Radiation Oncology
Our Radiation Oncology Department combines advanced technology, precision imaging and evidence-based planning to deliver safe, accurate and personalised cancer treatment. All treatments are carried out by a multidisciplinary team, integrating diagnostic imaging, pathology, molecular profiling and patient-specific dose assessments for optimal outcomes.
Modern Radiotherapy Techniques
- IMRT (Intensity Modulated Radiotherapy)
- VMAT (Volume Modulated Arc Therapy)
- IGRT (Image Guided Radiotherapy)
- SRS/SRT (Stereotactic Radiosurgery & Radiotherapy) [Cranial]
- SBRT (Stereotactic Body Radiotherapy)
How do Modern Radiotherapy Techniques optimise cancer outcomes?
- By providing superior toxicity profile in existing successful treatment settings, eg IMRT reduces xerostomia (dryness of mouth) in head-neck cancer
- By enabling superior tumor control in existing treatment settings, eg IMRT & IGRT enable dose escalation in prostate cancer, leading to superior disease control
- By providing disease control solutions in innovative treatment settings, eg SBRT for hepatocellular carcinoma
IMRT
- Is a form of treatment delivery to achieve highly conformal dose distribution, ie treatment dose fits on the target & spares normal tissue as far as possible
- Uses complex dose prescription techniques, called Inverse Planning, whereby the physician is able to specify desired dose-constraints to the target & normal tissues
Parotid dose , xerostomia & IMRT
- With conventional radiotherapy in head-neck cancer, all patients undergo irradiation of parotid glands to a high dose, leading to irreversibly damaged function: this leads to permanent dryness of mouth
- Research has shown Severe xerostomia (<25% of baseline) avoided if mean parotid dose kept to <20Gy (if one parotid is to be spared) or <25 Gy (if both are to be spared)
- IMRT enables parotid sparing and reduces the possibility of long-term xerostomia.
- Thus patients are able to achieve complete recovery of salivary function, facilitating better swallowing & speech functions, hence allowing for a better quality of life
- Research has also established that sparing of the parotid glands does not negatively impact tumor control.
IMRT for prostate cancer
- Radical radiotherapy is the curative option for organ-confined prostate cancer
- Radiotherapy dose escalation has been shown to improve disease control rates
- IMRT allows RT dose escalation while controlling doses to the adjacent anterior wall of the rectum
- Thus, IMRT in prostate cancer enables superior disease control with tolerable toxicity profile (rates of late radiation proctitis, causing bleeding per rectum are <5%)
IMRT & VMAT
- The linear accelerator treatment head has an array of small blocks called Multi-Leaf Collimators (MLCs).
- During IMRT delivery, the MLCs shape the beam aperture in a 1 combination of different irregular shapes. Delivery is comparatively slower at 15-20 minutes.
- VMAT is a more sophisticated form of IMRT, where not only is treatment more focused but it allows comparatively much faster treatment delivery, within 2-2.5 minutes.
- Faster treatment minimises patient movement & maximises comfort.
IGRT
- Image guided radiotherapy is a broad concept whereby frequent imaging is done in the treatment room for more accurate treatment delivery.
- IGRT is mainly to ensure accurate patient positioning and overcoming problems due to organ motion.
- Due to variations in patient setup & organ motion, an extra margin of tissue has to be radiated to deliver adequate dose to the tumor
- IGRT can help us to eliminate or at least, reduce this margin
- This results in much less normal tissue being irradiated to high doses
Stereotactic Radiotherapy
- Refers to extremely accurate localisation of a point in space
- Stereotactic radiotherapy refers to a technique of extremely focused radiotherapy
- It is usually delivered in a small number of fractions (1-5), with large dose/fraction (>4Gy/#), unlike conventional radiotherapy which is delivered in small doses over a long time (1.8-2Gy/#, once a day, 5 days a week for 5-7 weeks).
- Delivering a much higher dose over a shorter course of time, allows the radiation to be more effective biologically.
- The effect of stereotactic radiotherapy is akin to surgery.
- Stereotaxy was first achieved in cranial lesions, many of them benign, eg arterio-venous malformations, craniopharyngeoma, pituitary adenoma & acoustic neuroma
- These all feature treatment of a small target, adjacent to vital areas, to a dose much higher than the tolerance dose of nearby structures.
- Stereotactic radiotherapy is today, also the preferred treatment modality for brain metastases. It has been shown to be equivalent to surgery or whole brain radiotherapy.
- The first machine to deliver stereotactic radiotherapy was the Gamma knife, created by Lars Leksell (a neurosurgeon) in 1961. This machine uses 201 small telecobalt sources.
- Today, cranial stereotaxy can also be delivered by specially equipped linear accelerators (the so-called X-knife)
- Cranial stereotaxy initially was based on physically & invasively fixing a rigid frame to the patient’s cranium.
- The frame was required for the accurate localisation of the target on imaging.
- In the modern day, we have come to use non-invasive frames.
- Use of sophisticated pre-treatment imaging, such as in-room Cone Beam CT, has allowed us to do away with frames altogether.
SBRT
- Also called Stereotactic Ablative Body Radiotherapy (SABR)
- Extracranial stereotaxy has become possible because of Image Guidance in the treatment room
- SBRT is done for tumors of the lung, liver, pancreas, prostate & spine.
- SBRT is the most exciting recent development in lung cancer therapy. Early lung cancers, though rare, are curable by surgery.
However, many such patients have severe COPD & other medical comorbidities, precluding surgery. SBRT has provided an alternative to these patients. It has been shown to be as effective as surgery for localcontrol.
- SBRT to the liver/lung metastases achieves superior local control, as compared to using systemic therapy (chemotherapy) alone
- More feasible than surgery for patients with poorer performance status / with less accessible lesions
Frequently Asked Questions
No. Radiotherapy is not a form of heat and does not burn the body. It uses high-energy X-rays to destroy cancer cells while minimizing damage to surrounding healthy tissues.
Common side effects include skin darkening, skin peeling, mouth ulcers, difficulty swallowing and dry mouth. Most side effects improve within a few weeks after treatment. Dry mouth may persist longer and can take several months to two years to improve.
Patients may experience temporary skin darkening, mild peeling and itching in the treated area. These effects generally resolve within a few weeks after completion of radiotherapy.
Pelvic radiotherapy may cause indigestion, diarrhoea, nausea or vomiting. These symptoms are usually temporary and improve within a few weeks after treatment ends.
Common side effects include nausea, vomiting and low blood counts, which may increase the risk of infection and fever. Patients should immediately inform their healthcare team if they experience fever, persistent vomiting or diarrhoea.
Avoid rubbing the treated area or applying soap, oil or other products unless advised by your doctor. You may bathe normally with water. Staying well hydrated by drinking approximately 2–3 litres of water daily is recommended.
Yes. Patients are advised to use a soft toothbrush, rinse the mouth frequently with a salt-and-soda solution, avoid irritation to the treated area and follow all dietary and oral care instructions provided by the radiation oncology team. Men should avoid shaving over the treatment area and avoid wearing tight collars during treatment.
NABH Accredited Hospital
