Could an Imaging Test Predict How Well You’ll Respond to a Stem Cell Transplant?

A stem cell transplant can be a pretty grueling treatment that involves getting very high doses of chemotherapy, spending three to four weeks in the hospital, and enduring side effects like nausea, vomiting, mouth pain, infections, bleeding, and lung inflammation. And after all of that, you still may not get the results you want.

“If it’s going to cure the patient, I think it’s all worthwhile to go through,” Dr. Jakub Svoboda, medical oncologist at Penn Medicine, tells SurvivorNet. If, on the other hand, a stem cell transplant isn’t likely to result in a cure, it may not be a good choice for you.

One clue that can help your doctor decide whether a stem cell transplant is worth the risks involved is how well you responded to chemotherapy after your cancer relapsed. People with an aggressive lymphoma that didn’t respond well to chemotherapy tend not to have a good outcome from a stem cell transplant.

Having a combination imaging test called a PET/CT scan before a stem cell transplant can help pinpoint your response to chemo, and let you avoid some potentially severe side effects if this treatment isn’t likely to cure you. “The PET/CT technology has allowed us to select the patients who will likely benefit from autologous STEM cell transplant,” Dr. Svoboda says.

 

A View From the Inside

The PET/CT scan combines two common cancer imaging tests. PET stands for positron emission tomography. Before the test, you get an injection of a small amount of radioactive sugar, called fluorodeoxyglucose-18 (FGD-18). Because cancer cells use a lot more energy than healthy cells, they absorb the sugar in larger amounts. As the tracer collects in the cancer, it makes those areas light up and become visible, so your doctor can see them on the scan.

CT is short for computed tomography. It takes x-rays of your body from different angles, to create a cross-sectional view of your organs and tissues. The CT scan can reveal areas of your body that are enlarged from the cancer. It alone isn’t sensitive enough to pick up metabolically active areas of cancer, which is why the two tests are combined.

A computer combines the PET and CT images to give your doctor a highly detailed, three-dimensional view of your cancer. Having both of these tests together can show your doctor not only whether your cancer is shrinking, but also if it’s still active.

When people still have some metabolic activity within shrinking areas of cancer, “they actually don’t do well with the transplant,” Dr. Svoboda says.

If a Transplant Isn’t Right For You

It’s very helpful for doctors to have the information from a PET/CT scan, Dr. Svoboda tells SurvivorNet.  “You can then offer that patient a different treatment or steer them toward some of the novel therapies.”

One alternative to stem cell transplant is chimeric antigen receptor (CAR) T-cell therapy. It’s a promising treatment for some people with aggressive non-Hodgkin lymphoma that hasn’t responded to other treatments. CAR T-cell therapy involves genetically modifying your own immune cells so that they attack your cancer. “CAR T-cell therapy or other treatments actually may have a better chance at working than transplanting in this setting,” Dr. Svoboda says.

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