Brachytherapy is a type of radiation used to treat cancer. It uses a type of energy, called ionizing radiation, to kill cancer cells and shrink tumors.
Unlike external beam therapy (EBT), in which high-energy x-ray beams generated by a machine are directed at the tumor from outside the body, Brachytherapy involves placing a radioactive material directly inside the body.
Brachytherapy is used to treat cancers throughout the body, including cancers in organs such as the Prostate, Cervix, Head and neck, Ovary, Breast, Gallbladder & bile duct, Uterus & uterine cervix, Vagina, Esophagus, Bronchus, Eye, Brain, etc.
Brachytherapy is probably one of the best forms of conformal radiation therapy. The main advantage is that as the radiation source is within the tumor, it is possible to deliver a high dose of radiation to the tumor with very minimal or insignificant doses to the surrounding normal structures in the body. This approach reduces the risk of damage to healthy tissue and increases the likelihood of destroying the tumor. As the dose to the normal tissues is very minimal, large single doses of radiation can be delivered without any morbidity. Hence, the entire course of radiation can be delivered in a very short time. While conventional external radiotherapy takes 6-8 weeks for completion, brachytherapy delivers the entire course of radiation within just a few days. This causes immense benefit to the patients in terms of time and other resources.
Types of Brachytherapy
In permanent brachytherapy, also called seed implantation, needles that are pre-filled with the radioactive seeds are inserted into the tumor. The needle or device is then removed, leaving the radioactive seeds behind. X-rays, ultrasound or CT scans may be used to assist the physician in positioning the seeds. Additional imaging tests may be done after the implantation to verify seed placement.
In temporary brachytherapy, a delivery device, such as a catheter, needle, or applicator, is placed into the tumor using fluoroscopy, ultrasound or CT to help position the radiation sources. The delivery device may be inserted into a body cavity such as the vagina or uterus (intracavitary brachytherapy) or applicators (usually needles or catheters) may be inserted into body tissues (interstitial brachytherapy).
Depending upon the site and the stage of the tumor, brachytherapy can be used as the sole modality of treatment or in combination with external radiotherapy or surgery.
In certain early tumors, like that of head and neck cancers and prostate cancers, it is an alternative to radical surgery and external radiotherapy. In properly selected cases, it offers high cure rates with very minimal side effects.
Both LDR and HDR Brachytherapy is feasible in organ confined(early) prostate cancer. This can done as the sole modality of treatment or as a boost after 4-5 weeks of external radiotherapy.
HDR temporary Brachytherapy involves placing very tiny plastic catheters into the prostate gland, and then giving a series of radiation treatments through these catheters. The catheters are then easily pulled out, and no radioactive material is left in the prostate gland. A computer-controlled machine pushes a single highly radioactive iridium seed into the catheters one by one. As the computer can control how long this single seed remains in each of the catheters, we are able to control the radiation dose in different regions of the prostate. We can give the tumor a higher dose, and we can ensure that the urine passage (urethra) and rectum will receive a lower dose. This ability to modify the dose after the needles are placed is one of the main advantages of Brachytherapy over permanent seed implants
Brachytherapy is indeed one of the most sophisticated radiotherapy modality of treatment. In properly selected cases and in experienced hands, the cure rates are very high
Dr. P. Mahadev
Sr. Consultant Radiation Oncologist
Apollo Speciality Hospital Chennai