PET Scans Offer Hope in Fighting Breast Cancer

When breast cancer is found and treated in its earliest stages, the results can be life-saving. Julie Mack, M.D., radiologist with Lancaster Radiology Associates, echoes the well-known recommendation that “early detection is the best protection.”

To help achieve this, women are encouraged to perform monthly breast self-examination and see their doctors yearly for a clinical breast exam. If a woman is over 40 years of age, she should have a screening mammogram annually.

But what happens if a screening mammogram is abnormal or an exam shows changes?

Often the next step is a diagnostic mammogram and sonogram. A diagnostic mammogram includes more views of the breast that may help to evaluate possible changes on the screening mammogram. A sonogram may also be used because it provides more information about specific areas and can be particularly valuable if an abnormality is felt during a physical exam.

If these additional tests reveal suspicious findings, a radiologist will recommend a biopsy to help in the diagnosis of cancer.

Within the last few years, a new diagnostic tool has been of assistance in the fight against breast cancer. The PET (Positron Emission Tomography) scan can be useful to determine if disease has spread beyond the breast and to evaluate the response of tumors to treatment.

Scott Winner, M.D., of Lancaster Radiology Associates, has used the PET technology for more than two years at the P.E.T. Imaging Center at the Lancaster General Health Campus. PET scans show pictures of the actual biological functioning of the body by capturing images of the body’s chemistry at work. All cells use glucose (a form of sugar) as an energy source.

During a PET scan, a patient is injected with a glucose solution containing a tracer. Cancerous tissue appears “hot” or abnormally active on a whole-body PET scan. This is because cancer cells use more energy than healthy cells and thus more of the injected glucose solution.

Dr. Winner recalls the case of a patient whose doctors suspected she had a recurrence of breast cancer, but could not locate it. A PET scan was performed and the cancer was discovered. “We would never have found it without the PET scan,” Dr. Winner says.

A PET scan can also help the patient who has already been diagnosed with breast cancer and is undergoing treatment. Following chemotherapy, a PET scan can determine if a tumor still exists or if cancer has spread. While CT (computed aided tomography or CAT) scans have traditionally been used to assess the treatment’s effectiveness, those scans may not always be as accurate as a PET scan. For example, a scar located where a tumor was can resemble a residual tumor on a CT scan. However, on a PET scan scar tissue does not use glucose and therefore will not appear as “hot.”

“PET is an excellent problem-solving tool in patients diagnosed with breast cancer. PET studies offer a more accurate method to stage recurrent disease and are frequently used to determine if the disease has spread beyond the breast. This has a great clinical impact in breast cancer management. We can also use PET studies to help patients who are being treated for cancer to determine if the treatments are succeeding,” Dr. Winner says.

Dr. Mack specializes in screening women for breast cancer and assisting with the development of a care plan to obtain a rapid diagnosis. Because traditional screening and diagnostic methods can find breast tumors, using PET for primary diagnosis is rare. However, PET scans can be incredibly valuable for helping accurately stage the disease to offer the best treatment plans.

“A PET scan is not something I recommend for every breast cancer patient,” she explains. “However, PET scans have proven to be a powerful tool in those situations where standard imaging and staging procedures fall short of a full answer.”

Lancaster General is fortunate to have one of the few permanent (versus mobile) PET scanners in the region and the only one in Lancaster County.