To prospectively identify clinical/dosimetric predictors of acute/late hematologic toxicity (HT) in chemo-naÏve patients treated with whole-pelvis radiotherapy (WPRT) for prostate cancer.
Data of 121 patients treated with adjuvant/salvage WPRT were analyzed (static-field IMRT n=19; VMAT/Rapidarc n=57; Tomotherapy n=45).
Pelvic bone marrow (BM) was delineated as ilium (IL), lumbosacral, lower and whole pelvis (WP), and the relative DVHs were calculated. HT was graded both according to CTCAE v4. 03 and as variation in percentage relative to baseline. Logistic regression was used to analyze association between HT and clinical/DVHs factors.
Significant differences (p<0. 005) in the DVH of BM volumes between different techniques were found: Tomotherapy was associated with larger volumes receiving low doses (3-20Gy) and smaller receiving 40-50Gy. Lower baseline absolute values of WBC, neutrophils and lymphocytes (ALC) predicted acute/late HT (p⩽0. 001). Higher BM V40 was associated with higher risk of acute Grade3 (OR=1. 018) or late Grade2 lymphopenia (OR=1. 005). Two models predicting lymphopenia were developed, both including baseline ALC, and BM WP-V40 (AUC=0. 73) and IL-V40+smoking (AUC=0. 904) for acute/late respectively.
Specific regions of pelvic BM predicting acute/late lymphopenia, a risk factor for viral infections, were identified. The 2-variable models including specific constraints to BM may help reduce HT.
Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology. 2015 Dec 15 [Epub ahead of print]
Carla Sini, Claudio Fiorino, Lucia Perna, Barbara Noris Chiorda, Chiara Lucrezia Deantoni, Marco Bianchi, Vincenzo Sacco, Alberto Briganti, Francesco Montorsi, Riccardo Calandrino, Nadia Di Muzio, Cesare Cozzarini
Department of Medical Physics, San Raffaele Scientific Institute, Milan, Italy. Department of Medical Physics, San Raffaele Scientific Institute, Milan, Italy. , Department of Medical Physics, San Raffaele Scientific Institute, Milan, Italy. , Department of Radiotherapy, San Raffaele Scientific Institute, Milan, Italy. , Department of Radiotherapy, San Raffaele Scientific Institute, Milan, Italy. , Department of Urology, San Raffaele Scientific Institute, Milan, Italy. , Department of Radiotherapy, San Raffaele Scientific Institute, Milan, Italy. , Department of Urology, San Raffaele Scientific Institute, Milan, Italy. , Department of Urology, San Raffaele Scientific Institute, Milan, Italy. , Department of Medical Physics, San Raffaele Scientific Institute, Milan, Italy. , Department of Radiotherapy, San Raffaele Scientific Institute, Milan, Italy. , Department of Radiotherapy, San Raffaele Scientific Institute, Milan, Italy.