Assessment of Response in Patients who are Clinically free of Disease

Many patients who have undergone optimal cytoreductive surgery and subsequent therapy for epithelial ovarian cancer will have no evidence of disease at the completion of treatment. Tumor markers and radiologic assessments have proven to be too insensitive to exclude accurately the presence of subclinical disease. Therefore, a common technique used to evaluate residual disease has been the second-look operation. 279-281 A second-look operation is one performed on a patient who has no clinical evidence of disease after a prescribed course of chemotherapy, in order to determine the response to therapy. Most often, patients have undergone a formal reassessment laparotomy. The laparoscope also has been used in some of these cases but there is a 35% false-negative rate if laparoscopy is used as a second-look procedure.

If a second-look operation is performed, the proper surgery should be carried out to maximize the likelihood of detecting any microscopic residual disease. The technique of the second-look laparotomy is essentially identical to that of the staging laparotomy. The operation should be performed through a vertical abdominal incision. The incision may be initiated below the level of the umbilicus, so that if pelvic disease is detected in the absence of any palpable upper abdominal disease, a smaller incision might suffice. The incision can be extended cranially as needed. After first obtaining multiple cytologies, biopsies of the peritoneal surfaces should be performed, particularly from any areas of previously documented tumor. These are the most important areas to biopsy because they are most likely to contain residual cancer. Any adhesions or surface irregularities should be sampled. A pelvic and periaortic lymph node dissection below the level of the inferior mesenteric artery should be carried out in those patients whose nodal tissues were not previously removed, which is the case for most patients with stage III disease.

The ability to obtain a complete remission with a platinum-based therapy is dependent on the extent of residual disease at the time chemotherapy is initiated. Clinical trials have uniformly demonstrated that patients who have bulky disease (any tumor nodule greater than 2 to 3 cm in diameter) have less than a 10% likelihood of achieving a complete remission with induction chemotherapy with a platinum-based regimen. In contrast, patients who have small-volume disease after the initial laparotomy have a three to four times higher likelihood of achieving a complete remission. There is no evidence that prolonging the number of cycles of induction chemotherapy will increase the complete remission rate. In a prospective randomized trial of five versus 10 cycles of the PAC regimen, there was no statistically significant difference in overall survival and only 1 of 12 patients who were not in complete remission after five cycles of PAC achieved a complete remission with an additional five cycles of therapy. It appears that the maximum benefit from a platinum-based regimen is obtained with five to six cycles of chemotherapy.