External Beam Radiation Therapy (EBRT) for Neuroendocrine Neoplasms

Disclaimer: The information in this section is for education only and does not represent a standard care pathway or service. These treatments are not suitable for everyone, and careful patient selection by an experienced multidisciplinary team is essential. Always discuss your individual situation with your own specialist team.

External Beam Radiation Therapy (EBRT) uses high‑energy beams to damage cancer cells. In Neuroendocrine Neoplasms (NENs), it’s used selectively depending on tumour type, location, grade, and the overall treatment plan.

EBRT is an established medical treatment with roots dating back to the late 19th century, but modern EBRT is far more precise than older techniques, and new technologies now allow safe treatment of tumours that were previously difficult to target.

There is evidence via some studies (and anecdotally in my patient group) that EBRT has been used to treat patients with NETs (including Grade 3), Its use is infrequent indicating that patient selection is an important criterion, perhaps access to treatment too.

Note: This post only covers EBRT, which uses machines outside the body to target tumours. It should not be confused with Peptide Receptor Radionuclide Therapy (PRRT) which is a totally different type of radiotherapy delivered internally via a cannula. You can read more about PRRT by clicking here. Radiation therapy and radiotherapy are largely interchangeable terms, both referring to the use of high-energy radiation to treat cancer, though some distinctions exist in scope and delivery methods.

How does EBRT work?

It’s important to understand the layers of EBRT:

– the technique,
– the platform,
– the imaging guidance.

One of the reasons I include these distinctions is because the these terms get used interchangeably, particularly inside patient support groups where a patient/caregiver uses the technique or the platform in different contexts, i.e. ‘synonym soup’.

a. Radiotherapy techniques

These describe how the radiation dose is delivered.

IMRT / VMAT — shape the radiation beam to match the tumour while sparing nearby organs.
SBRT (Stereotactic Body Radiotherapy) — very precise, high‑dose treatment delivered in a small number of sessions. Effective for bone, lung, liver, and some adrenal NETs.
Adaptive radiotherapy — the plan is adjusted daily based on that day’s anatomy. Useful for tumours that move or sit close to sensitive organs.
IMPT (Intensity‑Modulated Proton Therapy) — the proton‑based equivalent of IMRT, used in selected cases.

These techniques can be delivered on different machines depending on the clinical situation.

b. Radiotherapy platforms (the machine that delivers the beam)

These machines generate and shape the radiation beam. They differ in precision, imaging capability, and suitability for soft‑tissue tumours.

Conventional LINAC (linear accelerator) The most common radiotherapy machine worldwide. Delivers high‑energy X‑rays (photons). Suitable for many NEN sites, especially bone, lung, and some liver lesions.
CyberKnife (robotic LINAC) A specialised LINAC mounted on a robotic arm. Delivers photon radiotherapy with sub‑millimetre precision and real‑time X‑ray tracking. Often used for lung, spine, prostate, and selected liver lesions. It is a platform, not a technique — it delivers SBRT rather than replacing it.
MRI‑LINAC (MRI‑guided radiotherapy) Combines a LINAC with real‑time MRI. Allows continuous visualisation of soft tissues and daily adaptive planning. Particularly useful for tumours that move or sit close to sensitive organs — such as pancreatic NENs.
Proton therapy systems Use charged particles (protons) instead of X‑rays. These machines are cyclotrons or synchrotrons, not LINACs. Protons deposit most of their energy at a specific depth (the Bragg peak), reducing dose to surrounding tissues. Best suited to fixed, predictable anatomy (brain, skull base, paediatrics). Less commonly used for mobile abdominal organs like the pancreas.

c. Imaging guidance (how the tumour is seen and tracked)

Imaging determines how accurately the tumour can be targeted.

Cone‑beam CT (CBCT) — standard on most LINACs; good for bone and lung but limited for soft‑tissue organs such as the pancreas or bowel.
X‑ray tracking — used by CyberKnife to follow tumour motion, often with implanted fiducials.
MRI guidance — used on MRI‑LINACs; provides clear soft‑tissue visibility and real‑time tracking. Allows the beam to pause automatically if the tumour moves.

Where EBRT fits in NEN treatment

You won’t find much of this in guidelines but there are studies and suggested use in papers. For example, SBRT is not listed as a standard of care in any major NEN guideline, including NCCN, ENETS, NANETS, or ESMO. This is because radiotherapy plays a selective, rather than central, role in NET management. That said, SBRT is mentioned in the NCCN guidelines in several site‑specific contexts, and there is a growing body of NET‑specific evidence supporting its use in carefully chosen situations.

References:

1. External Beam Radiotherapy in the Treatment of Gastroenteropancreatic Neuroendocrine Tumours: A Systematic Review

2. Several NET Centres discuss the use of EBRT as a treatment e.g. Moffatt – click here

3. The American Cancer Society (ACS) mentions radiation therapy for Lung NETs as an option for those who can’t have surgery. Click here.

4. Some early work on a ‘combo’ treatment using PRRT and EBRT – click here

4. Click here to read a previous compilation of EBRT capability (particularly emphasising the technique SBRT) in Neuroendocrine Neoplasms.

Disclaimer

I am not a doctor or any form of medical professional, practitioner or counsellor. None of the information on my website, or linked to my website(s), or conveyed by me on any social media or presentation, should be interpreted as medical advice given or advised by me.

Neither should any post or comment made by a follower or member of my private group be assumed to be medical advice, even if that person is a healthcare professional. Some content may be generated by AI which can sometimes be misinterpreted. Please check any references attached.

Please also note that mention of a clinical service, trial/study or therapy does not constitute an endorsement of that service, trial/study or therapy by Ronny Allan, the information is provided for education and awareness purposes and/or related to Ronny Allan’s own patient experience. This element of the disclaimer includes any complementary medicine, non-prescription over the counter drugs and supplements such as vitamins and minerals.

General Clinical Trials Disclaimer

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided in the clinical trials document. It’s very important to check the trial inclusion and exclusion criteria before making any contact. If you need questions, the articles here is very useful Questions to Ask About Clinical Trials | Cancer.Net

The inclusion of any trial within this blog should not be taken as a recommendation by Ronny Allan.

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