Peritoneal washing cytologic analysis of ovarian serous tumors of low malignant potential to detect peritoneal implants and predict clinical outcome

BACKGROUND: Patients with ovarian serous tumors of low malignant potential (OSLMP) who have peritoneal implants, especially invasive implants, are at an increased risk of developing tumor recurrence. To the best of the authors' knowledge, the ability of peritoneal washing (PW) cytology to detect the presence and type of peritoneal implants has not been adequately investigated, and its prognostic significance is unknown. METHODS: Records and PW specimens of 101 patients diagnosed with and treated for OSLMP between 1996 and 2010 at The University of Texas MD Anderson Cancer Center were retrospectively reviewed. Patients' staging biopsy findings were compared with the results of the authors' review of the PWs. Follow-up data were also analyzed. RESULTS: Of the 96 patients for whom staging biopsy results were available, 26 (27%) had peritoneal implants (17 noninvasive and 9 invasive), 19 (20%) had endosalpingiosis, and 51 (53%) had negative findings. The PW specimens of 18 of the 26 patients (69%) with peritoneal implants were positive for serous neoplasm, and a correlation was found between cytologic and histologic findings (P < .0001). The sensitivity, specificity, positive predictive value, and negative predictive value were 69%, 84%, 62%, and 88%, respectively. Four of 101 patients had disease recurrence; 3 of these patients had invasive implants and 1 patient had noninvasive implants. None of the patients who had negative staging biopsy findings or endosalpingiosis but did have PW specimens that were positive for serous neoplasm developed disease recurrence. CONCLUSIONS: PW cytology detects the presence of peritoneal implants with moderate accuracy. However, long-term studies are needed to determine whether positive PW cytologic findings are an independent predictor of tumor recurrence.