WASHINGTON — Urinary cytology was found to be “of limited use” in detecting whether pelvic cancer has invaded the bladder, Kelly L. Molpus, M.D., reported at the annual meeting of the Central Association of Obstetricians and Gynecologists.
He and his associates hypothesized that a pelvic tumor that has invaded the bladder might shed malignant cells that could be detected by microscopic examination of the urine, in much the same way that peritoneal “washes” are examined for the microscopic spread of ovarian or other cancers.
In a retrospective study using databases at two medical centers, the researchers reviewed the findings on urine samples collected from 93 women with pelvic cancer (mean age 48 years) who were treated between 1999 and 2004. The samples were collected when the women underwent cystoscopy for staging of their pelvic cancer.
Most of the women had primary cervical cancer. Six had locally extensive endometrial cancer; three each had vulvar, vaginal, or recurrent cervical cancer; one had ovarian cancer; and one had a primary rectal cancer that also involved the vagina, said Dr. Molpus, the McClure L. Smith Professor of Gynecologic Oncology at the University of Nebraska, Omaha.
Two-thirds of the samples were classified as normal on urinary cytology. The other one-third showed some abnormality, but these turned out to reflect benign changes such as inflammation or subclinical cystitis in most cases.
Urinary cytology detected malignant cells in only four women (4.3%), all of whom had extensive, locally advanced tumors. It failed to detect bladder invasion in three. In contrast, biopsy confirmed cancerous invasion of the bladder in all seven subjects (7.5%).
Thus, urinary cytology showed only a 57% sensitivity as a screen for detecting bladder invasion. It yielded “no additional information on the extent of disease in any patient with known stage I or II pelvic cancer,” so it was deemed to be “of limited diagnostic value,” Dr. Molpus said.
However, given its 100% specificity and 100% positive predictive value in this study, urinary cytology may be useful in specific situations, such as when bladder biopsy results are inconclusive or biopsy samples are inadequate or unavailable, he said.