Rectrospective analysis of radioguided Da Vinci lymphadenectomy in high-risk prostate cancer patients

Abstract

Background
According to the classification of D`Amico et al., patients with high-risk prostate cancer, should undergo radical prostatectomy with extended pelvic lymphadenectomy. Radioactive marking of the sentinel lymph nodes the day before surgery and targeted removal of the lymph nodes that are conspicuous in the SPECT/CT could provide a benefit in terms of the invasiveness and radicality of the surgery.
Methods
At the Ordensklinikum Linz GmbH Elisabethinen Hospital, 18 patients underwent preparation for radioguided surgery of the PSMA-positive lymph nodes following suspicious PET/CT findings. A retrospective analysis of the demographic data, surgical reports, imaging and histological findings was performed. In addition, the uptake of the lymph nodes was determined from the image data and lesion-to-background-ratios were calculated. All data were processed using descriptive statistics and a possible PET cut-off value was evaluated.
Results
The average age of all patients was 66 years (SD ± 4.57, 61.43 – 70.57years) and the mean BMI of the patients was 26.5 (SD ± 3.44, 23.06 – 29.94), which corresponds to being overweight. 6 patients had a T-score of T2c, 1 patient of T3, 4 of T3a and 2 of T3b. The ISUP classification covered all classes, with one being assigned to ISUP- classification group 1, 3 to ISUP- classification group 2, 3 to ISUP- classification group 3, 4 to ISUP- classification group 4 and 3 to ISUP- classification group 5. The calculation of lesion-to-background-ratios showed 3 low values (≤ 9) in the PET/CT dataset, which could indicate a possible Cut-off value. These ratios were also low in the corresponding SPECT/CT examination. All low lesion-to-background-ratios in SPECT/CT could not be assigned to any findings-relevant enrichment in SPECT/CT. The RGS was able to achieve a specificity of 83.33%, a sensitivity of 92.10%, a PPV of 76.92% and an NPV of 94.59%.
Conclusion
Despite the rather small number of patients included, this retrospective study shows promising results. RGS could be a low-invasive option for identifying and removing affected PSMA-positive lymph nodes in patients with high-risk prostate carcinoma. With regard to sensitivity and specificity, studies with larger numbers of patients are still required.

Date of Award	Jun 2024
Original language	English
Awarding Institution	FH Gesundheitsberufe OÖ GmbH
Supervisor	Julia Pilz (Supervisor) & Dominik Wurm (Supervisor)