CYTOREDUCTIVE SURGERY FOR OVARIAN CANCER

The diagnosis and management of ovarian cancer is one the greatest and most important challenges in oncology. Cancer of the ovary is diagnosed in approximately 25,000 women in the United States each year, more than 14,000 of whom die of the disease¹⁷—more than die from all other gynecologic malignancies combined. These grim statistics are a reflection of the fact that no effective means exists to screen for ovarian cancer. Most women with ovarian cancer are therefore diagnosed with advanced disease, and most of these women die of the disease. Thus, the burden of morbidity and mortality from ovarian cancer is comparable to that of much more prevalent diseases, such as breast cancer.

Tremendous advances have been made in chemotherapy for ovarian cancer over the past 20 years, but surgery remains the cornerstone of effective management of the disease. Repeated investigations have shown that cancer of the ovary is unusual among solid tumors in that surgical reduction of tumor volume is highly correlated with a prolongation of patient survival. Patients who are left with little or no visible residual cancer at the end of their initial surgery enjoy a dramatically improved survival time over women who have bulky residual tumor at the end of initial surgery or who are treated by chemotherapy alone. A review of the published studies of surgical cytoreduction revealed that women with less than 2 cm of residual tumor at the end of initial surgery had a median survival time of 37 months, whereas women with bulky residual disease had a median survival time of 17 months.¹¹ It is rarely appropriate, therefore, for a patient who is presumed to have ovarian cancer to be treated with chemotherapy alone. Thus, an integrated, multimodality approach is essential to the effective management of ovarian cancer.

The benefit of surgical cytoreduction of ovarian cancer is most clear at the time of initial surgery. Although no prospective, randomized trials of surgical cytoreduction for ovarian cancer have been performed, the accumulated retrospective evidence shows such a strong correlation between the volume of tumor remaining after initial surgery and survival time that most oncologists would consider such a trial unethical. The data show somewhat less benefit from surgical cytoreduction performed after initial presentation and surgery, but several recent, well-performed studies have demonstrated a benefit, particularly in patients who have chemotherapy-sensitive tumors that are cytoreduced to minimal or no residual disease.

Surgical cytoreduction can be performed in a large proportion of patients with limited morbidity. It is also clear, however, that an unsuccessful cytoreduction, that is, an extensive surgery that leaves the patient with tumor nodules 2 cm or larger in diameter, offers no appreciable survival benefit and may place the patient at risk for significant morbidity. There is no currently available technology that allows the surgeon to anticipate which patients have disease that is unresectable, although attempts have been made to do so.² The surgeon must be prepared, therefore, to determine intraoperatively whether a surgical cytoreduction can be safely completed. This is a crucial moment in the patient's care: if the decision is made inappropriately to attempt a complete debulking procedure, the patient may suffer undue morbidity, with little benefit. If the decision not to attempt a debulking is inappropriate, however, the patient may be doomed to a significantly shorter survival.

To be able to make and execute such a decision, the surgeon must be able to understand the natural history of ovarian cancer and the fundamentals of tumor kinetics as they pertain to ovarian cancer. He or she must also understand the evidence supporting surgical cytoreduction in the settings of a patient's initial surgery at the time of a second-look laparotomy and in the presence of known recurrent disease. These areas are reviewed, with the goal of delineating the rationale and appropriate application of surgical cytoreduction for ovarian cancer.