Biologically effective dose values for prostate brachytherapy: Effects on PSA failure and posttreatment biopsy results

Stock, Richard G.; Stone, Nelson N.; Cesaretti, Jamie A.; Rosenstein, Barry S.

doi:10.1016/j.ijrobp.2005.07.981

Cited by 226 publications

(139 citation statements)

References 32 publications

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“…The 10-year, disease-specific survival rates for 1561 men treated by brachytherapy, with or without EBRT and hormone therapy, have recently been published with a 96% survival, suggesting that the excellent results obtained using PSA as a surrogate marker appear to translate to actual clinical outcomes. 6 The durability of brachytherapy has been demonstrated in 10-and 12-year results from Seattle. No further recurrences were identified in patients who were deemed biochemically free at 12 years compared to 10 years of follow-up.…”

Section: Brachytherapy Resultsmentioning

confidence: 99%

“…This is interesting as by using the intention-to-treat approach, the confounding factor of lymph node sampling and down-staging is taken into account. Admittedly, not all comparative studies find in favour of surgery and Martinez et al 6 reported no significant survival difference between radiotherapy and surgery groups but this involved a relatively small study group (382 patients) and a short median follow-up of 5.5 years.…”

Section: Surgery Versus Radiotherapymentioning

confidence: 96%

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Prostate Cancer Treatment

Dehn¹

2006

annals

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Section: Brachytherapy Resultsmentioning

confidence: 99%

Section: Surgery Versus Radiotherapymentioning

confidence: 96%

Prostate Cancer Treatment

Dehn¹

2006

annals

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“…A rough calculation can compare the urethral biological effective dose (BED) in EBRT to the dose in 125 I implant low‐dose rate prostate brachytherapy according to Stock et al 25. For EBRT,

BED = D * (1 + d / (α / β))

For 125 I implant brachytherapy,

BED = false(R_{0} false/ λ false) * [1 + R_{0} false/ (false(μ + λ false) false(α false/ β false))]

where

R_{0} = D * λ, λ = 0.693 / T_{1 / 2},

T_{1 / 2} = 60 days for^{125} I and μ = 0.693 / t_{1 / 2}

25. From AAPM TG 137, for a prescription dose of 145 Gy for permanent 125 I implants, it is recommended that final dose to 10% of the urethra should be <150% (218 Gy) for an acceptable toxicity rate 22.…”

Section: Discussionmentioning

confidence: 99%

A quantitative assessment of the consequences of allowing dose heterogeneity in prostate radiation therapy planning

Sun

Smith

Ghose

et al. 2018

J Applied Clin Med Phys

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Target dose uniformity has been historically an aim of volumetric modulated arc therapy (VMAT) planning. However, for some sites, this may not be strictly necessary and removing this constraint could theoretically improve organ‐at‐risk (OAR) sparing and tumor control probability (TCP). This study systematically investigates the consequences of PTV dose uniformity that results from the application or removal of an upper dose constraint (UDC) in the inverse planning process for prostate VMAT treatments. OAR sparing, target coverage, hotspots, and plan complexity were compared between prostate VMAT plans with and without the PTV UDC optimized using the progressive resolution optimizer (PRO, Varian Medical Systems, Palo Alto, CA). Removing the PTV UDC, the median D1cc reached 144.6% for the CTV and the PTV, and an average increase of 3.2% TCP was demonstrated, while CTV and PTV coverage evaluated by D99% was decreased by less than 0.6% with statistical significance. Moreover, systematic improvement in the rectum dose volume histograms was shown (a 5–10% decrease in the volume receiving 50% to 75% prescribed dose), resulting in an average decrease of 1.3% (P < 0.01) in the rectum normal tissue complication probability. Additional consequences included potentially increased dose to the urethra as evaluated by PTV D0.035cc (median: 153.4%), delivering 283 extra monitor units (MUs), and slightly higher degrees of modulation. In general, the results were consistent when a different optimizer (Photon Optimizer, Varian Medical Systems) was used. In conclusion, removing the PTV UDC is acceptable for localized prostate cases given the systematic improvement of rectal dose and TCP. It can be particularly useful for cases that do not meet the rectum dose constraints with the PTV UDC on. This comes with the foreseeable consequences of increased dose heterogeneity in the PTV and an increase in MUs and plan complexity. It also has a higher requirement for reproducing the position and size of the target and OARs during treatment. Finally, with the PTV UDC completely removed, in some cases the maximum doses within the PTV did approach levels that may be of concern for urethral toxicity and therefore in clinical implementation it may still be necessary to include a PTV UDC, but one based on limiting toxicity rather than enforcing dose homogeneity.

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“…Other values used for BED calculations were t 1/2 ¼ 1 hour and T 1/2 ¼ 60 days for I-125 and 17 days for Pd-103. 3,4 The BED values for combined EBRT and BRT were obtained by adding the BED for each individual modality. 6 …”

Section: Calculation Of Bedmentioning

confidence: 99%

“…The biologically equivalent dose (BED) can be calculated for permanent BRT and fractionated EBRT. [2][3][4] It has been shown that the BED for permanent BRT is higher than that of conventional dose 3-dimensional conformal radiotherapy (3D-CRT). Intuitively, it would be reasonable to assume that dose escalation from 3D-CRT, either by BRT or by IMRT, should achieve better biochemical control (bNED) rates.…”

mentioning

confidence: 99%

Radiation dose escalation for localized prostate cancer

Wong

Vora

Schild

et al. 2009

Cancer

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BACKGROUND:In the current study, the effects of dose escalation for localized prostate cancer treatment with intensity‐modulated radiotherapy (IMRT) or permanent transperineal brachytherapy (BRT) in comparison with conventional dose 3‐dimensional conformal radiotherapy (3D‐CRT) were evaluated.METHODS:This study included 853 patients; 270 received conventional dose 3D‐CRT, 314 received high‐dose IMRT, 225 received BRT, and 44 received external beam radiotherapy (EBRT) + BRT boost. The median radiation doses were 68.4 grays (Gy) for 3D‐CRT and 75.6 Gy for IMRT. BRT patients received a prescribed dose of 144 Gy with iodine‐125 (I‐125) or 120 Gy with palladium‐103 (Pd‐103), respectively. Patients treated with EBRT + BRT received 45 Gy of EBRT plus a boost of 110 Gy with I‐125 or 90 Gy with Pd‐103. Risk group categories were low risk (T1‐T2 disease, prostate‐specific antigen level ≤10 ng/mL, and a Gleason score ≤6), intermediate risk (increase in value of 1 of the factors), and high risk (increase in value of ≥2 factors).RESULTS:With a median follow‐up of 58 months, the 5‐year biochemical control (bNED) rates were 74% for 3D‐CRT, 87% for IMRT, 94% for BRT, and 94% for EBRT + BRT (P <.0001). For the intermediate‐risk group, high‐dose IMRT, BRT, or EBRT + BRT achieved significantly better bNED rates than 3D‐CRT (P <.0001), whereas no improvement was noted for the low‐risk group (P = .22). There was no increase in gastrointestinal (GI) toxicity from high‐dose IMRT compared with conventional dose 3D‐CRT, although there was more grade 2 genitourinary (GU) toxicity (toxicities were graded at the time of each follow‐up visit using a modified Radiation Therapy Oncology Group [RTOG] scale). BRT caused more GU but less GI toxicity, whereas EBRT + BRT caused more late GU and GI toxicity than IMRT or 3D‐CRT.CONCLUSIONS:The data from the current study indicate that radiation dose escalation improved the bNED rate for the intermediate‐risk group. IMRT caused less acute and late GU toxicity than BRT or EBRT + BRT. Cancer 2009. © 2009 American Cancer Society.

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Biologically effective dose values for prostate brachytherapy: Effects on PSA failure and posttreatment biopsy results

Cited by 226 publications

References 32 publications

Prostate Cancer Treatment

Prostate Cancer Treatment

A quantitative assessment of the consequences of allowing dose heterogeneity in prostate radiation therapy planning

Radiation dose escalation for localized prostate cancer

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