Ans. CyberKnife is a revolutionary radiation therapy delivery system. It is a highly precise, image guided radiation therapy delivery system capable of taking care of the motion during treatment (Intra-fraction).
CyberKnife can treat tumours in almost any part of the body, deliver high dose of radiation precisely to the target and deliver minimal dose to the adjacent normal tissue, hence have minimal toxicity. Total treatment duration is only few days (usually 5 days), whereas it is usually 6 to 7 weeks in conventional radiation therapy treatment.
Ans. The major speciality of CyberKnife treatment is the high precision of treatment, real time image guided therapy, minimal acute toxicity and CyberKnife can deliver high dose of radiation in short time (Hypofractionated radiation therapy).
Ans. The dose delivery in CyberKnife is with dose painting method which is highly precise and deliver high dose to target while minimal dose to adjacent structures. CyberKnife is the only radiation therapy delivery system that takes care of tumour movement during treatment with real time tumour tracking. CyberKnife has the unique and effective tumour tracking system (Synergy). CyberKnife has the sub-millimeter accuracy in treatment delivery which no other system has.
Ans. Though most of the tumours in any part of the body can be treated with CyberKnife, usual indications are 1) lung, prostate, pancreas, liver, gall-bladder cancer, 2) benign/ low grade brain tumours and recurrent/ residual high grade brain tumours, 3) brain, liver, bone and lung metastasis, 4) recurrent or residual tumours especially in head & neck region, 5) boost treatment combined with IMRT.
Ans. Though tumour size is not the contraindication for CyberKnife treatment, but usually high dose treatment is done in relatively small volume disease. Post-operative adjuvant radiation therapy and prophylactic radiation therapy are not the usual indications of CyberKnife.
Ans. Though in CyberKnife high dose radiation is delivered in short time duration, excellent dose delivery ensures minimalacute toxicity. However, there is some concern about the long term effect of short course high dose radiation.
Ans. CyberKnife frameless stereotactic whole body radiation therapy is relatively new concept and almost 180 centers throughout the world (mostly in Northe America) have this machine. There are enough short and mid-term data showing the efficacy of this short course treatment.
Ans. Patient needs 3 to 4 days for preparation (PET scan, fiducial placement) and usually maximum 5 days for treatment. Usual stay is 1 to 2 weeks. However, recently protracted course of radiation (3 to 4 week course treatment for larger tumours) with CyberKnife and IMRT with CyberKnife boost treatment (in residual tumour after IMRT) is approved.
Ans. The cost varies with the number of treatment fractions and other preparation prerequisites. Usual cost is 2.25 to 4 lakhs. However, huge concession is considered by the management for economically challenged patients.
Ans. I personally feel that CyberKnife is the radiation therapy delivery system of the future. With more awareness, more matured treatment result data and better acceptability of short course treatment schedules the indications of CyberKnife will be extended.
Dr Debnarayan Dutta is consultant radiation oncologist at Chennai, India and one of the members of the CyberKnife team. He has done fellowship in stereotactic radiotherapy and author of more than 20 indexed publications, 10 international abstracts, two books, reviewer of journals.