Clinical observations on sixty-nine cases of in situ carcinoma of the urinary bladder.

In the course of screening 35,000 urological outpatients with urine cytological examinations, cytological indication of cancer was found in 106 patients in the absence of a cystoscopically visible bladder tumor. Sixty-nine of the 106 patients have biopsy-proven in situ carcinoma of the bladder, all transitional in type and anaplastic. Follow-up data on effects of therapy are available on 58 patients treated by various means, including total cystectomy, partial cystectomy, transurethral fulguration, intravesical thiotepa, and external radiation. The duration of symptoms before diagnosis was remarkably long, and the prolonged course of the in situ lesion was also noteworthy. Differences in the observed behavior of in situ bladder carcinoma may be due, in addition to differences in host resistance, to the existence of two pathogenetic forms of bladder cancer, one arising in an extensive field of abnormal epithelium and the other developing in a focal area of abnormality.