Objectives: The TNM classification is a worldwide benchmark for reporting the extent of malignant disease and is intended as a prognostic tool to predict the outcome in patients with cancer. Until 2004, no TNM classification was available for adrenocortical carcinoma (ACC) and different staging systems were used. Due to the rarity of this malignancy, the prognostic value of different staging systems has never been compared directly in a large series of patients.
Methods: We compared the new WHO stages based on a new TNM classification published in 2004 with the 2 most commonly used staging systems (Sullivan and Lee) using the German ACC Registry consisting of 256 patients (follow-up completeness index 92%). The WHO classification, which is close to the Sullivan system, differs from Lee in two major points: 1) any invasion into the surrounding tissue results in stage III, whereas Lee III indicates tumors with positive lymph nodes or invasion in neighboring organs or into the renal vein or ICV. 2) WHO IV includes both tumors that involve adjacent organs or metastatic tumors, whereas Lee IV is reserved for patients with distant metastases.
Results: Survival as assessed by Kaplan-Meier analysis differed significantly between all four Lee stages (P<0.05), whereas in the WHO and Sullivan systems survival in stage II was not significantly different from survival in stage III. 21/101 patients stage Lee II were classified as WHO III and 9/85 WHO II as Lee III leading to a trend towards improved survival in WHO III (5-year survival: 46% vs 33% in Lee III), whereas survival in stage II was comparable at 54%. Of note, tumor(thrombus) in the ICV was strongly associated with tumor recurrence in our series, but is not a criterion for WHO III. Due to the stricter criteria in Lee only 67 patients were classified as Lee IV but 80 as WHO IV leading to an estimated 5-year survival in Lee IV of 11% in contrast to 17% in WHO IV.
Conclusion: As the major objective of staging classifications is to predict the outcome of patients our data indicate the need for revision of the new WHO system.
01 - 05 Apr 2006
European Society of Endocrinology