Prostate-specific antigen doubling time subsequent to radical prostatectomy is a predictor of outcome following salvage external beam radiation therapy: A single-centre experience

Figures & data

Table 1. Patient characteristics and treatment details of definitive prostatectomy.

Characteristic	n (%)
Age at radical prostatectomy (years)
≤60	42 (55)
>60	34 (45)
pT stage
≤pT2	39 (51)
≥pT3	37 (49)
Seminal vesicle invasion
Present	8 (11)
Absent	68 (89)
Gleason score
<7	16 (21)
3 + 4 = 7	24 (32)
4 + 3 = 7	20 (26)
≥8	16 (21)
Margin status
Positive	51 (67)
Negative	25 (33)
Presurgery PSA level (ng/ml)
<10	41 (54)
>10	35 (46)

PSA = prostate-specific antigen.

Table 2. Postprostatectomy prostate-specific antigen (PSA) levels and salvage external beam radiation therapy (EBRT) treatment details.

Parameter	n (%)
Postoperative PSA nadir (ng/ml)
0	27 (36)
0.01–0.20	29 (38)
≥0.21	20 (26)
PSA at start of salvage EBRT
0–1	42 (55)
>1	34 (45)
PSADT postprostatectomy (months)
<6	25 (33)
≥6	51 (67)
Palpable nodule and/or MRI verified
Palpable nodule and/or MRI verified	20 (26)
Not palpable nodule and/or MRI verified	56 (74)
Biopsy
Biopsy positive	17 (22)
Biopsy negative	8 (11)
Biopsy not done	51 (67)
Timing of salvage EBRT after RP (months)
<24	23 (30)
≥24–48	18 (24)
≥48	35 (46)
Salvage EBRT dose (Gy)
60	7 (9)
64	1 (1)
70	68 (90)

PSADT = prostate-specific antigen doubling time; MRI = magnetic resonance imaging; RP = radical prostatectomy.

Figure 1. Proportion free from prostate-specific antigen (PSA) relapse following salvage external beam radiation therapy (EBRT) in relation to (a) surgical margin status, (b) pre-salvage EBRT PSA level 0–1.0 ng/ml or ≥1.0 ng/ml, (c) prostate-specific antigen doubling time (PSADT) 0–6 months or >6 months, (d) Gleason score (GS) 3 + 4 or less or GS 4 + 3 or more, and (e) absence or presence of seminal vesicle invasion (SVI).

Table 3. Multivariate analysis of predictors for biochemical-free recurrence following salvage external beam radiation therapy for prostate cancer.

Variable	HR (95% CI)	p
Gleason score		0.29
≤3 + 4	Reference
≥4 + 3	2.1 (0.5–8.0)
PSADT (months)		0.04
0–6	Reference
>6	0.3 (0.1–0.9)
Seminal vesicle invasion		< 0.05
Absent	Reference
Present	7.9 (1.7–36.6)

PSADT = prostate-specific antigen doubling time; HR = hazard ratio; CI = confidence interval.