Dedifferentiation in the metastatic progression of prostate carcinoma

BACKGROUND, Dedifferentiation is a distinctive feature of cancer progressio n. Detailed histologic analysis of primary prostate carcinoma and synchrono us lymph node metastases may improve our understanding of the complex proce ss of cancer progression and metastasis. METHODS. The authors studied 242 regional lymph node positive prostate carc inoma patients who underwent radical prostatectomy and bilateral lymphadene ctomy between 1987 and 1992 at the Mayo Clinic. Patients ranged in age from 47-79 years (median, 66 years). The median follow-up was 6.1 years. Gleaso n scores of lymph node metastases and primary tumors were compared and corr elated with systemic disease progression. Histologic dedifferentiation was defined as a higher Gleason grade in the lymph node metastases than in the primary tumor. Systemic disease progression was defined as the presence of distant metastases documented by biopsies, abdominal computed tomography, p lain radiograph, or bone scan. progression and metastasis. RESULTS. The 5-year systemic progression free survival (PFS) rate was 90%. The Gleason score in the lymph node metastases was higher than in the prima ry tumor in 45% of patients, lower in 12% of patients, and matched exactly in 43% of patients. The 5-year PFS was significantly different between pati ents with histologic dedifferentiation (88% +/- 3) and those without dediff erentiation (94% +/- 2) (P = 0.04). Adjusting for the Gleason grade of the primary tumor and total lymph node tumor volume, the relative risk for dise ase progression associated with dedifferentiation was 1.8 (95% confidence i nterval, 0.7-4.7; P = 0.25). CONCLUSIONS, The findings of the current study demonstrate the morphologic heterogeneity of metastases from prostate carcinoma. There is a trend towar d histologic dedifferentiation when prostate carcinoma metastasizes to regi onal lymph nodes. This dedifferentiation, although univariately significant , was not associated with disease progression when adjusted for lymph node tumor volume. Cancer 1999;86:657-63. (C) 1999 American Cancer Society.