Performance of free prostate-specific antigen ratio in differentiating between prostatic cancer and benign prostatic lesions at a referral hospital in South Africa

Figures & data

Figure 1: Quartiles of %FPSA ratio.

Figure 2: Diagnosis based on 25% FPSA ratio and histology.

Table 1: Comparison between prostate cancer and benign prostatic lesion patients

	n	PCA	Benign	p-value
Age (years)	130	66.78 ± 6.87(52–82)	65.09 ± 7.8(47–90)	0.000
PSA (ng/ml)	131	6.46 ± 2.76(0.70–9.90)	7.00 ± 2.06(1–10)	0.355
FPSA (ng/ml)	122	1.13 ± 0.611(0.10–2.33)	1.42 ± 0.84(0.26–4.88)	0.977
F/TPSA ratio	122	0.16 ± 0.09(0.02–0.41)	0.200 ± 0.105(0.06–0.70)	0.749

Note: In the benign lesion age category one patient was excluded as we did not have his age.

Table 2: Diagnostic utility of F/TPSA ratio at different cut-offs

F/TPSA ratio (%)	Sensitivity	Specificity	PPV⃰	NPV†
10	0.26	0.81	0.24	0.82
15	0.52	0.61	0.24	0.84
18	0.56	0.5	0.21	0.83
20	0.69	0.42	0.22	0.85
22	0.83	0.34	0.23	0.89
24	0.83	0.47	0.26	0.92
25	0.86	0.27	0.21	0.9
26	0.87	0.25	0.22	0.89
28	0.86	0.16	0.19	0.84
30	0.95	0.15	0.21	0.93

Notes: ^⃰PPV: positive predictive value.

^† NPV: negative predictive value.