The aim of this analysis was to assess the 5-year tolerance and survival in patients undergoing hypofractionated stereotactic boost after external beam radiotherapy (EBRT) for intermediate-risk prostate cancer.
Between August 2010 and April 2013, 76 patients with intermediated-risk prostate carcinoma were included in the study. A first course delivered 46 Gy using conventional fractionation. The second course delivered a boost of 18 Gy (3x6Gy) within 10 days using stereotactic body radiation therapy (SBRT). Gastrointestinal (GI) and genitourinary (GU) toxicities were assessed according to NCI-CTCAE (v4.0). Secondary outcome measures were overall, biochemical relapse-free, relapse-free survival, PSA kinetics, and patient functional status (urinary and sexual) according to the IIEF5 and IPSS questionnaires.
Sixty (79%) patients were treated by Cyberknife and 16 (21%) by linear accelerator. Median follow-up was 62 months (range, 29-69 months). The cumulative incidence of GU and GI grade ≥2 toxicities at Month 60 after the end of RT was 1.4% (95% CI: 0.1%-6.6%) and 9.3% (95% CI: 4.1%-17.1%), respectively. Biochemical relapse-free and relapse-free survival rates at 5 years were 87.4% (95% CI: 77.1%-93.2%) and 86.2% (95% CI: 75.8-92.3), respectively. The mean (SD) PSA variation within 3 months and 5 years post-RT was -1.20 ng/mL/month (0.79) and -1.30 ng/mL/year (1.05), respectively. There was no significant difference between the IPSS QoL score between inclusion and month 60. For IIEF-5 there was a significant difference between inclusion and month 60 (p=0.005) with a higher proportion of severe/non-interpretable disorders at 60 months.
The results of the trial demonstrate that the EBRT and SBRT combination is well tolerated and yields good efficacy results. These data provide a good basis for comparing EBRT and brachytherapy boost to EBRT and SBRT boost in future prospective studies .
International journal of radiation oncology, biology, physics. 2019 Oct 08 [Epub ahead of print]
David Pasquier, Didier Peiffert, Philippe Nickers, Philippe Maingon, Pascal Pommier, Thomas Lacornerie, Geoffrey Martinage, Emmanuelle Tresch, Eric Lartigau
Centre Oscar Lambret, Academic Department of Radiation Oncology, University Lille II, Lille, France; CRISTAL UMR CNRS 9189, Lille University, M3, Avenue Carl Gauss, Villeneuve-d’Ascq, France. Electronic address: ., Institut de Cancérologie de Lorraine-Alexis Vautrin, Nancy, France., Centre Oscar Lambret, Academic Department of Radiation Oncology, University Lille II, Lille, France., La Pitié Salpêtrière Charles Foix,UPMC, Paris, France., Centre Leon Berard, Department of Radiation Oncology, Lyon, France., Department of biostatistics, Centre Oscar Lambret, Lille, France., Centre Oscar Lambret, Academic Department of Radiation Oncology, University Lille II, Lille, France; CRISTAL UMR CNRS 9189, Lille University, M3, Avenue Carl Gauss, Villeneuve-d’Ascq, France.