Bladder spatial-dose descriptors correlate with acute urinary toxicity after radiation therapy for prostate cancer

Ilaria Improta; F. Palorini; C. Cozzarini; T. Rancati; b avuzzi; P. Franco; Claudio Degli Esposti; Elena Delmastro; G. Girelli; C. Iotti; V Vavassori; R Valdagni; c Fiorino

Bladder spatial-dose descriptors correlate with acute urinary toxicity after radiation therapy for prostate cancer

Ilaria Improta, F. Palorini, C. Cozzarini, T. Rancati, b avuzzi, P. Franco, Claudio Degli Esposti, Elena Delmastro, G. Girelli, C. Iotti, V Vavassori, R Valdagni, c Fiorino

Istituto Oncologico Candiolo

Research output: Contribution to journal › Article › peer-review

Abstract

Purpose: To assess bladder spatial-dose parameters predicting acute urinary toxicity after radiotherapy for prostate cancer (PCa) through a pixel-wise method for analysis of bladder dose-surface maps (DSMs). Materials & methods: The final cohort of a multi-institutional study, consisting of 539 patients with PCa treated with conventionally (CONV:1.8–2 Gy/fr) or moderately hypo-fractionated radiotherapy (HYPO:2.2–2.7 Gy/fr) was considered. Urinary toxicity was evaluated through the International Prostate Symptoms Score (IPSS) administered before and after radiotherapy. IPSS increases P10 and 15 points at the end of radiotherapy (DIPSSP10 and DIPSSP15) were chosen as endpoints. Average DSMs (corrected into 2 Gy-equivalent doses) of patients with/without toxicity were compared through a pixel-wise method. This allowed the extraction of selected spatial descriptors discriminating between patients with/without toxicity. Previously logistic models based on dose-surface histograms (DSH) were considered and replaced with DSM descriptors. Discrimination power, calibration and log-likelihood were considered to evaluate the impact of the inclusion of spatial descriptors. Results: Data of 375/539 patients were available. DIPSSP10 was recorded in 76/375 (20%) patients, while 30/375 (8%) experienced DIPSSP15. The posterior dose at 12 mm from the bladder base (roughly corresponding to the trigone region) resulted significantly associated to toxicity in the whole/HYPO populations. The cranial extension of the 75 Gy isodose along the bladder central axis was the best DSM-based predictor in CONV patients. Multi-variable models including DSM descriptors showed better discrimination (AUC = 0.66–0.77) when compared to DSH-based models (AUC = 0.58–0.71) and higher log-likelihoods. Conclusion: DSMs are correlated with the risk of acute GU toxicity. The incorporation of spatial descriptors improves discrimination and log-likelihood of multi-variable models including dosimetric and clinical parameters.

Original language	English
Journal	Physica Medica
Publication status	Published - 2016

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Bladder spatial-dose descriptors correlate with acute urinary toxicity after radiation therapy for prostate cancer. / Improta, Ilaria; Palorini, F.; Cozzarini, C.; Rancati, T.; avuzzi, b; Franco, P.; Esposti, Claudio Degli; Delmastro, Elena; Girelli, G.; Iotti, C.; Vavassori, V; Valdagni, R; Fiorino, c.

In: Physica Medica, 2016.

Research output: Contribution to journal › Article › peer-review

@article{4399bb92f4f84c979249a0a6fc8b9829,

title = "Bladder spatial-dose descriptors correlate with acute urinary toxicity after radiation therapy for prostate cancer",

abstract = "Purpose: To assess bladder spatial-dose parameters predicting acute urinary toxicity after radiotherapy for prostate cancer (PCa) through a pixel-wise method for analysis of bladder dose-surface maps (DSMs). Materials & methods: The final cohort of a multi-institutional study, consisting of 539 patients with PCa treated with conventionally (CONV:1.8–2 Gy/fr) or moderately hypo-fractionated radiotherapy (HYPO:2.2–2.7 Gy/fr) was considered. Urinary toxicity was evaluated through the International Prostate Symptoms Score (IPSS) administered before and after radiotherapy. IPSS increases P10 and 15 points at the end of radiotherapy (DIPSSP10 and DIPSSP15) were chosen as endpoints. Average DSMs (corrected into 2 Gy-equivalent doses) of patients with/without toxicity were compared through a pixel-wise method. This allowed the extraction of selected spatial descriptors discriminating between patients with/without toxicity. Previously logistic models based on dose-surface histograms (DSH) were considered and replaced with DSM descriptors. Discrimination power, calibration and log-likelihood were considered to evaluate the impact of the inclusion of spatial descriptors. Results: Data of 375/539 patients were available. DIPSSP10 was recorded in 76/375 (20%) patients, while 30/375 (8%) experienced DIPSSP15. The posterior dose at 12 mm from the bladder base (roughly corresponding to the trigone region) resulted significantly associated to toxicity in the whole/HYPO populations. The cranial extension of the 75 Gy isodose along the bladder central axis was the best DSM-based predictor in CONV patients. Multi-variable models including DSM descriptors showed better discrimination (AUC = 0.66–0.77) when compared to DSH-based models (AUC = 0.58–0.71) and higher log-likelihoods. Conclusion: DSMs are correlated with the risk of acute GU toxicity. The incorporation of spatial descriptors improves discrimination and log-likelihood of multi-variable models including dosimetric and clinical parameters.",

author = "Ilaria Improta and F. Palorini and C. Cozzarini and T. Rancati and b avuzzi and P. Franco and Esposti, {Claudio Degli} and Elena Delmastro and G. Girelli and C. Iotti and V Vavassori and R Valdagni and c Fiorino",

year = "2016",

language = "English",

journal = "Physica Medica",

issn = "1120-1797",

publisher = "Associazione Italiana di Fisica Medica",

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TY - JOUR

T1 - Bladder spatial-dose descriptors correlate with acute urinary toxicity after radiation therapy for prostate cancer

AU - Improta, Ilaria

AU - Palorini, F.

AU - Cozzarini, C.

AU - Rancati, T.

AU - avuzzi, b

AU - Franco, P.

AU - Esposti, Claudio Degli

AU - Delmastro, Elena

AU - Girelli, G.

AU - Iotti, C.

AU - Vavassori, V

AU - Valdagni, R

AU - Fiorino, c

PY - 2016

Y1 - 2016

N2 - Purpose: To assess bladder spatial-dose parameters predicting acute urinary toxicity after radiotherapy for prostate cancer (PCa) through a pixel-wise method for analysis of bladder dose-surface maps (DSMs). Materials & methods: The final cohort of a multi-institutional study, consisting of 539 patients with PCa treated with conventionally (CONV:1.8–2 Gy/fr) or moderately hypo-fractionated radiotherapy (HYPO:2.2–2.7 Gy/fr) was considered. Urinary toxicity was evaluated through the International Prostate Symptoms Score (IPSS) administered before and after radiotherapy. IPSS increases P10 and 15 points at the end of radiotherapy (DIPSSP10 and DIPSSP15) were chosen as endpoints. Average DSMs (corrected into 2 Gy-equivalent doses) of patients with/without toxicity were compared through a pixel-wise method. This allowed the extraction of selected spatial descriptors discriminating between patients with/without toxicity. Previously logistic models based on dose-surface histograms (DSH) were considered and replaced with DSM descriptors. Discrimination power, calibration and log-likelihood were considered to evaluate the impact of the inclusion of spatial descriptors. Results: Data of 375/539 patients were available. DIPSSP10 was recorded in 76/375 (20%) patients, while 30/375 (8%) experienced DIPSSP15. The posterior dose at 12 mm from the bladder base (roughly corresponding to the trigone region) resulted significantly associated to toxicity in the whole/HYPO populations. The cranial extension of the 75 Gy isodose along the bladder central axis was the best DSM-based predictor in CONV patients. Multi-variable models including DSM descriptors showed better discrimination (AUC = 0.66–0.77) when compared to DSH-based models (AUC = 0.58–0.71) and higher log-likelihoods. Conclusion: DSMs are correlated with the risk of acute GU toxicity. The incorporation of spatial descriptors improves discrimination and log-likelihood of multi-variable models including dosimetric and clinical parameters.

AB - Purpose: To assess bladder spatial-dose parameters predicting acute urinary toxicity after radiotherapy for prostate cancer (PCa) through a pixel-wise method for analysis of bladder dose-surface maps (DSMs). Materials & methods: The final cohort of a multi-institutional study, consisting of 539 patients with PCa treated with conventionally (CONV:1.8–2 Gy/fr) or moderately hypo-fractionated radiotherapy (HYPO:2.2–2.7 Gy/fr) was considered. Urinary toxicity was evaluated through the International Prostate Symptoms Score (IPSS) administered before and after radiotherapy. IPSS increases P10 and 15 points at the end of radiotherapy (DIPSSP10 and DIPSSP15) were chosen as endpoints. Average DSMs (corrected into 2 Gy-equivalent doses) of patients with/without toxicity were compared through a pixel-wise method. This allowed the extraction of selected spatial descriptors discriminating between patients with/without toxicity. Previously logistic models based on dose-surface histograms (DSH) were considered and replaced with DSM descriptors. Discrimination power, calibration and log-likelihood were considered to evaluate the impact of the inclusion of spatial descriptors. Results: Data of 375/539 patients were available. DIPSSP10 was recorded in 76/375 (20%) patients, while 30/375 (8%) experienced DIPSSP15. The posterior dose at 12 mm from the bladder base (roughly corresponding to the trigone region) resulted significantly associated to toxicity in the whole/HYPO populations. The cranial extension of the 75 Gy isodose along the bladder central axis was the best DSM-based predictor in CONV patients. Multi-variable models including DSM descriptors showed better discrimination (AUC = 0.66–0.77) when compared to DSH-based models (AUC = 0.58–0.71) and higher log-likelihoods. Conclusion: DSMs are correlated with the risk of acute GU toxicity. The incorporation of spatial descriptors improves discrimination and log-likelihood of multi-variable models including dosimetric and clinical parameters.

M3 - Article

JO - Physica Medica

JF - Physica Medica

SN - 1120-1797

ER -