A Systematic Post-QUANTEC Review of Tolerance Doses for Late Toxicity After Prostate Cancer Radiation Therapy

Olsson, Caroline; Jackson, Andrew; Deasy, Joseph O.; Thor, Maria

doi:10.1016/j.ijrobp.2018.08.015

Cited by 42 publications

(44 citation statements)

References 64 publications

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“…The rectal dose‐volume toxicity relationship is not fully understood. Although delivering 30–40 Gy to the rectum is generally accepted to be safe during EBRT, doses in the region of 100 Gy are commonly seen in the rectum during prostate brachytherapy, indicating that we do not fully understand the doses that the rectal wall can tolerate on small volumes . Furthermore, there is nothing to suggest that volumes smaller than 1 cc, that would not be revealed by DVH parameters, do not influence the risk of rectal toxicity.…”

Section: Discussionmentioning

confidence: 97%

“…Our results suggest that localized volumes of the rectal wall, in the path of a single beam, could exceed acceptable dose‐volume criteria for a single fraction when unplanned air cavities occur. However, with no fully validated model defining the link between rectal dose and late toxicity, the clinical implications of hotspots in the rectal wall exceeding current rectal dose constraints during MRgRT cannot be defined here …”

Section: Discussionmentioning

confidence: 99%

“…Although delivering [30][31][32][33][34][35][36][37][38][39][40] Gy to the rectum is generally accepted to be safe during EBRT, doses in the region of 100 Gy are commonly seen in the rectum during prostate brachytherapy, indicating that we do not fully understand the doses that the rectal wall can tolerate on small volumes. 27,30 Furthermore, there is nothing to suggest that volumes smaller than 1 cc, that would not be revealed by DVH parameters, do not influence the risk of rectal toxicity. Our results indicate that D 1cc increases by 45% when a large unplanned air cavity is present in the rectum; however, volumes smaller than 1 cc (0.01 cm 3 ) receive dose increases >60%.…”

Section: A Implications Of Unplanned Gas In the Rectal Wallmentioning

confidence: 99%

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Assessing localized dosimetric effects due to unplanned gas cavities during pelvic MR‐guided radiotherapy using Monte Carlo simulations

et al. 2019

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Purpose It has been proposed that beam modulation and opposing beam configurations can cancel effects of the Electron Return Effect (ERE) during MR‐guided radiotherapy (MRgRT). However, this may not always be the case for unplanned gas cavities outside of the target in the pelvic region. We evaluate dosimetric effects, including effects in the rectal wall, due to unplanned spherical air cavities during MRgRT. Methods Nine virtual cuboid water phantoms containing spherical air cavities (0.5–7.5 cm diameter) and a reference phantom without air were created. Monte Carlo dose calculations of 7 MV photons under the influence of a 1.5 T transverse magnetic field were produced using Monaco 5.19.02 Treatment Planning System (TPS) (Elekta AB, Stockholm, Sweden). Cavities in the path of a single and multiple beam plans were considered. Dose distributions of phantoms with and without air cavities were compared (ΔD%) using a spherical coordinate system originating in the center of the cavity. Effects in the rectal wall were quantified by comparing dose volume histogram (DVH) parameters for solid and gaseous filling from simulated rectal wall structures. Results Max(ΔD%) of ~70% and 20% were observed around large cavities in the path of a single and multiple beam plans, respectively. Approximately 45 cm3 of phantom surrounding the largest cavity in a single beam received dose changes of >10%. Dmean in the rectal wall was unchanged when comparing gaseous and solid filling in the path of a single beam; however, D1cc and Dmax increased by up to ~45% and ~63%, respectively. Conclusions Unplanned gas cavities in the path of a single beam during pelvic MRgRT with a 1.5 T transverse magnetic field cause dose changes which may impact toxicity in the rectal wall, depending on local dose and fractionation. Effects are reduced but not eliminated with a five‐beam plan.

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Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

Section: A Implications Of Unplanned Gas In the Rectal Wallmentioning

confidence: 99%

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Assessing localized dosimetric effects due to unplanned gas cavities during pelvic MR‐guided radiotherapy using Monte Carlo simulations

et al. 2019

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“…Therefore, in order to maintain a good QOL for patients after EBRT, the dose‐volume histogram parameters of the critical organs were more important than the total dose prescribed to the prostate. Dose‐volume tolerances of the critical organs after radiotherapy for prostate cancer have recently been upgraded and summarized …”

Section: Factors Affecting Qol After Ebrtmentioning

confidence: 99%

Quality of life after external beam radiotherapy for localized prostate cancer: Comparison with other modalities

et al. 2019

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In external beam radiotherapy for localized prostate cancer, acute toxicities are typically transient and mild. These symptoms will disappear within 4–8 weeks after external beam radiotherapy. Some patients might suffer from proctitis with bloody stools as late rectal toxicity. Therefore, it has been shown that external beam radiotherapy has a more pronounced negative impact on bowel function compared with other treatment modalities. However, the recent development of modern beam delivery techniques, including intensity‐modulated radiotherapy, allows us not only to deliver higher doses to the prostate, but also to decrease the doses to the critical organs, resulting in the maintenance of patients’ quality of life within satisfactory levels. Patients’ quality of life after external beam radiotherapy is also strongly related to the total dose, fractionation regimens, dose parameters of the critical organs and treatment plan quality, with a trade‐off between the radicality of external beam radiotherapy and potentially increased toxicity. Radiation oncologists should choose treatment parameters carefully to achieve a reasonable balance between a good oncological outcome and the patient's quality of life.

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“…We agree that minimizing high‐dose therapy is an important goal. However, large multi‐institutional reports, some of which were prospective, also have supported an association between low‐range to mid‐range rectal doses and late gastrointestinal toxicities, including fecal incontinence and late rectal bleeding, with one report identifying rectal dose thresholds in both the low‐dose to middle‐dose (10‐50 Gy) and high‐dose (55‐78 Gy) ranges . Ideally, any form of postprostatectomy radiotherapy would reduce both the low‐dose to middle‐dose and high‐dose regions; reducing low‐dose to middle‐dose regions for OARs may confer late toxicity benefits.…”

mentioning

confidence: 99%

Proton beam therapy after radical prostatectomy

Santos

Barsky

Vapiwala

2019

Cancer

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A Systematic Post-QUANTEC Review of Tolerance Doses for Late Toxicity After Prostate Cancer Radiation Therapy

Cited by 42 publications

References 64 publications

Assessing localized dosimetric effects due to unplanned gas cavities during pelvic MR‐guided radiotherapy using Monte Carlo simulations

Assessing localized dosimetric effects due to unplanned gas cavities during pelvic MR‐guided radiotherapy using Monte Carlo simulations

Quality of life after external beam radiotherapy for localized prostate cancer: Comparison with other modalities

Proton beam therapy after radical prostatectomy

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