Sun. May 9th, 2021

Radiation Oncology is a Continually Evolving Field: Moving Towards Precision and Impactful TherapyBy Dr Vineeta Goel, Associate Director Radiation Oncology, Max Super Speciality Hospital, Shalimar Bagh

Radiation therapy (RT) is a strong pillar of cancer treatment with almost 80% of cancer patients requiring radiation therapy during their treatment. An essential component in the management of cancer and used either alone or in combination with surgery or chemotherapy, radiation therapy is used both for curative as well as palliative goals.

Modern-day cancer care increasingly needs a joint multimodality approach. Of all the cancer patients cured, an estimated 50% are cured by surgery, about 40% by radiotherapy alone (or combined with other surgery/chemotherapy), and 10% by chemotherapy alone or combined with (radiotherapy/surgery). In developed countries, the radiotherapy utilization rate (RTU, the proportion of cancer patients requiring at least one treatment course of radiotherapy during the evolution of their disease) is approximately 50%. However, in developing countries such as India, it is widely believed that the optimal RTU rate is higher and may reach 70% to 80% in some situations.

RT has undergone almost an unimaginable change in technology in the recent past. Till almost a couple of decades ago, the therapy was given using a Telecobalt machine and would result in radiation doses to a large area without much scope for customization as per the extent of disease. This kind of RT resulted in more side effects.

What we see now is that radiation therapy equipment has undergone pathbreaking transformations and improvement in both hardware and software. RT is generally given using machines called Linear Accelerators (LA) which allows beam shaping and radiation intensity modulation to deliver precise radiation doses known as Intensity Modulated Radiation Therapy (IMRT). There is a CT scan attached within LA which allows real time verification of target before actual execution of treatment called as Image Guided Radiation Therapy (IGRT). Some of the LAs also have the capability of delivering breathing synchronized radiation therapy called Four Dimensional RT or gated radiation therapy. Radiation planning and calculations are all done through dedicated software known as planning systems which can create very quick and robust treatment plans.

As a result of all these advancements, radiation therapy has become precise, more effective and side effects have also reduced significantly.

Another milestone that RT has achieved is that organs like liver, kidney etc., which earlier could not be given the therapy, can now safely and effectively be given this radiation treatment. Also, some cancers which were considered relatively resistant to radiation therapy, can now be cured using high and precise radiation therapy with techniques such as SBRT or Stereotactic Body Radiation Therapy which help in overcoming radio resistance.

Similarly, brachytherapy (a form of internal radiation therapy) is now delivered in few minutes using HDR (High Dose Rate). Earlier, the same treatment was delivered over a period of 10 to 20 hours.

When I look back into my own journey as a radiation oncologist, it amazes me as to how far we have come, since till a few years ago this kind of progress in RT technology was almost unthinkable. And it is this progress which has made this therapy one of the stronger pillars of cancer treatment.

Technology- SBRT spine

It was a routine day in my hospital. I was called to see a young lady in the ward. This patient had a history of breast cancer, treated 4 years back and was now admitted with paralysis of both lower limbs/legs which she had for past 25 days. As I examined her, she was thin, frail and her legs were not moving at all. She already had a whole-body PET Scan with her which clearly showed that her cancer had spread to multiple bones including her spine which was causing paralysis of legs.

In case of such paralysis due to spinal cord compression, we see best results only when patients come to us in within 1-5 days on onset of paralysis. I was sure that this paralysis which was already 25 days old, was very unlikely to reverse and she would probably never be able to stand or walk.

When I discussed her MRI with our neurosurgeons, they said she still has a “small” chance of recovery in power in legs with spine surgery. We all decided to give her that ‘small chance’ and mercifully she began to show recovery in her legs after surgery which was very encouraging for everyone involved in her care.

After spine surgery, she required what is known as spine stereotactic radiation therapy for giving her best chance of disease control and neurological recovery. Spine SBRT is a high-end technique of radiation therapy in which we deliver very high and precise doses of radiation to spine/vertebrae while saving adjacent spinal cord and other critical structures. Delivering spine SBRT gets more challenging after spine fixation surgery as surgical fixation screws throw a lot of artifact and we cannot identify our target and spinal cord clearly on CT or MRI scans.

What really worked on her was the novel technique of a CT Myelogram. After much hard work, we could optimally use technology to safely push high radiation doses by SBRT for stubborn cancer cells around her spinal card. She started to walk gradually, and it was extremely gratifying and fulfilling to see such outcomes.

The Tumour Board

Another patient that I recall was a 45-year gentleman with cancer of upper part of the jaw called as maxillary cancer. He was already seen by several surgical oncologists and his cancer was declared inoperable or surgically unresectable. He came to us for palliative radiation therapy after getting opinions from several leading cancer centres. Since he was young and fit, his best chance of cure could only come from surgery and not radiation therapy.

As per standard practice at Max Institute of Cancer Care, we kept this case for a discussion in our ‘Tumour Board’. We all deliberated and discussed this case for hours and decided to treat him with a unique protocol of pre-operative radiation and chemotherapy followed by an attempt at surgery. After 5 weeks of radiation and chemotherapy, he responded well to the treatment and underwent successful surgery for his tumour. Nine years hence, he is doing quite well.

Another case of a 55-year-old with recurrent cancer of rectum and a tumour stuck to his prostate gland which could not be removed as he had a history of kidney transplant, was successfully treated when members of our tumour board came up with a unique solution of surgically removing the cancer and giving intra operative radiation therapy (IORT) to the prostate gland area where the tumour was stuck. A very unique solution and the best chance to cure our patient!
IORT is a technique of RT where a single high dose of radiation therapy is given to the tumour bed in the operation theatre itself. Since it delivers a high dose of radiation, it is especially useful in recurrent cases requiring reirradiation.

In my continuing journey, I see the road ahead paved with opportunities to bring to work the same commitment that my teachers had and to keep abreast with and integrate more and more novel technologies. These are what will ultimately help us bring better healthcare outcomes to our patients!

DISCLAIMER: The views expressed are solely of the author and does not necessarily subscribe to it. shall not be responsible for any damage caused to any person/organisation directly or indirectly.

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