Radiation therapy, either external beam irradiation or brachytherapy, remains a popular therapeutic modality for clinically organ-confined (stages T1 and T2) or locally invasive (stage T3) prostate cancer.<sup>19 Mettlin C., Jones G.W., Murphy G.P. Trends in prostate cancer care in the United States, 1974–1990: Observations from the patient care evaluation studies of the American College of Surgeons Commission on Cancer CA Cancer J Clin 1993 ;  43 : 83  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> Despite its popularity, a significant number of patients develop either biochemical or palpable local recurrence after treatment. Although the antitumor effects of radiation develop over several months and histologic resolution of the tumor may take more than 30 months,<sup>7 Crook J.M., Perry G.A., Robertson S., Esche B.A. Routine prostate biopsies following radiotherapy for prostate cancer: Results for 226 patients Urology 1995 ;  45 : 624  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> it is apparent that a positive posttreatment biopsy portends eventual clinical local recurrence and a negative biopsy cannot exclude recurrence. Up to 75% of patients with a positive biopsy after irradiation develop local recurrence within 10 years of therapy, as do 25% of those with a negative biopsy.<sup>40 Zietman A.L., Shipley W.U., Willett C.G. Residual disease after radical surgery or radiation therapy for prostate cancer. Clinical significance and therapeutic implications Cancer 1993 ;  71 : 959  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> Furthermore, local recurrence of prostate cancer after radiation therapy is often associated with the development of distant metastasis and ultimately death,<sup>10 Fuks Z., Leibel S.A., Wallner K.E. , e al. The effect of local control on metastatic dissemination in carcinoma of the prostate: Long-term results in patients treated with 125I implantation Int J Radiat Oncol Biol Phys 1991 ;  21 : 537  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 31 Scardino P.T., Frankel J.E.F., Wheeler T.M. , e al. The prognostic significance of post-irradiation biopsy results in patients with prostatic cancer J Urol 1986 ;  135 : 510

Cliccare qui per andare alla sezione Riferimenti, 39 Zagars G.K., von Eschenbach A.C., Ayala A.G. , e al. The influence of local control on metastatic dissemination of prostate cancer treated by external beam megavoltage radiation therapy Cancer 1991 ;  68 : 2370  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> with a median survival following detection of only 33 months.<sup>13 Hanks G.E., Martz K.L., Krall J.M. , e al. Analysis of independent variables affecting survival after recurrence of prostate cancer Int J Radiat Oncol Biol Phys 1989 ;  16 : 1431  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> Thus, a positive postirradiation biopsy indicates failure to achieve adequate local control of disease with significant resultant risk for both local and distant progression.

The advent of prostate-specific antigen (PSA) has provided a potent tool for monitoring the therapeutic response of localized prostate cancer. Following radiation therapy, a patient's serum level typically falls to a low but detectable value.<sup>9 Ferguson J.K., Oesterling J.E. Patient evaluation if prostate-specific antigen becomes elevated following radical prostatectomy or radiation therapy Urol Clin North Am 1994 ;  21 : 677

Cliccare qui per andare alla sezione Riferimenti</sup> The decline in serum PSA concentration, like the histologic clearance of the tumor, develops over a period of 12 months or more.<sup>12 Goad J.R., Chang S., Ohori M. , e al. PSA after definitive radiotherapy for clinically localized prostate cancer Urol Clin North Am 1993 ;  20 : 727

Cliccare qui per andare alla sezione Riferimenti, 35 Stamey T.A., Kabalin J.N., Ferrari M. Prostate specific antigen in the diagnosis and treatment of adenocarcinoma of the prostate. III. Radiation treated patients J Urol 1989 ;  141 : 1084

Cliccare qui per andare alla sezione Riferimenti, 38 Zagars G.K., Sherman N.E., Babaian R.J. Prostate specific antigen and external beam radiation therapy in prostate cancer Cancer 1991 ;  67 : 412  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> Although no specific posttreatment PSA level is indicative of long-term cure, Geist<sup>11 Geist R.W. Reference range for prostate-specific antigen levels after external beam radiation therapy for adenocarcinoma of the prostate Urology 1995 ;  45 : 1016  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> reported that a stable value of 0 to 2 ng/mL correlates with cancer control and Zagars<sup>37 Zagars G.K. Serum PSA as a tumor marker for patients undergoing definitive radiation therapy Urol Clin North Am 1993 ;  20 : 737

Cliccare qui per andare alla sezione Riferimenti</sup> reported that a PSA level above this value 3 months after treatment indicates a worse prognosis. Regardless of the absolute value, a rising PSA level can be detected in up to 80% of patients 5 years after therapy.<sup>34 Stamey T.A., Ferrari M.K., Schmid H. The value of serial prostate specific antigen determinations 5 years after radiotherapy: Steeply increasing values characterize 80% of patients J Urol 1993 ;  150 : 1856

Cliccare qui per andare alla sezione Riferimenti</sup> The relationship between such biochemical recurrence and biologically significant recurrence is the subject of considerable controversy. Nevertheless, detection of a rising PSA level after radiation therapy signals the presence of active local or distant recurrence and should prompt restaging if salvage therapy is considered.

Certainly, the impact of salvage therapy on the patient's quality of life and longevity must be carefully evaluated within the context of existing comorbidities. It should be kept in mind, however, that the patient who undergoes treatment of localized prostate cancer in the form of radiation therapy with curative intent has been selected for active treatment of his disease rather than observation. For this reason, the detection of recurrence after radiation therapy, either biochemical or histologic, signals the need for consideration of further therapy. The therapeutic options for these patients are the subject of this article.