Author: By Lynda Williams, Senior medwireNews Reporter
medwireNews: Initial findings from the STORM trial show no significant difference in acute toxicity between metastasis-directed therapy (MDT) and elective nodal pelvic radiotherapy (ENRT) for men with oligorecurrent nodal prostate cancer.
Piet Ost, from Ghent University in Belgium, explained at the 37th Annual European Association of Urology Congress in Amsterdam, the Netherlands, that although pelvic node recurrences are “increasingly diagnosed” in prostate cancer patients by molecular imaging, “there are no specific treatment recommendations for patients with limited nodal recurrences”.
To investigate further, the PEACE V Consortium investigators designed “the first randomized trial exploring the best treatment modality for oligorecurrent nodal prostate cancer”, the presenter continued.
The open-label, phase II study recruited 190 patients with up to five positive pelvic nodes visible on choline (17%) or PSMA (83%) tracer positron emission tomography (PET) after radical local therapy for prostate cancer.
Overall, 97 were randomly assigned to receive MDT consisting of salvage lymph node dissection (LND) or stereotactic body radiotherapy (SBRT; 30 Gy in three fractions), followed by a 6-month course of androgen deprivation therapy (ADT), while 93 men instead received salvage LND or a focal radiotherapy boost (65 Gy in 25 fractions) plus whole pelvis radiotherapy (45 Gy in 25 fractions) and ADT.
The participants had one (58%), two (26%) or three to five (15%) positives nodes.
The presenter observed that salvage LND was “rarely chosen” in the trial, with just 6% of MDT patients undergoing the procedure.
The secondary endpoint of acute toxicity was assessed using the CTCAE v4.0 grading scale for adverse events of at least grade 2 at baseline, 1 month and 3 months after treatment for 186 of the patients. Genitourinary toxicities included haematuria, urinary urgency, retention or incontinence, or cystitis, while gastrointestinal toxicities comprised diarrhoea, faecal incontinence, proctitis and rectal haemorrhage or pain.
For genitourinary toxicities, the MDT and ENRT patient groups had comparable rates for no increase in acute toxicity from baseline (75 vs 70%) and the development of grade 1 (17 vs 16%), grade 2 (8 vs 12%) and grade 3 (0 vs 1%) events, with no significant difference in the rate of grade 2 or more severe events (0 vs 1%).
Similarly, the majority of patients in the MDT and ENRT groups did not experience a significant increase in gastrointestinal toxicity from baseline (84 vs 75%). There were similar rates for grade 1 (13 vs 21%), grade 2 (3 vs 3%) and grade 3 (0 vs 1%) acute gastrointestinal toxicity and no significant difference for the rate of grade 2 or more severe events (3 vs 4%).
One patient with pre-existing grade 2 incontinence progressed to grade 3 and one patient experienced grade 3 diarrhoea after 3 months of follow-up; both patients were given ENRT.
Piet Ost concluded that “compared to MDT, ENRT does not seem to result in a clinically meaningful increase in acute [genitourinary] or [gastrointestinal] toxicity”.
But he emphasized that “the impact on quality of life and long-term toxicity of the two treatment modalities remain to be evaluated.”
Reference
Ost P, Siva S, Heikkilä R, et al. PEACE V – Salvage treatment of oligorecurrent nodal prostate cancer metastases (STORM): Acute toxicity of a randomized phase II trial. 37th Annual EAU Congress; Amsterdam, the Netherlands: 1–4 July 2022
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