Addition of a Focal Boost in External Beam Radiotherapy for Locally Advanced Prostate Cancer by Online Adaptive MR-guided Radiotherapy (AFFIRM)

Radboud University Medical Center

Status and phase: Not yet enrolling; Phase 2

Conditions: Prostate Neoplasm; Prostate Cancer

Treatments: Radiation: Ultrahypofractionated MR-guided radiotherapy boost

Study type: Interventional

Funder types: Other

Identifiers

NCT05373316

NL79869.091.22

Details and patient eligibility

About

The AFFIRM trial tests the safety and clinical feasibility of MR-guided hypofractionated focal boost radiotherapy for patients with locally advanced prostate cancer. External beam radiotherapy combined with androgen deprivation therapy is considered as the treatment of choice for patients with locally advanced non-metastatic prostate cancer with seminal vesicle invasion.The long-term results of the multicentre phase III study (FLAME trial) showed that addition of an isotoxic focal boost to the intraprostatic lesion improves biochemical disease free survival in intermediate to high-risk patients without impacting toxicity and quality of life.

This focal boost strategy is now proven for a conventional fractionation scheme (35 fractions). The current trend in radiotherapy for prostate cancer is (extreme) hypofractionation, reducing the number of fractions. For locally advanced prostate cancer, however, the data on extreme hypofractionation are scarce.

Enrollment: 95 estimated patients

Sex: Male

Ages: 18 to 100 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Men aged 18 years or older with histologically proven prostate carcinoma
• Imaging stage T3b (as defined on mpMRI) N0M0
• Intraprostatic lesion visible on MRI
• Capable of giving informed consent

Exclusion criteria

• History of radiotherapy to the pelvis or transurethral resection of the prostate (TURP)
• Contraindications for MRI according to the guidelines of the local department of Radiology, inability to lay on a treatment table for 45-60 minutes or severe claustrophobia
• Absence of pre-treatment PSMA PET CT
• WHO performance score > 2
• International Prostate Symptom Score ≥ 15
• PSA > 30
• Prostate volume >100c

Trial design

Primary purpose: Treatment

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

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95 participants in 1 patient group

MR-guided hypofractionated focal boost radiotherapy

Experimental group

Description:

External beam MR-guided (MR-linac) radiotherapy to the prostate and seminal vesicles of 5x7Gy (once weekly) with an isotoxic integrated focal boost up to 50Gy to the intraprostatic tumor as visible on multiparametric MR

Treatment:

Radiation: Ultrahypofractionated MR-guided radiotherapy boost