Practice patterns for prostate cancer in nine central and northern Italy radiation oncology centers: a survey including 1759 patients treated during two decades (1980-1998).

Purpose: Prostate cancer patients in Italy are offered the choice of the full spectrum of possible treatment options for their disease, but the diffusion of the more recent technological refinements among the Radiation Oncology centers is not homogeneous and there is a need to establish a reference "historical" data source. This retrospective study describes the changing patterns in prostate cancer patient practice and the therapeutic results obtained in nine Radiation Oncology centers of Northern and Central Italy (five in Northern Italy and four in Central Italy).

Methods And Materials: A total of 1759 prostate cancer patients, radically treated in the nine radiotherapy (RT) centers between 1980 and 1998, made up the study population. Data collected for each patient included clinical, pathologic, therapeutic features, and toxicity. The overall survival, disease-specific survival (DSS), and clinical relapse-free survival (RFS) were calculated for the whole series and for the subsets of patients defined by different clinical, pathologic, and therapeutic features, according to three accrual periods (A, 1980-1990; B, 1991-1994; and C, 1995-1998). Univariate and multivariate analyses were performed to identify prognostic factors related to survival and late adverse effects (cystitis and proctitis) probability.

Results: Patient accrual increased markedly during the 2 decades considered, and the percentage of cases with Stage C or D disease dropped from 49% (period A) to 43% (period B) to 37% (period C) (p < 0.0001, chi-square). The baseline prostate-specific antigen value was available for 10%, 76%, and 95% of the cases treated in the three different periods. The major changes in the therapeutic options were an increase in dose to the prostate (>66 Gy in 44%, 84%, and 93% of the patients treated in period A, B, and C, respectively); a reduction in treated volumes, including pelvic lymphatic drainage (56-39% before 1995, 22% thereafter); and an increase in cases treated in association with hormonal therapy (50% before 1991, 80% thereafter). Lower energy (<10 MV) photon beams were progressively abandoned (12% before 1990 vs. 6-7% thereafter), along with an increase in the use of blocks (60% in the last 4 years of the study vs. about 30-40% before 1995) and "conformal" RT (applied in 41% of cases treated after 1994). The actuarial RFS, DSS, and overall survival rate at 5 years was, respectively, 60% +/- 2%, 75% +/- 2%, 66% +/- 2% for period A; 74% +/- 2%, 90% +/- 1%, 83% +/- 2%, for period B; and 67% +/- 5%, 90% +/- 2%, 79% +/- 5% for period C. The actuarial overall survival, DSS, and RFS rate for the whole series of 1759 patients was 77% +/- 1%, 86% +/- 1%, and 68% +/- 1% at 5 years, respectively. Multivariate analysis showed that only American Urologic Association stage, grade, dose to the prostate, accrual period, association with hormonal treatment after (or both after and before) RT (only in terms of DSS and RFS), and baseline prostate-specific antigen value (only for RFS) retained prognostic significance in the final Cox model.

Conclusion: The increase in the accrual of prostate cancer patients radically treated with RT has been accompanied by considerable changes in the clinical features at presentation, as well as in the staging and treatment procedures. Patients treated more recently had better survival results. An earlier stage and more favorable grade were linked with better overall, DSS, and RFS at multivariate analysis. Lower prostate-specific antigen baseline values were also related to better RFS. Better results were obtained with higher radiation doses, and the dose to tumor seemed the most important treatment-related prognostic factor. The toxicity (cystitis and proctitis, every Radiation Therapy Oncology Group grade) was substantially the same in the different accrual periods, but larger treated volumes and higher doses appeared to increase the incidence of late effects.