similar trials are available, we will pool their results in meta-analyses.

  • For time-to-event data, HRs will be pooled using the generic inverse variance facility of RevMan 5.

  • For any dichotomous outcomes, we will calculate the RR for each trial and these will then be pooled.   

  • For continuous outcomes, we will pool the MDs between the treatment arms at the end of follow-up if all trials measured the outcome on the same scale, otherwise we will pool standardised mean differences (SMDs).

We will use random-effects models with inverse variance weighting for all meta-analyses (DerSimonian 1986).

Sensitivity analysis

We will perform sensitivity analyses excluding studies at high risk of bias.

Acknowledgements

We thank Jo Morrison for clinical and editorial advice, Jane Hayes for designing the search strategy, and Gail Quinn and Clare Jess for their contribution to the editorial process.

The National Institute for Health Research (NIHR) is the largest single funder of the Cochrane Gynaecological Cancer Group.

The views and opinions expressed therein are those of the authors and do not necessarily reflect those of the NIHR, NHS or the Department of Health.

Appendices

Appendix 1. MEDLINE search strategy

1 Uterine Cervical Neoplasms/
2 Cervical Intraepithelial Neoplasia/
3 CIN*.mp.
4 (cervi* adj5 (cancer* or tumor* or tumour* or malignan* or neoplas* or carcinoma* or adenocarcinoma* or precancer* or pre-cancer* or dysplasia)).mp.
5 1 or 2 or 3 or 4
6 surgery.fs.
7 (LLETZ or LEEP).mp.
8 transformation zone.mp.
9 (conisation or conization).mp.
10 laser.mp.
11 excis*.mp.
12 cryotherapy.mp.
13 6 or 7 or 8 or 9 or 10 or 11 or 12
14 HPV.mp.
15 exp Papillomavirus Infections/
16 exp papillomaviridae/
17 papillomavir*.mp.
18 14 or 15 or 16 or 17
19 5 and 13 and 18
20 randomized controlled trial.pt.
21 controlled clinical trial.pt.
22 randomized.ab.
23 placebo.ab.
24 clinical trials as topic.sh.
25 randomly.ab.
26 trial.ti.
27 20 or 21 or 22 or 23 or 24 or 25 or 26
28 19 and 27

key:

mp=title, abstract, original title, name of substance word, subject heading word, protocol supplementary concept, rare disease supplementary concept, unique identifier, pt=publication type, ab=abstract, sh=subject heading, ti=title

What's new

DateEventDescription
27 March 2014AmendedContact details updated.

Contributions of authors

Khadra Galaal is the main author of the protocol, Andrew Bryant developed and drafted the protocol, Esther van der Heijden helped in drafting the protocol. Alberto Lopes, Ruud Bekkers and Nagindra Das provided clinical expertise. All authors agreed the final version.

Declarations of interest

None known

Sources of support

Internal sources

  • No sources of support supplied

External sources

  • Department of Health, UK.

    • NHS Cochrane Collaboration programme Grant Scheme CPG-506

Ancillary