Rationale and Potential Clinical Applications for CyberKnife Robotic IMRT™

The CyberKnife® System as an Image-guided Intensity Modulated Radiotherapy Device: Rationale and Potential Clinical Applications for CyberKnife Robotic IMRT™

Donald B. Fuller, M.D., Radiation Oncologist Radiosurgery Medical Group (RSMG); CyberKnife Centers of San Diego

In clinical practice, the CyberKnife® Robotic Radiosurgery System has been almost exclusively used as a radiosurgical device, engineered to deliver conformal, ablative radiation treatments in one to five fractions to a wide variety of malignant lesions in the CNS, head and neck, lung, liver, pancreas, prostate and other sites.1-8 Although there is no medical reason why this device has not been used to deliver conventionally fractionated radiotherapy, this function has not previously been described, presumably due to the long treatment times associated with early-generation CyberKnife Systems. Nevertheless, the MultiPlan® Treatment Planning System is capable of computing very elegant intensity modulated radiotherapy (IMRT) dose distributions, and improvements in device efficiency have made the delivery of these IMRT plans feasible in clinical practice, thus leading to new CyberKnife treatment applications that would best be described as “Robotic IMRT™.”

The new CyberKnife VSI™ platform includes a number of enhancements that improve efficiency, including Sequential Optimization treatment planning, the Iris™ Variable Aperture Collimator (which allows for modulation of the beam during treatment9,15), the increased dose rate of a 1,000 MU/min linear accelerator and a 20% increase in robotic traversal speed. In addition, a treatment time reduction tool accessed during plan optimization allows the user to reduce the total number of treatment beams and nodes while still meeting treatment plan objectives.

Collectively, these enhancements create a device that can reduce treatment times by over half compared with predecessor CyberKnife Systems, while maintaining the precision and accuracy of the CyberKnife product.

SOURCE: ACCURAY FOCUS NEWSLETTER JAN, 2010

LIVER METASTASES TREATMENT

Stereotactic body radiation therapy for liver metastases


O Dawood, A Mahadevan, K Goodman ,European J Cancer 2009;45:2947-2959.





This review focuses on stereotactic body radiation therapy (SBRT) as an alternative, non-invasive approach to the treatment of liver metastases. Treatment considerations of SBRT for liver metastases are presented with particular emphasis on the challenges of organ motion and the low tolerance of the surrounding hepatic parenchyma. Multiple approaches to tumor motion are discussed, including tumor tracking versus motion-compensation techniques. Issues of patient eligibility criteria, patient set-up, target definition, treatment dosimetry and fractionation are also discussed. Clinical results to date from 15 published reports, including a summary of the latest in-press results from Stanford using the CyberKnife System, are presented. These clinical reports demonstrate the safety and efficacy of SBRT for liver metastasis with 18-month and 2-year local control rates ranging from 71-93% and 71-86%, respectively.


The review concludes by stressing the importance of addressing hepatic tumor motion to ensure the dose reaches the tumor and spares the surrounding normal tissue. The authors suggest more rigorous phase II clinical studies are necessary to establish the long-term durability of efficacy and toxicity results.


SOURCE : FOCUS NEWSLETTER - JAN 2010

CYBERKNIFE FOR GASTRIC CANCERS

Stereotactic body radiotherapy for isolated para-aortic lymph node recurrence after curative resection in gastric cancer

Metastases from gastric cancer are common and can progress rapidly; even with aggressive treatment 5-year survival rates are low. However, researchers from Korea Institute of Radiological & Medical Sciences hypothesized that there is a certain population of such patients in whom the disease follows a more indolent course, based on studies of patients with
resected liver metastases. This population may benefit from SRS of isolated metastases from
gastric primaries. Thus, they treated 7 such patients with the CyberKnife® System, delivering 45 to 51 Gy (median 48 Gy) in 3 fractions. The patients were followed for 14 to 33 months (median 26 months). Local control was achieved in 6 of 7 patients; 2 patients were disease-free, 3 were alive with disease, and 2 patients died of disease progression. Three-year actuarial overall survival was 43%, and disease-free survival was 29%. The authors conclude that the results support their hypothesis that an indolent subgroup with less aggressive disease progression who could benefit
from the use of local treatments such as CyberKnife Radiosurgery.
 
Source: Accuray's focus newsletter

PROGRESS IN RADIATION ONCOLOGY

PROGRESS IN RADIATION ONCOLOGY

Dr. Janos Stumpf - ADVISOR ONCOLOGY – CYBERKNIFE SERVICES

End of the month November, was an academic feast for the Indian Radiation Oncologists at Hyderabad.

The content of the conference can be summarized in three words: It was about Research, Discipline and Development, especially that of the new machines. It is our pride to realize and say that even latest knowledge about the technical progress has found its way to India, no matter how expensive the machines are. “Precision in Delivery of Radiation” is the mantra for all these technical aspects. Tomotherapy, Cyberknife and Rapid Arc are all the ways to do radio therapy on an extremely precise way.

Cyberknife was covered by two speakers. An eminent guest from California Dr.Nissar Syed was kind enough to give an over-all review about the machine. His talk was followed by the ‘Indian experience’ with Cyberknife based on more than hundred fifty cases treated already at ASH Chennai. Characteristics of the first 150 cases were presented. Apollo has considerable success:- partial remission even in majority of the ‘lost’ cases.

Beside the advantage of saving normal tissue in the brain or extracranially, CK represents a huge leap forward in treating moving targets like cancer in the lung, liver or in the prostate. All these three organs, move during the radiotherapy.



The first patient, Master Shanka had very serious neurological complaints at the time when he came to Apollo. He was attended by Sr. Consultant Neurosurgeon Dr.Balamurugan. However his attempt to remove the haemangioblastoma from the patient’s brainstem was confined to fail due to the dangerously high vascularity which is the nature of that kind of tumors. But this surgical nightmare can be converted into an advantage with the help of High Precision Irradiation (HPI). High vascularity means high density of endothelial cells which are covering the inner surface of the vessels. These vulnerable cells can react with an overgrowth for the exposure of radiation.


Few months after the success full Stereotactic Radiosurgery with CK, part of the tumor has been obliterated its overall size started to come down.This is why the patient has improved and could resume his normal life.

Fate of a patient with inoperable lung cancer is practically known at the time of the diagnosis. Only a very minimal percentage of the inoperable lung cancer cases can be saved by the combination of conventional irradiation with chemotherapy. CK seems to bring a new hope for these patients. A 57 year old gentleman from the neighboring Srilanka successfully conquered one cancer 10 years ago with the help of Apollo Speciality Hospital. He came with hope again when an inoperable lung cancer in his chest was diagnosed. Chemotherapy has failed unfortunately. And then Cyberknife seemed to come for his rescue. High precision and short duration, biologically very intensive radiation has resulted in an impressive remission of his advanced lung cancer without any side effects. This aggressive cancer does have the capacity of invading the rest of the body. As a matter of fact the same has been observed with that particular patient too. But for him this is not the “end of the road”. A second CK treatment is planned to attend all the new sites of cancers shown on the PET CT. Highly sophisticated tools in radiation oncology do allow us to provide longer control with reasonable if not excellent quality of life even in an aggressive cancer.

There is a beautiful sentence told by Rabindranath Tagore about the disease in general. “DEATH DOES NOT HURT US, BUT DISEASE DOES, BECAUSE DISEASE CONSTANTLY REMINDS US OF HEALTH AND YET WITHOLDS IT FROM US.”

This is double true for cancer. Quality of life of a patient has to be one of the primary concerns of an oncologists. Many cancers have a tendency to migrate to the bone, to the spine. These metastatic lesions have the capacity to paralyze the patients by compressing the spinal cord. Chemotherapy frequently has only temporary control over the progress and so does conventional radiotherapy. But high precision in CK helps. We have the technical skill and opportunity to give high precision irradiation to the spine and to arrest this type of tumours even before they cause the extremely bad condition of transverse lesion of the spine. A Professor from George-Towns University in Washington DC said “by now we hardly deal with paralysis due to metastasis to the spine. It is being attended with CK at a curable and controllable stage and the patient will not be confined to bed for the rest of his/her life.


The basic question: ‘How cancer can be tamed in general’ still remains unanswered. But the tremendous progress gives hope for both temporary control with good quality of life and for cure in many cases. It is our job and duty to know about new developments and to apply them with wisdom. This conference was all about this.

CYBERKNIFE SUCCESS STORY - TREATMENT OF PROSTATE CANCER

CYBERKNIFE SUCCESS STORY - TREATMENT OF PROSTATE CANCER

DR.MAHADEV Senior Consultant, Radiation Oncology

71 Yrs old Mr.Birendra Singh from Gopalganj, Bihar was devastated when he was diagnosed to have Prostate cancer. He had gone to his urologist for just a routine checkup because he was having difficulty in passing urine for the last couple of months. A routine PSA done was in the range of 15ng/ml. A transrectal biopsy revealed grade 2 adenocarcinoma of the prostate gland with a Gleason’s score of 3+4.

Mr.Singh went to Delhi for an opinion. He consulted various doctors which included several urologists, surgical oncologists and radiation oncologists.The options given to him included wait and watch, bilateral orchidectomy(removal of both testis), Radical prostatectomy, Brachytherapy(seed /HDR implant).The opinions were so varied that the family could not take a decision for 3 months.

Patient also consulted Apollo Hospitals at Ranchi in Jharkhand where he was advised to go to Apollo Speciality Hospital Chennai as all the treatment options were available there and he was also told that a full team of doctors decide on a treatment in the tumor board.

Mr Birendra Singh’s nephew who lives in the United States, meanwhile contacted his uncle from there and told him about a new treatment called the cyberknife which he had read on the internet. His nephew was very impressed by what he had read on the net- outpatient treatment, non-invasive, very precise radiation delivered robotically and just 5 sittings with practically no side effects. He asked his uncle to come to US for treatment as he thought it was unlikely that this treatment option would be available in India.

After going through all the treatment options Mr.Birendra Singh decided he would go in for Cyberknife as he found that to be the best treatment modality in his opinion. He visited Chennai in March 2009 to take a final decision. We had just then started using Cyberknife and we told him that the latest version of Cyberknife is now available here. He was told that the cost of cyberknife would be around 40,000 US dollars in US. We told him that the cost of treatment here would be Rs 400,000.

As we had just started Cyberknife Mr Singh was anxious about our technical capability. But when he came to know that the entire team was trained at the Stanford University, California, where actually the cyberknife was invented, he immediately decided to have the treatment here.

The first step in the treatment process was counselling him about the various treatment aspects.This included explaining to him the various stages of the treatment preparation ,planning and execution.The expected benefits and the various side effects that can be expected was explained to him in detail.The side effects that are normally seen with this treatment can be increased frequeny of micturition and bowel movemens.Very rarely, rectal bleeding can be seen as a late effect of radiotherapy.

The second step was placing 5 gold fiducials into the prostate gland transperinealy under transrectal guidance which took about half an hour. These fiducials are necessary for the machine to track the prostate gland during the entire course of treatment. Normally, we have to wait for a week after placing the fiducials for doing the planning CT scan. This is necessary because in the first couple of days, the seeds can migrate.

The third step in his planning was the making of a special type of bed called Vacloc for immobilization of the patient during treatment. Vacloc is a vacuum bed which takes the shape of the patient so that daily reproducibility of the patient in the same position can be achieved easily. This took about 10 minutes following which a CT scan was done with the patient lying in the vacloc in the treatment position.


Next, the Radiation oncologist contours the prostate gland, bladder and rectum. Then, the medical physicist puts on the treatment beams. The treatment plan was ready the next day and was reviewed by the oncologist and urologist.The treatment plan was finalized and the patient was asked to come for treatment the following day which happened to be a Tuesday. Patient was asked to have a light breakfast before 8 am and report for treatment at 10am.He was also asked to take a laxative the previous night and antacids.This preparation is a very important part of the treatment as improper bowel evacuation and gas in the bowel can interfere with the accuracy of the treatment.As cyberknife can achieve submillimeter target accuracy and continuously tracks the target while treatment ,it is absolutely essential that patients follow this preparatory regimen very carefully.Mr Singh was prescribed 5 treatment sittings on consecutive days.

Each treatment lasted for about 45-50 minutes and Mr.Birendra Singh completed his treatment on schedule on Saturday.He had initially booked his tickets for Sunday but as he did not have any side effects he preponed his journey to Saturday night.He was advised to have a PSA after 3 months which confirmed that the PSA had come down to normal values.

MR. BIRENDRA SINGH AFTER COMPLETING 5 TREATMENT SITTINGS

Mr.Singh Reported back to us in the first week of December. His PSA which was repeated was less that 1ng/ml which shows excellent response to treatment. There were practically no side effects during and after the treatment.



FOR MORE INFORMATION ON CYBERKNIFE TREATMENT IN PROSTATE CANCER< YOU MAY BLOG YOUR COMMENTS OR WRITE TO  lakshmipriya_b@apollohospitals.com