Carcinoma of the prostate: a critical look at staging

To stage accurately the extent of the disease comprehensive investigations were done on 75 patients with histologically documented carcinoma of the prostate. Estimation of bone marrow acid phosphatase appears to be the most sensitive test to detect blood-borne metastases. Serum acid phosphatase appears to be of little value in the detection of early blood spread and may have a role only in monitoring the effect of treatment on advanced disease. Bone scanning with technetium compounds has the disadvantage of non-specificity but has far greater sensitivity than a skeletal survey. Bone marrow cytology was not rewarding in the detection of early metastatic disease. Pedal lymphangiography is a highly inaccurate method to detect lymphatic spread of carcinoma of the prostate and pelvic lymphadenectomy, when indicated, remains the only truly adequate method to assess lymph node involvement. There was a 37 per cent incidence of metastatic lymph node pathology in 30 patients undergoing this procedure before either radical prostatectomy or deep x-ray therapy. A close correlation was found between stage and grade of disease and incidence of nodal pathology. There was some correlation between degree of nodal involvement and evidence of blood spread as detected by elevated bone marrow acid phosphatase levels. The significance of this finding remains unclear.