HDR Brachytherapy Plus Stereotactic Ablative Prostate Radiotherapy for Patients With Intermediate and High-risk Prostate Cancer

High-Dose-Rate Prostate Brachytherapy Combined With Stereotactic Ablative Prostate Radiotherapy for Patients Diagnosed With Intermediate and High-risk Prostate Cancer. Phase II Clinical Trial.

Dose escalation is nowadays a standard strategy in radiotherapy for prostate cancer. Besides, it is believed that due to the radiobiology characteristics of prostate cells (low alpha/beta ratio), the delivery of higher radiation doses per fraction could theoretically improve the efficacy of the treatment. In this context, the combination of prostate brachytherapy and external beam radiotherapy (EBRT) has proven to be the most effective method of dose escalation significantly improving disease control in randomized clinical trials. Unfortunately, this strategy is also associated with an increased risk of acute and late adverse events compared to conventional EBRT alone. It has been proposed that this increase in adverse events could be related to the use Low-Dose-Rate (LDR) brachytherapy and that High-Dose-Rate (HDR) brachytherapy (a more modern and accurate procedure) could reduce this risk.

On the other hand, Stereotactic Ablative Radiotherapy (SABR) is a high-precision radiation technique that allows the delivery of higher doses per fraction in fewer sessions, reducing the total treatment time.

The investigators hypothesized that the combination of two highly conformal radiation techniques (HDR brachytherapy and SABR) could be well tolerated, while reducing total treatment time and therefore improving patient quality of life.

This is a single arm Phase II clinical trial designed to test the feasibility, tolerability and impact on quality of life of the combination of High-Dose-Rate prostate brachytherapy and SABR for patients with intermediate and high-risk prostate cancer.

Inclusion Criteria:

• Histologically confirmed diagnosis of adenocarcinoma of the prostate.

• Intermediate or high-risk disease (as per NCCN criteria):

  • Intermediate risk:

• Clinical stage ≤ T2c

• Gleason score 7 and initial PSA ≤ 20 ng/ml.

• Gleason score ≤ 6 and initial PSA > 10 and ≤ 20 ng/ml.

  • High risk,at least one of the following:

• Clinical stage T3a-b.

• Gleason score 8-10.

• Initial PSA > 20 ng/ml.

• Life expectancy of more than 10 years

• Able and willing to complete Expanded Prostate Index Composite (EPIC) end EORTC questionnaires

• Eastern Cooperative Oncology Group (ECOG) of 0 - 2.

• Willing to give informed consent to participate in this clinical trial

• Give competent informed consent to participate in this trial.

Exclusion Criteria:

• Documented nodal or distant metastases.
• Previous pelvic radiotherapy.
• Clinical stage T4.
• Clinical stage T3a or T3b in which the coverture of the extraprostatic disease is not feasible (as deemed by the treating physician).
• Prostate volume > 70 cc (measured on MRI).
• Poor baseline urinary function defined as International Prostate Symptom Score (IPSS) >17
• Contra-indication to radical prostate radiotherapy
• Significant medical co-morbidity rendering patient unsuitable for general anaesthetic