Squamous metaplasia in hormonally treated prostatic cancer. Significance during follow-up

A prospective study of 59 hormonally treated prostatic cancer cases was undertaken during follow-up with sequential transrectal palpation and fine-needle aspiration. At initiation of therapy patients' ages ranged from forty-eight to eighty-two years (median, 68 years). The usual follow-up interval was 6 +/- 3 months, and follow-up periods ranged from six months to one hundred twenty months (median 48 months). The cytologic findings were categorized under four cytologic response types and palpation findings under five response grades. Four different degrees of squamous metaplasia (1+, 2+, 3+, 4+) were observed in smears, depending on semiquantitative determination of squamous metaplastic cells in relation to the total amount of benign and malignant epithelial cells in the smear. There were 341 follow-up observations in which both transrectal fine-needle aspiration cytology and palpation were done. In 306 of these, cytologic findings were found to be adequate. Comparison of squamous metaplasia with cytologic response types revealed a highly significant difference between the benign state and recurrence/frank malignancy. This was also true when frequency of squamous metaplasia was compared with palpatory response grades. It was found that squamous metaplasia can be a valuable adjunct to other cytomorphologic changes such as shrinkage of tumor cell size and decrease in size of nucleoli or its disappearance, in determining response to hormonal therapy.