Stereotactic Body Radiotherapy in lung cancer and lung metastases patient at Siriraj hospital

Abstract

Stereotactic body radiation therapy (SBRT) or stereotactic ablative radiation therapy (SABR) is a modern advanced radiotherapy technique. Due to its high dosage per fraction, this technique requires more accuracy and precision than the conventional technique. In the thoracic region, there are many indications for SBRT such as early-stage non-small cell lung cancer and oligo-lung metastases. This treatment usually involves and may affect normal tissue of complex organs such as bronchus, heart, lung, vessel, esophagus, spinal cord, chest wall, and brachial plexus. Breathing motion is also considered an essential factor affecting the movement of the tumor and nearby normal organs during treatment which leads to not only underdosage for target tissue, but also causes unnecessary normal tissue damage. To alleviate this, respiratory motion management is necessary for SBRT in lung tumors. There are five respiratory motion management techniques, i.e., envelope technique, breath hold technique, force shallow breathing with abdominal compression technique, gating and tracking motion technique. The application of these techniques depends on the radiotherapy machine between a general linear accelerator with an image-guided radiotherapy system and a dedicated radiotherapy machine for stereotactic radiotherapy. Besides motion management, treatment planning and plan evaluation are also delicate and meticulous processes when treating a patient with the SBRT technique. This article will review the current clinical practice guideline of SBRT in lung tumors with the machines at the division of Radiation Oncology, department of Radiology, Faculty of Medicine, Siriraj hospital.