Management

State-Of-The-Art Technologies in Radiation Therapy

Impressive and innovative technologies, which skilfully combine the latest advances in radiotherapy equipment, imaging and information technology, have provided unprecedented cure rates of an unmatched quality to patients fighting cancer

"The majority of cancer patients in our country, face great dilemma if called upon to choose a specific radiation technique for their own treatment" - Dr Subodh C Pande Consultant, Radiation Oncology Artemis Health Institute Gurgaon

Cancer is probably as old as mankind, yet its modern treatment has evolved only within the last century. The birth of radiotherapy may be credited to the pioneering work of Wilhelm Rontgen and Marie Curie in their discovery of X-rays and radium in the late nineteenth century. These invaluable scientific tools could be considered forerunners of radiotherapy that is practiced today. The current state-of-the art modalities epitomise the fruits of scientific research as a combined result of recent advances in medical imaging and information technology coupled with innovative brilliance and have contributed towards preservation of many human lives.

The Dawn

The era of radiotherapy began with Deep X-Ray Therapy (DXT); that however was not capable of penetrating into the deeper body tissues and deposited majority of the dose on the skin itself. This invariably resulted in 'radiation skin burns' with tumour recurrence already under way by the time they healed. Soon, DXT fell out of favour; but it remains valuable for providing important inputs regarding radio-sensitivity of organs, tolerance doses, extent of therapy etc., all of which have helped in the enunciation of modern principles of radiotherapy.

In the 1950's, Cobalt Therapy was introduced that could not only treat deep seated tumours effectively, but also spared the skin. It was also affordable and easily serviceable/ administered, and hence became the workhorse for radiotherapy. Its main drawback however lies in its gradually decaying radioactive source that calls for its replacement every five years, making it overall cost-ineffective.

Breakthrough

A significant breakthrough came in the form of invention of the linear accelerator in late 1950s, which has shown consistency in performance with immense potential for upgradation and flexibility to incorporate all new developments in the radiation field. It has been instrumental in ushering in the era of modern 'conformal radiotherapy', the essential focus of which is to effect the highest degree of 'cell kill' in the tumour volume while maximally protecting the surrounding normal tissues. This objective has driven clinicians and researchers alike to continuously improvise so as to widen the gap between damage to the tumour versus the normal tissues; this has resulted in an array of highly effective and patient-friendly radiotherapy modalities that are briefly enumerated below.

Sterotactic Radiosurgery (SRS) using the 'Gamma-Knife' was the earliest of these conformal therapies to be used in the 1950's for rather small, benign brain tumours with the skull immobilised within a metal frame.

The Nineties

In order to treat larger as well as malignant tumours with similar technique, Stereotactic Fractionated Radiation Therapy (SRT) using the more flexible Linear Accelerator based 'X-Knife' was developed in the 1990's. Both were based on the 'arc principle' and used fixed, rounded, metallic collimators to create 'pencil beams' that produced a precise, high dose envelope around the tumour periphery while ensuring a steep dose fall-off within few millimetres of the normal surrounding tissues; thus, resulting in annihilation of the tumour while virtually sparing them from its deleterious effects.

The Next Innovation

The next achievement was Intensity Modulated Radiation Therapy (IMRT) that used Multi-Leaf Collimators which could move dynamically under command of intelligent software so as to not only shape individual radiation beams meticulously, but also modify their individual intensities. This technique proved particularly helpful for high dose delivery to tumours situated very close to or encasing vulnerable organs or those presenting as scattered foci with sensitive tissues in between. The natural extension of IMRT was to ensure maximum precision in its delivery by obtaining a CT image of the target volume to document and rectify any external or naturally occurring internal organ movements prior to undertaking therapy each day.

Artemis Health Institute realised the clinical potential of such Image Guided IGRT (or Image Guided Radiation Therapy) and became the first healthcare institution in northern India to commission this modality in early 2008. This has proven its value many times over by producing high cure rates with minimal morbidity in nearly 600 patients treated at Artemis since then.

The Cyberknife and Tomotherapy are recent additions to the radiotherapy armamentarium that are capable of delivering IMRT using image guidance backed by a highly sophisticated planning software.

Cyberknife

Cyberknife delivers therapy through a Robotic System that is integrated with a linear accelerator by producing 'tight' dose envelopes around the tumour while allowing negligible dose to its vicinity. It is effective for tumours that are aligned or situated very close to sensitive parts like eyes and the spinal cord. It is especially helpful in the treatment of small to moderate tumour volumes and its usage suitability for larger areas is still under investigation. Tomotherapy on the other hand delivers radiation using rotational delivery of the beam as in a CT scanner, with the machine as well as the patient couch in motion, which is controlled by specialised software. As of now, these treatment procedures are not widely accessible to patients in India, primarily because of the substantial expenses involved - this is likely to delay their precise clinical testing in India.

These impressive and innovative technologies, which skillfully combine the latest advances in radiotherapy equipment, imaging and information technology, have provided unprecedented cure rates of an unmatched quality to patients fighting cancer. The majority of such patients in our country, however, face great dilemma if called upon to choose a specific radiation technique for their own treatment. It is therefore incumbent upon the relevant caregivers to explain to them the clinical pros and cons of each modality in simple lay terms, so as to help them in making optimal beneficial therapeutic choices.

Subodh@artemishealthsciences.com