Regional lymph node status in patients with bladder cancer found to be pathological stage T0 at radical cystectomy following systemic chemotherapy

Study Type - Therapy (case series) Level of Evidence 4 What's known on the subject? and What does the study add? Radical cystectomy with bilateral pelvic lymph node dissection is the gold standard for management of muscle invasive urothelial carcinoma of the bladder. Within the last decade randomized clinical trials have demonstrated that cisplatin-based multi-drug neoadjuvant chemotherapy enhances the overall survival after radical cystectomy in this population. Some experts have suggested that it may be possible to omit radical cystectomy in highly selected patients who exhibit a good clinical response to neoadjuvant chemotherapy. However this approach is predicated on our ability to accurately restage both the bladder (by postchemotherapy transurethral resection) and the regional lymph nodes (via CT). Both clinical staging modalities are known to have limitations and may provide false-negative results. Therefore, bladder sparing after neoadjuvant chemotherapy remains controversial. We reviewed the lymph node status of patients undergoing radical cystectomy with bilateral pelvic lymph node dissection following preoperative chemotherapy at Memorial Sloan-Kettering Cancer Center. We identified two separate groups of patients based on the different clinical Sr adios in which preoperative chemotherapy would be administered: those undergoing surgery after neoadjuvant chemotherapy for cT2-T4aN0 disease, and those undergoing consolidative surgery after definitive chemotherapy for cT4b, N0 or N+ disease. This manuscript defines the rates of lymph node involvement after preoperative chemotherapy in patients who were confirmed to be pT0 at cystectomy. The rate of lymph node involvement in patients achieving pT0 status after neoadjuvant chemotherapy appears to be very low while patients achieving pT0 status after chemotherapy for advanced (cT4bN0 or N+) disease are still at risk for persistent cancer in the regional lymph nodes. However, we do not address the limitations of clinical staging after chemotherapy in these pathologically staged groups of patients and continue to advocate for cystectomy and bilateral pelvic lymph node dissection in all patients with muscle invasive bladder cancer following appropriate chemotherapy. OBJECTIVE • To evaluate the effect of preoperative cisplatin-based chemotherapy on the regional lymph nodes of patients with bladder cancer who attain pathological T0 status in the bladder after chemotherapy followed by radical cystectomy. PATIENTS AND METHODS • Patients who underwent radical cystectomy at MSKCC for urothelial carcinoma of the bladder were retrospectively reviewed. • Those patients achieving pT0 status after preoperative chemotherapy were identified and classified into two groups, those rendered pT0: (i) after receiving neoadjuvant chemotherapy and (ii) after receiving definitive chemotherapy (defined in this case as chemotherapy given for unresectable or regionally metastatic disease). • These two groups were analyzed separately for lymph node status at cystectomy and regional lymph node recurrence. RESULTS • Of 169 pT0 patients, 24 patients (14%) had received neoadjuvant chemotherapy, whereas 17 patients (10%) had received definitive chemotherapy for unresectable or regionally metastatic disease. • No patient rendered pT0 after neoadjuvant chemotherapy had lymph node involvement at radical cystectomy or recurrence within the regional lymph node template. • Among patients with advanced disease rendered pT0 by definitive chemotherapy, 35% had lymph node involvement at radical cystectomy or subsequent recurrence within the dissection template. CONCLUSIONS • Patients achieving pT0 status after receiving neoadjuvant chemotherapy had no evidence of lymph node involvement at cystectomy. • Patients undergoing definitive chemotherapy for advanced disease followed by cystectomy experienced reduced rates of nodal involvement compared to the lymph node-positive rates predicted by preoperative clinical staging. However, there remains a risk of regional lymph node involvement in this group.