Peritoneal washing cytology in gynecologic cancers: long-term follow-up of 355 patients.

BACKGROUND: Microscopic evaluation of cells washed from the peritoneal cavity during surgery for gynecologic tumors is used to detect subclinical intraperitoneal metastases from these tumors. The prognostic significance of this test, however, has been questioned.

PURPOSE: Stressing histologic correlation and pitfalls in interpretation, we previously reported that the sensitivity of intraoperative peritoneal washing cytology was lower than was suggested earlier. This study evaluates the clinical utility of this test in the long-term follow-up of our patients.

METHODS: Staging (International Federation of Gynecology and Obstetrics [FIGO], 1971) and follow-up information was available for 355 unselected patients with primary tumors who had peritoneal washings performed during initial surgery at University Hospital-Stony Brook, NY, during the period from 1980 through 1989. There were 135 patients with endometrial carcinomas, 112 with ovarian carcinomas, 92 with cervical carcinomas, and 16 with borderline (i.e., of low malignant potential) ovarian tumors. The median follow-up of the patients was 57 months (range, 0-154 months). Follow-up data were obtained from the Tumor Registry at University Hospital-Stony Brook. Survival differences were determined by Kaplan-Meier analysis and were evaluated by two-tailed logrank test. RESULTS. Peritoneal washing cytology was positive at initial surgery for 120 (33.8%) of 355 patients, including 90 (80.4%) of 112 patients with ovarian carcinomas, five (31.2%) of 16 patients with borderline ovarian tumors, 17 (12.6%) of 135 patients with endometrial carcinomas, and eight (8.7%) of 92 patients with cervical cancers. For 203 patients with stage I tumors, the peritoneal cytology was positive in 29.4% of the patients with ovarian carcinomas, 18.2% with borderline ovarian tumors, 6.1% with endometrial carcinomas, and 5.2% with cervical carcinomas. By use of peritoneal histology as the standard, peritoneal cytology was highly specific (98.1%) but less sensitive (82.9%) in detecting intraperitoneal involvement. For patients with stage I tumors, 80.0% with ovarian carcinomas, 83.3% with endometrial carcinomas, and 100% with cervical carcinomas who showed positive cytology died of their cancer, compared with 25.0% with ovarian carcinomas, 13.0% with endometrial carcinomas, and 21.9% with cervical carcinomas who showed negative peritoneal cytology. Four (2.0%) patients with stage I tumors had positive peritoneal cytology but negative peritoneal histology. Of these patients, three (two with ovarian carcinoma and one with cervical carcinoma) died of their cancer, whereas one patient with a borderline ovarian tumor was free of disease at the last follow-up. Survival analysis indicated that peritoneal washing cytology stratified for stage provides better prognostic information for each primary cancer site studied than does stage alone. All patients with borderline ovarian tumors were alive at last follow-up, regardless of disease stage or peritoneal status.

CONCLUSIONS: Regardless of FIGO stage, positive peritoneal washing cytology predicted poor prognosis for women with epithelial tumors of the genital tract, except for patients with borderline ovarian tumors. Patients in whom peritoneal cytology was the only evidence of intraperitoneal spread were few, but the disease in such patients was associated with poor outcome.

IMPLICATIONS: Strict adherence to specialized cytologic criteria in peritoneal washing cytology allows for results that are highly predictive of survival. This information may be useful in stratifying women in therapeutic trials for treatment of genital tract carcinomas.