The FLAME trial demonstrated that the dose to the gross tumor volume (GTV) is associated with tumour control in prostate cancer patients. This raises the question if dose de-escalation to the remaining prostate gland can be considered. Therefore, we investigated if intraprostatic recurrences occur at the location of the GTV and which dose was delivered at that location.
For FLAME trial patients with an intra-prostatic recurrence, we collected pre-treatment images, GTV delineations, dose distributions and post-recurrence images. Pre-treatment images were registered to the post-recurrence images (PSMA-PET CT). An overlap between GTV and PSMA-PET activity was considered an intra-prostatic recurrence at the location of the primary tumor.
Twenty eight out of 535 patients in the FLAME trial had an intra-prostatic recurrence. Its location could be determined for 24 patients. One patient recurred in the prostate gland outside the GTV. The median D98% to the GTV was 76.5 Gy (range: 73.3-86.5 Gy). Only one patient with a recurrence in the GTV received a substantial focal boost of 86.5 Gy. The D98% of all remaining patients was < 81 Gy.
Intra-prostatic recurrences of intermediate- and high-risk prostate cancer patients treated with radiotherapy appeared predominantly at the location of the primary tumor. All but one patient did not receive a high dose to the GTV. Intra-prostatic failure is likely a consequence of the undertreatment of the primary tumor rather than the undertreatment of the remaining prostate gland.
Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology. 2024 Sep 13 [Epub ahead of print]
K Menne Guricová, F J Pos, I G Schoots, W V Vogel, L G W Kerkmeijer, E M Monninkhof, J C J de Boer, J R N van der Voort van Zyp, M Kunze-Busch, R J Smeenk, C Draulans, K Haustermans, P J van Houdt, U A van der Heide
Department of Radiation Oncology, the Netherlands Cancer Institute (NKI-AVL), Amsterdam, the Netherlands., Department of Radiology, the Netherlands Cancer Institute, Amsterdam, the Netherlands; Department of Radiology & Nuclear Medicine, Erasmus University Medical Center, Rotterdam, the Netherlands., Department of Radiation Oncology, University Medical Center Utrecht, Radiation Oncology, Utrecht, the Netherlands; Department of Radiation Oncology, Radboud University Medical Center, Nijmegen, the Netherlands., Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands., Department of Radiation Oncology, University Medical Center Utrecht, Radiation Oncology, Utrecht, the Netherlands., Department of Radiation Oncology, Radboud University Medical Center, Nijmegen, the Netherlands., Department of Radiation Oncology, University Hospitals Leuven, Leuven, Belgium., Department of Radiation Oncology, the Netherlands Cancer Institute (NKI-AVL), Amsterdam, the Netherlands. Electronic address: .