Feature | March 18, 2011 | Todd Loesch

Finding the Right Plan

Advancements in treatment planning boost physician confidence

The past 15 years have seen significant advances in treatment planning. Physicians can now work in 3-D, utilize dose planning and take advantage of techniques such as intensity-modulated radiation therapy (IMRT) and image-guided radiation therapy (IGRT).

While the diversity of advances has given doctors many more tools at their disposal, the one thing they have in common is that they all have resulted in an increased physician confidence and more focused therapy for the patient.

A Range of Systems Offers a Range of Capabilities
Like many cancer centers, The Gibbs Cancer Center, which is part of the Spartanburg Regional Healthcare System in South Carolina, utilizes several treatment planning systems. According to Michael Starnes, the center's manager of radiation oncology, Elekta's XiO is their workhorse planning system. It handles the bulk of cases, including breast, lung, brain and prostate cancer patients. Starnes also uses a Nucletron system for brachytherapy patients.

But the center's showcase is its TomoTherapy unit, which it purchased roughly five years ago. Although Starnes said the system is reserved for specialized cases, it has been a huge asset to the clinic.

"TomoTherapy has enabled us to treat a lot of different areas that before might have been hard for us," he said.

Despite the significant investment the system required - it has its own integrated planning system and dedicated internal network - the decision to purchase it was fairly simple.

Starnes admits that part of it was for prestige. At the time, no other clinic in South Carolina, North Carolina or Georgia had a TomoTherapy unit. But the main reason was that the system could do things other systems simply could not do, which would give Starnes and his team numerous clinical advantages.

"For us, it was kind of a no-brainer," he said. "We really wanted to raise the level of treatment for our patients, hopefully to minimize side effects, both long-term and acute."

The benefits were almost instantaneous. The system allows Starnes and his team to do 4-D planning, which not only measures the height, width and depth of the tumor, it also looks at how the tumor moves over time. This is especially important with lung and prostate tumors, which can move based on the patient’s breathing or other internal conditions. In those cases, knowing the exact location of the tumor is critical to effective treatment.

Using the TomoTherapy system, the team at the Gibbs center also can do stereotactic body radiation therapy (SBRT). In the past, Starnes said his team would have to send those patients to bigger research facilities, such as Duke or Wake Forest. Now they can treat them at their clinic. Not only does it make the center more competitive in the marketplace, the system also makes life easier for patients, since they don’t have to travel to multiple sites for treatment.

Starnes points out that their very first SBRT case underscored how helpful the TomoTherapy system can be. Just before ordering the system, the clinic had been working with a local man who needed SBRT. The team tried to refer him to Wake Forest, but the patient did not want to travel out of state. Once the TomoTherapy system was installed - and once the team monitored the patient's disease to make sure it hadn't progressed - the patient was able to receive treatment without having to travel.

The system does have one slight disadvantage, Starnes said, in that treatment plans take slightly longer, because patients get a computed tomography (CT) scan prior to treatment.

At the beginning of the treatment planning process, a patient meets with a radiation oncologist for a simulation appointment. The patient gets on a CT table and is fitted with an aquaplast mask, which lets the physician immobilize the patient and put localization marks on the mask. Starnes said it is imperative the marks are in the same place every day to make sure dose is given only to desired areas.

"When we're throwing a lot of radiation at your neck or your head, we really want to be sure we're in the exact same spot every day, the spot that we plan to treat," he said.

Dosimetrists then take the CT data and contour the majority of the patient, including structures such as the brain stem, spinal cord and parotid glands. Using those contours, the radiation oncologist then draws tumor volumes and any kind of affected nodal volumes.
After the plan has been entered into the machine and fine-tuned, the physics department determines the optimal treatment via a delivery quality assurance (DQA) plan. Finally, a phantom is irradiated to see whether the actual delivered dose matches up to the plan.

However, Starnes said the slightly longer treatment times are worth it.

"You can get a good plan fairly quickly, but sometimes that isn't necessarily the best plan for the patient," he said.

Increased Confidence in the Plans
Having confidence in treatment plans is essential, and technology can increase confidence levels. Such has been the experience of Domenico Delli Carpini, Ph.D., at the Bendheim Cancer Center, Greenwich Hospital, Greenwich, Conn. Delli Carpini relies on the Philips Pinnacle treatment planning system and verifies it with IBA Compass patient dose analysis software.

Fundamentally, the treatment planning process at Bendheim isn't much different from what Starnes does with TomoTherapy at the Gibbs Center. Based on the initial scan, a physician draws the contour and a physicist determines which gantry angles to use to best deliver dose. From there, the plan is fine-tuned to meet objectives that are individualized to each patient.

The Pinnacle plan is compared to one made using Compass. With the Compass system, a device attached to the gantry collects data as it rotates around the patient.

The benefits to this are two-fold: First, it lets Delli Carpini continuously sample data; second - and perhaps most importantly - it gives him a three-dimensional dose distribution. Without the 3-D view, he would be limited to taking two-dimensional snapshots.

Although these snapshots aren't necessarily a poor way of treatment planning, he said they aren't sufficient by themselves.

"Because the QA now gives me three-dimensional information, it gives me a lot of confidence," he said. "If I didn't have that, I would always question it."

With older methods, Delli Carpini would have to take as many as 10 planar views each time. Now, using the SmartArc delivery as part of the Pinnacle system, he can get all the data he needs in one gantry pass. This drastically increases patient comfort, since they don't need to be on the table as long. In fact, with SmartArc, the patient is only on the table for one or two minutes.

"I think it helps the patient relax more, knowing that it's just once around rather than 10 fields and 10 positions," he said.

Treatment Planning Advances are Better for Patients
The recent advances in treatment planning technology have made a huge impact on patients and the treatment planning teams. Patients are getting quicker plans, which increases comfort, and more accurate delivery, which in many cases can vastly improve the quality of life.
Starnes said TomoTherapy has helped reduce complications with head and neck patients. In the past, patients would walk around with water bottles, since most of the parotid gland would be destroyed during treatment.

Now, physicians are able to spare much of the parotid glands and give patients better salivary function than they would have had otherwise.
Both Starnes and Delli Carpini insist that the older methods are still valuable. In fact, in many cases the older systems are their clinics' workhorses. But both agree that new technology and software have significantly increased their confidence. And in cases where accuracy down to the millimeter is vital, that confidence is key.

"You can't really 'kind of know' where you are," Starnes said. "You have to know exactly where you are."