How is cervical cancer diagnosed, and what tumor features are considered in staging and pretreatment planning?
Cervical cancer is diagnosed histologically from tissue obtained via a cervical biopsy. Once the diagnosis is made, further workup is required for staging, which may include a combination of physical examination, chest radiography, barium enema examination, intravenous urography, colposcopy, hysteroscopy, cystoscopy, and/or proctoscopy with tissue sampling and histologic confirmation required for additional sites of suspected involvement. The FIGO staging of cervical cancer is clinical, as this allows for uniformity of staging in low-resource countries around the world. That is, tomographic imaging findings from CT, MRI, and PET imaging are not utilized to stage cervical cancer, although they are commonly used for delineation of disease sites and lesion sizes for pretreatment planning purposes. As such, clinical staging is less accurate than surgical staging.
MRI can be helpful for pretreatment planning by identifying parametrial involvement, invasion of the upper two thirds of the vagina, tumor extension into the adjacent structures, lymphadenopathy, and distant metastases. Parametrial invasion is an important criterion that determines whether a tumor is operable or not. A tumor without parametrial invasion can be resected, whereas a tumor with parametrial invasion is generally treated nonsurgically with radiation therapy and chemotherapy. Visualization of the hypointense inner cervical stroma on T2-weighted images indicates preservation of the parametrium, whereas disruption of this stromal ring by a lesion of intermediate-high signal intensity suggests parametrial invasion. PET is particularly useful to detect lymphadenopathy and distant metastatic disease that may not be evident on MRI.