Radiation Therapy

Radiation therapy is a cornerstone of cancer management that uses ionising radiation to damage tumour DNA, thereby inhibiting malignant cell division and inducing cell death. Treatments may be delivered externally (external beam radiotherapy) or internally (brachytherapy). External beam techniques include conventional two-dimensional fields, three-dimensional conformal radiotherapy (3D-CRT), intensity-modulated radiotherapy (IMRT), stereotactic body radiotherapy (SBRT) and particle therapies such as proton beam therapy. These modalities differ in the manner and precision with which dose is deposited: photons penetrate tissues with a gradual dose fall-off beyond the target, electrons treat superficial lesions with rapid surface dose deposition, and protons exploit the Bragg peak to spare distal normal tissues. Fractionation—dividing the total dose into daily sessions—exploits differences in repair and repopulation between tumour and normal cells. High-dose per fraction regimens (hypofractionation) are widely used in SBRT, while low-dose-rate approaches underpin many brachytherapy applications. Advances in imaging, treatment planning and delivery devices have enabled highly conformal dose distributions that maximise tumour control while mitigating toxicity. Modern practice integrates motion management (for example, respiratory gating or adaptive planning), real-time image guidance and biological modelling to tailor therapy to each patient’s anatomy, tumour motion and radiobiological characteristics.

Research from Nature Portfolio

Elective nodal irradiation in head and neck cancer models was found to deplete the draining lymph‐node reservoir and diminish systemic antitumour immunity. By sparing regional lymphatics during radiotherapy, investigators achieved enhanced priming of CD8+ T cells, reduced regulatory T‐cell expansion and superior control of distal metastases when radiotherapy was combined with immune checkpoint blockade. This work highlights the critical role of lymphatic anatomy in immune‐mediated tumour eradication.

A matrix‐array ultrasound transducer was paired with radiation acoustic imaging to produce real‐time, volumetric maps of dose deposition in phantoms, animal models and, for the first time, a patient with liver metastases. This ionising radiation acoustic imaging approach permits three‐dimensional visualisation of dose as it is delivered, offering unprecedented adaptive feedback to ensure on‐target accuracy and to guide adjustments during treatment.

Consensus recommendations for innovative drug–radiotherapy combinations have been published to accelerate clinical translation. These guidelines advocate adaptive trial designs, incorporation of mechanistic biomarkers, harmonised regulatory frameworks and multidisciplinary collaboration. Their aim is to validate synergistic regimens—particularly immunomodulatory agents used alongside standard radiotherapy—more efficiently and to broaden their application across tumour types.

Radiation Therapy publication trend

The graph below shows the total number of articles in radiation therapy across all publications each year (not limited to Nature Index journals).

Technical terms

Brachytherapy: Internal radiation treatment in which radioactive sources are placed within or adjacent to a tumour, producing a steep dose gradient that spares surrounding tissue.

Bragg peak: The sharp maximum in energy deposition by charged particles (protons or heavier ions) at the end of their range, used to achieve conformal dose delivery.

Conformal radiotherapy: Techniques that shape radiation beams in three dimensions to match the tumour geometry, minimising dose to normal tissues.

Fractionation: Division of the total radiation dose into multiple smaller doses (fractions) delivered over days to weeks, exploiting differential repair between normal and tumour cells.

Intensity-modulated radiotherapy (IMRT): An advanced external beam technique that varies beam intensity across multiple fields to tightly conform dose to complex target shapes.

Motion management: Strategies such as respiratory gating, breath hold or tumour tracking that account for organ motion during treatment delivery.

Stereotactic body radiotherapy (SBRT): Delivery of high-dose radiation in a small number of fractions with submillimetre targeting accuracy, often used for small, well-localised tumours.

Voxel-based dosimetry: Calculation of absorbed radiation dose for each voxel (three-dimensional pixel) in imaging studies, enabling personalised dose–response predictions.

References

1. Principles of Radiation Therapy.
2. Image-guided radiotherapy: from current concept to future perspectives. Nature Reviews Clinical Oncology (2012).
3. Elective nodal irradiation mitigates local and systemic immunity generated by combination radiation and immunotherapy in head and neck tumors. Nature Communications (2022).
4. Real-time, volumetric imaging of radiation dose delivery deep into the liver during cancer treatment. Nature Biotechnology (2023).
5. Clinical development of new drug–radiotherapy combinations. Nature Reviews Clinical Oncology (2016).
6. Voxel-based dosimetry predicting treatment response and related toxicity in HCC patients treated with resin-based Y90 radioembolization: a prospective, single-arm study. European Journal of Nuclear Medicine and Molecular Imaging (2023).
7. Comparison of liver exposure in CT-guided high-dose rate (HDR) interstitial brachytherapy versus SBRT in hepatocellular carcinoma. Radiation Oncology (2021).
8. Magnetic Resonance Imaging-Guided Adaptive Radiotherapy for Colorectal Liver Metastases. Cancers (2021).