Journal Article

Intensity-modulated radiotherapy for prostate cancer with seminal vesicle involvement (T3b): A multicentric retrospective analysis

Castelli, Joel, Pasquier, David, Hervé, Chloé, Goupy, Flora, Martinage, Geoffrey, Supiot, Stéphane, Latorzeff, Igor, de Crevoisier, Renaud, Monpetit, Erik, Schick, Ulrike, Le Proust, Bernadette

2019

Overview

No study has reported clinical results of external-beam radiotherapy specifically for T3b prostate cancer. The possibility of escalating the dose to the involved seminal vesicles (ISV) while respecting the dose constraints in the organs at risk is thus so far not clearly demonstrated. The objective of the study was to analyze the dose distribution and the clinical outcome in a large series of patients who received IMRT for T3b prostate cancer. This retrospective analysis included all patients who received IMRT and androgen deprivation therapy for T3b prostate cancer, between 2008 and 2017, in six French institutions, with available MRI images and dosimetric data. A total of 276 T3b patients were included. The median follow-up was 26 months. The median (range) prescribed doses (Gy) to the prostate and to the ISV were 77 (70-80) and 76 (46-80), respectively. The dose constraint recommendations were exceeded in less than 12% of patients for the rectum and the bladder. The 5-year risks of biochemical and clinical recurrences and cancer-specific death were 24.8%, 21.7%, and 10.3%, respectively. The 5-year risks of local, pelvic lymph node, and metastatic recurrences were 6.4%, 11.3%, and 15%, respectively. The number of involved lymph nodes (≤ 2 or ≥ 3) on MRI was the only significant prognostic factor in clinical recurrence (HR 9.86) and death (HR 2.78). Grade ≥ 2 acute and 5-year late toxicity rates were 13.2% and 12% for digestive toxicity, and 34% and 31.5% for urinary toxicity, respectively. The dose to the pelvic lymph node and the age were predictive of late digestive toxicity. IMRT for T3b prostate cancer allows delivery of a curative dose in the ISV, with a moderate digestive toxicity but a higher urinary toxicity. Lymph node involvement increases the risk of recurrence and death.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Adult / Aged / Aged, 80 and over / Analysis / Androgen Antagonists - adverse effects / Androgen Antagonists - therapeutic use / Androgens / Bioengineering / Biology and Life Sciences / Biopsy / Bladder / Cancer / Cancer therapies / Care and treatment / Chemoradiotherapy / Death / Deprivation / Digestive System Diseases - chemically induced / Digestive System Diseases - diagnosis / Dose-response relationship / Human health and pathology / Humans / Life Sciences / Lymph nodes / Lymph Nodes - drug effects / Lymph Nodes - radiation effects / Lymphatic system / Magnetic resonance imaging / Magnetic Resonance Imaging - methods / Male / Medical imaging / Medicine and Health Sciences / Metastases / Middle Aged / Mortality / Nodes / Nuclear medicine / Organs / Patients / Prostate - diagnostic imaging / Prostate - drug effects / Prostate - radiation effects / Prostate cancer / Prostatic Neoplasms - drug therapy / Prostatic Neoplasms - radiotherapy / Radiation Injuries - diagnosis / Radiation Injuries - etiology / Radiation therapy / Radiotherapy / Radiotherapy Dosage / Radiotherapy, Intensity-Modulated - adverse effects / Radiotherapy, Intensity-Modulated - methods / Rectum / Research and Analysis Methods / Retrospective Studies / Seminal vesicle / Seminal Vesicles - diagnostic imaging / Seminal Vesicles - drug effects / Seminal Vesicles - radiation effects / Toxicity / Treatment outcome / Urology and Nephrology