Dr. Kenneth Rosenzweig of Mount Sinai says stereotactic body radiation therapy delivers doses of radiation very precisely with high cure rates
The chair of the department of radiation oncology at Mount Sinai, Dr. Kenneth Rosenzweig specializes in treating cancers of the lung and liver. He’s been practicing in the field for 20 years.
WHO’S AT RISK
For a subset of lung and liver cancer patients, doctors are offering a concentrated, high-dose form of radiation that can be delivered very quickly — even during lunch break. “Stereotactic body radiation therapy (SBRT for short) is a specialized way of delivering very precise doses of radiation therapy to a very small area of the body,” says Rosenzweig. “Because we’re treating an area that’s very small, we’re able to use a much higher dose, which is a more effective way of treating cancer-and more convenient for the patient.”
The reason SBRT is not applicable for most cancers is because it delivers such high doses. “For instance a woman with breast cancer typically needs the whole breast irradiated,” says Rosenzweig. “You couldn’t use stereotactic treatment for that, because the high dose-per-fraction couldn’t be used for an area that large.”
Two groups currently benefiting from SBRT are patients with early stage lung cancer and patients with liver cancer. “For the liver and lung cancers, the benefit is that those tumors are frequently found while the cancer is still small, which makes it a more viable treatment option,” says Rosenzweig. “This should increasingly be the case as lung cancer screening becomes more common, which will allow us to do a better and better job of catching lung cancers early.” SBRT is also proving effective in treating patients whose tumors have spread to the spine.
While just about anyone can develop cancer of the lung or liver, some groups do carry a particular risk. “The primary risk factor for lung cancer is smoking, though 15% of lung cancer patients are not smokers,” says Rosenzweig. “The people most affected by liver cancer are patients with underlying liver disease, especially hepatitis.”
SIGNS AND SYMPTOMS
While the pathway to diagnosis can vary, most patients with liver cancer or early stage lung cancer are not diagnosed as the result of symptoms. “Most patients with early stage lung cancer are asymptomatic, though some cases will present with bronchitis or coughing up blood,” says Rosenzweig. “A typical diagnosis scenario is that someone has a CT scan for a different reason, and the scan finds a lung abnormality.”
Liver cancer patients are usually first diagnosed with underlying liver diseases that can progress to cancer. “Typically, these patients have had liver problems that were picked up because they were tired or having flu-like symptoms, and the doctor ran a blood test that found hepatitis or cirrhosis,” says Rosenzweig. “Once the underlying liver disease is diagnosed, most patients undergo routine analysis to make sure that they don’t develop liver cancer — and that it’s caught quickly if they do.”
For most lung, liver and spinal tumors, the first and ideal treatment option is surgery. “The standard-of-care treatment for most of these tumors is surgery — if you can cut it out, that’s the preferable way to go,” says Rosenzweig. “However, many patients are not good candidates for surgery, whether due to their age or other medical problems — and SBRT gives them an effective treatment option.”
In the past, early-stage lung cancer patients who weren’t eligible for surgery were difficult to treat. “The conventional treatment used to be 30 radiation treatments, once a day for six weeks— and the cure rate was only 50%,” says Rosenzweig. “With SBRT, we’re typically doing three to five treatments over the course of a week, and the cure rates are over 90%. I had one patient who walked over and got her treatments on her lunch break— her lung cancer was cured, and she never took time off work.”
The process of delivering SBRT to the patient is extremely precise. “The doctor works with a group of physicists to come up with a plan to treat the tumor and spare the normal tissue, and each patient receives a custom mold to help them keep perfectly still during the treatment,” says Rosenzweig. “The treatments themselves are radiation beams delivered by machines that can deliver very focused doses of radiation — we are always within two millimeters of the target to make sure that we’re not overtreating normal tissue.” With regular radiation therapy, that margin is half an inch to an inch.
Liver cancer patients have a wider variety of treatment options. “There are excellent treatments, including surgical resection, liver transplant, and chemotherapy, both by injection and by mouth, but the problem is that these treatments eventually stop working,” says Rosenzweig. “In these cases, SBRT can help get an excellent control of the tumor — for these patients, it’s about chronic cancer management, not a cure.”
One of the main advantages of SBRT is how well the body tolerates it. “Patients feel tried, but they can usually recover at home without much problem — it’s very unusual that patients spend even one night in the hospital,” says Rosenzweig. “There can be some skin redness, and other side effects depending on what part of the body is irradiated; some people get a little bit of a cough or nausea.”
The biggest discovery of the past five years is the benefit of delivering extremely high doses of radiation — five to 10 times the typical daily dose. “At the high dose, radiation is much more effective at killing cancer than when you break it up into smaller doses,” says Rosenzweig. “Unfortunately, due to the underlying physics of how radiation travels through the body, big doses of radiation therapy are as yet only applicable to situations where there’s a very small tumor. There are research protocols looking at using SBRT for pancreatic cancer, prostate cancer, and sarcomas, but those haven’t been proven yet.”
QUESTIONS FOR YOUR DOCTOR
If you’re a current or former smoker, be proactive and ask, “Is lung cancer screening right for me?” If you are diagnosed with early-stage lung cancer, liver cancer, or metastatic spinal tumors, then ask, “Is my tumor a candidate for SBRT?” It’s also important to go to a busy clinic where the doctors and staff have a lot of experience, so don’t be shy about asking, “How many of these treatments have you performed?” One of the remarkable things about SBRT is that it allows patients the option of an effective treatment that doesn’t take over their lives. “I say to patients, we’re going to be able to cure or contain your cancer, and you won’t have to be restricted by your treatments,” says Rosenzweig. “You’re going to be able to move on with your life.”
WHAT YOU CAN DO
Members of the American Society for Radiation Oncology run a superb patient-focused site at RTAnswers (rtanswers.org). For additional up-to-date information on research and treatment options, check Mount Sinai (mountsinai.org/patient-care/service-areas/radiation-oncology).
See a specialist
“The more you do SBRT, the better you become at doing,” says Rosenzweig.
-and be sure that they’re examining all the options for treatment.
Ask about lung cancer screening.
If you do have a history of smoking, talk to your doctor about whether lung cancer screening is appropriate for you.
“No matter what your health situation, it’s going to be worse with smoking,” says Rosenzweig.
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