Page 38 - Towards personalized therapy for metastatic prostate cancer: technical validation of [18F]fluoromethylcholine

Chapter 2
Table 3. Optimal thresholds for different SUV measures. SUVmax
Standard Uptake Value (SUV)
Threshold
Pattern type
Ben
Mal
Sensitivity (95% CI)
Specificity (95% CI)
AUC (95% QR)
Late (30 min p.i.) Difference
Relative Difference
SUVmeanA50
Late (30 min p.i.) Difference Relative Difference
2.32 A
B 2 34 (78-98)
88 0.93 (64-99) (0.88-0.94) 94 0.90 (71-100) (0.87-0.97) 94 0.98 (71-100) (0.95-0.99)
88 0.95 (64-99) (0.91-0.95) 94 0.89 (71-100) (0.84-0.98) 94 0.97 (71-100) (0.92-0.99)
-0.31 A
B 1 31 (68-94)
-0.19 A
B 1 35 (82-99)
1.66 A
B 2 37 (91-100)
-0.18 A
B 1 30 (65-92)
-0.15 A
B 1 34 (78-98)
15 3 92
16 6 84
16 2 95
15 0 100
16 7 81
16 3 92
Pattern type: A = SUVearly > SUVlate; B = SUVearly ≤ SUVlate
Ben benign, Mal malignant, CI confidence interval, AUC area under the ROC curve, QR quartile range Difference = SUVlate – SUVearly
Relative difference = (SUVlate – SUVearly) / SUVearly
In the 17 patients with 34 enlarged [18F]FCH positive pelvic nodes, histopathological confirmation was obtained in 4 (11 LN); all had type B time trends at [18F]FCH PET/CT. During follow-up, 3 patients (6 LN) had radiological nodal progression; from these five LN had a type B pattern and one LN proved to be false negative: type A trend and radiological progression. In 3 other patients, with only pathologically enlarged pelvic lymph nodes (6 LN) to explain an elevated PSA and with a type B pattern, PSA normalized upon therapy, accompanied by shrinkage of these nodes. PSA decrease and disappearance of a solitary (type B) pelvic node was observed in another patient who was treated with pelvic radiotherapy that focused on a suspected recurrence in prostate and this lymph node.
Six other patients (with 9 type B and 1 type A pelvic lymph nodes) were treated with systemic therapy, because of local recurrence and/ or skeletal metastases. Finally, the patient with both 2 inguinal and 3 pelvic LN (type A in the inguinal and type B in the pelvic nodes) was treated with RT (prostate) and ADT because of confirmed bone oligometastases at presentation. In these 7 patients, PSA decreased over time and radiological regression of all 13 enlarged pelvic nodes together with stable dimensions of the inguinal nodes were recorded, as well. However, this did not unequivocally confirm the LN status due to the use of systemic therapy for coexistent bone metastases.
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