Introduction
Among the most powerful tools available in modern oncology, radiation therapy has helped millions of cancer patients around the world achieve remission, manage symptoms, and improve quality of life. Yet for many patients and families hearing the word “radiotherapy” for the first time, it raises more questions than answers.
What exactly does radiation therapy do to cancer cells? How is it different from chemotherapy? What does the experience actually involve? At Kokilaben Dhirubhai Ambani Hospital, our department of radiation oncology believes that informed patients are empowered patients.
What Is Radiation Therapy?
Radiation therapy, also known as radiotherapy, is a cancer treatment that uses high-energy radiation to damage the DNA of cancer cells, preventing them from dividing and ultimately causing them to die. It is one of the three primary modalities of cancer treatment alongside surgery and chemotherapy, used in more than half of all cancer cases at some point during treatment.
Unlike systemic treatments such as chemotherapy, radiation therapy for cancer is primarily a local treatment, precisely targeting the area where cancer is present while preserving surrounding healthy tissue as much as possible.
How Radiation Therapy Works
Understanding how radiation therapy for cancer functions at a cellular level helps patients appreciate both its effectiveness and its rationale:
- High-energy radiation damages the DNA within cancer cells. DNA is the instruction set that tells cells when to grow, divide, and function
- When DNA is sufficiently damaged, cancer cells lose the ability to divide and reproduce. They may die immediately or become incapable of further replication over time
- Damaged cancer cells are gradually broken down and cleared by the body’s natural processes, a process that continues for weeks or even months after treatment ends
- This is why the full effect of radiation therapy is not immediate. Treatment is typically delivered in multiple sessions over days or weeks to accumulate sufficient damage to cancer cells while allowing healthy tissue to recover between sessions
- The ratio of damage between cancer cells and healthy cells is managed through precise dose planning, fractionation (dividing total dose into multiple smaller sessions), and advanced imaging guidance
Types of Radiation Therapy
The types of radiation therapy available at Kokilaben Dhirubhai Ambani Hospital span the full range of modern radiotherapy techniques, selected based on cancer type, tumour location, size, and patient-specific factors:
- External Beam Radiation Therapy (EBRT) — The most common form of radiation therapy. A machine positioned outside the body directs focused beams of high-energy radiation at the tumour. The machine does not touch the patient and can rotate around the body to deliver radiation from multiple angles
- Intensity-Modulated Radiation Therapy (IMRT) — An advanced form of EBRT that uses multiple beams of varying intensity, allowing a higher dose to be delivered to the tumour while reducing exposure to surrounding healthy tissue. Widely used in head and neck, prostate, and pelvic cancers
- Image-Guided Radiation Therapy (IGRT) — Combines radiation delivery with real-time imaging to account for any movement of the tumour between sessions, improving precision and reducing the margin of healthy tissue irradiated
- Stereotactic Radiosurgery (SRS) and Stereotactic Body Radiation Therapy (SBRT) — Deliver very high doses of radiation in one or a small number of precisely targeted sessions. Used for brain tumours, spinal lesions, lung, liver, and other sites where extreme precision is required
- Volumetric Modulated Arc Therapy (VMAT) — A form of IMRT where the radiation machine rotates continuously around the patient, delivering treatment faster and with greater efficiency while maintaining precision
- Brachytherapy (Internal Radiation Therapy) — A radioactive source is placed directly inside or adjacent to the tumour, delivering a concentrated dose from within. Commonly used in cervical, prostate, breast, and endometrial cancers
- Proton Therapy — Uses protons rather than X-rays to deliver radiation. Protons deposit the majority of their energy at the tumour site with minimal exit dose, reducing radiation to surrounding structures. Particularly beneficial in paediatric cancers and tumours near critical structures
- Systemic Radiation Therapy — Uses radioactive substances administered orally or intravenously that travel to specific cancer cells throughout the body. Radioiodine for thyroid cancer and radiolabelled antibodies for certain blood cancers are established examples
Radiation Therapy Procedure
The radiation therapy procedure at Kokilaben Dhirubhai Ambani Hospital follows a structured, carefully planned pathway:
Step 1 – Consultation and Assessment
- Your radiation oncologist reviews your diagnosis, imaging, pathology, and overall health to determine whether radiation therapy is appropriate and which type is most suitable
Step 2 – Simulation and Planning
- A dedicated simulation session is conducted, usually involving a CT scan and sometimes MRI or PET imaging, with the patient positioned exactly as they will be during treatment
- Immobilisation devices such as custom moulds or masks are created to ensure consistent positioning across all sessions
- The imaging data is transferred to a treatment planning system where the radiation oncologist and medical physicist design a precise dose plan targeting the tumour
Step 3 – Treatment Delivery
- Treatment sessions are typically short, often 15 to 30 minutes, and conducted daily, five days a week, over a course of several weeks depending on the protocol
- Each session begins with imaging verification to confirm precise positioning before radiation is delivered
- The radiation itself is painless. Patients lie still on the treatment table while the machine delivers the planned dose
Step 4 – Monitoring and Review
- Regular clinical reviews are conducted throughout the treatment course to assess response, manage side effects, and adjust the plan if needed
- Blood tests, imaging, and clinical assessments are scheduled at appropriate intervals
Step 5 – Follow-Up Care
- After completing the radiation therapy procedure, patients enter a structured follow-up programme including imaging and clinical assessment to monitor treatment response and detect any recurrence early
When Is Radiation Therapy Recommended?
Cancer treatment radiation therapy is recommended in a range of clinical contexts, determined by the cancer department in collaboration with our multidisciplinary tumour board:
- As primary treatment — For cancers where radiation therapy alone can achieve cure or complete local control, such as early-stage laryngeal, cervical, prostate, and certain head and neck cancers
- Alongside surgery — Before surgery (neoadjuvant) to shrink a tumour and improve resectability, or after surgery (adjuvant) to eliminate residual cancer cells and reduce the risk of local recurrence
- In combination with chemotherapy — Concurrent chemoradiation enhances the effectiveness of both modalities for cancers including cervical, head and neck, oesophageal, and rectal cancers
- For palliation — To relieve symptoms such as pain from bone metastases, bleeding, airway obstruction, or neurological symptoms caused by brain or spinal metastases, even when cure is not the goal
- As salvage treatment — For localised recurrence after prior surgery or systemic therapy
- For haematological cancers — Total body irradiation and targeted nodal radiation play a role in the treatment of certain lymphomas and leukaemias
Benefits of Radiation Therapy
- Local tumour control : Effective at eliminating cancer cells within a defined treatment area, often achieving complete local response
- Organ preservation : Allows treatment of tumours in critical locations, such as the larynx, bladder, or rectum, without surgical removal, preserving function and quality of life
- Non-invasive delivery : External beam radiation therapy requires no incisions, anaesthesia, or hospitalisation in most cases
- Combination synergy : Enhances the effectiveness of chemotherapy and immunotherapy when used concurrently
- Palliative benefit : Provides meaningful and often rapid relief from pain, bleeding, and other cancer-related symptoms
- Technological precision : Modern radiation therapy techniques spare healthy tissue to a degree that was not achievable with earlier technology, reducing long-term side effects
Preparing for Radiation Therapy
Practical steps to prepare for a course of radiation therapy:
- Attend all pre-treatment appointments: Simulation, planning, and verification sessions are essential steps that directly affect the accuracy of your treatment
- Inform your team of all medications and supplements: Some may interact with radiation or affect treatment tolerability
- Maintain good nutrition: Adequate caloric and protein intake supports tissue repair and reduces fatigue. Ask for a referral to our oncology dietitian before treatment begins
- Protect the treatment area: Avoid applying creams, lotions, or deodorants to the treatment area unless specifically approved by your radiation oncologist
- Arrange transport and support: Daily sessions can be fatiguing. Having a consistent support person for transport and daily assistance is advisable, particularly in the later weeks of treatment
- Prepare your skin: Wear loose, soft clothing over the treatment area to reduce irritation. Avoid sun exposure to treated skin
- Stay hydrated: Adequate hydration supports overall health and helps manage certain side effects, particularly during pelvic radiation treatment
- Ask questions: Our radiation oncology team encourages patients to ask about every aspect of their treatment plan. Understanding the process reduces anxiety and improves treatment adherence
Ready to learn more about radiation therapy at Kokilaben Dhirubhai Ambani Hospital? Contact our department of radiation oncology or speak with a specialist at our cancer department today.
Conclusion
Radiation therapy for cancer has evolved into one of the most precise and versatile tools in modern oncology, used alone, alongside surgery, or in combination with systemic treatments across stages and tumour types. At Kokilaben Dhirubhai Ambani Hospital, our radiation oncology team delivers expert, technology-driven care at every step. If you or a family member has been advised to consider radiation therapy, we are here to guide you with clarity and confidence.
Frequently Asked Questions
Is radiation therapy painful?
Radiation therapy itself is not painful, it feels similar to having an X-ray. Some side effects during the treatment course, such as skin irritation, may cause discomfort, but these are actively managed by our clinical team.
How long does radiation therapy treatment last?
Most standard courses last three to seven weeks, with daily sessions five days per week. Some protocols, such as stereotactic treatments, can be completed in one to five sessions. Duration depends on cancer type, stage, and the recommended protocol.
Is radiation therapy safe?
Yes. Modern radiation therapy uses advanced imaging, computer-guided planning, and precision delivery to maximise tumour dose while protecting surrounding healthy tissue. All treatment plans are reviewed and approved before delivery begins.
Does radiation therapy affect healthy cells?
Some healthy cells in the treatment area may receive low doses of radiation. However, healthy cells repair radiation damage more effectively than cancer cells, and fractionated delivery gives healthy tissue time to recover between sessions.
How many sessions of radiation therapy are usually required?
Standard courses typically involve 25 to 35 daily fractions over five to seven weeks. Hypofractionated or stereotactic protocols may require significantly fewer sessions. Your radiation oncologist will explain your specific schedule during the planning phase.
