Imaging in cervical cancer

Cervical cancer traditionally has been staged clinically. Advances in imaging could improve the staging of cervical cancer by facilitating the detection of lymph node metastases and micrometastases in distant organs. Such progress could lead to improvements in treatment selection and therefore increase overall survival rates. At the Second International Conference on Clinical Cancer (Houston, TX, April 11-14, 2002), a panel composed of gynecologic oncologists, radiation oncologists, and diagnostic radiologists reviewed relevant technologies. Advances in lymphangiography, ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), and lymphatic mapping were reviewed, along with the impact of these advances on the diagnosis, treatment, and survival of patients with cervical cancer. Few cancer centers still use lymphangiography, but the sensitivity of this method ranges from 28% to 83%, with specificity ranging from 47% to 100%. The roles of transabdominal and transvaginal ultrasonography in evaluating cervical cancer are expected to expand when new contrast agents increase the sensitivity of these techniques to parametrial invasion and lymph node metastases; meanwhile, ultrasonography's most significant contributions may involve the identification of uterine and cervical leiomyomas and the evaluation of urinary tract obstruction. Advances in CT have made it a rival technique to MRI, but limitations prevent CT from providing definitive information on certain parameters. MRI, which is valuable because of its superior soft tissue contrast resolution, multiplanar capabilities, and cost-effectiveness, is used to determine the size of the cervix and to detect certain types of invasion, characteristics of lymph nodes, and the presence of disease in the ureter, lung, and liver. PET with 2-[fluorine-18]fluoro-2-deoxy-D-glucose has been found to detect abnormal lymph node regions better than CT does but PET can also be used in conjunction with CT to measure tumor dimensions. PET also has become a method for identifying tumors that are unresponsive to chemoradiation. When used together with immunohistochemical and molecular techniques as well as conventional stains, sentinel lymph node mapping, an important development in the surgical management of solid tumors, is expected to improve gynecologic cancer management. Advances in imaging methods and in contrast agents, along with advances in the combined use of the two, are expected to make imaging technologies more valuable in cervical cancer assessment.