Elsevier

Gynecologic Oncology

Volume 127, Issue 1, October 2012, Pages 147-152
Gynecologic Oncology

Impact of the new FIGO 2009 staging classification for vulvar cancer on prognosis and stage distribution

https://doi.org/10.1016/j.ygyno.2012.06.005Get rights and content

Abstract

Objective

In 2009, FIGO modified staging of vulvar cancer — the performance of the new classification relative to the prior system has not been assessed. We sought to investigate the impact of the 2009 FIGO vulvar cancer staging system on stage distribution and prognostic ability of the 2009 sub-stage classifications in a large cohort of uniformly staged cases with long-term followup.

Methods

Patients undergoing surgery for vulvar cancer were identified from 2 institutions (Mayo Clinic and Medical University, Gdansk, Poland) using a similar surgical approach. Inclusion criteria required primary surgery for invasive vulvar cancer for cases with > 1 mm invasion with complete inguinal/femoral lymphadenectomy. The technique of inguinofemoral node dissection used in both institutions was designed to remove both superficial and deep inguinofemoral nodes. A retrospective review was performed and all cases were assigned stage using the 1988 and 2009 FIGO systems after reviewing pathology slides. Cause-specific survival (CSS, death due to cancer) was estimated using the Kaplan–Meier method and compared using the Cox proportional hazards model t for the first 10 years after surgery.

Result

A total of 468 patients met inclusion criteria. Thirty-one percent (n = 155) were down-staged, and 1 case up-staged using 2009 staging. The new system fails to effectively separate 10-yr CSS for stage I and II cases (p = 0.52), while FIGO 1988 failed to separate stages II and III (p = 0.41). We observed a difference in survival for stage I and II cases based on tumor diameter. For smaller stage II lesion (≤ 4 cm vs. > 4 cm) we observed no difference in survival compared to all stage IB cases (p = 0.25) Considering node positive disease, patients with 2009 FIGO stages ΙΙΙA, ΙΙΙB, and ΙΙΙC were not significantly different in terms of CSS (p = 0.17). However, CSS approached significance between patients with extracapsular vs. intracapsular disease (p = 0.072). For stages IIIA and IIIB (excluding extracapsular spread, IIIC), we observed that the number of positive nodes and diameter of lymph node metastasis were not significantly associated with CSS. When comparing bilateral nodal involvement vs. unilateral cases with at least 2 involved nodes, we found no statistical difference in CSS (p = 0.30).

Conclusion

This is the largest cohort study to evaluate the effect and prognostic performance of the new FIGO vulvar cancer staging system. The new staging does not stratify survival between stages I and II and reduces CSS in stage I cases. Our results suggest that lesion size in node negative cases is an important prognostic variable that could be addressed in future staging classifications. Among the node positive cases, the current classification results in slight differences in CSS, primarily between intra- and extra-capsular disease and not according to the number of positive nodes and lymph node metastasis diameter. Finally we observe that bilateral nodal disease does not appear to impact CSS, justifying it being omitted from the 2009 staging system and that separating node positive (2009 stage III) from node negative (2009 stage II) cases is justified.

Highlights

► New FIGO system does not provide an overall improved prognostic ability. ► Tumor diameter is an important factor and is not addressed for stages I and II. ► Number and diameter of LN metastases have limited influence on survival. ► Accurately dropped bilaterality as it does not appear to play a role in outcome.

Introduction

Vulvar cancer is the fourth most common gynecologic cancer and comprises 5% of malignancies of the female genital tract. In the United States, there are approximately 4340 new cases of vulvar cancer and 940 deaths from this disease annually [1]. Surgery is the mainstay of treatment for early stage vulvar cancer and the most important prognostic factor is the regional spread to lymph nodes or other distant metastatic sites [2], [3]. Some studies have shown that the incidence of vulvar cancer appears to be increasing particularly in young women [4], [5]. In 1988 the International Federation of Gynecology and Obstetrics (FIGO) modified the staging system for vulvar cancer to one based upon surgical pathologic factors recognizing the inaccuracy of clinical prediction of lymph node status [6]. The new surgical staging system was shown to be more accurate in assigning patients to their corresponding stage, and the resultant prognostic ability was improved compared to the prior clinical staging [7]. In 2009 the FIGO staging system for vulvar cancer was again revised making substantial changes to stage assignment [8], [9] (Table 1). The primary changes effectively shifted locoregional disease to the lower urethra, vagina or anus to stage II, effectively separating these cases from lymph node positive patients. Additionally, larger size, non-metastatic primary lesions were lumped with smaller lesions into stage I. The latter change could have consequences if tumor diameter is an important risk factor in non-metastatic cases: it would both decrease survival in stage I tumors and also lose an important factor in determine need for ongoing surveillance. Finally, the number of lymph nodes involved, and extent of involvement of nodes were more carefully sub-staged within stage III cases to presumably capture the impact of volume of metastatic disease.

The prime purposes of standardized staging systems are to allow accurate prognostication, identify groups at highest risk of failure, and thus most in need of more aggressive treatments/surveillance, and to compare outcomes across centers and countries. As such the impact of changes in FIGO staging systems should be carefully assessed to see if the new system accomplished those goals better than the prior system. The purpose of this study therefore was to measure the impact on prognostic classification of the new FIGO staging system relative to the 1988 staging in a well staged cohort of patients. A secondary goal was to determine if alternative sub-stage definitions should be considered in future classification systems.

Section snippets

Methods

This was a retrospective study: IRB approval was obtained from both institutions. Eligible cases included invasive squamous vulvar cancer patients who underwent staging surgery from two institutions (Division of Gynecologic Surgery, Mayo Clinic, Rochester, Minnesota and Department of Gynecology, Gynecologic Oncology and Gynecologic Endocrinology Medical University, Gdansk, Poland). Inclusion criteria required cases to have primary surgical management for invasive vulvar cancer to include

Results

A total of 468 patients met inclusion criteria. Cases were performed from 1955 to 1990 (Mayo Clinic, n = 394) and 1998–2008 (Medical University, Gdansk, Poland, n = 74). Fifteen of the cases with lymph node involvement had one missing slide but were staged according to surgical and pathology report reviews which contained sufficient detail for assignment: 6 cases had visible nodal metastases > 5 cm and were classified as having extracapsular spread; 8 cases were described as having multiple

Discussion

In the present study we attempt to show the effects of the new 2009 FIGO staging system for vulvar cancer using a large independent retrospective cohort from 2 centers. We observed that the new system down-stages 31% of cases, with a single case being up-staged due to grossly ulcerated lymph nodes. The new classification has grouped prior 1988 stages I and II into a single stage I, minimizing the effect of size on prognosis when the lesion is confined to the vulva or perineum: our data suggest

Conflict of interest statement

The authors declare that there are no conflicts of interest.

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Accepted for a plenary oral presentation at the SGO 43rd Annual meeting on women's cancer March 24–27, 2012, Austin, Texas.

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