Dr J Mathangi, Consultant, Radiation Oncology, BGS Gleneagles Global Hospitals, Bengaluru, highlights benefits of technology-driven radiation oncology to annihilate a tumour while preserving the integrity of adjacent healthy tissue
Radiotherapy’s contribution to fight cancer is significant. The impact of radiotherapy in cancer survival has been estimated at 40 per cent, compared to 49 per cent of patients being cured by surgery and 11 per cent of patients for systemic treatments. It can be used to treat almost all cancers, anywhere in the body. It can be used alone or alongwith other treatments like surgery or chemotherapy. Radiation therapy allows organ conservation, may be a curativeoption for patients with inoperable disease, and may allow a curative approach for patients who have significant co-morbidity that precludes surgery. Radiotherapy has a major positive impact on local cancer control and is a highly effective in palliation of symptoms like pain, bleeding.
Recent developments
Continuing improvements in techniques and technologies are increasing the precision and accuracy of radiotherapy, allowing treatments that minimise the impact on healthy tissue and reduce treatment related morbidity. Notable developments to date are in the areas of intensity modulated radiotherapy (IMRT), Image guided radiotherapy (IGRT), stereotactic body radiation therapy (SBRT), 4D imaging, Gating and Tracking techniques for tumours moving with respiration, adaptive radiotherapy and particle therapy.
Intensity modulated radiotherapy (IMRT)
Historically, the maximum radiation dose that could be given to a tumour site has been restricted by the tolerance and sensitivity of the surrounding nearby healthy tissues.
The 3D conformal radiotherapy shapes radiation beams to closely approximate the shape of the tumour whereas in IMRT, the intensity of the radiation can be changed to spare more adjoining normal tissue. Because of this an increased dose of radiation can be delivered to the tumour in spite of a dose limiting sensitive adjacent critical structure. This helps in improving the loco regional tumour control and indirectly improving the survival.
Volumetric modulated Arc therapy (VMAT/ RapidArc)
This is an improvisation of IMRT by optimising the whole tumour as a single volume and the treatment delivered in an arc fashion. This allows 360o freedom of placing the beams to improve shaping and better sparing. Also it helps in faster treatment delivery resulting in lesser time for tumour movement during treatment and a greater patient comfort.
Stereotactic radiotherapy (SRS/ FSRT/ SBRT)
A stereotactic radiation treatment uses a specially designed coordinate-system for the exact localisation of the tumours in the body in order to treat it with very high doses of radiation, using several beams of various intensities aimed at different angles to precisely target the tumour. This can be used in the brain (stereotactic radiosurgery-SRS) and rest of the body (stereotactic body ablative radiotherapy- SBRT) for small well defined inoperable tumours
4D imaging, gating and tracking techniques: The tumour movement with respiration can be imaged and taken into account for radiotherapy treatment planning with the help of 4D – CT, MRI and even PET scans. This along with the use of Gating (treating only in a given phase) or tracking (tracking the tumour in all phases of respiration) techniques helps us to reduce the amount of normal tissues with the treatment fields.
Integration of imaging in radiotherapy and adaptive treatments: The improvements in imaging features with high-quality images, 4D scans identifying tumour motion, PET/CT scans to show the different tumour biology and the real extent of tumour, integration of CT/ MRI/ PET CT/ DSA images all in a single platform ultimately allows clinicians to have accurate patient contouring, treatment planning and treatment deliveries. The integration of imaging devices with treatment machines allows the clinician to do imaging tests with good image quality on the treatment couch to check the position of the patient and the tumour before and during the treatment course. The important advantage is the adaptive treatments that can be adjusted as tumour and patient characteristics change throughout the course of radiotherapy like weight loss or the tumour size reduction in head and neck cancers and bladder cancers. Adaptive treatments improve patient outcomes and reduced long- term side effects
Radiotherapy and tumour biology
Radiotherapy is by its nature a personalised treatment. Every patient’s plan is unique and tailored to their particular clinical circumstances and anatomy. It can be conceptualised as a biological intervention with profound effects at the cellular and molecular level, modulated through cellular signalling pathways and the immunological axis. With the evolution and better understanding of individual tumour biology, radiotherapy treatments and doses can be tailored to the specific tumour characteristics, with molecular and biological imaging enabling the already personalised therapy to be even more targeted.
Patient awareness and involvement in cancer care
Patient awareness about new radiotherapy techniques and technologies will continue to increase in the coming years due to increasing availability of information via the Internet and increased awareness through multidisciplinary care teams. The role of the healthcare provider will increasingly be of a partner, who explains and demystifies the vast quantities of information, making them understand the best technique that suits the patient and his tumour making it advantageously personalised.
Communication and information sharing
Clinicians must communicate with one another and coordinate and share the experiences and results that enhance better healthcare. With a mobile patient population, increasing numbers will present following initial treatment to a different radiotherapy centre and require re-treatment with radiotherapy or develop a second malignancy (requiring treatment with radiotherapy). Technological solutions to expedite the transfer the relevant imaging and previous radiotherapy treatment details to the treating radiotherapy centre will be important.
Future developments
Imaging with CT for radiation therapy can be performed for simulation, daily set-up, adaptive planning, retreatments, therapy follow-up and monitoring – all of which can contribute to a patient’s cumulative lifetime dose for radiation exposure. To meet the imaging demands and addressing cumulative radiation doses, new solutions such as standalone MRI simulators that can produce images suitable for treatment planning, treatment delivery units that use MRI for on-board patient imaging, more biological imaging techniques etc. may take hold in future.
Challenges in India
State-of-the-art technology is available within the private sector and a few hospitals in the public sector, but 75 per cent of patients in the public sector in India do not have access to timely radiotherapy. This inequity in access to radiotherapy in the public sector is amplified in rural areas. where majority of Indians live.
Opportunities in India
A number of innovative initiatives to improve cancer treatment and access have emerged that could support such an investment. These include local production of equipment, twinning programmes between institutions in high and low-income countries to exchange knowledge and expertise, and non-governmental and state-sponsored schemes to sponsor and support patients in their cancer journey.
Medical tourism
Outstanding healthcare facilities and affordable costs of treatment has made India one of the most popular choices for medical tourism in the area of cancer care. This opportunity needs to be capitalised upon by streamlining the process and creating more facilities to choose from.
Epilogue
The challenges in cancer care delivery can be overcome by making radiation oncology technology widely available. The offshoot of this endeavour would be associated increase in medical tourism in the field of cancer care. The end result would be a combination of exemplary service to humanity and sizeable economic development.
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