Artificial intelligence-based measurements of PET/CT imaging biomarkers are associated with disease-specific survival of high-risk prostate cancer patients

Figures & data

Table 1. Clinical characteristics of patients in the test set (n = 285).

	All patients (n = 285)		Palliative treatment (n = 66)		Curative treatment (n = 219)
Age, yrs
Median, (IQR)^a	69	(65–72)	70	(67 − 73)	68	(64 − 72)
Gleason scale, No (%)
≤ 6	11	(4%)	1	(2%)	10	(5%)
3 + 4	45	(16%)	5	(8%)	40	(18%)
4 + 3	38	(13%)	7	(11%)	31	(14%)
8	69	(24%)	16	(24%)	53	(24%)
9–10	122	(43%)	37	(56%)	85	(39%)
PSA, ng/ml
Median, (IQR)^a	21	(10–36)	29	(13–56)	19	(9–32)
T-stage, No (%)
T1	49	(17%)	6	(9%)	43	(20%)
T2	104	(36%)	16	(24%)	88	(40%)
T3	129	(45%)	41	(62%)	88	(40%)
T4	3	(1%)	3	(5%)	0	(0%)
N1-stage, No (%)	41	(14%)	29	(44%)	12	(5%)
M-stage, No (%)
M1a	11	(4%)	11	(17%)	0	(0%)
M1b	10	(3%)	9	(14%)	1	(0.5%)
Follow-up time, yrs
Median, (IQR)^a	5	(4.4–5.7)	4.5	(3.5–6)	5	(4.6–5.7)
Number of prostate cancer deaths, No (%)	23	(8%)	18	(27%)	5	(2%)

^a Interquartile range.

Figure 1. Study selection process. The Standards for Reporting Studies of Diagnostic Accuracy (STARD) flow chart.

Figure 2. Kaplan-Meier survival plots of the patients in the test group. The figure compares the survival curves between Gleason score, prostate SUV_max, PSA and lesion VOLUME (n = 285). The upper curves of each graph represent the proportion of patients with values equal or below the median level of the variable of interest (or Gleason ≤ 7 respectively), whereas the lower curves represent the proportion of patients with values above the median level of the variable of interest (or Gleason > 7 respectively). p-value was calculated using the log-rank test.

Table 2. Associations between disease-specific survival and AI-based PET/CT measurements of biomarkers, as well as clinical data using univariate proportional regression analysis.

Variables	Adjusted for treatment (n = 285)		Palliative treatment (n = 66)		Curative treatment (n = 219)
	HR β* (95% CI^§)	p	HR β* (95% CI^§) ^†	p	HR β* (95% CI^§) ^†	p
VOLUME ^a	1.03 (1.01–1.05)	0.008	1.03 (1.01–1.06)	0.008	1.01 (0.9–1.08)	0.7
TLU ^b	1.6 (1.08–2.4)	0.02	1.7 (1.06–2.7)	0.03	1.3 (0.56 − 3.2)	0.5
Fraction (%) ^c	1.03 (1.01–1.06)	0.005	1.04 (1.01–1.07)	0.007	1.02 (0.9–1.07)	0.4
Prostate SUVmax ^d	1.1 (0.9–1.3)	0.2	1.1 (0.9–1.3)	0.3	1.1 (0.8–1.4)	0.5
Lesion SUVmean ^e	1.4 (0.7–2.7)	0.3	1.4 (0.7–3.0)	0.4	1.3 (0.4–4.3)	0.6
Clinical data
Age	0.9 (0.8–0.98)	0.01	0.9 (0.8–0.95)	0.005	1.0 (0.8–1.09)	0.5
PSA (log) ^h	1.4 (0.8–2.3)	0.2	1.5 (0.8–2.7)	0.2	1.0 (0.4–2.7)	0.9
Gleason score ^i	1.2 (0.4–3.0)	0.8	1.2 (0.4–3.9)	0.7	0.8 (0.1–5.1)	0.8
Metastatic disease^‡	2.2 (0.8–5.8)	0.1	1.6 (0.5–4.5)	0.4	10.4 (1.7–63)	0.01

^a Volume of prostate gland voxels with Standardized Uptake Value (SUV) >2.65; ^b Product of SUV_mean × VOLUME reflecting the Total Lesion Uptake (TLU);.

^c Fraction of lesion VOLUME related to the total volume of the prostate gland; ^d Maximum SUV within the prostate; ^e Average SUV of voxels with SUV >2.65;.

^h Prostate-specific antigen (logarithmic); ⁱ Patients with Gleason >7 and reference Gleason $\le$7; * Hazard ratio β; ^§ 95% Confidence Interval; ^† Univariate analysis stratified for treatment; ^‡ Defined as N1 or M1.

Data availability statement

The data that support the findings of this study are available from the corresponding author, [EP], upon reasonable request.