Staging & Surgical Management of Ovarian CancerWHEC Practice Bulletin and Clinical Management Guidelines for healthcare providers. Educational grant provided by Women's Health and Education Center (WHEC). Ovarian cancer remains the most lethal of gynecologic malignancies, and its mortality exceeds the combined mortality from both cervical and endometrial cancer in the United States. Ovarian malignancy is the fourth most common cause of cancer death in American women and accounts for 5% of all cancer deaths. In the United States about 1 in 70 women will develop ovarian cancer in her life-time, and 1 in 100 women will die of this disease. The grim realities of ovarian cancer result primarily from a failure to improve early diagnosis. At the time of diagnosis about 70%-75% of patients have advanced-stage disease and the 5-year survival of women with such disease remains only 25%-30%. The majority (85%-90%) of malignant ovarian tumors seen in the United States are epithelial. The purpose of this document is to understand and evaluate advances in the surgical management of ovarian cancer, staging and prognostic factors. Important progress has been made in the management of ovarian malignancy in recent years. Insightful overview of the current understanding of the ovarian malignancy as well as the areas of continuing challenges are also discussed in this series of the articles exploring different aspects of ovarian cancer. While therapy for ovarian malignancy has undergone important progress, there is growing concern about the quality of life of these patients. The contributors to this symposium include many of the experts who have advanced the management of this disease, and their articles thoughtfully describe the progress and point to future areas of reproductive research (1). Signs, Symptoms and Pre-Operative Evaluation: Most women with ovarian cancer have no symptoms for long periods of time. When symptoms do develop, they are often vague and non-specific. A high index of suspicion is warranted in all women between the ages of 40 and 69 years who have persistent gastrointestinal symptoms that cannot be diagnosed. In advanced-stage disease, patients most often have symptoms related to the presence of ascites, omental metastases, or bowel metastases. The symptoms include abdominal tension, bloating, constipation, nausea, anorexia or in premenopausal patients there may be complaint of irregular or heavy menstrual cycle. The most important sign of epithelial ovarian cancer is the presence of pelvic mass on physical examination. Frequently encountered non-ovarian causes of apparent adnexal masses are diverticulitis, tubo-ovarian abscess, carcinoma of the cecum or sigmoid, pelvic kidney, and uterine or intraligamentous myomas. Diagnosis: Serum CA 125 levels have been shown to be useful in distinguishing malignant from benign pelvic mass. For a postmenopausal patient with an adnexal mass and a very high serum CA 125 (>95 U/ml), there is a 96% positive predictive value for malignancy. For premenopausal patients, however, the specificity of the test is low because the CA 125 level tends to be elevated in common benign conditions (2). The size of lesion is important. If a cystic mass is >8 cm in diameter, the probability is high that the lesion is neoplastic, unless the patient has been taking clomiphene citrate or other agents to induce ovulation. Patients whose lesions are suggestive of malignancy (ie; predominantly solid, relatively fixed, or irregularly shaped) should undergo laparotomy, as should postmenopausal patients with adnexal masses. The diagnosis of an ovarian cancer requires an exploratory laparotomy. Pre-operative evaluation: Before the planned exploration the patient should undergo routine hematologic and biochemical assessment. X-ray chest and an assessment of the urinary tract with intravenous pyelography are also useful. Abdominal and pelvic computed tomography (CT) or magnetic resonance imaging (MRI) are of no value for a patient with a definite mass. A CT and MRI should be performed for patients with ascites and no pelvic mass to look for liver or pancreatic tumors. If the hepatic enzyme values are normal, the likelihood of liver disease is low. Liver-spleen scans, bone scans, and brain scans are unnecessary unless symptoms or signs suggest metastases to these sites. The preoperative evaluation should exclude other primary cancers metastatic to the ovary. A barium enema or colonoscopy is indicated in some patients over 45 years of age to exclude a primary colonic lesion with ovarian metastasis. An upper gastrointestinal radiographic series or gastroscopy is indicated if symptoms indicate gastric involvement. Bilateral mammography is indicated if there is any breast mass, because occasionally breast cancer metastatic to the ovaries can simulate primary ovarian cancer. Cervical cytologic study should be performed, although its value for the detection of ovarian cancer is very limited. Patients who have irregular menses or postmenopausal vaginal bleeding should have endometrial biopsy and endocervical curettage to exclude the presence of uterine or endocervical cancer metastatic to the ovary. Spread Patterns: Ovarian epithelial cancers spread primarily by exfoliation of cells into the peritoneal cavity, lymphatic dissemination and by hematogenous route. Prognostic Factors: The morphology and histologic pattern, including the architecture and grade of the lesion, are important prognostic variables (4). Surgery accurately stages a patient and allows the evaluation of a series of variables that are often used to select post-operative therapy and prognosis. These factors are: Staging: The importance of thorough surgical staging cannot be overemphasized, because subsequent treatment will be determined by the stage of disease. Ovarian epithelial malignancies are staged according to the FIGO system: Stage I: Growth limited to the ovaries Stage II: Growth involving one or both ovaries with pelvic extension Stage III: Tumor involving one or both ovaries with peritoneal implants outside the pelvis and/or positive retroperitoneal Stage IV: Growth involving one or both ovaries with distant metastasis. If pleural effusion is present, there must be positive Initial Surgery for Ovarian Cancer: The ovarian tumor should be removed intact, if possible and a frozen histologic section should be obtained. For patients whose pre-operative evaluation suggests a probable malignancy, a midline or paramedian abdominal incision is recommended to allow adequate access to the upper abdomen. Staging involves following steps: Borderline Malignant Epithelial Neoplasms -- the principal treatment of borderline ovarian tumors is surgical resection of the primary tumor. Extensive sectioning of the neoplasm is necessary to rule out truly invasive characteristics. Patients have a high survival rate and even lesions that behave in a malignant fashion usually have a typically indolent course. Conservative management and surgery should be considered when future fertility is desired. Stage I Low-grade, Low-risk -- for patients who have undergone a thorough staging laparotomy and for whom there is no evidence of spread beyond the ovary, abdominal hysterectomy and bilateral salpingo-oopherectomy are appropriate therapy. The uterus and the contralateral ovary can be preserved in women with stage Ia, grade 1 or 2 disease who desire to preserve fertility. The conditions of the women should be monitored carefully with routine periodic pelvic examinations and determinations of serum CA 125 levels. Generally, the other ovary and the uterus are removed at the completion of childbearing. Stage I High-grade, High-risk -- for patients whose disease is more poorly differentiated or in whom there are malignant cells either in ascetic fluid or in peritoneal washings, complete surgical staging must be performed. The surgery should include the performance of a hysterectomy and bilateral salpingo-oopherectomy in addition to the staging laparotomy. Cytoreductive Surgery for Advanced-stage Disease -- the operation to remove the primary tumor as well as the associated metastatic disease is referred to as debulking surgery. The concept is simply to diminish the residual tumor burden to a point at which adjuvant therapy will be optimally effective. All forms of adjuvant therapy are most effective when a minimal tumor burden exists. Removal of large ovarian masses and omental involvement often reduces the tumor burden by 80%-90%. Benefits of lymphadenectomy in patients with bulk residual disease remains questionable (7). The GOG investigators evaluated the effect of the diameter of the largest residual disease on survival in patients with suboptimal cytoreduction. They demonstrated that cytoreduction, so that, the largest residual mass was <2 cm resulted in a significant survival benefit, but all residual diameters >2 cm had equivalent survival. Therefore, unless the mass can be cytoreduced to <2 cm, residual diameter did not influence survival. Resection of a portion of bowel should be considered only when such a resection will result in removal of all gross tumor. Role of Interval Cytoreduction -- although aggressive surgical cytoreduction is the foundation of management in women with advanced ovarian carcinoma, not all patients will be candidates for upfront surgical debulking (ie, intra-parenchymal liver metastases), and optimal debulking may expose a patient to unacceptable morbidity. Likewise, even for those women who are medically fit to withstand surgery, a small percentage, despite maximum effort by a gynecologic oncologist, will not undergo optimal cytoreduction at the time of their initial surgery. It is this group of patients in whom interval cytoreduction may be beneficial (8). In an attempt to predict which patients will successfully undergo optimal cytoreduction, several authors have developed radiographic criteria or have used CA 125 levels to help direct the decision to operate first or treat with neoadjuvant chemotherapy. Role of Second-Look Surgery -- currently, second-look surgery has a role only in assessing pathologic response to clinical trial therapy. Following standard chemotherapy, CA 125 physical examination and computed tomography can be used to assess clinical response (9). Gynecology Oncology Group (GOG) study of 158 addressed the issue of second-look surgery indirectly. At the time of treatment randomization, the decision to undergo second-look laparotomy or laparoscopy at the completion of chemotherapy was made by the treating clinician. Second-look surgery was mandatory and was not a statistical end point of the study. 50% of patients in the study underwent second-look surgery. The statement was made that there was no difference in relapse-free survival for patients registered for second-look surgery vs. no second-look surgery. Thus the conclusion was drawn that second-look surgery did not affect survival. Role of Laparoscopy -- it can be used for second-look surgery, for staging of presumed "early" ovarian cancer, for placement of an intraperitoneal port for administration of intraperitoneal chemotherapy and for assessment of response to treatment (when more conventional measures of response are not useful). Laparoscopy is also appropriately used in assessment and removal of an adnexal mass. Laparoscopy has been reported to be useful in secondary cytoreduction. In some very special instances, laparoscopy in combination with mini-laparotomy has been useful in cytoreduction (10). Recurrent Ovarian Cancer: Patients with complete cytoreduction to microscopic disease are often cured with adjuvant chemotherapy. There is growing evidence that these patients with microscopic residual disease are excellent candidates for intraperitoneal chemotherapy, and this mode of chemotherapy delivery may be their best opportunity for cure. Patients with optimal cytoreduction also may benefit from intraperitoneal chemotherapy, but cure is less likely. For patients with suboptimal cytoreduction, intravenous chemotherapy with a combination of carboplatin and paclitaxel is the current standard therapy. Most of these patients will experience recurrence of cancer, with small chance of cure. An unfortunate reality of advanced ovarian cancer is that the majority will eventually suffer recurrence and will die of disease. The search for novel therapeutic in ovarian cancer continues. Unlike primary therapy, there is no established standard of treatment of recurrence. It is unclear if patients benefit from platinum-based re-challenge at first recurrence or at subsequent relapse. Also unclear is the best combination of agents to use. Most physicians initially retreat platinum-sensitive patients with carboplatin and paclitaxel. Other agents are considered for second recurrence insensitivity. Additional research is also focusing on immune-based therapy, including vaccines and monoclonal antibodies that specifically target tumor cells. The ultimate therapy may come in the form of individualized gene therapy, focusing on each patient's cancer-forming genetic aberrations. Until curative agents are identified, these patients must be treated with compassion and consideration for quality of life. "First do no harm" is especially pertinent in treating patients with primary and recurrent ovarian cancer (11). Survival: For early ovarian cancer, appropriate surgical staging and adjuvant chemotherapy for selected cases will result in survival rates of 90-95%. For advanced ovarian cancer, survival depends primarily on the success of the initial surgical procedure. Salvage chemotherapy is important in ovarian cancer because many patients respond to several salvage regimens. Relative survival varies by age, women younger than 65 years are about twice likely to survive 5 years (56%) following diagnosis as women 65 years and older (28%). Overall, the 1- and 5-year relative survival of ovarian cancer patient is 76% and 45% respectively. If diagnosed at the localized stage, the 5 years survival rate is 93%, however, only about 19% of all cases are detected at this stage. For women with regional and distant disease, 5-year survival rates are 69% and 30% respectively. The 10 year relative survival rate of all stages combined is 38%. Apparent declines in survival rates from previous years are due to recent changes in the classification of malignant ovarian tumors rather than true reduction in survival (12). Because of high response rate of ovarian cancer, even after relapse, it is probably better to consider 10-year survival as the ideal end point. Finally, new biologic agents, in combination with traditional surgery and chemotherapy, may result in further improvement in survival for patients with ovarian cancer. Summary: Advances in surgical techniques and approaches have contributed to the increase in survival for the patients of ovarian cancer. The surgeon makes a difference in survival. Access to specialist surgeons continues to be very important in the care of women with ovarian cancer to ensure adequate staging, optimal cytoreduction and application of secondary cytoreduction when appropriate. An optimal surgical approach should be carried out whenever possible. This is defined as the removal of all bulk tumor with the intent to leave minimal residual tumor (no individual mass >1-2 cm in diameter). It is not possible to advocate any one operation for all patients, and the clinician must make a judgment at the time of surgery. Unquestionably, patients with small residual tumor volumes have a better prognosis with any post-operative therapy. Even when optimal debulking is not possible, bilateral salpingo-oopherectomy, total abdominal hysterectomy, and omentectomy may afford significant palliation for the patient. Prognosis depends very much on stage, but other factors are also pertinent. References: |