Initial therapy for early ovarian carcinoma

Abstract

Approximately 33% of women with invasive ovarian tumors present with what appears to be early epithelial ovarian cancer (FIGO Stages I and II) accounting for approximately 6000 new ovarian cancer cases each year in the United States. A better understanding of the natural history and patterns of spread of this disease has led to an increased awareness of the importance of thorough operative staging, cytoreductive surgery, and accurate determination of the extent of residual disease. These staging studies have documented frequent understaging of such patients. Results from such surgical staging studies indicate that only about 25% of women operated on in the United States have an initial surgical incision adequate to allow evaluation of the entire pelvis and abdominal cavity. As a result about 33% of patients thought to be free of disease at initial surgery have residual disease and in 75% the disease has spread intraabdominally. These studies have important implications for the design of future adjuvant trials. Fortunately, these accurate staging studies have defined groups of patients who require adjuvant treatment as well as those who do not. It is now apparent that certain groups of patients with Stage II and high-risk Stage I disease are at risk for failure throughout the abdominal cavity. Any form of adjuvant therapy, if it is to succeed, must obviously encompass this entire area. With this in mind, several prospective clinical trials have tested a variety of adjuvant approaches. Present evidence would suggest that systemic chemotherapy, intraperitoneal radioisotopes (32P) or whole abdominal irradiation have the potential to eradicate micrometastases throughout the area at risk. The need for adjuvant therapy is dependent upon the accuracy of initial surgical staging. If initial surgical evaluation was incomplete, the five year survival rates for Stage I (70%) and Stage II (40% to 50%) disease are poor enough that most investigators would advocate some sort of adjuvant therapy. However, comprehensive and accurate surgical staging will define subsets of ovarian cancer patients with such good prognoses (five year survival of 90% to 95%) that no adjuvant treatment is required. With the known risk of late second malignancies in ovarian cancer patients treated with long-term adjuvant chemotherapy, the identification of patients who do not require further treatment represents an advance. Accurate surgical staging coupled with proper adjuvant therapy designed to treat areas of high risk have improved the survival rate of patients with early ovarian cancer.