Radiation treatment uses high-energy particles or waves to damage the DNA of cancer cells, which prevents them from growing and dividing. This therapy is highly effective for many types of cancer, but the total time commitment varies significantly depending on the specific method used and the goal of the treatment. The duration can range from a single, short session to a continuous course spanning several months.
Pre-Treatment: The Planning Phase
Before any radiation is delivered, patients must undergo a planning process to ensure the treatment is targeted precisely and safely. This phase begins with a simulation, where a specialized CT scan is performed with the patient lying in the exact position they will be in for every daily treatment. The simulation often takes around one to two hours, as the team creates custom immobilization devices like molds or headrests to ensure stillness and reproducibility.
The simulation scan allows the radiation oncologist, medical physicist, and dosimetrist to accurately map the tumor’s location and shape, along with the surrounding healthy organs. The team calculates the precise angles, shapes, and intensity of the radiation beams needed to deliver the prescribed dose while minimizing exposure to nearby sensitive tissues. This dose calculation and plan design can take up to one or two weeks to complete before the first treatment session can begin.
Duration of Daily Treatment Sessions
The time commitment for a single, daily radiation appointment is short. While the total appointment time may last between 10 and 45 minutes, the actual delivery of the radiation beam is very brief, typically lasting only about one to five minutes.
The majority of the time spent in the treatment room is dedicated to patient setup, not the radiation itself. Radiation therapists use the marks placed during the planning phase, along with daily imaging checks, to position the patient exactly as they were during the simulation. This setup is performed to ensure the beam is aligned to the millimeter.
The Total Treatment Course: External Beam Radiation Therapy Timelines
External Beam Radiation Therapy (EBRT) is the most common form of treatment, and its total duration is governed by fractionation. This principle divides the total prescribed dose into smaller, daily doses, allowing healthy tissues to repair themselves between sessions while cancer cells accumulate lethal damage. Treatment is typically delivered five days a week, Monday through Friday, with weekend breaks.
For treatment delivered with a curative intent, the standard course often lasts approximately five to eight weeks. This duration is required to achieve the high total radiation dose, often between 60 to 80 Gray, necessary to eradicate the tumor while protecting normal tissue. Cancers like prostate, breast, and head and neck often follow these multi-week protocols.
Alternative schedules have emerged for specific situations, offering shorter timelines. Palliative radiation is given to relieve symptoms, such as pain from bone metastases, and often uses a short course, sometimes consisting of a single session or a few treatments delivered over one to three weeks. Advanced techniques like Stereotactic Body Radiation Therapy (SBRT) and hypofractionation deliver a much higher dose per session, allowing the entire course to be completed in just one to five treatments total.
Alternative Timelines: Internal and Systemic Radiation
Treatments that do not use an external beam follow different timelines based on their method of delivery. Internal radiation, known as brachytherapy, places radioactive sources directly inside or next to the tumor. This shortens the treatment time by delivering a high dose locally and eliminates the need for weeks of daily external treatments.
High-Dose Rate (HDR) brachytherapy is often delivered in a few concentrated sessions over one to five days, with each session lasting only 10 to 20 minutes before the radioactive source is removed. Low-Dose Rate (LDR) brachytherapy, such as permanent seed implants for prostate cancer, involves a single procedure lasting about an hour. The seeds remain in the body afterward, delivering a continuous, low dose of radiation over several weeks or months until their radioactivity naturally decays.
Systemic radiation involves injecting or ingesting a radioactive drug that travels through the bloodstream to find and destroy cancer cells throughout the body. The active treatment time is immediate, but patients may need to take special precautions due to the radioactivity. This often involves a short hospital stay of one to two days or isolation at home for a few days to a week until the radiation level falls to safe levels for others.