Preliminary Results of Three-Dimensional Conformal Radiotherapy as Salvage Treatment for a Rising Prostate-Specific Antigen Level Postprostatectomy

Abstract

The purpose of this study is to determine the effectiveness of three-dimensional conformal radiotherapy delivered to the fossa of the prostate and seminal vesicles as salvage treatment for a prostate-specific antigen (PSA) level that becomes undetectable and subsequently begins to rise postprostatectomy. Between August 1994 and December 1997, 14 patients with prostate cancer whose PSA became undetectable after a radical prostatectomy subsequently developed a rising PSA, had no evidence of metastatic disease, and were treated with three-dimensional conformal radiotherapy at the University of California, Davis Cancer Center. Gleason scores ranged from 4 to 9 (29% of the patients had a Gleason score > or =8). The seminal vesicles were involved in three (21%) cases and the surgical margins were involved in seven (50%) cases. PSA values ranged from 0.3 to 6.7 (median: 0.7) ng/ml at the start of radiotherapy. Daily 1.8-2.0-Gy fractions were administered to total doses at isocenter ranging from 60.6 to 74.2 (median: 64.9) Gy. None of the patients received hormonal therapy. Follow-up ranged from 13 to 36 (median: 22) months. For patients with a preradiotherapy Hybritech PSA < or = 1.0 ng/ml, the Kaplan-Meier estimate of the 2-year biochemical disease-free survival rate is 67%, whereas for patients with a preradiotherapy PSA more than 1.0 ng/ml, the 2-year biochemical disease-free survival rate is 20% (p = 0.17). Because of the small number of patients, the difference is not statistically significant. A positive microscopic margin had no impact on the results obtained with salvage radiotherapy. Only one of four patients with a poorly differentiated adenocarcinoma remains free of disease. Acute toxicity was mild and did not require medication (Radiation Therapy Oncology Group grade I): four (29%) patients experienced genitourinary morbidity and three (21%) patients experienced gastrointestinal morbidity. With regard to late toxicity, one (7%) patient developed a urethral stricture requiring dilatation (Radiation Therapy Oncology Group grade III). All five patients who were potent at the start of radiotherapy remain potent. Medicare's median reimbursement for salvage three-dimensional conformal radiotherapy in this study ($7,512 in 1999 U.S. dollars) is equivalent to its reimbursement for a 17-month course of goserelin hormonal therapy. Patients with prostate cancer who develop an undetectable followed by a rising PSA postprostatectomy should be referred for salvage treatment with radiotherapy when their PSA is still less than or equal to 1.0 ng/ml. Salvage three-dimensional conformal radiotherapy is well tolerated and is less expensive than more than 17 months of goserelin.

Adjuvant and Salvage Radiotherapy after Radical Prostatectomy

“…Results vary between 10 and 73%, with different patient selection criteria being the most probable explanation for that enormous divergence (table 3) [13,18,29,[31][32][33][34][35][36][37][38][39][40][41][42][43][44]. Pooled data from 6 larger studies show a PSA decrease into the unde- [46] reported on 53 patients, more than half of whom had persisting PSA levels after RP and therefore possibly a worse prognosis.…”

Radical Prostatectomy in High-Grade Prostate Cancer, Salvage and Adjuvant Radiotherapy

“…A low pretreatment PSA level is an important factor for sRT to be successful. The borderline value of PSA for excellent results of sRT is 1.5 and 2.0 ng/ml, respectively [29][30][31][32][33][34][35][36][37] . Other prognostic factors for the efficacy of sRT are: PSADT [38][39][40][41][42] , PSA before RP [22,23] , seminal vesicle invasion [23,24,27,43,44] and extracapsular extension [27,43,44] .…”

Salvage radiotherapy following radical prostatectomy

“…Previously published reviews 62–64 have found long term rates of GU toxicity (≥grade 2) to be in the range of 0–10%, 51,52,65–77 and GI toxicity rates (≥grade 2) in the range of 0–10% 44,65,66,77,78 …”

“…Previously published reviews [62][63][64] have found long term rates of GU toxicity (Նgrade 2) to be in the range of 0-10%, 51,52,[65][66][67][68][69][70][71][72][73][74][75][76][77] and GI toxicity rates (Նgrade 2) in the range of 0-10%. 44,65,66,77,78 Several studies have looked at health related quality of life outcomes following SRT.…”