Influence of concomitant distant lymph node metastases in metastatic hormone-sensitive prostate cancer patients with bone metastases

Introduction: Most patients with metastatic hormone-sensitive prostate cancer (mHSPC) are burdened by bone metastases. However, the impact of concomitant distant lymph node metastases at diagnosis in these patients is unknown. Materials and methods: We relied on the FRAMCAP database (FRAnkfurt Metastatic Cancer database of the Prostate) to compare time to metastatic castration-resistant prostate cancer (mCRPC) and overall survival (OS) between M1b vs. M1a+b mHSPC patients. Univariable and multivariable Cox regression models were applied. Results: Among 432 patients, 64% harbored M1b vs. 36% M1a+b mHSPC. PSA was significantly higher in M1a+b vs. M1b patients (81 vs. 44 ng/ml, p<0.05), as well as rates of LATITUDE high-risk (76% vs. 55%) and CHAARTED high-volume disease (70% vs. 50%) (both p<0.001). Regarding time to mCRPC, median time to CRPC was 26 vs. 16 months for M1b vs. M1a+b patients (hazard ratio [HR]: 1.6, p<0.01). Regarding OS, median OS was not significantly different, with median OS of 53 vs. 47 months for M1b vs. M1a+b patients (p=0.9). After controlling for patient and tumor characteristics in multivariable Cox regression analyses, concomitant lymph node metastases were not an independent risk for shorter time to CRPC or OS in patients with bone metastases (both p>0.15). Conclusion: Patients with concomitant distant lymph node metastases in mHSPC with bone metastases (M1a+b) harbor more unfavorable baseline cancer characteristics relative to M1b without lymph node metastases, translating into significantly shorter time to mCRPC. However, after controlling for patient and tumor characteristics, neither time to mCRCP nor OS seems not be affected by concomitant lymph node metastases.