Invasive cervical cancer is a devastating cancer affecting women. According to the American Cancer Society, an estimated 12,900 cases of invasive cervical cancer are expected to be diagnosed annually. Incidence rates have decreased steadily over the past several decades as the Pap test has become more prevalent. Annually in the US, there are an estimated 4,100 deaths related to cervical cancer. Mortality rates have declined sharply over the past several decades as well. However, both incidence and mortality rates have begun to level off in recent years.
Atlanta: American Cancer Society; 2015
The primary cause of cervical cancer is infection with certain types of human papillomavirus (HPV). Importantly HPV infections are common in healthy women and only rarely result in cervical cancer. Persistence of HPV infection and progression to cancer may be influenced by many factors, such as immunosuppression, high parity (number of childbirths), and cigarette smoking.
Early cancers of the cervix can be found by a Pap test; a relatively painless, simple procedure that should be performed annually for women over the age of 18. This test collects cells from the cervix and examines them under a microscope to look for evidence of cancer. Survival for patients with an early pre-invasive lesion is nearly 100%, with curative treatment possible through local procedures. Of particular interest is that the PET findings at presentation of cervical cancer are predictive of disease-free recurrence. Patients with positive PET and CT scans of the retroperitoneal nodes have the worst prognosis. Patients with positive PET and negative CT scans have nearly as poor a prognosis, whereas patients with negative PET scans of these nodes, irrespective of CT findings, have a substantially better prognosis.1
When cervical cancer has not been found at this pre-invasive stage, tests are performed to determine if and how far the cancer has spread. If lymph nodes are involved with disease, the cancer may have spread systemically. PET imaging increases the accuracy for detecting lymph node and metastatic disease in patients with advanced-stage cervical cancer.2
Early determination of how far the invasive cervical cancer has spread is key to selecting the most appropriate treatment.
Atlanta: American Cancer Society; 2015
The stage of cervical cancer and the presence or absence of nodal disease will alter the therapeutic management of patients. Accurate staging before radiation therapy allows modification of the treatment field to include treatment to other areas of disease.
PET has been found to be of value for detection of cervical cancer metastases.1 Using PET may reduce unnecessary surgical interventions, help modify radiation fields and change therapeutic approaches.1
Accurate staging before radiation treatment helps modify radiation fields and changes therapeutic approaches.
Amit A, et al. The role of hybrid PET in the evaluation of patients with cervical cancer. Gynecologic Oncology 2006;100:65-69
After treatment is complete, it is important to know if any active cancer cells remain in the body. This is called restaging. A follow-up whole-body PET scan is used to restage the entire body for the presence or absence of active tumor.
If the cancer cells have been destroyed they will not absorb the radioactive glucose. Conversely, if the cancer has come back, the PET scan can detect the accumulation of radioactive glucose much sooner than the CT scan can detect the change. This helps the physician determine if the treatment was successful or if the tumor has returned.
Often, scar tissue at the site of surgical resection or radiation treatment may appear as an abnormality on the CT scan. The PET portion of the scan can detect any accumulation or absence of radioactive glucose, which helps the physician differentiate scar tissue, from recurrent tumor or residual disease. If retreatment by surgery, radiation therapy or chemotherapy is necessary and can be detected and restarted as soon as possible, it will improve the chance of beating the disease.
After treatment at follow-up visits, depending on the stage of the cancer, doctors may order additional tests and procedures to determine if the cancer has returned. PET provides meaningful information for the early evaluation of therapeutic response and long-term follow-up.1
PET can be used to image tumor response to therapy and to detect recurrence in treated lesions.
Magne N, et al. New trends in the evaluation and treatment of cervix cancer: the role of FDG-PET. Cancer Treat Rev. 2008 Dec; 34(8):671-81
PET is a noninvasive test that physicians utilize to stage the body for the presence or absence of active tumor, localize the tumor, assess the tumor response to treatment and detect recurrence in treated lesions.
PET Utilization for Cervical Cancer
Source: Atlas of Clinical Positron Emission Tomography by Sallie F. Barrington, Michael N. Maisey and Richard R. Wahl. Oxford University Press, Inc. New York, NY.
Oncologic PET/CT: A primer for radiologists by Stephen Humes, MD. AuntMinnie.com