[18F]-fluorocholine PET/CT for preoperative lymph node staging of Prostate Cancer.study: Preliminary results of a prospective

[¹⁸F]-fluorocholine PET/CT for preoperative lymph node staging of Prostate Cancer.

Preliminary results of a prospective study

Mads H Poulsen¹, Kirsten Bouchelouche², Oke Gerke^2,3, Henrik Petersen², Birgitte Svolgaard⁴, Niels Marcussen⁵, Niels Svolgaard¹, Mattias Ögren², Werner Vach³,Poul F. Høilund-Carlsen², Ulla Geertsen¹, Steen Walter¹.

1. Odense University Hospital, Department of Urology, Odense, Denmark. 2. Odense University Hospital, Department of Nuclear Medicine, Odense, Denmark. 3. University of Southern Denmark, Department of Statistics, Odense, Denmark. 4. Odense University Hospital, Department of Radiology, Odense, Denmark. 5. Odense University Hospital, Department of Pathology, Odense, Denmark.

Introduction and objective

This study evaluates the effect of preoperative [¹⁸F]-fluorocholine (FCH) PET/CT for detection of regional lymph node metastases from prostate cancer.

 

Material and method

A prospective planned registered consecutive study has begun and the first 25 patients have been evaluated. From 1^th January to 30^th July 2008 the patients have been FCH PET/CT scanned prior to standard regional bilateral lymphadenectomy in fossa obturatoria. Following the lymphadenectomy the histopathological examination of the lymph nodes (the gold standard) was compared with the result of the FCH PET/CT scan which had been blinded. The inclusion criteria were prostate cancer and PSA>10 and/or Gleason ≥ 7 and/or T-stage ≥ 3 and that the patient awaited lymphadenectomy prior to curative therapy.  

 

Results

The mean age of the patients was 66.2 year (range 62-75). The mean PSA level was 20.1 (range 6-60). The average Gleason score was 7.1 (range 5-9). 4 patients (16%) were T1, 5 (20%) T2, and 16 (64%) T3. On average, 5.0 (range 2-11) lymph nodes were removed per patient.

The histopathological examination of the removed lymph nodes revealed metastases in 3 patients: 2 patients with a single node with metastasis, and 1 patient with 3 lymph nodes with metastases. FCH PET/CT showed a high tracer uptake in 4 patients, the former 3 and a 4^th patient.

In all patients, there was a high tracer uptake in the prostate gland, consistent with their biopsy proven prostate cancers.

	Pathological examination  + metastases	Pathological examination - metastases
FCH PET/CT + metastases	12 % (3 /25 patients)	4 % (1 /25 patients)
FCH PET/CT - metastases	0 % (0 /25 patients)	84 % (21 /25 patients)

 

Sensitivity, specificity, positive predictive value and negative predictive value of FCH PET/CT for patient based lymph node staging of prostate cancer were 100 %, 95.4 %, 75 % and 100 %, respectively. The 95% confidence intervals were [29.24%, 100%], [77.16%, 99.89%], [19.41%, 99.37%] and [83.89%, 100%], respectively.

Seven other patients had lymph nodes with a high tracer uptake in lymph nodes located in the lower abdomen and pelvis; these lymph nodes were all placed outside the region of the lymphadenectomy.

Nine patients in all had other additional findings, primarily within their lungs or in the mediastinum.

 

Conclusion

Our results supports the use of FCH PET/CT as a tool for lymph node staging of prostate cancer. However since this is in contrast with other studies, larger prospective studies are needed to further clarify the value of FCH PET/CT for lymph node staging of prostate cancer.