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Abstract
Introduction Inguino-femoral lymph node dissection plays a crucial role in the management of vulvar cancer. The procedure is associated with high complication rates, including infection, lymphocysts/lymphoedema and wound dehiscence. Several skin incision techniques exist and practice among gynecology oncologists is variable. Little evidence exists to guide surgeons regarding the optimal surgical approach. This study aimed to determine the difference in 30-day complication rates, number of lymph nodes and length of stay between patients undergoing the modified oblique and classical ‘lazy S’ skin incision.
Methods A retrospective review between January 2014 and September 2018 was performed in the University Hospital of Wales, Cardiff. All cases of inguino-femoral lymph node dissection performed for vulvar cancer were included in the study without exclusion. Data collected included age, body mass index (BMI), incision type, suture material, length of hospital stay, complication rates, cancer stage, lymph node count, lymph node positivity rate and recurrence rates. Data were analyzed using SPSS software and clinical significance was set as p<0.05.
Results Thirty-five cases of classical ‘lazy S’ and 14 cases of modified oblique were included in the analysis. The mean patient age was 65 years (range 41–86) in the classical ‘lazy S’ group and 58 years (range 19–81) in the modified oblique group. The mean BMI was 28 kg/m2 (range 18–45) in the classical ‘lazy S’ group and 29 kg/m2 (range 20–36) in the modified oblique group. In the classical ‘lazy S’ group, the stage classification was as follows: stage IB (18), II (2), IIIA (3), IIIB (4), IIIC (8). In the modified oblique group, the stage classification was: stage IB (8), II (4), IIIA (2). Grade 3–4 complications were statistically significantly more common after the classical ‘lazy S’ versus the modified oblique operation (20/35, 57.1% vs 2/14, 14.3%, p<0.02). Mean number of nodes harvested was statistically significantly higher in the classical ‘lazy S’ group compared with the modified oblique group (11.1 nodes, range 6–17 vs 7 nodes, range 4–11, p<0.001). Node positivity rate was higher in the classical ‘lazy S’ group compared with the modified oblique group (28.6% vs 10%, p=0.08). Mean hospital stay was statistically significantly longer in patients undergoing classical ‘lazy S’ versus modified oblique (10.7 vs 4.5 days, p=0.02). One case of groin node recurrence occurred and this patient was in the classical ‘lazy S’ arm.
Conclusion The rate of overall and serious complications was lower after modified oblique skin incision compared with classical ‘lazy S’. However, the absolute lymph node count and lymph node positivity rate were higher in the ‘lazy S’ group.
- vulva
- surgical procedures, operative
- lymph nodes
- lymphatic metastasis
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Highlights
Lazy S incision in inguino-femoral lymph node dissection is associated with higher grade 3–4 postoperative complications.
Lazy S incision in inguino-femoral lymph node dissection may result in higher mean lymph node count.
Options for inguino-femoral lymph node dissection are evaluated when sentinel mapping is not feasible.
Introduction
Although cancer of the vulva is rare, accounting for approximately 4–6% of all gynecological malignancies,1 the overall incidence is increasing; therefore, research into its prevention and best management is increasingly important. Factors contributing to the increasing incidence include improved population life expectancy and increased prevalence of human papillomavirus (HPV) infection.2 It is likely that primary prevention strategies such as HPV vaccination and smoking cessation will impact on incidence in years to come and efforts to improve uptake and adherence to these programs should continue to be made. Research aimed at improving management in rarer cancers is challenging. Our group is interested in the surgical approach to inguino-femoral lymph node dissection in the management of vulvar cancer.
Inguino-femoral lymph node dissection plays an important role in the management of vulvar cancer aimed at reducing the incidence of groin metastasis. Inguino-femoral lymph node dissection is associated with a high incidence of complications and morbidity.3–10 Complications may lead to a poor patient experience, prolonged hospital stay, increased cost of care, and perhaps most importantly, a delay in commencement of adjuvant therapy. A significant development in the surgical management of vulvar cancer over recent years has been the incorporation of sentinel lymph node mapping as standard of care in early stage disease.11 This technique has been demonstrated as accurate with reduced morbidity.12 Many patients now benefit from this less invasive approach; however, not all patients have disease appropriate for this technique. The British Gynecological Cancer Society (BGCS) recommend the use of sentinel lymph node mapping in patients with unifocal disease that is greater than 1 mm in invasive depth but less than 4 cm in overall tumor size.13 In addition, there needs to be a representative vulvar lesion for the injection site, no tumor encroachment on the urethra, vagina or anus, and no clinical/radiological evidence of involved lymph nodes.13 Inevitably, this leaves a number of patients in whom sentinel lymph node mapping is not appropriate and full node dissection is therefore required. Ensuring the optimal surgical approach to complete inguino-femoral lymphadenectomy is carried out, both in terms of postoperative morbidity and oncological outcome, is therefore still very relevant.
Several surgical techniques to achieve inguino-femoral node dissection have been described in the literature. The original procedure, described by Rutledge and colleagues,14 which involved an en bloc dissection through a radical, butterfly incision, has been modified with the the aim of reducing the significant morbidity (70–90% wound breakdown and chronic, debilitating lymphoedema in 9%) associated with the procedure. These modifications have included a ‘triple incision’ approach,4 5 8 9 and saphenous vein sparing surgery.6 The triple incision appeared to reduce complication rates8–10; however, the benefit of sparing of the saphenous vein is less convincing.15 Over recent years, there has been a shift towards less invasive incision types with the aim of reducing morbidity. The European Society of Gynecological Oncology (ESGO) describes the use of a linear incision along the medial four fifths of a line drawn between the anterior superior iliac spine and the pubic tubercle, approximately 1 cm above and parallel to the groin crease.15 Despite these changes in technique, complications remain high and little evidence exists comparing techniques in order to guide practice. In some parts of the world, the procedure is being carried out using a minimally invasive approach.16–18 A theoretical risk of increasingly less invasive surgical approaches is that the node harvest is compromised, potentially missing the presence of metastatic disease. Little research has been done comparing different surgical techniques, and most of the work that does exist comes from the fields of dermatology and plastic surgery and is related to the management of skin cancer.
Anecdotally, the surgical approach to inguino-femoral lymph node dissection in the UK is variable. Due to the rarity of vulvar cancer, randomized trials of therapeutic approaches are uncommon and most studies are based on retrospective reviews; the consequence is that the evidence on which practice is based is relatively limited and likely inferior in quality compared with other more common cancers. Knowledge of the optimal surgical technique to effectively perform the procedure while minimizing the risk of postoperative complications would be of significant value to the patient and clinician. This work compares 30-day complication rates and lymph node counts between two surgical incisions commonly used in the UK to achieve inguino-femoral lymph node dissection.
Methods
In this retrospective review, all cases of groin node dissection performed in the University Hospital of Wales, Cardiff between January 2013 and September 2018 were reviewed. During this time period, two different incisions were performed (Figure 1) by different surgeons and the complications, lymph node harvest and lymph node positivity rates were compared. The incision performed was dependent on the surgeon performing the operation: two surgeons performed only the classical ‘lazy S’ approach and one surgeon only performed the modified oblique approach. The classical ‘lazy S’ incision, first described by Neville Hacker in 1981, involves an 8–10 cm vertical incision midway along the inguinal ligament in the shape of a ‘lazy S’ (Figure 1, right). This incision was closed with either sutures or skin staples and typically a surgical drain was left in situ. The modified oblique incision is slightly superior and parallel to the inguinal ligament at a length of approximately 4–5 cm between the anterior superior iliac spine and the pubic tubercle (Figure 1, left). The incision is closed with sub-cuticular monocryl sutures without a drain. The inguinal and femoral nodes are then dissected using the femoral vessels as the deep margin, the adductor longus muscle as the medial margin, the sartorius muscle as the lateral and the inguinal ligament as the superior margin.
Surgical pictures of incisions. Modified oblique incision is slightly superior and parallel to the inguinal ligament at a length of approximately 4–5 cm between the anterior superior iliac spine and the pubic tubercle. Classical ‘lazy S’ incision involves an 8–10 cm vertical incision midway along the inguinal ligament in the shape of a ‘lazy S’.
A case of groin node dissection was considered as one anatomical side. Two cases of groin node dissection were therefore reported for patients undergoing bilateral groin node dissection. Data collected included patient age, body mass index (BMI), number of lymph nodes collected, number of positive lymph nodes, histological stage, length of stay, complications and recurrence rates. Complications were classified using a modified version of the Clavien-Dindo classification system to specifically address the problems encountered with surgery of this nature (Table 1). Data were analyzed using SPSS software with statistical significance considered at a p value<0.05.
Modified Clavien-Dindo classification of complications after inguino-femoral lymph node dissection
Results
Over the five-year period, 49 inguino-femoral lymph node dissections were performed. Thirty-five were performed using the classical ‘lazy S’ incision and 14 were performed using the modified oblique incision. Characteristics including age, BMI and cancer stage in each group are summarized in Table 2. The mean number of lymph nodes harvested was significantly higher using the classical ‘lazy S’ incision compared with the modified oblique incision (11.1, range 6–17 vs 7, range 4–11, p<0.001) (Figure 2). The median lymph node count was also higher in the classical ‘lazy S’ group compared with the modified oblique group (10 vs 7, respectively). In terms of lymph node metastases, positive lymph nodes were seen more frequently in the classical ‘lazy S’ group compared with the modified oblique group (10/35, 28.6% vs 1/10, 10.0%), however this did not reach statistical significance (p=0.08).
Node count per surgical incision in inguino-femoral lymph node dissection.
Baseline characteristics of population
The length of stay was significantly shorter for patients after a modified incision compared with a classical incision (4.5, range 2–9 vs 10.7, range 2–41, p=0.02).
The complications are reported in Table 3. Overall, there were no differences in complication rates between the classical ‘lazy S’ incision compared with the modified oblique incision (31/35, 88.6% vs 11/14, 78.6%, χ2=0.204, p=0.65). More serious complications (defined as grade 3 or 4 complications, including wound dehiscence with or without vacuum-assisted closure system and life-threatening complications requiring higher level of care) were statistically significantly more common after classical ‘lazy S’ compared with modified oblique (20/35, 57.1% vs 2/14, 14.3%, χ2=5.79, p<0.02) (Table 3). Of note, seven of 35 patients who underwent the classical ‘lazy S’ incision had a wound breakdown which required vacuum-assisted closure system for healing and no patient in the modified oblique arm required this type of system for wound healing.
Complications for skin incision in inguino-femoral lymph node dissection
Method of skin closure (suture based) and drain use (no drain) was standardized in the modified oblique group of patients, however there was variance in practice, due to surgeons discretion at time of surgery, in the classical ‘lazy S’ group. To determine any association with skin closure technique and use of drains and complication rates, the classical ‘lazy S’ group was sub-analyzed. There were five patients with missing data. A drain was used in 26/30 (86.7%) patients. The absolute number and percentage of grade 3–4 complications was higher in patients with a drain than in those without a drain, however this did not reach statistical significant (16/26, 61.5% vs 0/4, 0.0%, χ2=3.092, p=0.08). In terms of wound closure, there was one patient with missing data. Skin closure was performed with skin clips in 20/34 (58.8%) and suture-based closure was performed in 14/34 (41.2%). Absolute number and percentage of grade 3–4 complications were more common in the skin clip group; however this was not statistically significant (14/20, 70.0% vs 6/14, 42.9%, χ2=1.510, p=0.22).
Discussion
In this study, overall post-operative complications were not significantly different between the two incision types; however, the modified oblique incision was associated with statistically significant fewer grade 3+ complications. In the ‘lazy S’ incision group, the majority of patients received a surgical drain and had skin clip skin wound closure. Although complications were higher in those patients with a surgical drain and in those with skin clips, probably due to the small sample size, these findings did not reach statistical significance. It is not possible to be certain whether it is the incision in isolation that is responsible for the complication rates or whether it is a combination of factors, including patient factors (BMI, age, smoking status, comorbidities) and surgical factors (incision type, use of surgical drains, skin closure technique).
Wound dehiscence, particularly when a vacuum-assisted closure system is required, results in protracted healing times, delay in initiation of adjuvant therapy if needed, and increased care requirements, therefore having a significant impact on both patients and healthcare providers. However, an important consideration when choosing the best incision is the potential difference in mean lymph node count. In this review, the modified oblique incision technique was associated with a significantly lower mean lymph node count and a lower (but not statistically significant) node positivity rate than the classical ‘lazy S’ incision. This finding may have a clinical impact on patients in terms of accurate staging and appropriate use of adjuvant therapy.
A retrospective review of 41 patients undergoing inguinal lymph node dissection for skin cancer compared four different surgical approaches, two of which are relevant to practice in gynecology oncology (vertical ‘S’ and modified oblique).19 Hospital stay was significantly less in the modified oblique group compared with the vertical ‘S’. Major complication rates were also significantly higher in patients who had a vertical ‘S’ incision compared with modified oblique. This study made no reference to the number of lymph nodes removed.
Several studies have been published investigating the importance of lymph node count and recurrence in vulvar cancer. Van Beekhuizen et al20 identified a node count of less than nine was associated with an increased risk of recurrence. Another study by Diehl et al21 found that resection of more than six nodes per groin did not improve recurrence rates. Panici et al22 found that resection of less than 15 lymph nodes in bilateral lymphadenectomy had a negative impact on survival.
The reason for the difference in complication rates and lymph node counts is not clear, but it could be hypothesized that a larger incision leads to excision of a larger tissue bulk, resulting in more lymph nodes but also a larger potential space which may encourage complications. Obviously, the use of sentinel lymph node dissection has been a significant development in vulvar cancer management since the publication of the GROINS I and GROINS II trials. These studies showed that sentinel lymph node dissection could detect nodal metastases in most patients with regional spread of disease and is associated with lower complication rates than complete lymphadenectomy.11 23–25 Therefore, sentinel lymph node dissection is now considered standard of care for patients with unilateral tumors smaller than 4 cm without clinically or radiologically suspicious groin nodes. However, sentinel lymph node dissection is not recommended for tumors larger than 4 cm, multi-focal tumors, cases where representative injection is not possible, tumors that encroach the vagina, urethra or anus, or where there is clinical or radiological suspicion of metastatic spread.11
It is important that the differences found between the two incisions performed in this review are interpreted with caution. The review is limited by its retrospective nature, comparison of only three surgeons performing different incisions in one center, and small sample size. Additionally, other factors related to surgical technique such as drains and wound closure technique probably also contribute to complications. Despite this, the review does highlight the implications of variable practice in this area of gynecology oncology. We believe that although vulvar cancer is relatively rare, efforts should still be made to build a strong evidence base on which to practice. A larger retrospective review of several centers is suggested to determine differences in outcomes between surgical incisions.
References
Footnotes
Twitter @drsadiejones
Contributors SEFJ was responsible for design, data collection, data analysis and write up of this project.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available upon reasonable request. Data are available upon reasonable request.