Background: Anatomy of the lymphatic drainage guides the extent of inguinal lymph node dissection in penile cancer.
Objective: To prospectively assess the lymphatic drainage of penile cancer with single-photon emission computed tomography CT (SPECT-CT) and implications for the extent of inguinal lymph node dissection.
Methods: We assessed the lymphatic drainage of 62 patients with at least unilateral clinical lymph node-negative (cN0) status with SPECT-CT at our tertiary referral centre. We evaluated 122 cN0 inguinal basins and compared them to the histopathological outcome. The inguinal regions were divided into ten different Daseler zones on SPECT-CT. The surgical team filled in a corresponding scheme at sentinel node biopsy and sent lymph nodes from each Daseler zone individually for histopathological examination.
Results: SPECT-CT successfully visualized lymphatic drainage in 116 of the 122 cN0 inguinal basins (95.1%). The vast majority of sentinel nodes and all metastatic nodes were located in central and superior inguinal zones, including six metastatic nodes in lateral superior zones. Minimal lymphatic drainage was seen to the inferior Daseler zones and no metastatic deposits were located here. No direct pelvic drainage was observed.
Conclusions: Penile cancer lymphatic drainage is primarily to sentinel in the superior and central zones of Daseler. Colleagues practicing a modified inguinal lymph node dissection as a standard in cN0 patients are encouraged to include all these zones, while the inferior zones can be omitted. This study confirms the absence of lymphatic drainage directly to the pelvic region and supports the practice of omitting pelvic nodes from sentinel node biopsy.
Keywords: Penile cancer; anatomical mapping; inguinal lymph node dissection; lymph node metastases; sentinel node biopsy; single-photon emission computed tomography CT (SPECT-CT).