Endometrial cancer staging: who should get it?
Endometrial cancer staging: who should get it?
Abstract & Commentary
By Robert L. Coleman, MD, Associate Professor, University of Texas; M.D., Anderson Cancer Center, Houston, is Associate Editor for OB/GYN Clinical Alert.
Dr. Coleman reports no financial relationship to this field of study.
Synopsis: Surgeons operating on patients with endometrial cancer frequently decide in whom systematic staging is required based on intraoperative assessment of uterine and extrauterine features.
Source: Case AS, et al. A prospective blinded evaluation of frozen section for the surgical management of endometrial cancer. Obstet Gynecol. 2006;108:1375-1379.
Case and her co-authors performed a blinded and prospective evaluation of the accuracy of frozen section analysis in a cohort of 60 patients undergoing a surgical staging attempt. Their institutional policy was to formally stage all patients regardless of the uterine tumor characteristics. However, the uterine specimen was sent to the pathology lab and underwent frozen section evaluation by standard techniques. The information was blinded to the surgeons and to the pathologists (different physicians) performing the final uterine evaluation. They were also blinded to the referent histological diagnosis for which the surgery was indicated. Overall, 76% of patients were formally staged. The concordance of grade by frozen section and final pathology was 58%. Higher grade tumors had better concordance. Nearly half of the grade 1 tumors were upgraded on final diagnosis. Depth of myometrial invasion was concordant in 67% of cases. Nearly half of the patients with no suspected myometrial invasion were upstaged on the basis of identified myometrial invasion. Preoperative histology correlated to final histology in just 56% of the specimens; however, higher grade tumors were more consistently identified preoperatively. If a commonly used criteria to decline formal staging (grade 1 or 2 tumors and less than 50% invasion) was followed, the authors report they would have missed upstaging 18% of their patients in whom they would have administered adjuvant therapy, including 2 with metastatic nodal disease. They concluded that frozen section for grade and depth of myometrial invasion correlates poorly with final pathology and should not be used as criteria to determine in whom surgical staging should be performed.
Commentary
In 1988, FIGO amended the staging scheme for endometrial cancer to include findings based on surgical extirpation. This was done principally to more accurately reflect the distribution of disease and address the inconsistency of clinical staging. A series of clinico-pathological studies from the Gynecologic Oncology Group and others identified that extrauterine disease, particularly nodal metastases, could be related to grade, depth of myometrial invasion and histology. In this analysis, patients with low grade and superficially invasive tumors were found to have a very low probability of nodal spread and represented a cohort in whom the added morbidity of nodal staging could be safely avoided. Since that time, several retrospective studies have documented that intraoperative evaluation by frozen section could provide important "real-time" information so that the decision to stage or not to stage could be made following hysterectomy. Early reports suggested that the correlation of frozen section diagnosis and final diagnosis was more than 90%. However, pathologists were frequently aware of the determinations by referent pathology and intraoperative assessment. More recent studies, including the Case article, have questioned the accuracy of frozen section and through more careful investigation, have documented that significant variations exist, particularly in patients with lower grade and stage disease.
The clinical implication is these findings are relevant but must be considered in the context of institutional policies and attitudes toward adjuvant therapy and operative morbidity. The institution from which this report comes only treats those patients with documented extrauterine disease. In this setting, the absence of accurate staging information would proscribe adjuvant therapy based on the potential for missed disease. The authors document that this situation would have arisen in nearly one in five patients. Differing policies or attitudes to adjuvant therapy may alter the importance of accurate surgical staging information. For instance, preliminary data presented from the A Study in the Treatment of Endometrial Cancer trial, suggested there was no therapeutic impact of surgical staging in early endometrial cancer. Final scrutiny of these data when available will help to clarify the decision tree of whom to and not to stage and assess its impact on survival.
References
- Frumovitz M, et al. Frozen section analyses as predictors of lymphatic spread in patients with early-stage uterine cancer. J Am Coll Surg. 2004;199:388-393.
- Goff BA, Rice LW. Assessment of depth of myometrial invasion in endometrial adenocarcinoma. Gynecol Oncol.1990; 38:46-48.
- Kir G, et al. Eur J Gynaecol Oncol. 2004;25:211-214.
- Kucera E, et al: Accuracy of intraoperative frozen-section diagnosis in stage I endometrial adenocarcinoma. Gynecol Obstet Invest. 2000;49:62-66.
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