Radiation Therapy for Prostate Cancer

Radiotherapy (or radiation therapy) and surgery are the cornerstones for treatment of prostate cancer. 

When is radiation therapy an option for treating prostate cancer?

  • Radiotherapy may be used alone in patients with low-risk disease.
  • Radiotherapy may be used following surgery, either immediately in patients with high-risk factors or in those with a rising PSA.
  • Radiotherapy may be used for patients with more advanced disease, typically in conjunction with hormone therapy, and in patients with symptomatic bone metastases.

External radiation


Intensity modulated radiotherapy (IMRT)  conforms the radiation dose to the shape of the target tissues in three dimensions, minimizing radiation to nearby normal tissues, including the rectum and bladder. IMRT has been associated with excellent outcomes with less toxicity than the traditional 3DCRT approach.

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Image-Guided Radiation Therapy (IGRT) With IGRT, a patient is imaged while on the treatment table immediately prior to radiation treatment. By performing advanced imaging before every radiation treatment, the radiation target is precisely adjusted for each episode of treatment. Such adjustments are needed because the position of the prostate may change from day to day due to differences in the amount of air in the rectum and urine in the bladder. Previous techniques required that patients be imaged once at the beginning of treatment and periodically during treatment.

Due to the precision targeting of IGRT on the prostate, the radiation dose can be increased without risking damage to normal surrounding tissues.

IGRT is delivered on a Varian Trilogy, a sophisticated, state-of-the-art linear accelerator equipped with an on-board imager. IGRT is standard for all patients receiving radiotherapy at UC San Diego Health, whether they are receiving radiotherapy as a primary therapy or in combination with other treatment, such as surgery or hormone therapy.

Internal radiation


Brachytherapy for Prostate CancerBrachytherapy, or internal radiation therapy, involves implanting dozens of tiny radioactive seeds in the cancerous prostate. The seeds release radiation for weeks or months, after which they are no longer radioactive. The radiation in the seeds can't be aimed as accurately as external beams, but are less likely to damage normal tissue. Once the seeds have lost their radioactivity, they become harmless and can stay in place indefinitely.

UC San Diego Health uses both low dose rate brachytherapy (LDR) or high dose rate brachytherapy. HDR brachytherapy is typically combined with external bean radiotherapy to treat high risk disease. This technique enables a targeted and biologically effective radiation dose to be delivered to the cancerous prostate.