282P - Predictors of outcomes in patients with clinically lymph node-positive prostate cancer after definitive radiotherapy

Background

Previous studies have suggested that benefits of definitive radiotherapy might be limited to specific patients in clinically lymph node (cN+) prostate cancer (PC). However, beneficial subgroup remains to be elucidated. Thus, this study aimed to analyze survival outcomes and prognostic factors after definitive radiotherapy and androgen deprivation therapy (definitive RT+ADT) in these patients and to define subgroups of patients who would benefit from definitive RT+ADT the most.

Methods

A total of 60 patients with cN1 PC treated with definitive RT+ADT in a single tertiary hospital were accrued. Their clinicopathological variables were analyzed and a new subgroup was identified based on statistically significant variables.

Results

At a median follow-up of 31 months, ADT duration ≥ 24 months (p=0.043, HR= 0.26) and positive biopsy core ≥ 75% (p=0.044, HR= 5.29) showed significant relationships with distant metastasis-free survival. Overall survival showed significant relationships with ADT duration ≥ 24 months (p=0.002, HR= 0.06) and number of lymph node (LN) metastases ≥ 4 (p=0.019, HR= 7.17). For prognostic subgroup analysis, patients were divided into three risk groups: low-risk group (LN metastases < 4 and ADT ≥ 24 months), high-risk group (LN metastases ≥ 4 and ADT < 24 months), and intermediate-risk group (all remaining cases). Three-year actuarial overall survival rates for the low-, intermediate-, and high-risk groups were 100%, 93.3%, and 45.7%.

Conclusions

ADT duration and number of LN metastases were important prognostic factors in patients with cN1 PC receiving definitive RT+ADT, with low-risk cN1 PC patients showing better outcomes than others.

Clinical trial identification

Editorial acknowledgement

English proof by Harrisco.

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.