What Is SBRT? Benefits, Uses and Eligibility

SBRT, short for stereotactic body radiotherapy, is a way of giving very high doses of radiation to a tumour with pinpoint accuracy, in just one to five sessions instead of weeks of daily treatment. You may also hear it called SABR. Nothing is cut open, and it’s done as an outpatient. It only suits some tumours, though: usually small ones, few in number, and sitting where the beams can reach them safely.

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Dr. Sandeep Nayak, who provides cancer treatment in Bangalore, says patients hear “radiation in one to five sessions” and assume it’s a weaker option. “It’s the opposite. Each session carries a much bigger dose, delivered with very tight precision, and that’s why so few are needed. For an early lung cancer in someone who can’t have surgery, it’s the standard. For someone who can have surgery, we talk it through, because the best choice isn’t automatic. And for a few isolated spots of spread, it can be a way of treating them directly.”

The idea is simple, though the planning behind it is careful:

• A bigger dose, in far fewer visits. Each SBRT session gives a much larger dose than conventional radiation, so the course is one to five sessions, not twenty or thirty.
• Precision does the heavy lifting. You’re positioned in a custom mould, the tumour is mapped on scans, and imaging is repeated before each session. The team also accounts for breathing movement, so the beams follow the tumour while the tissue around it gets far less. Our radiation therapy page explains how planning works.
• No cut, and usually no hospital stay. You lie still while the machine moves around you, and you go home the same day. A session can take a while, because the set-up is so careful, but you won’t feel the radiation itself.
• Side effects are usually mild and depend on where the tumour is. Tiredness and some skin redness are common. Lung treatment can bring a cough or chest wall soreness, and treatment in the abdomen can cause nausea. Rarer, more serious effects exist, which is why you’re monitored afterwards.

SBRT isn’t for everyone, and it works best in a few specific situations:

• Early-stage lung cancer when surgery isn’t possible. It’s the standard treatment for early lung cancer in people who can’t have surgery, and an option for some who choose not to. Our lung cancer treatment in Bangalore page explains the choices.
• A few spots of spread. When cancer has spread to just one to five places, a trial (SABR-COMET) tested treating those spots with SBRT on top of standard care. The results are encouraging, and larger trials are still testing it.
• Other sites too. It’s also used for tumours in the liver, spine and other bones, prostate, adrenal glands, kidney and, in selected cases, pancreas.
• Who qualifies. Usually a small tumour, often under about 5 cm, a limited number of tumours, a position that’s not too close to delicate organs such as the bowel or spinal cord, and general fitness to lie still during treatment.

Two people with the same cancer can be offered different plans. A few things decide it:

• The tumour’s size, number and exact position. A small tumour in a clear spot suits SBRT. One pressed up against the spinal cord or bowel may not.
• The type and stage of the cancer. Whether it’s the only tumour or part of wider spread changes the whole plan.
• Whether surgery is possible, and what you prefer. For some early cancers, surgery and SBRT are both reasonable, and the choice is a shared one.
• Your general health and past treatment. Lung function matters for chest tumours, and radiation you’ve already had in the same area can limit what’s safe to repeat.
• A joint team review. The surgeon, radiation oncologist and medical oncologist should look at your scans together. Our oncology team can walk you through it.

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