Eur. Urol. 2019 Jul 19
Metastasis-directed Therapy in Treating Nodal Oligorecurrent Prostate Cancer: A Multi-institutional Analysis Comparing the Outcome and Toxicity of Stereotactic Body Radiotherapy and Elective Nodal Radiotherapy.
Abstract
Background
Stereotactic body radiotherapy (SBRT) and elective nodal radiotherapy (ENRT) are being investigated as metastasis-directed treatments in oligorecurrent prostate cancer (PC); however, comparative data are still lacking.
Objective
To compare outcome and toxicity between both treatments. Primary endpoint was metastasis-free survival, adjusted for selected variables (aMFS).
Design, setting, and participants
This was a multi-institutional, retrospective analysis of 506 (SBRT: 309, ENRT: 197) patients with hormone-sensitive nodal oligorecurrent PC (five or fewer lymph nodes (LNs; N1/M1a), treated between 2004 and 2017. Median follow-up was 36 mo (interquartile range 23-56).
Intervention
SBRT was defined as a minimum of 5 Gy per fraction to each lesion with a maximum of 10 fractions. ENRT was defined as a minimum dose of 45 Gy in up to 25 fractions to the elective nodes, with or without a simultaneous boost to the suspicious node(s). The choice of radiotherapy (RT) was at the discretion of the treating physician, with treatments being unbalanced over the centers.
Outcome measurements and statistical analysis
In total, 506 patients from 15 different treatment centers were included. Primary treatment was radical prostatectomy, RT, or their combination. Nodal recurrences were detected by positron emission tomography/computer tomography (97%) or conventional imaging (3%). Descriptive statistics was used to summarize patient characteristics.
Results and limitations
ENRT was associated with fewer nodal recurrences compared with SBRT (p < 0.001). In a multivariable analysis, patients with one LN at recurrence had longer aMFS after ENRT (hazard ratio: 0.50, 95% confidence interval 0.30-0.85, p = 0.009). Late toxicity was higher after ENRT compared with that after SBRT (16% vs. 5%, p < 0.01). Limitations include higher use of hormone therapy in the ENRT cohort and nonstandardized follow-up.
Conclusions
ENRT reduces the number of nodal recurrences as compared with SBRT, however at higher toxicity. Our findings hypothesize that ENRT should be preferred to SBRT in the treatment of nodal oligorecurrences. This hypothesis needs to be evaluated in a randomized trial.
Patient summary
This study investigated the difference between stereotactic and elective nodal radiotherapy in treating limited nodal metastatic prostate cancer. Nodal relapse was less frequent following elective nodal radiotherapy than following stereotactic body radiotherapy, and thus elective nodal radiotherapy might be the preferred treatment.
Related Questions
When do you consider lymphadenectomy vs pelvic lymph node RT in a lymph node recurrence after prior prostatectomy or prostate-only RT?
I typically recommend a modified GETUG P07 (OLIGOPELVIS) treatment paradigm in this setting because I believe it has a favorable toxicity and short term treatment efficacy as well as the best evidence basis at this time. This regimen consists of a fractionated, extended pelvic nodal field with conco...
How would you treat pelvic node recurrence after prior RP and adjuvant XRT prostate bed only?
RT to pelvic nodes to aortic bifurcation, boost positive nodes, plus ADT.
Would you offer salvage radiation in a patient s/p radical prostatectomy with imaging showing local recurrence as well as oligometastatic disease in the pelvis?
For oligonodal regional recurrence, I would treat the entire pelvic nodes and fossa and consider enrollment on RTOG 3506. If oligomet is to pelvic bone, I have rarely treated fossa/nodes/pelvic bone lesion (PET identified) in those wanting to be very aggressive and understanding the lack of data the...
Would you offer PA nodal XRT in a patient with rising PSA and multiple PET positive nodes after previous prostate XRT treatment that is otherwise locally controlled?
This is a great question, and one that is being explored more and more, particularly for young, healthy patients with well-controlled primary disease. In addition, we are seeing more of these patients due to novel developments in imaging that can detect disease at much lower PSA values than before (...