Role of PET-CT Scan in Ovarian Cancer

Ovarian cancer begins in the ovary and invades other tissues or organs and spreads. Sometimes symptoms are vague or not present at all in an early stage of ovarian cancer, so the cancer is diagnosed at a later, more advanced stage. Imaging tests are helpful to determine how far the disease has advanced, to help plan treatment, and to follow the patient's response.

Combined "metabolic information" from PET and detailed images of anatomy from CT give more information about ovarian cancer using a PET-CT scan. It is useful in locating regions of high metabolic activity, determining the extent of the spread of cancer, determining the response to therapy, and identifying possible cancer recurrence. In general, however, PET-CT is not the first or only test used for the diagnosis of ovarian cancer. MolecularDiagnostics and Therapy provides PET-CT imaging services that can support the evaluation of cancer-related conditions when recommended by a doctor.

What Is a PET-CT Scan?

PET-CT is a type of scan that combines Positron Emission Tomography and Computed Tomography. Concurrently utilizes two imaging technologies in one examination. Using the CT component, detailed pictures are formed of the internal structures of the body, such as organs, tissues, lymph nodes, and so on. The PET component gives information about the metabolic level in tissue(s). A radiotracer is injected before the scan, usually a compound called fluorodeoxyglucose (FDG).

Some cancer cells are more active in using glucose than healthy cells are, causing some areas of the PET scan to light up. If PET and CT images are used together, doctors make comparisons between abnormal metabolic activity and its anatomical location. This is of benefit when assessing some types of cancer.

Why Is PET-CT Used in Ovarian Cancer?

In some patients with ovarian cancer where more information is required about the cancer than provided by traditional imaging, PET-CT might be suggested. An important function it has is determining whether the cancer has spread. Ovarian cancer invades (metastasizes) into the abdominal and pelvic cavity and spreads to the lymph nodes and distant organs, such as the lungs and liver. PET-CT is helpful in locating increased metabolism, which means cancer involvement. The PET-CT is also helpful if doctors suspect a return of the ovarian cancer. Locating and determining the extent of the recurrent cancer helps the doctor determine the next steps in cancer management if the cancer has come back after treatment.

PET-CT for Cancer Staging

Cancer progresses to a certain level before diagnosis, known as staging. It is important because if the disease is confined to the ovaries or if it has spread to other regions of the body, the treatment differs. Contrast-enhanced computed tomography (CT) of the abdomen and pelvis, with or without chest imaging, is sometimes used to get a baseline diagnosis in ovarian cancer. In specific cases, PET-CT is useful to provide more information, especially if there is a possibility of metastasis or recurrence. The PET component shows areas of increased metabolic activity, and the CT component details their exact anatomical location. The information helps doctors understand the full extent of the disease.

Role of PET-CT in Detecting Cancer Spread

Ovarian cancer also invades the lining of the abdominal cavity, various lymph nodes, the liver and spleen, and other parts. Since this spread is detectable, it is taken into consideration for treatment planning. PET-CT is useful to help locate metabolically active lesions that may not be seen using traditional imaging modalities. But in some instances, very small lesions or special kinds of tumors are not observed with a PET-CT. Increased tracer uptake is observed in cases of inflammation and in certain non-cancerous situations. Hence, PET-CT findings must always be correlated with the patient's clinical presentation, clinical history, laboratory studies, and other imaging tests.

PET-CT and Treatment Response

Another great advantage of a PET-CT is that it also delivers details on metabolic activity. This sometimes aids the physician in determining the response of the tumor to therapy. For instance, if there is still some abnormal metabolic activity after systemic therapy (e.g., chemotherapy), the reduced activity is a sign of response to the systemic therapy. PET-CT can thus be used to help evaluate treatment efficacy in some patients. The scan does not look at metabolic activity only to interpret the information. Treatment response is also assessed by noting changes in tumor size and other data obtained from a computed tomography scan in addition to clinical data.

PET-CT for Recurrent Ovarian Cancer

Ovarian cancer recurrence following treatment. Recurrence is detected at the correct stage, which aids in a proper management plan for the next steps. If recurrence is suspected due to symptoms, physical examination results, laboratory results, or abnormalities seen on other imaging tests, PET-CT gives more information on the location and extent of the disease. It is useful in defining abnormal metabolizing processes all over the area scanned, and in separating some “suspicious” areas from adjacent tissues. But PET-CT isn't flawless, and the information from the test is to be interpreted alongside all of the other clinical signs.

What Happens During a PET-CT Scan?

The patient is typically injected with a radiotracer before the scan, and the signals sent from the tracer are captured by the scanner. Time allows the tracer to pass through the body and penetrate the tissues. During this waiting time, the patient is encouraged to lie still. An alternative method of measuring blood glucose levels is also performed, especially in people who have a history of diabetes, as blood sugar changes have an impact on the results of FDG PET. Once the tracer has been stored, the patient gets to lie on the scanning table. The table passes through the PET-CT scanner, which takes a series of images. Usually, the PET part takes longer, but the CT part only takes a short time.

Is PET-CT Accurate for Ovarian Cancer?

PET-CT can provide valuable information, but no imaging test is 100% accurate. Its usefulness depends on factors such as the type and size of the tumor, its metabolic activity, the stage of disease, and the reason for performing the scan. Some small tumors may not be detected, while infections or inflammation can sometimes appear similar to cancer because they may also show increased metabolic activity. For this reason, PET-CT should not be considered a standalone test that confirms or excludes ovarian cancer. Doctors interpret PET-CT findings together with other investigations and, when required, tissue diagnosis.

PET-CT vs CT in Ovarian Cancer

CT and PET-CT provide different types of information. A conventional CT scan primarily provides detailed anatomical information and is an important imaging test for evaluating ovarian cancer. PET provides information about metabolic activity. When combined, PET-CT can provide both anatomical and functional information in a single examination. The choice between PET-CT, MRI, ultrasound, or other investigations depends on the patient's individual situation and the clinical question the doctor needs to answer.

Benefits of PET-CT in Ovarian Cancer

One of the major benefits of PET-CT is that it combines two types of information in one examination. This can help doctors locate areas of abnormal metabolic activity more precisely. PET-CT may help in evaluating metastatic disease, suspected recurrence, and treatment response in selected patients. It can also provide information about disease activity that may not be apparent from anatomy alone. At the same time, PET-CT has limitations. It involves exposure to a small amount of radiation, and certain cancers or small lesions may show limited tracer uptake. Blood glucose levels can also influence FDG PET results.

When May Your Doctor Recommend a PET-CT Scan?

A doctor may recommend PET-CT when additional information is required for evaluating the extent of ovarian cancer, suspected spread, treatment response, or possible recurrence. It is important not to undergo PET-CT simply because it is considered a more advanced scan. The appropriate imaging test depends on the patient's condition, previous scan findings, and the specific question that needs to be answered.

Conclusion

PET-CT is a potentially useful imaging modality in the treatment of the selected patient with ovarian cancer. PET can be used in conjunction with detailed anatomical information obtained from CT to aid in the evaluation of disease extent, determine possible disease spread, prognosis of treatment, and further investigation of suspected disease recurrence. But PET-CT is, in general, not the first or only test performed when a person gets a diagnosis of ovarian cancer. The results obtained should be interpreted in conjunction with clinical evaluation and other investigations, as indicated, including blood tests, ultrasound, CT, and MRI.

Molecular Diagnostics and Therapy offers advanced PET-CT and nuclear medicine services to support patients undergoing recommended cancer imaging and evaluation. With its diagnostic facilities, we aim to provide comprehensive imaging support based on the clinical requirements of each patient.