CANCER TREATMENT
In the last decade, cancer has overtaken heart disease as the number one cause of mortality in the United States.
Lung cancer remains the leading cause of cancer death in both men and women, and the American Cancer Society estimates that 30 percent of all cancer deaths are tobacco related.
Unlike prostate cancer where a blood test can detect cancer in its early stages, there is no tumor marker for lung cancer, and plain chest x-rays are poor detectors of early stage lung cancer. However, recent studies using CAT scan screening in high-risk smokers are encouraging.
The standard of care for early stage lung cancer remains surgery, either lobectomy (removal of a piece of one lung) or pneumonectomy (removal of an entire lung).
Patients with medical or physical conditions that make surgery very risky are often referred for radiation – or do not receive any treatment at all.
Despite the significant competing medical conditions, risk of dying from lung cancer can still exceed 50 percent favoring treatment. Long-term survival of an untreated Stage I lung cancer is just 6 percent at five years.
Stereotactic Body Radiotherapy
Stereotactic Body Radiotherapy is a highly focused beam of radiation is delivered to the tumor in the lung providing a high central dose but minimal dose to surrounding healthy lung.
Historically, radiation would require 6-8 weeks of daily treatment, Monday through Friday, and this can be difficult for patients with functional limitations.
There is now an alternative – Stereotactic Body Radiotherapy (SBRT). A highly focused beam of radiation is delivered to the tumor in the lung providing a high central dose but minimal dose to surrounding healthy lung.
The original site where stereotactic treatment was pioneered was in the brain. Currently, SBRT is utilized in primary and/or metastatic tumors of the lung, liver, bone, pancreas, adrenal and prostate.
The first reports of SBRT were published in the mid 1990s and the technology has been refined over the last decade. Currently, patients complete treatment within a week and each painless session is less than 30 minutes.
No sedation is needed and treatment is noninvasive – no needles, no IVs, no cutting. Candidates are patients with a small solitary lung nodule, less than 5 cm and deemed to not be surgical candidates.
At the time of treatment, patients lay comfortably on the treatment couch while a pinpoint beam of radiation is focused on the tumor. There are no diet or activity restrictions during treatment. After the treatment is completed, a follow up CAT scan or PET/CT scan is obtained approximately a month later to assess for tumor response.
High Success Rate
A meticulous quality assurance program is imperative when treating with SBRT. Multiple institutions report control of the treated lung lesion in the 90-96 percent range. The MIMA Cancer Center started its SBRT program in 2006 and the local control rate is 95 percent.
Because tumors can move with the breathing cycle, attention to target motion is imperative. Verification of target position prior to treatment is crucial and ensures accurate dose delivery. Centers providing SBRT require technology that can precisely determine the location and extent of target motion and deliver the high dose with great geometric precision and spare dose to healthy surrounding tissue.
There are different systems available to deliver SBRT. RapidArc allows the entire treatment to be delivered in one or two arcs, a more efficient treatment than with multiple static beams.
Most patients complete treatment in less than 15 minutes, other systems can require 45-120 minute sessions. Extended treatment times have a negative effect on patient comfort which, in turn, can adversely affect precise delivery of the entire radiation dose.
Now, inoperable patients have an alternative, one that is fast, noninvasive and carries an excellent chance at tumor ablation with low risk of side effects. Current studies are assessing this modality in patients who are operative candidates.
My hope is that our population will continue to heed the hazard warnings of tobacco abuse and avoid ever hearing the words, “You have lung cancer.”
Dr. Nanialei Golden
ABOUT THE AUTHOR
Nanialei M. Golden, MD, received her medical degree from Chicago Medical School, completed her Radiation Oncology residency at Northwestern University in Chicago, Illinois, and did her fellowship in Gamma Knife Radiosurgery at the University of California, San Francisco. After practicing at Holmes Regional Medical Center in Melbourne, Florida for six years, Dr. Golden joined the MIMA Cancer Center in 2004. She is currently the Radiation Oncology Medical Director and is Chairman of the weekly MIMA Cancer Center Tumor Board and is active on many cancer related committees including the Brevard County American Cancer Society Board of Directors. She has extensive experience in Image Guided Radiation Therapy (IGRT), Intensity Modulated Radiation Therapy (IMRT), Brachytherapy (including prostate and gynecologic malignancies), Stereotactic Body Radiotherapy (SBRT) and Stereotactic Radiosurgery (SRS), and she lectures internationally on those cancer therapeutics. In 2010, Dr. Golden received her Fellowship through the American College of Radiation Oncology for 10+ years of meritorious service in the field of Radiation Oncology.
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