This article is a review of The Role of Adjuvant Radiation in Endometrial Cancer.
In this issue of ONCOLOGY, Diavolitsis et al have provided an excellent overview of the literature and state of our understanding of the role of adjuvant therapy in the treatment of endometrial cancer. Their analysis brings some order to the confusing array of empirical evidence, traditional beliefs, and prospective trial results that have shaped our understanding of endometrial cancer and options for its treatment. The authors make a strong case for limiting the use of tailored adjuvant treatment to the minority of patients who have multiple risk factors for recurrence. However, the authors’ recommendations regarding specific indications for vaginal irradiation, external-beam irradiation, and chemotherapy remain somewhat vague, reflecting uncertainties that have persisted as a result of the long use of poorly defined risk classifications systems and the related large gaps in the available level 1 evidence.
The Price of Imprecise Language
Imprecise risk classification systems have made it difficult to interpret patient characteristics in reports of prospective and retrospective studies and have, therefore, made it difficult to generalize findings to individual patients. In 1988, the International Federation of Gynecology and Obstetrics (FIGO) tried to improve its classification system by incorporating important prognostic information obtained at the time of hysterectomy. However, this staging system remains problematic for a number of reasons.
First, although the predictive value of the staging system was improved by addition of an assessment of the depth of myometrial invasion—one-half or less of the myometrium vs more than one-half of the myometrium—this dichotomy is controversial because the relationship between myometrial invasion and outcome is probably continuous. Second, two groups of patients—those with cancer cells in peritoneal washings and those with positive regional (pelvic or aortic) lymph nodes—were advanced to the stage III group, and this created an extremely heterogeneous category that places patients whose only risk factor is positive peritoneal cytology (now considered to have little independent predictive value) alongside patients who have bulky regional disease or other very high-risk features. Third, although FIGO’s histologic grading system was improved, special variants that have a vastly more aggressive behavior than endometrioid carcinomas, and that probably require very different treatments, were relegated to a footnote.
Complicating the issues of the surgical staging system itself are inconsistencies in the way this system is applied. In particular, surgeons vary widely in the extent of surgical staging performed at the time of hysterectomy, causing a form of stage migration that compromises the generalizability of outcomes from one experience to another.