CyberKnife Radiosurgery in lung cancer

Stereotactic radiosurgery in lung cancer DR.DEBNARAYAN DUTTA, Consultant Radiation Oncologist, Apollo speciality hospital Chennai

Radiosurgery is a non-invasive option in early lung cancer. High dose precise radiosurgery has immense potential. Early data from phase II studies have shown excellent loco-regional control and survival function. CyberKnife Radiosurgery in lung cancer has following advantages: 1.     Cyberknife has the unique technology of ‘see and shoot’. In this technology before each treatment field matching of the target and ‘intra-fraction motion correction’ is done, hence minimal normal lung comes in the radiation field. 2.      Cyberknife has sub-millimeter treatment accuracy. Margin (planning target volume) required (where normal lung comes) is minimal around the target. High dose region volume is minimal with Cyberknife and lung toxicity is expected to be lower compared with conventional treatment. 3.     Cyberknife has the multiple isocentric technique with non-coplanar field arrangement, hence have unmatched conformity index (uniform dose is delivered). Cyberknife use ‘pencil beam’ with multiple small beamlets delivered from various angles (maximum 1200 different position) hence ‘penumbra’ margin is less. 4.     As dosimetry is favorable and total dose delivered with Cyberknife is not higher compared with conventional fraction (usual dose delivered with Cyberknife 60 Gy/3 fr/ 1 week) there is no expected increase in lung toxicity with Cyberknife. Phase II prospective studies with Cyberknife have not shown any increase in radiation induced pneumonitis. 5.     ‘STAR trial’ is a multicentric randomized study initiated by MD Anderson Cancer Centre may provide answer to impact of Cyberknife on lung toxicity. There are other few ongoing clinical studies with hypofractionated radiation therapy on lung cancer that will provide useful information in near future   For more information of successful treatments using cyberknife you may please blog your comments or write to lakshmipriya_b@apollohospitals.com Radiosurgery in brain tumours Short course radiation therapy is the one of the most talked about subject in recent years and also a fascinating research zone. Hypofractionated radiation therapy is an old concept, but only in recent years with tremendous improvement in radiation therapy delivery technologies there is a significant visible surge in it’s applicability in clinical practice. Modern radiation therapy technology is capable of delivering high dose to the target while sparing majority of the adjacent critical structures. Hence, it is possible to deliver short course of treatment regimen with higher dose per fraction without increasing in toxicity. In brain tumours, radiosurgery with gamma-knife is considered standard of care in many of the clinical indications such as small meningiomas, acaustic schwannomas, residual low grade gliomas, AVMs and solitary/ oligo brain metastasis. Gamma-knife radiosurgery is in clinical practice for more than five decades.  There are several prospective and randomized studies (level I evidence) with long-term follow up data supporting the use of radiosurgery in these clinical indications. Other indications of radiosurgery are pituitary tumour, craniopharyngiomas, glomus tumours, chordomas and others. Robotic radiosurgery (CyberKnife®) is precision radiosurgery delivery system and an extension of gamma-knife system. CyberKnife uses the principle of gamma-knife, but with linear accelerator source instead of multiple cobalt sources. CyberKnife is capable to treating all tumours indicated for gamma-knife with similar accuracy. This modern tool has some additional advantages from gamma-knife, such as 1) CyberKnife can use fractionated treatment, hence relatively larger tumours can be treated, 2) require only thermoplastic mask, no need for invasive frame, 3) has inverse planning system, can spare critical structure, 4) there is a ‘intra-fraction’ correction technology with imaging, 5) there is no need to change the source, hence may be more cost effective and 6) can be used to treat extra-cranial tumours also. CyberKnife has a linear accelerator attached with a robot and is capable of treatment from various coplanar and non-coplanar field arrangements. CyberKnife has sub-millimeter accuracy and unmatched dose distribution.  The advanced technology behind CyberKnife uses image guidance technology and computer-controlled robotics to deliver and extremely precise dose of radiation to targets, avoiding the surrounding healthy tissue, and adjusting for patient and tumor movement during treatment. In conclusion, CyberKnife is an extension of gammaknife radiosurgery delivery system. This machine has immense promise to treat with short course regimens with high dose and improve local control without increasing toxicities.

CYBERKNIFE FOR PROSTATE TREATMENT - WHAT PATIENTS FEEL

CYBERKNIFE FOR PROSTATE CANCER _ WHAT PATIENTS FEEL

Compensating for Prostate Movement: The prostate gland can move unpredictably throughout the course of treatment that makes the ability to track, detect and correct for motion critically important. Unlike any other radiation treatment, the CyberKnife System continually tracks and automatically corrects for the movement of the prostate in real time. This enables the system to correct the beam direction so that it is focused on the prostate throughout the entire treatment. The robot constantly monitors and aligns the real time location of the prostate to ensure any adjustments in the beam delivery match the prepared treatment plan while automatically correcting for any movement during a treatment by relaying critical logistical information to the system software. Safety mechanisms are in place to ensure that the beam of radiation is ‘locked on’ to the intended target should your prostate move out of acceptable range. For example, if a gas bubble is moving through the rectum or the bladder starts to fill during treatment, a system correction compensating for movements of the prostate automatically occurs.



Reduced Treatment Time: Compared to alternative treatments that can take up to 8 - 9 weeks (including relocation in some cases) or 40 - 45 sessions of radiation therapy, an entire CyberKnife® treatment plan can be completed in 4 to 5 sessions. Each treatment session is typically completed in one hour or less. the CyberKnife System is designed to treat with a higher per-fraction dose given its superior accuracy. This substantially reduced treatment timeframe is advantageous for busy men seeking the least amount of disruption to their daily lives.



A Non-Invasive Procedure: Aside from the placement of tiny gold markers called fiducials inside of the prostate, a pre-treatment procedure that assists the imaging system to more accurately target tumors, the CyberKnife treatment process is completely non-invasive. No incisions, anesthesia or hospitalization are required. The CyberKnife robot moves quietly around a patient who lies comfortably on the treatment table. The robot will move in nearly every direction to fully deliver the prescribed treatment dose.This is in contrast to laparoscopic surgery or a traditional prostatectomy that involves incisions and associated risks. Surgical procedures usually involve general anesthesia which may last up to several hours. As with any surgical procedure, potential risks include bleeding and infection and, depending on a patient’s overall health condition, other complications including incontinence and/or erectile dysfunction. In addition, surgery requires mandatory hospitalization and catheterization.

And compared to High-Dose-Rate brachytherapy (HDR) the CyberKnife System delivers the same dose of killing radiation to the prostate, but does so without the insertion of multiple catheters. HDR typically involves a hospital stay, over a 24 hour period, and places 15-20 catheters into the prostate, through the perineum. Through these catheters a machine pushes a single highly radioactive iridium seed into the catheters one by one. Low-Dose-Rate, or LDR brachytherapy (also known as seed brachytherapy) is also an invasive procedure in which dozens of radioactive seeds are permanently implanted in the prostate with needles inserted through the perineum to deliver radiation over many weeks.



WHAT PATIENTS SAY ABOUT PROSTRATE CANCER



A CyberKnife Coalition survey conducted between February – March 2011, 304 participants were asked why they chose CyberKnife SBRT over other treatment options.

Here is what they said:

84% Most comfortable with risk/side effects

81% Seemed like the best options among my choices

66% Offers the latest technology

59% Convenience

59% Most likely to eradicate/eliminate the cancer

36% Least amount of time away from work

18% Not a surgical candidate

Additional results of this survey found that:

99% of patients described their treatment as successful

93% of patients indicated that SBRT did not interrupt their normal life routine

98% of patients indicated they would recommend SBRT treatment to others

99% of patients indicated they would choose to be treated with SBRT again

 

APollo Hospitals has treated more that 70 prostate cases and the results have been very promising. Patient have been under 2-3 year follow up.

 

Source. www.cyberknifeforprostate.com/

 

 

FOR MORE INFORMATION  YOU CAN BLOG YOUR COMMENTS OR WRITE TO Lakshmipriya_b@apollohospitals.com