Pelvic lymph node irradiation for prostate cancer: who, why, and when?

Prostate cancers are best characterized by their clinical (TNM) stage, Gleason score, and serum prostate-specific antigen (PSA) level. These 3 factors are known to influence the risk of pelvic nodal involvement. By combining these prognostic factors, nomograms and equations have been developed and are widely used in clinical practice as an accurate way of predicting the probability of a given pathological stage. Patients who have a significant risk of pelvic nodal metastasis will likely have higher biochemical failure rates. Results from the multi-institutional prospective trials have shown that patients at an intermediate to high risk for pelvic nodal involvement experience disease progression-free survival benefits from the use of whole pelvic radiotherapy combined with hormone therapy. Yet, significant biological interactions between radiation treatment volumes and timing of hormone therapy have been shown. Further study of these issues is necessary to define the best treatment for patients at significant risk of pelvic lymph node involvement.