Targeting with radiation
Patients at Long Beach Memorial’s Todd Cancer Institute know the power of modern radiation therapy.
They’ve seen their tumors shrink or disappear after treatment with state-of-the-art radiation technologies. “Because we have a complete array of advanced radiation therapies, treatment can be precisely tailored to each patient’s needs, even in the most complex or challenging cases,” says Nisar Syed, M.D., medical director of radiation oncology.
External beam radiotherapy is one of the technologies available at the Todd Cancer Institute. This includes Varian image-guided radiation therapy and TomoTherapy, two state-of-the-art radiotherapy methods that help doctors attack tumors with laser-sharp accuracy. Both combine imaging and treatment capabilities in a single machine.
“Image-guided therapies use a built-in CT scanner to pinpoint the exact location of tumors before each treatment,” says Dr. Syed. “Frequent imaging is important because tumors can change shape or position from day to day.” Additionally, both machines deliver radiation doses that are computer-designed to match the exact contour and depth of the tumor—a capability known as intensity-modulated radiation therapy. This means that patients can receive higher doses of radiation with less damage to the healthy tissue surrounding the tumor. Another feature is the ability to deliver powerful beams of radiation in a continuous, 360-degree multi-directional attack on tumors—a key capability in stereotactic surgery.
“Stereotactic surgery involves targeting a tumor from many different directions with multiple radiation beams, which are delivered simultaneously,” says Ajmel Puthawala, M.D., associate director of radiation oncology. “The effect is an ‘invisible blade’ of powerful radiation, delivered directly to the growth without affecting surrounding healthy tissue.”
In addition to external beam radiation, which comes from a source outside the body, the Todd Cancer Institute offers internal radiation therapies. Called brachytherapy, this method involves placing a radioactive material directly inside or close to a tumor. “Brachytherapy can be temporary or permanent,” explains Dr. Syed, who is one of the world's leading authorities on the subject. With temporary brachytherapy, a radioactive material is placed in or near the tumor for a specific amount of time and then withdrawn. For example, MammoSite® therapy involves the implantation of a small saline-filled balloon catheter inside the space left by removal of a breast tumor. Doctors then insert a tiny radiation-tipped wire into the balloon for a 10-minute treatment twice daily for five days. When therapy is completed, the balloon is removed.
On the other hand, permanent brachytherapy involves the implantation of dozens of radioactive seeds, which stay in place indefinitely. Once their radioactivity is depleted, the seeds remain in the body with no effect on the patient. Prostate cancer is often treated this way.
The overall advantage of brachytherapy is that high doses of radiation can be administered with minimal harm to healthy tissue, allowing patients to resume their normal activities almost immediately. “Radiation therapy is often combined with hyperthermia—heat treatments that can make some tumors more sensitive to radiation and harm other cancer cells that radiation can’t affect,” says Dr. Puthawala.
What’s next? The Todd Cancer Institute will acquire groundbreaking technology called proton beam therapy, which involves firing streams of protons—positively charged subatomic particles—into tumors. “We’ve been approved to proceed with the architecture and engineering of the proton therapy project, making us one of only 13 centers in the country planning to acquire this leading-edge technology,” says Priti Nagar, director of radiation oncology. “Our high-tech, high-touch approach makes a tremendous difference for patients and their families.”