Pelvic Lymph Node Dissection Surgery
Pelvic lymph node dissection (PLND) has a role in the treatment of several genitourinary cancers but is most commonly used in bladder cancer and prostate cancer. Others include urethral cancer and penile cancer. PLND has an additional role in the management of gynecologic cancers and other pelvic malignancies. While the anatomic approach is similar, the focus of this article is urologic indications.
History of the procedure
After it had been demonstrated that patients with breast and colon cancer with lymph node metastases could be cured surgically, attempts were made to apply lymphadenectomy to cancers of the pelvic organs. In 1932, Godard and Kaliopoulos reported pelvic lymphadenectomy with total cystectomy for bladder cancer. In 1950, Leadbetter and Cooper also were proponents of pelvic lymphadenectomy with cystectomy for bladder cancer.
The principal urologic indications for PLND occur in bladder cancer and in prostate cancer. Other urologic scenarios in which PLND is performed include selected cases of urethral and penile cancer.
In bladder cancer, pelvic lymph node dissection (PLND) is performed at the time of a radical cystectomy or a partial cystectomy. For these patients, PLND provides staging information and can be therapeutic. Several studies, including by Skinner and Vieweg et al, have confirmed that patients with pelvic lymph node metastases can be cured with PLND during radical cystectomy. However, the curability seemed to hold for organ-confined cancer (pathologic T stage 2) but not for non–organ-confined cancer
The decision to perform PLND for prostate cancer prior to performing radical retropubic prostatectomy is based on the probability of pelvic lymph node metastases.
Pelvic lymphadenectomy in the setting of penile cancer is controversial. However, an argument can be made that PLND is a reasonable therapy for a young patient, given that some evidence shows that pelvic lymphadenectomy may lengthen survival. Adjuvant chemotherapy should also be considered if pelvic lymph nodes are positive.
Primary cancers of the entire urethra or posterior urethra in females and in the bulbomembranous urethra in males are usually associated with invasion and a high incidence of pelvic nodal metastases. Pelvic lymphadenectomy is performed along with exenterative surgery because, occasionally, patients with nodal metastases can be cured.
Urethral carcinoma in male patients is classified into 3 groups based on the location of the lesion: (1) penile, (2) bulbomembranous, or (3) prostatic. Most cases (59%) occur posteriorly and involve the bulbomembranous urethra. Less frequent sites include the penile (33%) and the prostatic (7%) portions. In women, approximately 50% of carcinomas occur in the distal urethra.
Lymphatic metastases in the inguinal lymph nodes typically result from tumor in the anterior urethra, while pelvic lymphatic metastases are associated with posterior urethral tumors. Like its male counterpart, the female urethra has an anterior portion that comprises the distal one third of the urethra and a posterior portion that comprises the remaining proximal two thirds. The distal third drains into the inguinal nodes, and the proximal two thirds empty into the pelvic lymph nodes.
Metastatic prostate cancer that involves the pelvic lymph nodes is generally considered to be incurable with surgery. In such cases, PLND cannot be undertaken as a therapeutic procedure; instead, its purpose is to accurately determine whether the patient would benefit from more aggressive, definitive therapy. Essentially, the PLND is a staging procedure that can prevent the morbidity of a radical prostatectomy in patients unlikely to benefit from the procedure.
Pelvic lymphadenectomy in the setting of penile cancer is controversial. General agreement indicates that the probability of finding positive pelvic lymph nodes is increased in the presence of positive inguinal lymph nodes. Also known is the fact that survival of patients with positive iliac nodes is limited. Therefore, some would argue against PLND for penile cancer.
There are 8-10 external iliac lymph nodes. These receive efferent lymphatics from the inguinal nodes, the lymphatics of the iliac fossa, and the lower anterior abdominal wall and afferent lymphatics from the pelvic viscera
The internal iliac lymph nodes receive afferents from the pelvic viscera. Their efferents pass to the common iliac nodes.
There are 4-6 common iliac nodes whose efferent lymphatics pass to the lumbar nodes.
The lymphatics of the pelvis follow the arteries, and the group of nodes accompanying each is named accordingly: internal iliac, external iliac, and common iliac.