CyberKnife Lung Cancer Treatment

LUNG CANCER
The CyberKnife® Robotic Radiosurgery System was cleared by the U.S. Food and Drug Administration in 2001 to treat tumors anywhere in the body, including the lung. Despite its name, the CyberKnife System is not a surgical procedure. In fact, there is no cutting involved. Instead, the CyberKnife System delivers high doses of radiation directly to lung tumors. The CyberKnife System offers patients who cannot undergo lung cancer surgery due to their poor medical condition, or who refuse surgery, a minimally invasive alternative treatment for lung cancer. CyberKnife lung cancer treatments are typically performed on an outpatient basis in one to five days, requiring no overnight hospital stays. Most patients experience minimal to no side effects with a quick recovery time.

What is Lung Cancer?
How is It Detected?
How is It Treated?
How Does the CyberKnife Treat Lung Cancer?
References

Watch The Video

What is Lung Cancer?
Lung cancer is the abnormal growth of cells in the lung resulting in a lung tumor. If the abnormal cells originated as lung cancer cells, the resulting collection of cells is called a primary lung tumor. If the abnormal cells originated in another part of the body, such as the colon or liver, and were carried to the lungs by the blood or other bodily fluids, then it is considered a metastatic lung tumor.¹
More than 215,000 cases of primary lung cancer cases are expected to be diagnosed in the United States in 2008. Lung cancer is the leading cause of cancer death in both men and women, and is expected to result in approximately 161,840 deaths – or about 29% of all cancer deaths – in the U.S. this year.² About 13% of primary lung tumors are considered small cell, including oat cell cancer, mixed small cell/large cell carcinoma and combined small cell carcinoma. The remaining 87% of lung tumors are classified as non-small cell,² which include squamous cell carcinoma, large cell carcinoma and adenocarcinoma.

How is Lung Cancer Detected?
Lung cancer typically develops without early symptoms, so when symptoms do occur, the cancer is often advanced. Patients may see their doctor for a persistent cough, coughing up blood, painful breathing or coughing, shortness of breath, or other symptoms. In its early stages, primary lung cancer does not usually cause symptoms. Unfortunately, most primary lung cancers are diagnosed at late stages.
Primary or metastatic lung cancer can be diagnosed a number of different ways. Often it is detected during a standard chest X-ray. CT (Computed Tomography) scans, PET-CT (Positron Emission Tomography-Computed Tomography) scans and MRIs (Magnetic Resonance Imaging) also can be used to further identify a lung tumor. A lung cancer diagnosis can be confirmed by either performing a biopsy in which a small piece of tissue is examined or by analyzing fluid to determine if it contains a protein that is specific to tumor cells. Doctors then determine the “stage,” or extent of the disease, by establishing how big the tumor is and how much it has spread.¹

How is Lung Cancer Treated?
Lung cancer treatment depends on the type and the stage of cancer. Lung cancer can be treated with surgery, chemotherapy and radiation; and these are often combined to offer the most effective treatment.¹ Options for treating a metastatic tumor depend on the stage of the primary cancer. The various lung cancer treatments are described in detail below.
Surgery:
Surgery or surgical resection is often used to remove a tumor. For early stage lung cancer, the preferred treatment for otherwise healthy patients is a lobectomy, in which the surgeon removes a lobe of the lung. Lobectomies can be performed in two ways. One method is called a thoracotomy, in which the ribs are cut and spread to allow the surgeon to access the lobe of lung that needs to be removed. The second type of lobectomy is less invasive and done using video-assisted thorocoscopic surgery (VATS). During this procedure, small incisions are made and a camera is placed in the chest to guide the surgeon performing the surgery. Some patients with early stage lung cancer may not require that an entire lobe be removed. This procedure is called a wedge resection or segmentectomy, and can reduce the amount of normal lung tissue removed.
To be effective as possible, lung cancer surgery must not only remove the visible tumor, but eliminate any microscopic traces of the disease that remain in the surrounding tissue. Studies comparing lobectomies to wedge resections have shown that the lobectomy results in better survival rates and is more effective in removing all of a patient’s disease.
For those patients whose primary lung cancer is more advanced, as well as those who have large tumors or multiple metastatic tumors that cannot be removed by lobectomy or segmentectomy, more extensive surgery is required. In these cases, surgeons may perform a pneumonectomy, during which the entire lung is removed.
Although surgery is effective for some stages of lung cancer, patients can experience significant risk of complications, including infection, bleeding, and respiratory and cardiac problems. These complications can also lead to loss of lung function and/or a decreased quality of life.³ Open lobectomy and video assisted thorascopic surgery have local control rates and 5-year survival rates of 60-80%.^4-7
Lung cancer surgery is typically used alone for patients with very small tumors and early-stage lung cancer. However, some patients may not be well enough to undergo surgery because they suffer from other cardiac or breathing problems. For later stages of lung cancer, typically stage II and higher, surgery is often combined with chemotherapy and, perhaps, radiation therapy.

Radiation therapy:
Radiation therapy, also referred to as radiotherapy, is a non-invasive procedure that uses radiation to kill lung cancer cells. Five-year survival rates for early stage primary lung cancer patients undergoing this type of treatment have been reported in the range of 10-30%, which is lower than the survival rates of patients treated with surgery.^10-12
Conventional radiation therapy, called external beam radiation therapy, typically involves delivery of wide beams of radiation that encompass both the tumor and a significant amount of surrounding healthy tissue. These wide beams of radiation are necessary because tumors move as patients breathe. During this treatment, the radiation dose is limited to decrease the toxicity to the patient that can result from injuring healthy lung tissue. Therefore, conventional external beam radiation therapy is usually delivered in small doses of 30 to 40 sessions over four to six weeks. Rates of toxicity range widely in published studies,^3-16 with short-term severe toxicity ranging from 10-30%¹³ and long-term severe toxicity (radiation pneumonitis) reported as 18%; attempts to increase the dose of radiation being delivered using conventional radiation therapy methods have resulted in even greater toxicity.¹⁵
Because tumors with the chest can move large amounts as the patient breathes, it is necessary to irradiate with wide fields that include a large amount of normal surrounding tissue during this treatment. However, several techniques – such as respiratory gating, breath holding and the use of frames – have been developed to better compensate for this tumor motion and allow for smaller radiation fields to be used.
Respiratory gating:
Respiratory gating is a technique in which radiation is delivered when the tumor is thought to be in a certain location during a patient’s breathing cycle. Gating makes a number of assumptions about the location of the lung tumor, such as: it is always in that same location during a specific point in a patient’s breathing pattern; a patient’s breathing pattern does not change throughout a treatment; and a patient is breathing the same during a treatment as he or she was breathing during the planning phase. In reality, many patients breathe differently throughout the treatment, particularly if they are nervous or fall asleep. These changes in breathing patterns may result in errors in radiation delivery.
Breath holding:
Breath holding involves a patient taking a full breath and then holding it for several seconds. As the patient holds his or her breath, the radiation beam is switched on and then turned off just before the patient begins to breathe normally again. Breath holding assumes a tumor will be in a certain location when the patient breaths in. This may not always be the case, depending on the depth of a patient’s breath. Breath holding also may be very difficult for patients with advanced lung disease.
Frames:
Frames enable physicians to apply pressure to a patient’s abdomen to decrease the movement of the diaphragm and chest cavity. Although frames reduce tumor movement within the chest, they do not completely eliminate it. This technique also can be uncomfortable and may be very restrictive for patients who have baseline breathing problems or advanced lung disease.
Techniques such as gating, breath holding and frames have allowed physicians to deliver much higher doses of radiation in as few as three to five sessions with a procedure called stereotactic body radiation therapy (SBRT). This alternative treatment for lung cancer has been shown to be more effective than conventional radiation therapy, with three-year survival rates ranging from 52-88%^17-20 and a five-year local control rate of 95%.²¹ Although SBRT enables doctors to spare more normal lung tissue than conventional methods, it still typically requires large margins around tumors to ensure that the radiation is delivered to the tumor and to account for the inaccuracies of gating, breath holding or frame usage.
Chemotherapy:
Chemotherapy is used when cancer cells are thought to be located throughout the body or they are present in a patient’s blood or other fluids, which is often the case with metastatic lung tumors and advanced-stage lung cancer. Chemotherapy medication is delivered orally or through an IV (into a vein), and is given to a patient either as the sole treatment or in combination with surgery or radiation. Chemotherapy affects both normal tissue and the cancer cells, so patients may experience side effects, such as severe nausea and vomiting, infections, fatigue and weight loss.²² Based on randomized clinical trials chemotherapy is recommended in addition to local treatment for patients with later-stage disease.²² Disease-free 5-year survival for patients treated with chemotherapy following surgery range from 48-89% depending on how advanced the disease is.²²
Radiosurgery:
Radiosurgery devices, such as the CyberKnife Robotic Radiosurgery System, offer patients a new option for the treatment of lung cancer. The CyberKnife® System is used to treat lung cancer patients who cannot tolerate surgery, have an inoperable tumor, or are seeking an alternative to surgery. The challenge that doctors face with tumors in the lung is that those tumors move as the patient breathes. Unlike traditional radiation therapy, the CyberKnife System precisely identifies the tumor location as the patient breathes normally during treatment and can be used, in some cases, to treat lung tumors non-invasively.

How Does The CyberKnife® Treat Lung Cancer?
The challenge that doctors face with tumors in the lung is that those tumors move as the patient breathes. Radiosurgery devices, such as the CyberKnife® Robotic Radiosurgery System, offer patients a new option for the treatment of lung cancer. Unlike traditional radiation therapy, the CyberKnife System precisely identifies the tumor location as the patient breathes normally during treatment and can be used, in some cases, to treat lung tumors non-invasively.
Lung cancer treatment with the CyberKnife System involves a team approach, in which several specialists participate. The patient’s team may include:
a Surgeon
a Radiation Oncologist
an Interventional radiologist
a Medical Physicist
a Radiation Therapist
Medical Support Staff
Once the team is in place, the patient will begin preparation for CyberKnife treatment.
As part of the diagnosis, doctors will identify the location and size of the lung tumor. Depending on these results, some patients may not require the implantation of fiducial markers. The CyberKnife System will use only the identifying characteristics of the tumor itself to clearly visualize the tumor within the chest and track the tumor as the patient breathes normally.
Some tumors may require the placement of fiducials within the lung to help the CyberKnife System pinpoint the tumor’s exact location. In that case, the patient will be scheduled for a short outpatient procedure beforehand in which three to five tiny gold seeds -- called fiducial markers -- are inserted into the tumor or surrounding lung tissue. These markers may be placed by putting a small needle through the chest, guided by CT scan or an ultrasound. Alternatively, a camera might be passed through the patient’s mouth and into the airways or into the esophagus to allow access to the tumor. If fiducials are required, the patient must wait approximately one week before CyberKnife treatment planning can begin to ensure that fiducial movement has stabilized.
Before CyberKnife treatments can begin, patients will be fitted for a special body cradle. The cradle is made of a soft material that molds to the patient’s body and is designed to make treatment more comfortable and to ensure body position is the same for each treatment session. The patient also will be fitted with a special vest, which is worn during CyberKnife treatment and enables the robot to correlate chest motion and breathing patterns with the tumor position. The data generated with the vest allows the CyberKnife robot to precisely follow the tumor’s motion as it delivers each beam of radiation, ensuring safe and accurate radiation delivery.
While lying in the cradle, a CT scan will be performed to locate the patient’s tumor. This CT data will be used by the CyberKnife team to determine the exact size, shape and location of the tumor. A MRI or PET scan also may be necessary to fully visualize the tumor and nearby anatomy. Once the imaging is done, the patient will remove his or her vest and it will be stored with the custom-fit body cradle for use in CyberKnife treatment.
A treatment plan will be specifically designed by a medical physicist in conjunction with the patient’s doctors. Patients will not need to be present at this time. During treatment planning, the CT, MRI and/or PET scan data will be downloaded into the CyberKnife System’s treatment planning software. The medical team will determine the size of the area to be targeted by radiation and the radiation dose, as well as identifying critical structures – such as the spinal cord or vital organs – where radiation should be minimized.
At this time, the CyberKnife System will be able to calculate the optimal radiation delivery plan to treat the lung tumor(s). Each patient’s unique treatment plan will take full advantage of the CyberKnife System’s extreme maneuverability, allowing for a safe and accurate lung cancer treatment. After the treatment plan is developed, the patient will return to the CyberKnife Center for treatment. The treatment is usually delivered in one to five sessions.
For most patients, the CyberKnife treatment is a completely pain-free experience. They may dress comfortably in street clothes and the CyberKnife center may allow the patient to bring music to listen to during the treatment. The patient also may want to bring something to read or listen to during any waiting time, and be accompanied by a friend or family member to provide support before and after treatment.
When it is time for treatment, the patient will be asked to put on their vest and lie on their custom body cradle. The radiation therapist will ensure the vest is properly adjusted and that the patient is positioned correctly on the treatment couch.
As treatment begins, the location of the lung tumor will be tracked and detected continually as the patient breathes normally. The medical team will be watching every step of the way as the CyberKnife tracks the patient’s lung tumor as it moves, and safely and precisely delivers radiation to it.
The CyberKnife System’s computer-controlled robot will move around the patient’s body to various locations from which it will deliver radiation. At each position, the robot will stop. Then, special software will determine precisely where the radiation should be delivered by correlating breathing motion with the tumor. Nothing will be required of the patient during treatment, except to relax and lie as still as possible.
Once treatment is complete, most patients quickly return to their daily routines with little interruption to their normal activities. If treatment is being delivered in stages, the patient will need to return for additional treatments over the next several days as determined by their doctors. After CyberKnife treatments, most patients experience minimal side effects, which typically go away within the first week or two after treatment. Doctors will discuss all possible side effects prior to treatment. In addition, doctors may prescribe medication to control any side effects, should they occur.
After completing CyberKnife radiosurgery treatment, it is important for patients to schedule and attend any follow-up appointments. The patient should be aware that his or her tumor will not suddenly disappear. Response to lung cancer treatment varies from patient to patient. Clinical experience thus far has shown most patients respond very well to CyberKnife treatments. Doctors will monitor the outcome in the months and years following a patient’s treatment, often using CT scans or PET-CT scans.

Prostate

Lung

Brain

Spine

Liver

Pancreas

Other

References

1. U.S. Center for Disease Control and Prevention
2. American Cancer Society, “Cancer Facts & Figures, 2008”
3. Korst, R.J., Ginsberg, R.J., Ailawadi, M., Bains, M.S., Downey, R.J., Jr., Rusch, V.W. and Stover, D., Lobectomy improves ventilatory function in selected patients with severe COPD, Ann Thorac Surg, 66 (1998) 898-902.
4. Dominioni, L., Imperatori, A., Rovera, F., Ochetti, A., Torrigiotti, G. and Paolucci, M., Stage I nonsmall cell lung carcinoma: analysis of survival and implications for screening, Cancer, 89 (2000) 2334-44.
5. Flehinger, B.J., Kimmel, M. and Melamed, M.R., The effect of surgical treatment on survival from early lung cancer. Implications for screening, Chest, 101 (1992) 1013-8.
6. .Pennathur, A., Abbas, G., Christie, N., Landreneau, R. and Luketich, J.D., Video assisted thoracoscopic surgery and lobectomy, sublobar resection, radiofrequency ablation, and stereotactic radiosurgery: advances and controversies in the management of early stage non-small cell lung cancer, Curr Opin Pulm Med, 13 (2007) 267-70.
7. West, D., Rashid, S. and Dunning, J., Does video-assisted thoracoscopic lobectomy produce equal cancer clearance compared to open lobectomy for non-small cell carcinoma of the lung?, Interact Cardiovasc Thorac Surg, 6 (2007) 110-6.
8. Ginsberg, R.J. and Rubinstein, L.V., Randomized trial of lobectomy versus limited resection for T1 N0 non-small cell lung cancer. Lung Cancer Study Group, Ann Thorac Surg, 60 (1995) 615-22; discussion 622-3.
9. Martini, N., Bains, M.S., Burt, M.E., Zakowski, M.F., McCormack, P., Rusch, V.W. and Ginsberg, R.J., Incidence of local recurrence and second primary tumors in resected stage I lung cancer, J Thorac Cardiovasc Surg, 109 (1995) 120-9.
10. Dosoretz, D.E., Katin, M.J., Blitzer, P.H., Rubenstein, J.H., Salenius, S., Rashid, M., Dosani, R.A., Mestas, G., Siegel, A.D., Chadha, T.T. and et al., Radiation therapy in the management of medically inoperable carcinoma of the lung: results and implications for future treatment strategies, Int J Radiat Oncol Biol Phys, 24 (1992) 3-9.
11. Haffty, B.G., Goldberg, N.B., Gerstley, J., Fischer, D.B. and Peschel, R.E., Results of radical radiation therapy in clinical stage I, technically operable non-small cell lung cancer, Int J Radiat Oncol Biol Phys, 15 (1988) 69-73.
12. Sibley, G.S., Jamieson, T.A., Marks, L.B., Anscher, M.S. and Prosnitz, L.R., Radiotherapy alone for medically inoperable stage I non-small-cell lung cancer: the Duke experience, Int J Radiat Oncol Biol Phys, 40 (1998) 149-54.
13. Dosoretz, D.E., Galmarini, D., Rubenstein, J.H., Katin, M.J., Blitzer, P.H., Salenius, S.A., Dosani, R.A., Rashid, M., Mestas, G., Hannan, S.E. and et al., Local control in medically inoperable lung cancer: an analysis of its importance in outcome and factors determining the probability of tumor eradication, Int J Radiat Oncol Biol Phys, 27 (1993) 507-16.
14. Sibley, G.S., Jamieson, T.A., Marks, L.B., Anscher, M.S. and Prosnitz, L.R., Radiotherapy alone for medically inoperable stage I non-small-cell lung cancer: the Duke experience, Int J Radiat Oncol Biol Phys, 40 (1998) 149-54.
15. Yorke, E.D., Jackson, A., Rosenzweig, K.E., Braban, L., Leibel, S.A. and Ling, C.C., Correlation of dosimetric factors and radiation pneumonitis for non-small-cell lung cancer patients in a recently completed dose escalation study, Int J Radiat Oncol Biol Phys, 63 (2005) 672-82.
16. Rosenzweig, K.E., Fox, J.L., Yorke, E., Amols, H., Jackson, A., Rusch, V., Kris, M.G., Ling, C.C. and Leibel, S.A., Results of a phase I dose-escalation study using three-dimensional conformal radiotherapy in the treatment of inoperable nonsmall cell lung carcinoma, Cancer, 103 (2005) 2118-27.
17. Baumann, P., Nyman, J., Lax, I., Friesland, S., Hoyer, M., Rehn Ericsson, S., Johansson, K.A., Ekberg, L., Morhed, E., Paludan, M., Wittgren, L., Blomgren, H. and Lewensohn, R., Factors important for efficacy of stereotactic body radiotherapy of medically inoperable stage I lung cancer. A retrospective analysis of patients treated in the Nordic countries, Acta Oncol, 45 (2006) 787-95.
18. Fritz, P., Kraus, H.J., Muhlnickel, W., Hammer, U., Dolken, W., Engel-Riedel, W., Chemaissani, A. and Stoelben, E., Stereotactic, single-dose irradiation of stage I non-small cell lung cancer and lung metastases, Radiat Oncol, 1 (2006) 30.
19. Onishi, H., Araki, T., Shirato, H., Nagata, Y., Hiraoka, M., Gomi, K., Yamashita, T., Niibe, Y., Karasawa, K., Hayakawa, K., Takai, Y., Kimura, T., Hirokawa, Y., Takeda, A., Ouchi, A., Hareyama, M., Kokubo, M., Hara, R., Itami, J. and Yamada, K., Stereotactic hypofractionated high-dose irradiation for stage I nonsmall cell lung carcinoma: clinical outcomes in 245 subjects in a Japanese multiinstitutional study, Cancer, 101 (2004) 1623-31.
20. Uematsu M, Shioda A, Suda A, et al. Computed tomography-guided frameless stereotactic radiotherapy for stage I non-small cell lung cancer: a 5-year experience. Int J Radiat Oncol Biol Phys 2001;51:666-670
21. Miyamoto, T., Baba, M., Yamamoto, N., Koto, M., Sugawara, T., Yashiro, T., Kadono, K., Ezawa, H., Tsujii, H., Mizoe, J. E., Yoshikawa, K., Kandatsu, S., and Fujisawa, T. Curative treatment of Stage I non-small-cell lung cancer with carbon ion beams using a hypofractionated regimen. Int.J.Radiat.Oncol.Biol.Phys, 67[3], 750-758. 2007.
22. Pisters, K.M., Evans, W.K., Azzoli, C.G., Kris, M.G., Smith, C.A., Desch, C.E., Somerfield, M.R., Brouwers, M.C., Darling, G., Ellis, P.M., Gaspar, L.E., Pass, H.I., Spigel, D.R., Strawn, J.R., Ung, Y.C. and Shepherd, F.A., Cancer Care Ontario and American Society of Clinical Oncology adjuvant chemotherapy and adjuvant radiation therapy for stages I-IIIA resectable non small-cell lung cancer guideline, J Clin Oncol, 25 (2007) 5506-18.