EBRT, External Beam Radiation Therapy, is a non-invasive technique for treating prostate cancer. It uses high energy X-ray beams to destroy the cancer cells while sparing a maximum of healthy tissue thanks to advanced technologies such as intensity-modulated radiation therapy (IMRT) or image-guided radiation therapy (IGRT).
EBRT is an option suitable for patients with localised or locally advanced prostate cancer. It is particularly indicated for men at intermediate or high risk and for those with comorbidities that limit a surgical approach.
EBRT requires rigorous planning and precise follow-up to guarantee effectiveness and limit complications.
Pre-treatment assessment
Before staring the radiotherapy a prostate MRI and a simulation scan are carried out to define precisely the target volume. In addition to the daily imaging before each session, fiducial markers (metal markers placed in the prostate) can be used to ensure optimal positioning.
Procedure
Traditionally the treatment was administered in 35 radiotherapy sessions spread over seven weeks. With technological progress, hypofractionated or ultra hypofractionated radiotherapy protocols that reduce the number of sessions from 20 to 5 have become commonplace. The use of devices such as the MRI-Linac, combining radiotherapy and MRI in real time, permits increased precision and promise even shorter treatment periods in the future.
Hospitalisation
The treatment is on an out-patient basis.
Follow-up
The patient can continue normal activities during treatment. Regular monitoring is essential, including PSA tests to assess the treatment effectiveness and imaging examinations (MRI, PSMA PET) can be carried out if necessary.
External radiotherapy offers a number of benefits:
- Non-invasive treatment: No surgery is needed.
- Proven effectiveness: Comparable to surgery for local control of the disease.
- Flexibility of protocols : Adaptation to patient’s characteristics and stage the disease has reached
- Increased comfort: Significant reduction in number of sessions thanks to hypofractionation.
Although generally well tolerated, EBRT can have side effects in the short and long term.
Urinary and digestive effects
Temporary irritations of the bladder and rectum can lead to a frequent desire to urinate, burning sensation when urinating or intestinal disorders. These effects are generally temporary but in rare cases they can persist (cystitis or radiation proctitis)
Sexual function
In the long term, approximately 20% to 50% of patients may experience erection problems, this depending on age, comorbidities and the use of associated hormone therapy.
Associated hormone therapy
For intermediate or high risk cancers, hormone therapy (equivalent to chemical castration) is prescribed in addition to the radiotherapy (during 6 to 36 months). This combination boosts the effectiveness of the treatment but can cause side effects such as hot flushes, fatigue, loss of libido and reduced muscle mass. These effects bring a need for an adapted follow-up with a recovery that depends on the duration of exposure to hormone therapy
Stereotactic radiotherapy guided by MRI-Linac: a revolution
Stereotactic Body Radio Therapy (SBRT) consists of administering higher doses of radiation per session, making it possible to reduce the total number of sessions while maintaining an equivalent effectiveness. This approach is particularly pertinent for prostate cancer as it is an organ that is insensitive to conventional fractionation. The development of MRI-Linac devices, combining high precision radiotherapy and MRI in real time, represents major progress. These devices allow the prostate and its movements (due to breathing or the urinary function) to be visualised during the treatment, guaranteeing optimal targeting while reducing the necessary safety margins
Traditionally administered in 35 sessions, prostate radiotherapy has already seen a significant reduction thanks to standard hypofractionated radiotherapy protocols (20 sessions) and ultra hypofractionated radiotherapy protocols (5 sessions). This progress is based on a better understanding of prostate radiobiology and technological innovations.
With MRI-Linac this trend is being reinforced: imaging in real time minimises the margins, thereby reducing the exposure of healthy tissue. This opens the door to even shorter treatment periods, with experimental protocols of just two sessions. These reduced formats reduce constraints for patients and could improve access to treatment while at the same time reducing costs for the health service.