Ascites cytology with immunohistochemistry accurately diagnoses advanced ovarian cancer in postmenopausal women and can be used as the basis for neoadjuvant chemotherapy, researchers in Israel report.
“This will allow treating older and friable patients with ovarian cancer, who were previously submitted to invasive procedures under anesthesia in order to achieve the diagnosis,” Dr. Dan Grisaru of Tel Aviv Sourasky Medical Center told Reuters Health by email. “Moreover, the immunostainings of the ascites cells may differentiate those patients with ascites and other types of cancer that will receive different protocols for their cancer.”
Most studies have reported sensitivities in excess of 98% when using cytology to diagnose ovarian cancer, but one recent study had high false-negative results (only 67.1% of patients had positive ascites cytology).
Dr. Grisaru and colleagues evaluated the performance of ascites cytology in the diagnosis of ovarian malignancy in their study of 551 patients older than 51 years and sought to determine whether it can replace a diagnostic tissue biopsy that precedes the prescription of neoadjuvant chemotherapy.
Overall, 224 patients had malignant cells on both cytology and diagnostic histology samples, and 65 patients had benign results from both cytology and histology, the researchers report in Menopause.
In the remaining 262 cases, all were negative for malignancy on cytology and positive for malignancy in the final pathology. There were no false-positive cytology results.
The sensitivity of ascites cytology for diagnosing malignancy of any origin was 46.1%, with 100% specificity, 19.8% negative predictive value and an overall test accuracy of 52.4%.
Among the 551 patients, 155 had ovarian cancer; of these, 125 patients had malignant cells on cytologic examination of ascites fluid. Ascites cytology was 80.6% sensitive for diagnosing ovarian cancer, with 100% specificity, 16.7% negative predictive value and 81.4% overall accuracy.
Cytokeratin 7 (CK7) was positive by immunohistochemistry in 100% of cases, as was CA-125. CK20 was positive in only 1.4% of cases, and CEA was negative in all cases of ovarian cancer.
Including the current study, the authors note, no study has reported false-positive cytology results that could have led to unnecessary neoadjuvant chemotherapy.
“We already started using this protocol of sending the ascitic fluid to cytology and immunostainings in patients that are candidates for neoadjuvant treatment,” Dr. Grisaru said. “If the cytology result is positive for ovarian cancer, the patient will start the chemotherapy. If the result is negative, we proceed to laparoscopic evaluation of the abdomen.”