Local recurrence map to guide target volume delineation after radical prostatectomy.

Area of Science:

• Oncology
• Radiation Oncology
• Medical Imaging

Background:

• Radical prostatectomy (RP) is a common treatment for prostate cancer.
• Recurrent prostate cancer after RP requires precise radiation therapy planning.
• Accurate contouring of the prostatic fossa clinical target volume (PF-CTV) is crucial for effective treatment.

Purpose of the Study:

• To map the anatomical locations of recurrent prostate cancer after RP.
• To guide the contouring of the PF-CTV in cases of non-visible recurrence or when MRI is unavailable.
• To improve target definition for conformal radiation therapy in the adjuvant or salvage setting.

Main Methods:

• Selected ten patients with MRI-detected, biopsy-proven local recurrences post-RP.
• Delineated recurrence areas on MRI and mapped them onto template images.
• Evaluated coverage of recurrence areas using RTOG-consensus PF-CTV contours on CT templates.

Main Results:

• Recurrences varied significantly in superoinferior and anteroposterior directions.
• Locations ranged from the superior retrovesical region to the posterior urogenital diaphragm.
• RTOG-PF-CTV contours showed marginal or lacking coverage for posterolateral and inferior recurrences.

Conclusions:

• Prostate cancer recurrence locations exhibit considerable variation post-RP.
• RTOG-consensus PF-CTV contours may require modifications, especially in posterolateral and inferior regions.
• Improved target definition can enhance conformal radiation therapy for recurrent prostate cancer.