Radiation therapy (RT) is a common, non-surgical treatment for bladder cancer. This approach uses high-energy rays to destroy cancer cells and is often employed to preserve the bladder, avoiding surgical removal. The precise number of radiation treatments is not fixed and varies based on the specific treatment plan developed by the oncology team. This variability is influenced by the overall goal of the treatment, the cancer’s stage, and whether other therapies, like chemotherapy, are used concurrently. Careful planning ensures the correct dose is delivered to the tumor while minimizing exposure to healthy surrounding tissue.
Goals and Context of Bladder Cancer Radiation
The primary factor determining the number of radiation treatments is the goal of the therapy, which is categorized into either curative or palliative intent. Curative, or definitive, treatment is administered when the cancer is localized, typically for muscle-invasive bladder cancer, with the aim of eliminating the disease entirely. This often forms part of a trimodality approach that includes transurethral resection of the bladder tumor (TURBT) and chemotherapy, with the ultimate goal of preserving the patient’s bladder. A curative approach requires a high total dose of radiation to be effective against the tumor, which translates into a higher number of sessions over a longer period.
Conversely, palliative radiation is used when the cancer is advanced or metastatic, and the goal shifts to managing symptoms and improving the patient’s quality of life. This may involve controlling pain, stopping bleeding in the bladder, or addressing issues with urination caused by the tumor. Palliative treatment schedules are intentionally shorter, using fewer, higher-dose treatments to minimize the overall burden on the patient. For instance, a palliative course might involve as few as one to five treatments, providing rapid relief from symptoms.
Standard Radiation Treatment Schedules (Fractionation)
For patients receiving curative treatment, the total number of sessions is determined by “fractionation,” which involves dividing the total prescribed radiation dose into smaller, manageable daily doses, or fractions. This process allows healthy tissue, like the bladder lining, to repair some of the damage between treatments while still delivering a lethal dose to the cancer cells.
A conventional fractionation schedule for bladder cancer involves treatments administered five days a week. The total duration usually spans approximately six to seven weeks, resulting in a total number of fractions ranging from 30 to 35 sessions. For example, a common conventional protocol is 64 Gray (Gy) delivered in 32 fractions over about six and a half weeks. This regimen is designed to balance tumor destruction with protecting sensitive pelvic organs.
A newer approach is hypofractionation, which uses fewer treatments with a higher dose per session. This shorter schedule is often preferred as it is more convenient for patients and has been shown to be equally effective in many cases. A standard hypofractionated regimen involves delivering 55 Gy in 20 fractions, shortening the overall treatment time to four weeks.
The total radiation dose needed to destroy the tumor remains fixed, but the way it is split into fractions directly dictates the total number of sessions. Studies have demonstrated that this moderately hypofractionated schedule is non-inferior to the longer conventional course in terms of local control and late toxicity.
For palliative care, even more condensed schedules are used, such as three fractions given on alternate days in a single week, or a course of five to six fractions over a few weeks, focusing solely on symptom relief.
Integration with Chemotherapy (Chemoradiation)
In the curative setting, radiation therapy is often paired with chemotherapy in a combination approach known as chemoradiation, which is the standard for bladder preservation. Chemotherapy drugs, such as cisplatin or gemcitabine, act as “radiosensitizers,” making cancer cells more susceptible to the effects of the radiation. This concurrent use maximizes the effectiveness of the radiation without increasing the total radiation dose.
The addition of chemotherapy does not typically change the number of radiation fractions administered; the schedule still follows the 20-fraction or 30-to-35-fraction plan. Chemotherapy is given on specific days during the overall radiation timeline, often involving infusions at the beginning of the radiation course and sometimes again in the middle.
This combined therapy requires careful coordination between the medical and radiation oncology teams. Chemotherapy can increase side effects, such as gastrointestinal or urinary issues. If these become severe, the treatment team may need to schedule a short break in the radiation sessions. Although the planned number of fractions remains constant, these temporary breaks can slightly extend the overall calendar time beyond the initial four to seven weeks.