For vulvar cancer treatment, surgery is often an integral part. Potential procedures, in increasing order of radicality, include wide local excision (WLE), radical partial vulvectomy, and radical complete vulvectomy.
Of these, wide local excision is appropriate only for microinvasive tumors (stage IA) of the vulva. With this excision, also termed simple partial vulvectomy, 1-cm surgical margins are obtained around the lesion. Deep surgical margins measuring 1 cm are also preferred. This deep margin usually corresponds to Colles fascia (Fig. 38-25).
With radical partial vulvectomy (Section 46-25), tumor-containing portions of the vulva are completely removed, wherever they are located. Skin margins are 1 to 2 cm, and excision extends deep to the perineal membrane (Fig. 31-7). Radical partial vulvectomy is typically reserved for unifocal lesions that are clinically confined to the labia majora, labia minora, mons, vestibule, and/or perineum and that have limited involvement of the adjacent urethra, vagina, and/or anus. Moreover, only patients with a solitary tumor that is not too large or too extensive and with an otherwise normal vulva are considered for this vulva-conserving surgery.
A. Vulvar cancer following radiation therapy and in preparation for surgical excision. B. Radical partial vulvectomy. C. Final surgical closure. (Used with permission from Dr. David Miller.)
Radical total vulvectomy (Section 46-26) is a complete dissection of vulvar tissue to the level of the perineal membrane and the periosteum of the pubic rami or symphysis. Adequate margins will generally require an incision in the labiocrural fold that extends down to the fourchette and up over the mons pubis. All intervening subcutaneous tissue is excised. Lesions involving or adjacent to the clitoris may require wider margins cephalad to the mons. Such radical resections are performed for large midline or multifocal vulvar cancers. Flap reconstruction is occasionally needed and described in Section 46-28. Contraindications to a radical complete vulvectomy include poor surgical risk, poor patient compliance, and metastatic disease beyond regional lymph nodes.
Of the three procedures shown in Figure 31-8, the en bloc incision, colloquially termed the butterfly or longhorn incision, has largely been abandoned. It has survival rates equivalent to radical complete vulvectomy but carries significantly greater morbidity.
Types of vulvectomy used in the treatment of vulvar cancer. A. En bloc radical vulvectomy with bilateral inguinofemoral lymphadenectomy. B. Radical complete vulvectomy with bilateral inguinofemoral lymphadenectomy. C. Radical partial vulvectomy with ipsilateral inguinofemoral lymphadenectomy.
This procedure is usually an integral part of surgical cancer staging and accompanies radical partial or radical complete vulvectomy. It is recommended for all vulvar squamous carcinomas that invade deeper than 1 mm on initial biopsy or have a tumor diameter >2 cm regardless of invasion depth (stages IB-IVA). To maximize metastatic disease detection and staging accuracy, surgical evaluation of the groin nodes is recommended. Traditionally, both the superficial inguinal and deep femoral lymph nodes have been removed for evaluation of metastatic disease (Gordinier, 2003). Moreover, lymph nodes may be excised unilaterally or bilaterally. Traditionally, an ipsilateral inguinofemoral lymphadenectomy is performed for a “lateralized” vulvar lesion, namely, one that lies >2 cm beyond the midline. Bilateral node excision is recommended for all lesions within 2 cm of the midline. Aside from acquiring staging information, inguinofemoral lymphadenectomy may also be used to debulk large, cancerous lymph nodes.
Entire steps for lymphadenectomy are described and illustrated in Section 46-27. To summarize, the superficial inguinal lymph nodes lie within the fatty tissue caudal to the inguinal ligament and superficial to the thigh’s fascia lata. This node-containing tissue is dissected free to reach the fossa ovalis. Here, deep femoral nodes are excised from their location medial to and alongside the femoral vein. For these deep nodes, a modified approach preserves the cribriform fascia (portion of fascia lata overlying the fossa ovalis) by removing the deep femoral nodes through the cribriform fascia’s perforations. This modification yields cancer recurrence rates comparable to those obtained following classic inguinofemoral node dissection (Bell, 2000; Hacker, 1983). Advantageously, complication rates of wound breakdown, infection, and lymphedema are significantly decreased (Table 31-4). However, a classic inguinofemoral node dissection on occasion is required to reach these deep femoral lymph nodes. In such cases, the cribriform fascia is transected, lymph nodes are removed, and the sartorius muscle can then be transposed over the femoral vessels. This transposition may reduce the risk of postoperative erosion into the skeletonized femoral vessels if superficial wound dehiscence occurs. However, this transposition does not reduce overall postoperative wound morbidity rates (Judson, 2004; Rouzier, 2003).
TABLE 31-4Postoperative Complications of Inguinofemoral Lymphadenectomy ||Download (.pdf) TABLE 31-4 Postoperative Complications of Inguinofemoral Lymphadenectomy
|Complication ||No. of Events ||Percent of Groins |
Surgical evaluation of the groin nodes has been reported to confer a superior prognosis compared with primary groin irradiation. A phase III randomized controlled trial conducted by the Gynecologic Oncology Group (GOG) showed that patients undergoing primary groin dissection experienced significantly fewer groin recurrences and a better prognosis compared with women receiving groin irradiation (Stehman, 1992b). Furthermore, limiting node dissection to only the superficial inguinal nodes also confers a higher groin recurrence rate compared with historical controls undergoing removal of both superficial and deep nodes (Stehman, 1992a). Higher than acceptable groin recurrence rates have also been described for patients who received primary groin irradiation (Manavi, 1997; Perez, 1993). Thus, in general, both deep and superficial inguinal lymph node removal is recommended to allow for thorough evaluation for nodal metastasis. But, because of groin dissection morbidity, this advantage has been challenged for those with early-stage disease and clinically negative nodes. Namely, recent evidence supports the use of sentinel lymph node biopsy in vulvar lesions <4 cm in diameter and assures a low false-negative rate of undetected nodal metastasis.
Sentinel Lymph Node Biopsy
As another less morbid option, selective dissection of a solitary node or nodes, termed sentinel lymph node biopsy (SLNB), dramatically reduces surgical morbidity yet adequately assesses nodal involvement. Physiologically, the first lymph node to receive tumor lymphatic drainage is termed the sentinel lymph node. Thus, a sentinel lymph node devoid of disease implies absent lymph node metastases within the entire lymph node basin. SLNB is not performed if groin node metastases are clinically suspected.
Currently, both lymphoscintigraphy and isosulfan blue dye techniques are recommended when performing SLNB for vulvar cancer (Levenback, 2008). To begin, intraoperative lymphatic mapping is accomplished by injecting radionuclide intradermally at the tumor border that lies closest to the ipsilateral groin. For midline tumors, both sides of the tumor are injected. A handheld gamma counter aids attempts to identify the sentinel node subcutaneously, and the skin is marked by pen over the strongest signal. Next, isosulfan blue dye is injected at the same tumor border. Last, the groin skin over the prior pen mark is incised approximately 5 minutes later (Fig. 31-9). The tracer and dye are taken up by the specific node that drains the tumor site first. The handheld gamma counter signal may assist in localizing the sentinel node, and/or it can be visually identified by its blue color. Once identified, it is separated and excised from the other nodes within that regional group.
Sentinel lymph node evaluation. A. Blue dye and radiotracer are injected at the tumor periphery. B. Blue dye is taken up by the specific node that drains the tumor site. C. This sentinel node can be visually identified, separated from the other nodes within the regional group, and removed for evaluation.
Several studies have confirmed the accuracy of SLNB to predict vulvar cancer metastasis in the inguinal lymph nodes. One multicenter trial by the GOG reported the sensitivity of this technique was >90 percent and the false negative rate was 2 percent for tumors measuring <4 cm. Patients with tumors measuring ≥2 cm and invading to a depth >1 mm and with clinically negative nodes were included in the study (Levenback, 2012). SLNB for patients with a vulvar lesion that does not involve midline structures but that also does not meet the definition of a lateralized lesion is appealing as it potentially avoids unnecessary groin exploration on one side (Coleman, 2013).
A second study, the GROningen International Study on Sentinel nodes in Vulvar cancer (GROINSS-V), evaluated SLNB for patients with squamous cell cancer of the vulva measuring <4 cm. It too confirmed the predictive value of SLNB. Moreover, this study concluded that the risk of metastasis to additional inguinal lymph nodes increases with sentinel-node metastasis size (Oonk, 2010; Van der Zee, 2008). Last, one ongoing prospective study (GROINSS-V-II) is observing early-stage vulvar cancer patients with a sentinel node metastasis measuring ≤2 mm to see if complete inguinofemoral lymphadenectomy can be safely replaced by adjuvant radiotherapy following vulvectomy.
Microinvasive Tumors (Stage IA)
Within the FIGO system, stage I vulvar cancers are divided into two categories. Stage IA lesions measure ≤2 cm in diameter, are confined to the vulva or perineum, and display stromal invasion ≤1 mm. These lesions, termed microinvasive cancers, reflect a subpopulation in which the risk of inguinal metastasis is negligible (Binder, 1990; Donaldson, 1981; Hacker, 1984). Women with microinvasive stage IA tumors tend to be younger and have multifocal disease associated with HPV. For probable cure, these patients can undergo wide local excision with a 1-cm margin. Lymphadenectomy is not indicated because associated lymph node metastasis is rare.
Patients with early-stage vulvar cancer typically present with T1B and T2 lesions (stage IB and II) of the vulva and clinically negative groin nodes. For stage IB lesions, radical resection of the primary tumor and inguinofemoral lymphadenectomy is recommended. If adequate margins and dissection to the perineal membranes can be achieved, then radical partial vulvectomy offers similar recurrence rates but less morbidity than radical complete vulvectomy (Tantipalakorn, 2009). Because 20 to 30 percent of women with T1 and T2 disease will have diseased nodes, SLNB and/or inguinofemoral lymphadenectomy is performed. As described on page 685, lesion laterality and clinical impression regarding groin involvement guides the decision to perform ipsilateral or bilateral groin dissection.
Stage II cancers are most often managed with a larger radical partial excision. For example, a 4-cm lesion involving the clitoral hood may be managed by an anterior hemivulvectomy and bilateral inguinofemoral lymphadenectomy. Again, reported experience with conservative surgery suggests identical local recurrence rates if 1- to 2-cm surgical margins are achieved (Burke, 1995; Farias–Eisner, 1994; Tantipalakorn, 2009). Occasionally, a radical complete vulvectomy may be required, depending on tumor size and location.
By definition, stage III vulvar cancers include node-positive tumors. Affected patients have T1 or T2 vulvar lesions with regional nodal spread that is not fixed or ulcerated. Most patients with clinically negative nodes have typically undergone a radical partial or complete vulvectomy and inguinofemoral lymphadenectomy. However, in cases where groin nodes are grossly positive and resectable, “nodal debulking” is performed but further nodal dissection is forfeited. This allows adjuvant radiotherapy to treat any residual microscopic disease yet minimize additional groin dissection morbidity. In practice, most women with stage III vulvar cancer are treated with adjuvant radiation therapy directed to both groins and the pelvis.
Efficacy for this was shown in a randomized GOG trial of 114 patients with invasive squamous cell carcinoma of the vulva and diseased groin nodes. Adjuvant radiation to both groins and the pelvic midplane proved superior to extended pelvic node resection. However, 12 percent of women completing radiotherapy still relapsed in the groin and pelvis, and 8.5 percent at distant sites (Homesley, 1986; Kunos, 2009).
Nodal metastasis does not increase the risk of recurrence on the vulva. Hence, adjuvant radiation to the vulva is the treating physician’s decision and guided by margin status, tumor size, and LVSI.
The addition of platinum-based chemotherapy concurrent with radiation therapy stems from treatment of cervical cancer. Also, extrapolation of apparent efficacy in phase II trials of more locally advanced vulvar cancer suggests a role for this for postoperative patients with lymph node metastases (Moore, 1998, 2012). To improve control in both inguinal and pelvic lymph nodes and survival rates, a randomized phase III trial (GOG protocol #185) is currently comparing adjuvant radiation therapy and the combination of radiation plus weekly cisplatin chemotherapy in vulvar cancer patients with positive nodes.
These locally advanced vulvar cancers involve the proximal urethra, proximal vagina, bladder or rectal mucosa, or pelvic bone and may or may not have affected inguinal lymph nodes. With stage IVA vulvar cancers, women occasionally can be treated with radical primary surgery. Much more often, tumor size and location necessitate some form of exenterative surgical procedure to remove the entire lesion with adequate margins. Such unresectable, locally advanced vulvar cancers can be effectively treated with neoadjuvant chemoradiation to drastically minimize the surgical resection required. Two Phase II studies conducted by the GOG have demonstrated the feasibility of this approach using cisplatin regimens (Moore, 1998, 2012). An on-going Phase II trial is currently evaluating the efficacy of cisplatin, gemcitabine, and intensity-modulated radiation therapy (IMRT) for primary treatment of locally advanced squamous cell carcinoma of the vulva. As described in Chapter 28, IMRT offers greater sculpting of radiation delivery to minimize toxicity.
Our current practice is to offer preoperative cisplatin-based chemoradiation to women with inoperable primary tumors or with extensive lesions that would require pelvic exenteration. In cases without fixed groin nodes, pretreatment inguinofemoral lymphadenectomy is performed to determine the need for groin irradiation. If groin nodes are fixed or ulcerated, then primary chemoradiation is administered.
If residual disease remains on the vulva following chemoradiation, then local resection is indicated. If there has been complete clinical response, the primary tumor site undergoes excisional biopsy to confirm pathologic response. Unresected groins that are clinically or radiographically positive 8 weeks after surgery are biopsied by fine-needle aspiration (FNA). If the FNA is positive, a targeted excision of the groin is performed.
In contrast, for stage IVB vulvar cancer, treatment is individualized. A multimodality approach is used to achieve palliation.