[18F]fluoroethylcholine-PET/CT imaging for radiation treatment planning of recurrent and primary prostate cancer with dose escalation to PET/CT-positive lymph nodes

Abstract

BackgroundAt present there is no consensus on irradiation treatment volumes for intermediate to high-risk primary cancers or recurrent disease. Conventional imaging modalities, such as CT, MRI and transrectal ultrasound, are considered suboptimal for treatment decisions. Choline-PET/CT might be considered as the imaging modality in radiooncology to select and delineate clinical target volumes extending the prostate gland or prostate fossa. In conjunction with intensity modulated radiotherapy (IMRT) and imaged guided radiotherapy (IGRT), it might offer the opportunity of dose escalation to selected sites while avoiding unnecessary irradiation of healthy tissues.MethodsTwenty-six patients with primary (n = 7) or recurrent (n = 19) prostate cancer received Choline-PET/CT planned 3D conformal or intensity modulated radiotherapy. The median age of the patients was 65 yrs (range 45 to 78 yrs). PET/CT-scans with F18-fluoroethylcholine (FEC) were performed on a combined PET/CT-scanner equipped for radiation therapy planning.The majority of patients had intermediate to high risk prostate cancer. All patients received 3D conformal or intensity modulated and imaged guided radiotherapy with megavoltage cone beam CT. The median dose to primary tumours was 75.6 Gy and to FEC-positive recurrent lymph nodal sites 66,6 Gy. The median follow-up time was 28.8 months.ResultsThe mean SUVmax in primary cancer was 5,97 in the prostate gland and 3,2 in pelvic lymph nodes. Patients with recurrent cancer had a mean SUVmax of 4,38. Two patients had negative PET/CT scans. At 28 months the overall survival rate is 94%. Biochemical relapse free survival is 83% for primary cancer and 49% for recurrent tumours. Distant disease free survival is 100% and 75% for primary and recurrent cancer, respectively. Acute normal tissue toxicity was mild in 85% and moderate (grade 2) in 15%. No or mild late side effects were observed in the majority of patients (84%). One patient had a severe bladder shrinkage (grade 4) after a previous treatment with TUR of the prostate and seed implantation.ConclusionsFEC-PET/CT planning could be helpful in dose escalation to lymph nodal sites of prostate cancer.

Evaluation of Prostate Cancer with 11C-Choline PET/CT for Treatment Planning, Response Assessment, and Prognosis

“…In the overall population, the disease-free survival rate was 56%, whereas in patients treated with metastasis-directed S-RT, the disease-free survival rate was 80%. Similar results were reported by Würschmidt et al (29) for recurrent PCa in 19 patients treated with intensity-modulated radiotherapy for BCR after RP. A standard dose was delivered to the prostatic bed with a boost (65 Gy) for 18 F-choline PET/CT-positive lymph nodes.…”

Early Biochemical Relapse After Radical Prostatectomy: Which Prostate Cancer Patients May Benefit from a Restaging11C-Choline PET/CT Scan Before Salvage Radiation Therapy?

“…Conversely, patients in whom distant metastases or locoregional LN involvement is suspected may not benefit from S-RT: they are usually treated with ADT regardless of the site of recurrence. Recently, it was suggested that aggressive therapeutic approaches in PCa patients with proven distant recurrence could be feasible and increase the biochemical free survival (12)(13)(14). PET/CT using 11 Cor 18 F-labeled choline may have a role in this scenario (15).…”

Abiraterone and Volumetric Modulated Arc Therapy for Second Recurrence of Node-Positive Prostate Cancer – A Case Repo

“…Wurschmidt et al treated PET/CT positive lesions in lymph nodes with 66.6 Gy [16]. However, in direct contrast, in the study by Casamassima et al the lymph node lesions detected with an 11 C-choline PET/CT scan, were treated with 50 Gy in 25 fractions plus 24 Gy in an additional boost [9].…”