Radiation Oncology

External Beam Radiation Therapy services -

• Conventional Radiation Therapy - Two dimensional radiotherapy(2DRT) or Electron Beam therapy
• Conformal Radiation Therapy - Three Dimensional Conformal Radiotherapy(3DCRT) or Intensity Modulated Radiotherapy(IMRT) 
• Image guided Radiotherapy(IGRT) with On-Board Imaging(OBI) facility
• Rapid Arc or Volumetric Modulated Arc Therapy(VMAT)
• Stereotactic Radiation techniques - Stereotactic Radiosurgery(SRS), Stereotactic Radiotherapy(SRT) & Stereotactic Body Radiotherapy(SBRT) with the Micro Multi-Leaf Collimator(MMLC) facility
• Magna-field Irradiation techniques - Total Body Irradiation(TBI) or Total Lymphoid Irradiation(TLI/STLI) or Total Skin Electron Therapy(TSET)
• Add-On attributes - Movement management, Breath Hold Techniques, 6 DOF Couch Setup, Fusion based planning(PET/CT or MRI fusion), modern versatile Treatment Planning System(Eclipse TPS)
• Brachytherapy System with stand-alone Treatment Planning system (service available from July’23)
• Intra-operative Radiotherapy system (service available from July’23)

Radiation Oncology is an essential component of cancer management and has stood the test of time for over a century in this aspect. Nearly 70% of all cancer patients will need the services of this speciality at one point of time or the other. As the therapeutic policies have changed over the last few decades, the role of radiotherapy too has undergone some significant changes. Also, the slew of technological advances that have impacted this speciality, have completely altered the application of this therapy as well as allowed for far more challenging roles for this speciality.

Radiotherapy was always considered to be a relatively toxic therapy and was usually neglected & deferred by patients, causing these patients to have quicker progression of disease as well as poorer quality of life parameters too. However, with the advent of the new age linear accelerators & the other modern radiation delivery equipment, the treatment related toxicity/side effects have significantly reduced. This has ensured completion of radiation treatments effectively and in association with other modalities, which has ensured far better therapeutic outcomes as well as improved patient reported Quality of Life scores.

Radiotherapy is primarily used with the intent of -

• Curative (Radical) therapy - where we use radiation to effect cure for the patient - hence treatments will be longer and to full doses as per the requirement of the disease it is being applied for.
• Palliative therapy - used in advanced disease where we are just trying to minimize the serious symptoms and discomfort faced by the patients, and not trying to effect cure. The treatments are usually shorter and as convenient as can be made for the patient
• Salvage therapy - As diagnostic imaging and oncology directed treatments have improved, clinicians do find themselves in scenarios where radical treatments cannot be fully ruled out. In these scenarios, salvage radiotherapy too can be applied in the hope for an excellent response and possible long term survival of such patients.

Radiotherapy is delivered basically in two forms -

• External Beam Radiotherapy (EBRT) wherein the high energy X-rays are generated from a source away from the patient’s body. These X-rays are then shaped and modulated using the sophisticated delivery apparatus to ensure that the beam is directed only towards the tumour and the surrounding normal tissues receive as low a dose as possible. The Linear Accelerator is one such machine and we at Aster CMI Hospital have the VARIAN TRUEBEAM STX unit, the most high end equipment available in the market currently. This machine allows for varied techniques to be applied as per need for the particular patient(Mentioned later)
• Brachytherapy (Internal radiation) treatment - this is a specialized modality of radiation delivery in which the radiation sources are placed directly within the tumour or very close to it. This modality is useful in certain specific kinds of cancers like gynecological, head&neck, esophageal, urological, biliary, soft tissue and skin tumours. This therapy allows for delivery of very high doses to the tumour and very low doses to the surrounding normal tissues, hence ensuring a large therapeutic benefit for adequately chosen patients.

Sequencing of Radiotherapy -

• Radiation alone - In few cancers radiation can be used as a sole curative therapy option. Sometimes chemotherapy is added as a concurrent therapy to enhance the effectiveness of radiation. Cancers of the head & neck region, uterine cervical cancers, lung & urological cancers are some examples
• Neoadjuvant or Upfront radiation - In some cancers, radiation along with concurrent chemotherapy is delivered prior to surgery, to improve resectability, organ sparing options and outcomes for the patient. Cancers of the gastrointestinal tract, bladder cancers, soft tissue cancers are few such examples
• Adjuvant or post-operative radiation - Here radiation is delivered after surgical removal of the tumour to enhance the local control and reduce the chances of recurrence and/or spread of the disease. Cancers of the breast, head/neck region and brain tumours are common examples.
• Per-operative or Intra-operative radiotherapy (IORT) - in this specialised applicators allow for delivery of local radiation directly to the tumour bed(operative bed) to maximize control and reduce overall toxicity. Used in abdominal tumours, sarcomas, breast cancers and recurrent cancer settings.

External Beam Radiotherapy Techniques -

• Conventional therapy techniques (Two dimensional radiotherapy) - open field techniques, electron therapy is used in patients undergoing palliative therapy or in those where the adjacent normal tissue exposure is minimal and will not compromise the long term outcomes for the patient
• Conformal therapy techniques - Three Dimensional Conformal Radiotherapy (3DCRT) or Intensity Modulated Radiotherapy (IMRT) are techniques used when we have significant normal tissues adjacent to the area of interest and there is a need to block these regions to minimize long term toxicities.
• Image guidance techniques - Image guided Radiotherapy (IGRT) is a specialised technique in which on board images are acquired of the patient in treatment position and verified to match with the planning setup to allow for correction of any small deviations during daily setup. 
• RapidArc techniques - RapidArc or Volumetric Modulated Arc Therapy (VMAT) is a process in which treatment is delivered in an arc fashion. This allows for treating complex target volumes, even those which are wrapped around crucial normal tissues.
• Stereotactic Radiation techniques - Stereotactic Radiosurgery (SRS), Stereotactic Radiotherapy (SRT) & Stereotactic Body Radiotherapy (SBRT) are sophisticated methods to deliver high doses of radiation in lesser number of fractions. This improves the biological effective doses to tumours ensuring provision of curative doses to tumours which could not have been achieved in the more conventional techniques previously available. In a properly chosen patient, this technique could even replace a surgical exploration. 
• Magna-field Irradiation techniques - such as Total Body Irradiation (TBI) or Total Lymphoid Irradiation (TLI/STLI) are used in hematological as well as some solid cancers as part of the therapeutic process or as a conditioning regimen for bone marrow transplant treatment. We also can apply Total Skin Electron Therapy (TSET) in certain skin malignancies. Also, Hemi-Body irradiation techniques for the treatment of cases such as multiple symptomatic metastatic disease. 
• Some additional nuances applied during delivery of radiation -
  • Movement management - some tumours are known to move during therapy and this could create a scenario of missing them completely, especially if movement is not accounted for. This is seen in lung tumours, upper abdominal tumours, pelvic cancers such as those of prostate/bladder. Here specialised techniques of tumour tracking, gated radiation delivery and fiducial based verification and delivery is used. Also, with the use of 4D CT scans we can exactly quantify the degree of movement and use this knowledge for planning 
  • Breath Hold Techniques - Normal breathing too can complicate treatment delivery. Breath-Hold techniques (ex. DIBH) can minimize the breathing excursions for the patient and allow for radiation delivery without increasing doses to surrounding structures.
  • 6 DOF Couch Setup - Daily setup of patients could be compromised leading to translational as well as rotational deviations from initial setup. Presence of on-board imaging and 6 DOF couch setup allows for corrections of all these excursions and provides sub-millimeter treatment accuracy.  
  • Fusion based Treatment planning - Certain cancers, which are placed in deep seated locations surrounded by crucial normal tissues can be a challenge to visualize adequately. In these situations we use additional imaging modalities, such as PET/CT & MRI scans, to enhance visualization and also to ensure that the un-involved normal tissues are spared completely. These techniques are used commonly for Brain tumours, lung tumours, head/neck tumours as well as abdominal/pelvic tumours.
  • Treatment Planning system -  VARIAN ECLIPSE version 15.6 treatment planning system along with the ARIA Oncology Information System are an essential component to allow for smooth transition from simulation to planning to verification and then delivery of treatment for patients at our department. These systems ensure easy computation and planning of complex radiotherapy procedures without much hassles. The sophisticated system allows for running multiple plans simultaneously as well as faster throughput which ensures seamless treatment planning & delivery.