Prostate-specific membrane antigen (PSMA) position emission tomography (PET)/computed tomography (CT)-based salvage elective nodal radiotherapy (sENRT) yields relatively high survival for patients with prostate cancer lymph node (LN) recurrence, according to a study published online Oct. 10 in the European Journal of Nuclear Medicine and Molecular Imaging.
Paul Rogowski, MD, from University Hospital in Munich, Germany, and colleagues retrospectively examined 100 consecutive patients treated with PSMA-PET/CT-based sENRT for LN recurrence. Due to biochemical persistence or biochemical recurrence (76 and 24 percent, respectively), patients underwent a PSMA-PET/CT scan after radical prostatectomy. Patients were followed for a median of 37 months.
The researchers found that PSMA-PET/CT detected one, two, and three or more LN metastases in 35, 23, and 42 percent of patients, respectively. Overall, 83, 2, and 15 percent had only pelvic, only paraaortic, and pelvic and paraaortic LN metastases, respectively. Cumulatively, a total dose converted to EQD21.5 Gy of 66, 70, 65.1, and 47.5 Gy was delivered to the prostatic fossa, local recurrence (if present), PET-positive lymph nodes, and lymphatic pathways, respectively. In 83 percent of patients, concomitant androgen deprivation therapy (ADT) was administered. Biochemical recurrence-free survival (BRFS) at one, two, and three years was 80.7, 71.6, and 65.8 percent, respectively; the corresponding values for distant metastasis-free survival were 91.6, 79.1, and 66.4 percent. Correlations were seen for concomitant ADT, longer ADT duration (≥12 versus <12 months), and LN localization (pelvic versus paraaortic) with improved BRFS.
“Overall, these results are very promising in comparison to other studies reporting on PET/CT based ENRT with simultaneous integrated boost to macroscopic LN metastases,” the authors write.
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