The primary objectives when dealing with newly diagnosed penile cancer are complete resection of the primary penile tumor and assessment of the inguinal and pelvic lymph nodes (LNs). The primary site of metastatic spread of penile carcinoma occurs via the regional lymphatic system, first to the inguinal lymph node (ILN) chain and then to the iliac and pelvic LNs. Inguinal metastatic spread can be unilateral or bilateral, and crossover drainage from the right to left groin or vice versa can also occur. Metastatic spread from the ILNs to the contralateral pelvis or from the right to left pelvis, however, has never been reported. There have also been no reports of skip lesions with direct lymphatic drainage from penile tumors to the pelvic LNs. Further spread from the true pelvis to the retroperitoneal LNs is beyond the regional drainage system of the penis and represents systemic metastatic disease.
The presence and extent of regional LN metastases is the single most important prognostic factor in determining the long-term survival of patients with penile cancer. Careful examination of the groin and pelvis through physical examination and cross-sectional imaging, therefore, is essential for appropriate clinical staging. The management of ILNs in patients with normal groins on physical examination is dependent on the stage and grade of the primary penile tumor. Tumors with a low risk of inguinal metastatic spread (~5%) include those that are low grade (G1/G2) as well as pathological stage Tis, Ta, or T1a and no lymphovascular invasion (LVI). Surveillance of ILNs with serial imaging and physical examination is most appropriate in this clinical scenario. For penile tumors that are pathological stage T1b (LVI present), pT2 to pT4, or high grade (G3/G4), the risk of occult metastatic ILN involvement ranges from 20% to 30% in clinically normal groins. Prophylactic bilateral inguinal lymphadenectomy (inguinal lymph node dissection [ILND]) is recommended in cN0 patients with high-risk primary penile tumors because this results in better long-term survival compared with surveillance alone (5-year overall survival [OS], 74% vs 63%, respectively). Additionally, delaying ILND until groins become clinically positive (cN+) may result in worse oncologic outcomes (5-year cancer-specific survival [CSS], 16%–45%).
In patients with unilateral (cN1) or bilateral palpable groins (cN2), the likelihood of ILN disease is much greater (~50%). Whereas in the past antibiotic therapy was given for 4 to 6 weeks to rule out LN enlargement from infectious or inflammatory conditions in questionable cases (i.e., with low-risk primary penile tumors), current guidelines recommend fine-needle aspiration (FNA) with ultrasonography of any clinically suspicious node for an immediate diagnosis. Bilateral ILND is subsequently recommended in cN+ patients and in those with a positive FNA for appropriate disease staging and treatment.
In patients with fixed ILNs (cN3) or bulky disease (≥4 cm), neoadjuvant chemotherapy should be considered followed by ILND in clinically responsive cases. Whereas responders who undergo surgical consolidation can experience a 5-year survival rate as high as 37%, nonresponders do poorly with rapid systemic progression.
Standard Inguinal Lymph Node Dissection
Preoperative Preparation and Patient Positioning
After administration of prophylactic antibiotics, the patient is positioned supine with the legs abducted and the thighs externally rotated. Elastic stockings are placed to the level of the knee, and after the operation, they are extended to the thigh to minimize postoperative lower extremity lymphedema. Venous compression devices are also placed over the stockings to minimize the risk of deep vein thrombosis (DVT). The patient is prepped and draped to visualize the umbilicus, pubic tubercle, anterior superior iliac spine (ASIS), and anterior thigh in the surgical field to provide adequate exposure ( Fig. 133.1 ). A 16-Fr Foley catheter is placed into the bladder.
Several incision techniques have been described, including a Gibson, S-shaped, T-shaped, elliptical, and straight incision parallel to the inguinal ligament. An elliptical incision over the groin with resection of the skin and the superficial layers should be considered when the overlying tissue is broken down by infection or prior therapy or when the overlying skin is involved with disease secondary to direct tumor invasion ( Fig. 133.2 ). For more localized disease, however, we prefer a horizontal incision parallel to the inguinal ligament approximately 2 cm below it ( Fig. 133.3 ). The boundaries of dissection include: the inguinal ligament superiorly, the adductor longus muscle medially, and the sartorius muscle laterally ( Fig. 133.4 ). The floor of the dissection consists of the fascia lata for a superficial dissection and the pectineus muscle for a deep dissection.
Superficial Inguinal Lymph Node Dissection
The skin is incised obliquely from the ASIS to the pubic tubercle 2 cm below and parallel to the groin crease. Skin and subcutaneous tissue flaps are developed about 8 cm superiorly and 6 cm inferiorly to the margins of the surgical boundary ( Fig. 133.5 ). Care should be taken to preserve the superficial blood supply to the flaps, thus minimizing the risk of postoperative skin necrosis, infection, and wound breakdown. Additionally, the skin flap edges should be handled gently; they should be covered with saline-moistened sponges, and grasping of the flap edges with forceps, should be avoided because this could potentially crush and devascularize the tissue.
After the skin incision and subcutaneous tissue dissection, a surgical plane is developed beneath Scarpa fascia ( Fig. 133.6 ). The superior boundary of the ILND is established extending to the level of the external oblique fascia, external inguinal ring, and spermatic cord medially ( Fig. 133.7 ). The superficial fascia and areolar tissue over the inguinal ligament is cleared down to the fascia lata of the thigh, and the superficial inguinal nodes are removed.
Deep Inguinal Lymph Node Dissection
The fascia lata is then incised just below the inguinal ligament along its lateral margin, and the dissection is carried down through the fascia lata overlying the sartorius muscle laterally and the thinner fascia of the adductor longus muscle medially. The deep inguinal nodes are then resected by both blunt and sharp dissection using clips for meticulous control of lymphatic channels in order to avoid a lymphatic leak ( ). The femoral vessels are skeletonized in the femoral triangle, and resection is carried medially to laterally over the femoral vein, artery, and nerve. The cutaneous nerves and branches of the femoral vascular system supplying the overlying subcutaneous tissue are divided for adequate hemostasis, and the motor nerves are preserved. The surgical dissection is continued along the femoral vessels superiorly until the femoral canal is reached. At the level of the saphenofemoral junction, the saphenous vein is ligated as part of this approach.
After superficial and deep ILND is completed, the sartorius muscle can be transposed as a rotational flap by releasing its attachments from the ASIS, providing myocutaneous coverage over the femoral vessels and nerve. The sartorius flap is then sutured to the reflection of the inguinal ligament for support using 2-0 Vicryl interrupted sutures. To prevent a lymphocele formation, all subcutaneous lymphatics at the periphery of the dissection are controlled, and at least one closed-suction Jackson-Pratt (JP) drain is placed under the tissue flaps. The wound is subsequently closed in multiple layers with 2-0 and 3-0 Vicryl sutures, and the muscle and subcutaneous tissues are reapproximated to obliterate any potential dead space. This can minimize the risk of a postoperative fluid collection (i.e., seroma) that may serve as a potential source for infection. The skin incision is closed with staples or a running 3-0 Monocryl subcuticular stitch. If the skin edges do not reapproximate easily or if they are nonviable, a split-thickness skin graft is applied instead.
Immediately after surgery, ambulation is strongly advised. Patients are only typically maintained on bed rest for 48 to 72 hours postoperatively if a myocutaneous or other large skin flap is used. The JP drain(s) is removed when there is minimal residual output (<30–50 cc/day over consecutive shifts). It is also important in the perioperative period to maintain patients with a history of DVT or pulmonary embolism (PE) on low-molecular-weight heparin (~28 days) as soon as it is determined that this is safe from a minimal postoperative bleeding risk standpoint to minimize occurrences of thromboembolic events.
Modified Inguinal Lymph Node Dissection
In 1988, Catalona described a modified lymphadenectomy in patients with clinically normal groins but a high-risk primary penile tumor. A shorter skin incision is used, and the area of dissection is limited superomedially. Dissection is not carried lateral to the femoral artery or caudal to the fossa ovals. Additionally, the saphenous vein is preserved, and no muscle flap transposition is performed ( Fig. 133.8 and ). By targeting the superomedial quadrant of the inguinal region, this approach can maintain desired oncological control (because this is the most frequent site of ILN metastasis) and decrease the morbidity associated with the operation by limiting the length of the incision, the amount of surgical dissection, and the amount of the locoregional lymphatic drainage of the lower extremities that is disturbed. It is important to note, however, that the authors recommend each LN package be sent for frozen section analysis using this modified technique, and if any positive LNs are found on frozen section, proceed with a standard ILND.