Measurement of tumor size in early cervical cancer: an ever-evolving paradigm

The major tenets in accurately assessing tumor size in patients with early stage cervical cancer currently include physical examination, imaging studies, and pathologic evaluation. It is estimated that when comparing clinical stage based on physical examination and final pathology, the concordance diminishes as stage increases: 85.4%, 77.4%, 35.3%, and 20.5% for stage IB1, IB2, IIA, and IIB, respectively. Vaginal involvement and larger tumor diameter are considered the main causes of stage inaccuracy. When considering imaging studies, magnetic resonance imaging (MRI) provides the highest level of accuracy in the assessment of cervical tumor size. Its accuracy in determining tumor location within the cervix is approximately 91% and in predicting tumor size 93%. MRI imaging is also significantly more accurate in measuring tumor size, delineating cervical tumor boundaries, and local tumor extension when compared with computed tomography (CT) scan. When comparing with pelvic ultrasound, the accuracy of both imaging techniques (MRI and pelvic ultrasound) in the assessment of tumor size in small versus large tumors is comparable. Pertaining to pathology, the depth of invasion should be measured by convention from the nearest surface epithelium, which equates to tumor thickness. In the setting where tumor is found both in the conization and hysterectomy specimen, the horizontal extent should be measured by summing the maximum horizontal measurement in the different specimens and the depth of invasion measured as the maximum depth in either specimen. A new pattern-based classification for endocervical adenocarcinomas recommends the description of patterns of invasion for human papillomavirus (HPV)-related adenocarcinomas as this is associated with differing risks of lymph node involvement.