Intraoperative radiation therapy (IORT) is single dose of focused radiation therapy delivered at the time of surgery.
Brachytherapy is an internal form of radiation therapy and is considered the most conformal (focused/precise) technique.
Brachytherapy when use intraoperatively becomes further focused and spot on.
In cancer treatment, there are several indications of using IORT, with the commonest being
- Recurrent lymph node within the region previously treated with radiation therapy. These lymph nodes can be in neck, axilla (arm pit) or abdomen.
- Recurrent cancer in primary (or site of origin of cancer) where either previously radiation has been done or in sites where it’s difficult to get surgical margins clear at microscopic level (at the level of cells). Common cancers where it is used are rectal cancer, mouth cancers and some pediatric cancers.
Pre-operatively patient is jointly evaluated by Surgical and Radiation Oncologist in OPD to take decision regarding need for IORT.
Surgery is done in a special OT with brachytherapy machine in Operation theatre. After surgical removal of tumour, IORT applicator is placed and secured (stitched) to tumour bed (region from where tumour is removed). A quick IORT brachytherapy plan is generated depending on size of applicator and radiation dose to be delivered (generally takes 10 minutes). After planning IORT applicator is connected to brachytherapy machine and radiation therapy is delivered usually over 20-30 minutes. Brachytherapy applicator is then removed and surgical oncologist completes surgery.
IORT with Brachytherapy is the most focused and precise form of radiation therapy as its penetration is only about a centimeter deep to where applicator is placed.
It gives high dose to tumour bed with minimum dose to surrounding normal organs.