Radiation therapy (RT) is a common and effective treatment modality for prostate cancer, using high-energy rays to damage cancer cells while minimizing harm to surrounding healthy tissues. The total length of time a patient spends in active treatment can vary dramatically, ranging from a single day to over two months. This wide variance is entirely dependent on the specific delivery method chosen by the care team, which is tailored to the tumor characteristics and the patient’s overall health. Understanding the duration of each option is key to managing expectations and planning around the treatment schedule.
The Necessary Preparation and Planning Phase
Before any radiation dose is delivered, a comprehensive preparation and planning phase must occur, which typically spans one to two weeks. This process begins with an initial consultation to review the patient’s diagnosis, medical history, and overall goals for treatment. The next step is a simulation appointment, often a computed tomography (CT) scan, performed while the patient is positioned exactly as they will be for every treatment session.
During this simulation, the radiation team may place tiny, non-radioactive markers, called fiducials, directly into the prostate gland to help precisely track its movement during future treatments. The patient may also be asked to follow specific instructions, such as maintaining a full bladder or empty rectum, to ensure the prostate is in a consistent position and to protect nearby organs. Following the simulation, medical physicists and dosimetrists use the collected imaging data to create a treatment plan, calculating the exact radiation dose distribution and beam angles, a process known as dosimetry.
Traditional External Beam Radiation Schedules
The longest course of treatment is the traditional approach, known as conventional fractionation, which uses external beam radiation therapy (EBRT) like Intensity-Modulated Radiation Therapy (IMRT). This method delivers a small, consistent daily dose of radiation, typically between 1.8 and 2.0 Gy (Gray). This prolonged schedule allows normal, healthy tissues near the prostate, such as the bladder and rectum, time to repair themselves between treatments.
A full course of conventional EBRT typically requires 39 to 45 individual treatment sessions, delivered five days a week. The total duration for this treatment schedule is approximately eight to nine weeks. Although the daily treatment itself only takes a few minutes, patients must commit to attending the clinic five days a week for over two months.
Accelerated and Hypofractionated Treatment Courses
Modern treatment advancements allow for significantly shorter schedules through hypofractionation, which delivers a higher dose of radiation per session. This is possible because prostate cancer cells are more sensitive to larger doses of radiation compared to surrounding healthy tissues. This understanding has led to two main accelerated approaches that reduce the total number of visits.
Moderate Hypofractionation
Moderate hypofractionation involves delivering a slightly larger dose per fraction, reducing the overall number of sessions to between 20 and 28. This compresses the entire treatment course into four to six weeks, nearly cutting the traditional treatment time in half. For suitable patients, this accelerated schedule has been shown to be equally effective in controlling the cancer while offering logistical benefits.
Ultra-Hypofractionation (SBRT)
The most condensed external beam schedule is ultra-hypofractionation, often delivered using Stereotactic Body Radiation Therapy (SBRT). SBRT uses highly focused, intense beams to deliver a very high dose of radiation in just a few sessions. This approach is typically completed in only four to five treatment sessions spread over one to two weeks, representing the shortest external beam option. This rapid schedule is increasingly becoming a standard option for patients with low- or intermediate-risk disease.
Internal Radiation Therapy (Brachytherapy)
Internal radiation therapy, known as brachytherapy, places radioactive sources directly inside the prostate gland, offering highly localized treatment.
Low-Dose-Rate (LDR) Brachytherapy
LDR brachytherapy involves the permanent implantation of tiny, rice-sized radioactive seeds into the prostate during a single procedure. The active treatment time for the patient is limited to this one procedure, which typically lasts less than 90 minutes and is often performed on an outpatient basis. These permanent seeds emit radiation continuously over several months, with the majority of the dose delivered within the first few months before the radioactivity naturally decays.
High-Dose-Rate (HDR) Brachytherapy
HDR brachytherapy uses temporary implants to deliver a very high dose of radiation in a short time. HDR treatment typically involves one to five short treatments delivered over one to five days, with the radioactive source removed immediately after each session. HDR is sometimes used as a powerful boost in combination with a shorter course of external beam radiation therapy to maximize the total dose delivered to the tumor.