Dec. 13, 2022
Urothelial carcinoma is the most common type of bladder cancer in the United States. There are two main types of urothelial carcinoma of the bladder: muscle-invasive bladder cancer (MIBC) and nonmuscle-invasive bladder cancer (NMIBC). This distinction depends on whether or not the cancer cells extend into the muscle layers of the bladder wall.
These two types of urothelial carcinoma of the bladder are treated quite differently. Traditionally, MIBC is treated with surgical removal of the bladder, known as radical cystectomy. Radical cystectomy is the most invasive procedure performed in all of urology and is associated with significant complications and patient morbidity. Thus, it is often reserved for patients with only the most aggressive types of bladder cancer. On the other hand, NMIBC is often treated with endoscopic tumor removal, and sometimes with medications delivered directly inside the bladder, called intravesical therapy. However, some patients with NMIBC also receive radical cystectomy for a variety of reasons, including:
- Having an aggressive form of NMIBC associated with high rates of cancer progression.
- Significant symptoms related to the bladder cancer warranting bladder removal.
- Persistent high-grade NMIBC despite multiple attempts at endoscopic resection and intravesical therapies.
What is lymph node dissection?
Radical cystectomy entails three key components: removal of the bladder, urinary diversion to reroute the urinary tract to allow for urinary drainage, and removal of lymph nodes in the pelvis and sometimes lower abdomen, known as lymph node dissection. In patients with MIBC, lymph node dissection has been demonstrated in multiple studies to be associated with improved diagnosis of locally advanced cancer.
Lymph node removal can identify cancer that has spread to the lymph nodes, which can then prompt additional therapies after radical cystectomy. Thus, lymph node removal provides prognostic information for patients with MIBC. Several studies also have suggested that lymph node dissection for MIBC may perhaps be associated with improved cancer control after surgery, which is hypothesized to be related to removal of micrometastatic cancer contained within the pelvic lymph nodes.
National and international bladder cancer guidelines support the role of lymph node removal during radical cystectomy for patients with MIBC. However, the role of lymph node removal during radical cystectomy for patients with NMIBC is less clear. Very few studies have examined the impact of lymph node dissection specifically among patients with NMIBC.
These studies have been either limited in size or limited in the cancer-related outcomes that they assess. In fact, the American Urological Association guidelines provide no guidance around if patients with NMIBC should undergo lymph node removal during radical cystectomy. As a result, a significant proportion of patients across the United States either receive a very limited lymph node removal or, in some cases, no lymph node removal at all.
Role of lymph node removal during radical cystectomy
To help address this gap in scientific knowledge, a team of researchers at Mayo Clinic, led by Abhinav Khanna, M.D., M.P.H., and Stephen A, Boorjian, M.D., formed a collaboration with colleagues from Cleveland Clinic and MD Anderson Cancer Center to examine the role of lymph node dissection during radical cystectomy for NMIBC. The team pooled together its shared experience in radical cystectomy for NMIBC, which included 1,647 patients treated across the three centers over the span of four decades. The researchers found that a greater extent of lymph node removal during radical cystectomy in patients with NMIBC was associated with lower rates of cancer recurrence, death from bladder cancer and death from any cause.
Results of this 2022 study published in The Journal of Urology found that patients with NMIBC who are undergoing radical cystectomy also should receive a lymph node dissection and that lymph node dissection should not be omitted simply because patients do not have MIBC. This research addresses a gap in the existing scientific literature and may provide guidance for surgeons performing radical cystectomy in the NMIBC patient population. Indeed, patients who undergo radical cystectomy for NMIBC at Mayo Clinic often receive extensive lymph node dissections, and this practice is now supported by scientific evidence.
For more information
Khanna A, et al. Role of lymphadenectomy during radical cystectomy for nonmuscle-invasive bladder cancer: Results from a multi-institutional experience. The Journal of Urology. 2022;207:551.
Refer a patient to Mayo Clinic.