Detection rate of PET/CT in patients with biochemical relapse of prostate cancer using [68Ga]PSMA I&T and comparison with published data of [68Ga]PSMA HBED-CC

To determine the detection rate of PET/CT in biochemical relapse of prostate cancer using [Ga-68]PSMA I&T and to compare it with published detection rates of [Ga-68]PSMA HBED-CC. We performed a retrospective analysis in 83 consecutive patients with documented biochemical relapse after prostatectomy. All patients underwent whole body [Ga-68]PSMA I&T PET/CT. PET/CT images were evaluated for presence of local recurrence, lymph node metastases, and distant metastases. Proportions of positive PET/CT results were calculated for six subgroups with increasing prostate specific antigen (PSA) levels (< 0.5 ng/mL, 0.5 to < 1.0 ng/mL, 1.0 to < 2.0 ng/mL, 2.0 to < 5.0 ng/mL, 5.0 to < 10.0, >= 10.0 ng/mL). Detection rates of [Ga-68]PSMA I&T were statistically compared with published detection rates of [Ga-68]PSMA HBED-CC using exact Fisher's test. Median PSA was 0.81 (range: 0.01 - 128) ng/mL. In 58/83 patients (70 %) at least one [Ga-68]PSMA I&T positive lesion was detected. Local recurrent cancer was present in 18 patients (22 %), lymph node metastases in 29 patients (35 %), and distant metastases in 15 patients (18 %). The tumor detection rate was positively correlated with PSA levels, resulting in detection rates of 52 % (< 0.5 ng/mL), 55 % (0.5 to < 1.0 ng/mL), 70 % (1.0 to < 2.0 ng/mL), 93 % (2.0 to < 5.0 ng/mL), 100 % (5.0 to < 10.0 ng/mL), and 100 % (>= 10.0 ng/mL). There was no significant difference between the detection rate of [Ga-68]PSMA I&T and published detection rates of [Ga-68]PSMA HBED-CC (all p > 0.05). [Ga-68]PSMA I&T PET/CT has high detection rates of recurrent prostate cancer that are comparable to [Ga-68]PSMA HBED-CC.