Extended lymph node dissection may improve survival for patients with bladder cancer

CHICAGO — Extending pelvic lymph node dissection from six fields to 14 may extend RFS and cancer-specific survival for patients with bladder cancer undergoing radical cystectomy, according to the results of a study presented at the ASCO Annual Meeting.

Although researchers observed a trend toward benefit with extended lymph node dissection, the improvement did not reach statistical significance.

“We observed a trend improvement — but no significant improvement — in RFS, cancer-specific survival and OS in favor of an extended lymph node dissection in the intention-to-treat population,” Juergen E. Gschwend, MD, PhD, professor and chair of the department of urology at the Technische Universität München School of Medicine in Munich, Germany, said during a presentation.

Retrospective research has shown the extent of pelvic lymph node dissection for patients with bladder cancer undergoing radical cystectomy may impact survival.

To further evaluate this association, Gschwend and colleagues randomly assigned 375 patients with high-grade T1 or invasive urothelial bladder cancer to receive limited (n = 191) or extended (n = 184) pelvic lymph node dissection. Patients who were treated with neoadjuvant chemotherapy or radiotherapy were excluded; patients who received adjuvant chemotherapy were included in analysis.

Limited pelvic lymph node dissection included six fields: bilateral obturator, internal and external iliac nodes. Extended pelvic lymph node dissection included eight additional fields: bilateral deep obturator fossa, presacral, paracaval, interaortocaval and paraaortal nodes up to the inferior mesenteric artery.

RFS served as the study’s primary endpoint. Cancer-specific survival was a secondary endpoint.

The tumor was locally confined ( pT2 pN0) in 49.6% of patients, and 24% of patients were node positive. The median number of nodes dissected was 19 in the limited group and 32 in the extended group.

A greater proportion of patients in the extended arm achieved 5-year RFS than in the limited arm, but this difference did not reach statistical significance (69.3% vs. 62%; HR = 0.8; 95% CI, 0.54-1.19).

Patients in the extended arm also demonstrated a trend toward improved 5-year cancer-specific survival compared with patients in the limited arm (66.2% vs. 77.5%; HR = 0.7; 95% CI, 0.45-1.1), these data also were not statistically significant.

These data may have been influenced by the study’s ambitious endpoints, inclusion of T1 patients with positive nodes, and a high drop-out rate, Dean F. Bajorin, MD, FACP, medical oncologist and Frederick R. Adler senior faculty chair at Memorial Sloan Kettering Cancer Center, said during discussion portion of the presentation.

“Despite the challenges in terms of the number of nodes, I think this has changed the surgical narrative to [that of] prospective randomized national trials which can provide a platform for future research,” Bajorin said during the “There is benefit in this trial with regard to adjuvant chemotherapy, which has not been seen in randomized trials. This changes the mindset of node dissection from a diagnostic procedure to that of a therapeutic procedure and shows a genuine benefit from more surgery.”– by Nick Andrews

References:

Gschwend JE, et al. Abstract 4503. Presented at: ASCO Annual Meeting; June 3-7, 2016; Chicago.

Disclos ure: Gschwend reports consultant/advisory roles with, and honoraria and travel accommodations and expenses from, Amgen, Astellas Pharma, Bristol-Myers Squibb, GlaxoSmithKline, Janssen, MSD, Novartis, Pfizer and Roche. Please see the abstract for a full list of relevant financial disclosures.