Sentinel lymph node biopsy using dynamic lymphoscintigraphy combined with ultrasound-guided fine needle aspiration in penile carcinoma

Abstract

The purpose of this study was to assess the utility of sentinel lymph node lymphoscintigraphy (SLNL) and ultrasound-guided fine needle aspiration cytology (FNAC) in patients with penile carcinoma. A prospective study was undertaken of 64 patients with stage T1 (or greater) clinically N0 squamous cell carcinoma of the penis. Patients underwent SLNL and bilateral groin ultrasonography with or without FNAC. Following intradermal blue dye, patients underwent unilateral or bilateral sentinel lymph node excision biopsy (SNB). 17 patients had sentinel nodes that contained metastases (21 nodal basins). Lymphatic drainage was demonstrated in all patients by lymphoscintigraphy. Bilateral drainage was seen in 57/64 patients. 61/64 patients had ultrasonography of the inguinal basins on the same day as FNAC of 38 basins. FNAC showed malignancy in eight basins. FNAC was negative in six basins, which were subsequently shown to be positive following SNB. 82 inguinal basins did not warrant FNAC by ultrasound criteria, of which 5 contained metastases at SNB. The sensitivity and specificity of ultrasonography was 74% and 77%, respectively. The positive and negative predictive values were 37% and 94%, respectively. Two patients had a negative initial SNB; however, ultrasonography identified a metastatic node and re-evaluation of the sentinel node confirmed micro-metastases. There has been no evidence of recurrence in any patients with negative SNB (during 6-28 months' follow-up). In conclusion, when investigating clinically stage N0 penile cancer, the combination of SNB and groin ultrasonography, with or without FNAC, identifies accurately those with occult nodal metastases. Ultrasonography alone is not adequate as a staging technique, and SNB alone might miss between 5% and 10% of metastases.

Lymph node metastases and prognosis in penile cancer

“…Bilateral LNM [21] . However, bilateral nodal involvement was presented in about 15% to 54% of all node-positive penile cancer patients in large case series 14 [ , 15,[22][23][24] .…”

“…Nowadays, more and more penile cancer patients with clinical negative lymph nodes were subjected to less invasive staging procedures such as sentinel nodal biopsy, and superficial or modified dissection . [21,[45][46][47][48][49] . Regardless the metastases deposit, extensive dissection is performed if one positive lymph node is found.…”

Update in the management of penile cancer

“…The sentinel lymph node(s) is thus located visually and with a probe. This has been accomplished via an open technique through skin flaps (54) or by first marking the overlying skin after detection of radioactivity (55)(56)(57). A criticism of DSNB is that the false negative rate is a relatively high 15-16% (56,58) with a consequently low sensitivity that has deemed the technique insufficient by some researchers (54).…”

“…These two modalities were used in a complementary fashion in a more recent paper. Sonographic criteria included increased size, abnormal shape, absence of echogenicity in the hilum, hypoechogenicity of the node, necrosis, and abnormal vascularity (57). At a median follow up of 11 months the respective sensitivity and specificity for US compared to DSNB were 74 and 77%; interestingly, US identified two patients with metastasis who were originally considered negative by DSNB (57).…”

Imaging in primary penile cancer: current status and future directions

“…Another prospective study of 64 patients with clinically N0 squamous cell carcinoma of the penis concluded that the combination of sentinel node biopsy and groin ultrasonography, with or without FNAC, is optimal in identifying occult nodal metastases. Ultrasonography alone is not adequate as a staging technique, and sentinel node biopsy alone might miss between 5% and 10% of metastases [26]. In patients with clinically palpable nodes, DSNB has been shown to be less useful due to false negative results as the lymphatics are blocked by the cancer cells [16].…”