Retroperitoneal drainage versus no drainage after pelvic lymphadenectomy for the prevention of lymphocyst formation in patients with gynaecological malignancies
Abstract
This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:
To assess the effects of retroperitoneal drainage versus no drainage after pelvic lymphadenectomy on lymphocyst formation and related morbidities in gynaecologic cancer patients.
Background
Pelvic lymphadenectomy, the systematic removal of lymph nodes surrounding major pelvic blood vessels in the retroperitoneum, is an important component of the surgical management of gynaecologic malignancies, particularly those originating from the cervix, endometrium and ovary. Knowledge of metastatic status of the removed pelvic lymph nodes provides valuable staging and prognostic information that guide postoperative adjuvant treatment. In addition, removal of both bulky and microscopic metastatic nodes could potentially improve treatment outcome. However, the procedure is associated with postoperative complications, important of which is lymphocyst formation and its related morbidities (Benedetti‐Panici1997; Yamamoto 2000).
A Lymphocyst, defined as a collection of lymphatic fluid in the retroperitoneal space, is well‐known as a specific complication of pelvic lymphadenectomy (Benedetti‐Panici1997; Ilancheran 1988; Livingston 1980; Petru 1989). The reported incidence of lymphocyst following gynaecological cancer surgery varies from 1 to 29% (Lopes 1995).These differences could be explained by the use of various surgical techniques, the difference in extent of lymphadenectomy and the use of different diagnostic methods (Srisomboon 2002; Yamamoto 2000). The mechanism of lymphocyst formation is unknown. However, previous radiotherapy, positive nodes and prophylactic heparin has been considered as possible risk factors (Yamamoto 2000). Most lymphocysts occurred within the first two to four weeks after surgery (Conte 1990). Although frequently asymptomatic, lymphocysts can lead to leg oedema, ureteral obstruction, pelvic pain, deep venous thrombosis, ileus, secondary infection and fistula (Franchi 2007).
Retroperitoneal drainage has been traditionally recommended as a method to prevent lymphocyst formation and associated postoperative morbidities (Symmond 1961; Symmond 1966; Van Nagell 1976). The procedure is performed by placement of passive or active suction drains to remove lymphatic fluid or blood that accumulate in the operative fields. This practice became surgical dogma. However, recent prospective and retrospective studies have challenged this policy by demonstrating that there was no advantage to the routine use of retroperitoneal drainage following radical hysterectomy and pelvic lymphadenectomy (Franchi 2007; Lopes 1995; Patsner 1995; Srisomboon 2002). In fact, the drain itself as a foreign body, could disturb the reparative and absorptive functions of the peritoneum and contribute to the formation of lymphocyst (Maitland 1970).
Our aim is to determine whether there is clear evidence to support the omission of retroperitoneal drainage following pelvic lymphadenectomy in patients with gynaecologic malignancies.
Objectives
To assess the effects of retroperitoneal drainage versus no drainage after pelvic lymphadenectomy on lymphocyst formation and related morbidities in gynaecologic cancer patients.
Methods
Criteria for considering studies for this review
Types of studies
Randomised controlled trials (RCTs) that compared the effect of retroperitoneal drainage versus no drainage after pelvic lymphadenectomy in gynaecologic cancer patients with clinically meaningful postoperative outcomes will be considered. However, quasi‐RCTs will be excluded. The trials that will be included in the final analysis must have clear random allocation criteria with appropriate allocation concealment. Also, the included studies must not have significant violations of allocation procedure and exclusions after allocation.
Types of participants
Participants are patients with gynaecological malignancies who underwent systematic pelvic lymphadenectomy with or without paraaortic lymphadenectomy as part of their surgical treatment regardless of lymphadenectomy approaches (transperitoneal or extraperitoneal) and surgical approach (open or laparoscopic).
Types of interventions
Main intervention
Retroperitoneal drainage, which is defined as placement of passive or active suction drains in pelvic retroperitoneal spaces following pelvic lymphadenectomy regardless of drainage route (transabdominal or transvaginal), surgical management of pelvic peritoneum (left open or sutured close) and surgical management of vaginal stump (open or close).
Comparison intervention
No drainage, which is defined as no placement of passive or active suction drains in pelvic retroperitoneal spaces following pelvic lymphadenectomy regardless of surgical management of pelvic peritoneum (left open or sutured close) and surgical management of vaginal stump (open or close).
Types of outcome measures
The following outcomes will be recorded if the information are available.
Primary outcomes
Rate of lymphocyst formation; asymptomatic and symptomatic (categorical data) The diagnosis of lymphocyst must be made by imaging studies such as ultrasound, computerised tomography (CT), or magnetic resonance imaging (MRI). The techniques used for diagnosis will be described.
Secondary outcomes
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Treatment of symptomatic lymphocysts, i.e. radiologically guided drainage, laparoscopic deroofing, laparotomy (categorical data)
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Rate of related postoperative morbidities: febrile morbidity, wound infection, wound dehiscence, sepsis, symptomatic ascites, leg oedema, deep venous thrombosis, ureteral obstruction, bowel obstruction/ileus, fistula formation (categorical data)
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Blood transfusion (categorical data)
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Change of related serum chemistry: protein and albumin level (continuous data), albumin infusion (categorical data)
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Duration of surgery (continuous data)
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Time to return of bowel function (continuous data)
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Hospital stay (continuous data)
Search methods for identification of studies
Electronic searches
All articles which describe RCTs of retroperitoneal drainage versus no drainage after pelvic lymphadenectomy in gynaecologic cancer patients will be obtained from the following sources:
(1) The Gynaecological Cancer Review Group's Specialised Register of controlled trials will be searched for any relevant trials
(2) The Cochrane Controlled Trials Register (CENTRAL) on the Cochrane Library (latest issue) will be searched in all fields using the following search string:
1 genital neoplasms, female/ or pelvic neoplasms/
2 "gynecologic* cancer" or "gynaecologic* cancer"
3 "gynecologic* malignan*" or "gynaecologic* malignan*"
4 fallopian tube neoplasms/su [Surgery]
5 exp ovarian neoplasms/su [Surgery]
6 exp uterine neoplasms/su [Surgery]
7 "fallopian tube" AND (cancer OR cancers OR carcinoma OR carcinomas OR tumour OR tumours OR tumor OR tumors OR neoplasm OR neoplasms OR malignant OR malignancy)
8 (ovary OR ovarian) AND (cancer OR cancers OR carcinoma OR carcinomas OR tumour OR tumours OR tumor OR tumors OR neoplasm OR neoplasms OR malignant OR malignancy)
9 (uterine OR uterus) AND (cancer OR cancers OR carcinoma OR carcinomas OR tumour OR tumours OR tumor OR tumors OR neoplasm OR neoplasms OR malignant OR malignancy)
10 #1 OR #2 OR #3 OR #4 OR #5 OR #6 OR #7 OR #8 OR #9
11 lymphadenectom*
12 "lymph node dissection*"
13 "lymph node excision*"
14 lymphocyst
15 lymphocele/
16 "lymphatic cyst*"
17 #11 OR #12 OR #13 OR #14 OR #15 OR #16
18 "suction drainage*"
19 "pelvic drain*" or "pelvic drainage*"
20 "retroperitoneal drainage*"
21 "pelvic reperitonealization"
22 #18 OR #19 OR #20 OR #21
23 #10 AND #17 AND #22
(3)The MEDLINE electronic database (Appendix 1)
(4)The EMBASE electronic database (Appendix 2)
Searching other resources
(1) The citation lists of relevant publications, systematic reviews, review articles, abstracts of scientific meetings and included studies will be searched.
(2) Personal communication with experts, specialists in the field and the study authors or relevant publications will be conducted in an attempt to identify unpublished studies.
Data collection and analysis
Selection of studies
The study selection will be undertaken by both review review authors (KC and CK). The titles and abstracts of articles found in the search will be screened by both KC and CK. The review authors will discard studies that are clearly ineligible but aimed to be overly inclusive rather than risk losing relevant studies. Then, full text copies of the eligible articles will be obtained. Both review authors will independently assess whether the studies meet the inclusion criteria, with disagreements resolved by discussion. Further information will be sought from the study authors where papers contain insufficient information to make a decision about eligibility.
Data extraction and management
Review authors will independently extract information using the pre‐designed data extraction form. Discrepancies will be resolved by discussion. For each included trial, information will be collected regarding the location of the study, methods of the study, the participants(age range, eligibility criteria), the nature of the interventions and data relating to the outcomes specified above. Where possible, missing data will be sought from the study authors.
Assessment of risk of bias in included studies
Methodological quality
The quality of all eligible studies will then be assessed independently by the two review authors following the guidelines of the Cochrane Handbook of Systematic Reviews of Interventions (Higgins 2008), with discrepancies resolved by discussion. The assessment will be conducted by detailed descriptions of these following standardised items and each items will be rated as follows: clearly yes: rate A; not sure: rate B (seek details from study authors); clearly no: rate C.
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Was the assigned treatment adequately concealed prior to allocation? (Appendix 3)
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Were the outcomes of patients who withdrew or were excluded after allocation described and included in an "intention to treat" analysis?
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Were the outcome assessors blinded to assignment status?
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Were the treatment and control group comparable at entry?
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Were the subjects blinded to assignment status following allocation?
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Were the treatment providers blinded to assignment status?
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Were the care programmes, other than the trial options, identical?
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Were the withdrawals or loss to follow‐up less than 10% of the study population?
The information regarding methodological quality will be presented in a separate table providing a context for discussing the reliability of the results.
Data synthesis
Statistical analysis will be performed in accordance with the guidelines for statistical analysis developed by the Cochrane Collaboration (Deeks 2008).
Subgroup analysis and investigation of heterogeneity
Heterogeneity (variations) between the results of different studies will be examined by inspecting the forest plot of a meta‐analysis for variation in effects. Formal statistical tests such as the statistical tests of homogeneity of 2 x 2 tables and the I2 value will also be considered in conjunction with the graphical approaches to determine between‐study differences.
For categorical data, results for each study will be expressed as a relative risk with 95% confidence intervals (CI) and combined for meta‐analysis with RevMan 5 software.
For continuous data, results from each study will be expressed as a weighted mean difference (WMD) with 95% CI and combined for meta‐analysis with RevMan software. Meta‐analytic methods for continuous data assume that the underlying distribution of the measurements is normal. Where data are clearly skewed and results reported in the publication as median and range with non parametric tests of significance, the results will be reported separately in the result section of the review.
For meta‐analysis, the fixed effects or random effects model will be used depending on the outcome of the tests of homogeneity.
Sensitivity analysis
Sensitivity analyses will be performed where there is uncertainty or disagreement regarding inclusion of studies, data extraction and missing data/drop‐outs.
