Proper staging techniques in testicular cancer patients

Abstract

Testicular cancer has become a highly curable neoplasm, and research efforts in the 1990s are focusing on ways to improve staging and treatment so as to limit cost and morbidity. Our group has performed a number of recent studies that help to answer a number of important clinical questions. First, do we need to order computed tomography of the chest (CCT) to stage all newly diagnosed patients? Second, how accurate is contemporary era abdominal CT to stage the retroperitoneum in low-stage nonseminoma patients, and are there techniques that may improve accuracy? Third, can histological primary tumor factors be useful to predict stage in low-stage nonseminoma patients? In a study of 201 testicular cancer patients [117 (58%) NSGCT, 84 (42%) seminoma] who had both CCT and chest X-ray (CXR) in initial staging, CXR alone was found to be sufficient initial chest staging in all seminoma patients and in NSGCT patients who had a negative abdominal (CTA). For low-stage patients without retroperitoneal adenopathy, CCT had unacceptable false-positive rates, which precipitated additional invasive maneuvers. For higher stage NSGCT patients with retroperitoneal disease on initial CTA, CXR alone missed a significant number of occult thoracic metastases and CCT remains indicated. In a study of 57 clinical stage 1 NSGCT all having negative staging CTA followed by surgical staging, third and fourth generation CT had a 67% accuracy in predicting retroperitoneal metastases. This contemporary experience shows a 33% false-negative abdominal CT staging rate. Consideration of any nodes, regardless of size, in the primary echelon retroperitoneal areas as indicative of retroperitoneal metastases may hold promise for improving accuracy of CTA in low-stage NSGCT testis cancer. In a study of 92 clinical stage 1 NSGCT patients, determination of primary tumor vascular invasion (VI) and percentage of tumor composed of embryonal carcinoma component (%EMB) was found to be a useful staging tool. A multivariate model using VI and %EMB was able to predict correct stage in 86% of the study cohort, and a probability table with these two variables was created. Using these histological variables in a neural network artificial intelligence program, an expert correctly predicted stage in 92% of patients. In the 1990s chest staging should be tailored to tumor cell type and retroperitoneal disease status. Staging of the retroperitoneum utilizing abdominal CT remains problematic due to the inability to detect microscopic metastases. Primary tumor histological factors, particularly vascular invasion and quantitation of embryonal carcinoma, are clinically useful staging tools.