Pet Scan Monitors Cancer Treatment

By Roger Schlueter, Belleville News-Democrat, Ill.

Call it a hunch, a woman’s intuition or what you will, but Dr. Susan Laduzinsky just knew her cancer treatment was not working.

Last September, doctors were stunned to find a tumor of surprising proportions growing inside the right breast of this 49-year-old radiation oncologist at the Cancer Treatment Center in Swansea.

Just eight months before, her regular mammogram had shown nothing. Suddenly, she had a virtual boulder measuring nearly 3 inches across — several times the size of the usual “early-stage” cancer. Within a week, she was on dose-dense chemotherapy as doctors tried to shrink the tumor before surgery.

But midway through that initial treatment, Laduzinsky was convinced the toxic concoction just wasn’t working.

“I just didn’t think much was happening,” she said. “In fact, I thought if anything it was actually growing. I thought there were more changes, more thickening in my breast.”

That was a frightening feeling, particularly considering the size of her tumor. But to find out for sure, Laduzinsky turned to a tool that’s being increasingly utilized by doctors as they try to individualize treatments for cancer patients: a positron emission tomography — or PET — scan.

In cases like Laduzinsky’s, PET scans apparently can show early on how much of the tumor is being killed off by the potent drugs. So, if one treatment is not working, doctors can move on to something else.

And, Laduzinsky? Well, let’s say this was one time she was glad her intuition failed her. Her PET scan revealed that although the tumor had not shrunk in size, its activity level had dropped substantially, an important indication that she was en route to a cure.

As a result, she completed her chemo treatments, underwent a mastectomy in January and is now by all indications cancer-free. She will always be grateful for the reassurance the PET scan gave her in November.

“It’s a very tough treatment,” Laduzinsky said of the chemotherapy. “There’s no doubt about it. I was in great shape before all this started. I was exercising daily and eating right. Doing everything correctly. And, it has really worn me down considerably.

“So, if you don’t know if the treatment is doing you any good, it’s very difficult to continue something like that. For me, it really was incredibly helpful.”

It’s even more helpful for one of Laduzinsky’s colleagues at the center, Dr. Jorge Frank. As a medical oncologist, Frank plans chemo regimens for the center’s patients. He wants to know whether people are responding to his treatments as quickly as possible, so he is making increasing use of the center’s PET-CT scanner to do just that.

Take lymphomas, for example. Until PET came along, patients with the common malignancy of the lymph-gland system had to suffer through six to eight treatments not knowing whether the medicines were doing them any good, Frank said.

Now, Frank can judge treatment effectiveness after four treatments. If the PET-CT scan is negative — as about 83 percent are — the patient has a good prognosis. If it’s not completely negative, Frank knows to try something else to save a patient needless suffering and expense.

“So, it guides us not to give the patient four more treatments of the same thing that’s not going to help the patient,” said Frank, who also uses PET to help “stage” the tumor, find its exact location and check for cancer recurrence after treatment. “We can switch treatments in the middle of the river. That’s how this whole thing is just evolving.”

PET is so valuable because it lets doctors look into the body in a totally different way than other forms of imaging. Rather than showing simple structure like an X-ray or CT scan, the PET can show function or activity inside the structure.

A patient is injected with a radioactive sugar. Like normal tissue, most active tumors absorb a lot of sugar for food. A PET scan shows to what extent the tumor is metabolizing this sugar.

In Laduzinsky’s case, this is what made all the difference. A CT scan showed her tumor was the same size, which, without the PET, would have suggested the chemotherapy was a waste of time.

But when that crucial PET image in November was compared to her initial scan, it showed far fewer “hot spots” in the tumor — areas that were actively processing that sugar. In other words, a growing part of the tumor now was dead.

According to a report at the San Antonio Breast Cancer Conference just last December, this was cause to celebrate.

“If after the first few cycles of chemotherapy you can see a decrease by 50 percent of the intensity of the breast cancer on the PET scan, that’s a very good indicator that you’re going to get a complete response to the chemotherapy,” Laduzinsky said. “And, that’s exactly what happened to me.”

Some might wonder the importance of all this, considering that, because of the tumor’s size, Laduzinsky had to undergo a mastectomy anyway. But as a cancer doctor, she knows that even women with small tumors and negative lymph nodes have a 25 percent chance of recurrence. Knowing her chemotherapy was effective was additional comfort.

“When you have a large tumor, you want to give very intense treatment in order to have any chance of being cured of the disease,” she said. “This way you know up front whether or not there has been some response to the treatment.”

Even the federal government is starting to acknowledge the potential usefulness of PET scans in treatment evaluation. Currently, the Food and Drug Administration will not consider PET data when it decides whether or not to approve new cancer drugs; drug companies are allowed to submit only older forms of imaging.

But last month, a group that includes the FDA, the National Cancer Institute and Medicare as well as patient-advocacy groups and drug makers said it was considering adding a PET-scan project to current lymphoma research.

The short-term goal will be to convince the FDA that PET scans should be considered in judging a drug’s effectiveness at shrinking tumors. The long-term goal would be to establish PET as a standard cancer treatment evaluation tool. Patients would be regularly scanned after a few rounds of treatment to see whether dosages should be changed or medications switched.

And, lymphoma is just the start. George Demetri, a cancer researcher at the Dana Farber Cancer Institute, for example, said he could see tumor changes in as little as 24 hours when he used PET to evaluate drug treatments for a rare type of stomach cancer.

Now, Laduzinsky says, it’s a matter of convincing insurance companies. Including the radioactive sugar, a single PET scan costs about $3,500 at the center. But Laduzinsky argues it may be a bargain in the long run.

“Chemotherapy is incredibly expensive, so that the cost of doing the test is cheaper than the next round of chemo,” she said. “Besides, all the toxicity could require hospitalization, more antibiotics, all different kinds of things. So, it’s probably a money saver for the insurance companies to not have to give chemotherapy that’s not going to work.”

For patient peace of mind, it would be priceless, she added.

“The last thing you want to do is go through this toxic treatment and not know if it’s doing you any good. And, otherwise, you don’t know. I mean you hope and you pray, but you just have no idea.”

Contact reporter Roger Schlueter at 239-2465 or rschlueter@bnd.com

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Copyright (c) 2006, Belleville News-Democrat, Ill.

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