Efficacy of Local Treatment in Prostate Cancer Patients with Clinically Pelvic Lymph Node-positive Disease at Initial Diagnosis

Background

There is limited evidence supporting the use of local treatment (LT) for prostate cancer (PCa) patients with clinically pelvic lymph node-positive (cN1) disease.

Objective

To examine the efficacy of any form of LT ± androgen deprivation therapy (ADT) in treating these individuals.

Design, setting, and participants

Using the National Cancer Database (2003–2011), we retrospectively identified 2967 individuals who received LT ± ADT versus ADT alone for cN1 PCa. Only radical prostatectomy (RP) and radiation therapy (RT) were considered as definitive LT.

Intervention

LT ± ADT versus ADT alone.

Outcome measurements and statistical analysis

Instrumental variable analyses (IVA) were performed using a two-stage residual inclusion approach to compare overall mortality (OM)-free survival between patients who received LT ± ADT versus ADT alone. The same methodology was used to further compare OM-free survival between patients who received RP ± ADT versus RT ± ADT.

Results and limitations

Overall, 1987 (67%) and 980 (33%) patients received LT ± ADT and ADT alone, respectively. In the LT ± ADT group, 751 (37.8%) and 1236 (62.2%) patients received RP ± ADT and RT ± ADT, respectively. In IVA, LT ± ADT was associated with a significant OM-free survival benefit (hazard ratio = 0.31, 95% confidence interval CI] = 0.13–0.74, p = 0.007), when compared with ADT alone. At 5 yr, OM-free survival was 78.8% (95% CI: 74.1–83.9%) versus 49.2% (95% CI: 33.9–71.4%) in the LT ± ADT versus ADT alone groups. When comparing RP ± ADT versus RT ± ADT, IVA showed no significant difference in OM-free survival between the two treatment modalities (hazard ratio = 0.54, 95% CI = 0.19–1.52, p = 0.2). Despite the use of an IVA, our study may be limited by residual unmeasured confounding.

Conclusions

Our findings show that PCa patients with clinically pelvic lymph node-positive disease may benefit from any form of LT ± ADT over ADT alone. While not necessarily curative by itself, the use of RP or RT could be the first step in a multi-modality approach aiming at providing the best cancer control outcomes for these individuals.

Patients summary

We examined the role of local treatment for clinically pelvic lymph node-positive prostate cancer. We found that the delivery of radical prostatectomy or radiation therapy may be associated with an overall mortality-free survival benefit compared with androgen deprivation therapy alone.