Is α/β for prostate tumors really low?

Fowler, Jack F.; Chappell, Rick; Ritter, Mark A.

doi:10.1016/s0360-3016(01)01607-8

Cited by 612 publications

(351 citation statements)

References 33 publications

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“…Due to the variety of radiobiological parameters associated with prostate TCP modeling in the literature, 24 , 25 , 26 , 27 , 28 in this study various combinations were tested in order to match the average biochemical control recorded in ten years of HDR data collection at our institution. A lower

α / β

value of 1.5 Gy and clonogen density of 10 5 appeared to reproduce, on average, the observed control of 70%–80%, confirming the hypothesis that a lower

α / β

ratio could be more appropriate to model its TCP (26) .…”

Section: Discussionmentioning

confidence: 99%

“…TCP values were obtained by using a Poisson model, (21) while NTCP parameters were obtained by using a Lyman‐Kutcher‐Burman (LKB) model 22 , 23 . Since there is much discussion on the appropriate parameters to be used in order to model tumor control for prostate cases, 24 , 25 , 26 , 27 , 28 different combinations of modeling values were used in this analysis. As previously performed by Uzan and Nahum, (20) the

α / β

ratio was varied between 5 and 1.5 Gy.…”

Section: Methodsmentioning

confidence: 99%

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Comparison of IPSA and HIPO inverse planning optimization algorithms for prostate HDR brachytherapy

Panettieri

Smith

Mason

et al. 2014

J Applied Clin Med Phys

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Publications have reported the benefits of using high‐dose‐rate brachytherapy (HDRB) for the treatment of prostate cancer, since it provides similar biochemical control as other treatments while showing lowest long‐term complications to the organs at risk (OAR). With the inclusion of anatomy‐based inverse planning optimizers, HDRB has the advantage of potentially allowing dose escalation. Among the algorithms used, the Inverse Planning Simulated Annealing (IPSA) optimizer is widely employed since it provides adequate dose coverage, minimizing dose to the OAR, but it is known to generate large dwell times in particular positions of the catheter. As an alternative, the Hybrid Inverse treatment Planning Optimization (HIPO) algorithm was recently implemented in Oncentra Brachytherapy V. 4.3. The aim of this work was to compare, with the aid of radiobiological models, plans obtained with IPSA and HIPO to assess their use in our clinical practice. Thirty patients were calculated with IPSA and HIPO to achieve our department's clinical constraints. To evaluate their performance, dosimetric data were collected: Prostate PTV D90(%),V100(%),V150(%), and V200(%), Urethra D10(%), Rectum D2cc(%), and conformity indices. Additionally tumor control probability (TCP) and normal tissue complication probability (NTCP) were calculated with the BioSuite software. The HIPO optimization was performed firstly with Prostate PTV (HIPOPTV) and then with Urethra as priority 1 (HIPOurethra). Initial optimization constraints were then modified to see the effects on dosimetric parameters, TCPs, and NTCPs. HIPO optimizations could reduce TCPs up to 10%–20% for all PTVs lower than 74 cm3. For the urethra, IPSA and HIPOurethra provided similar NTCPs for the majority of volume sizes, whereas HIPOPTV resulted in large NTCP values. These findings were in agreement with dosimetric values. By increasing the PTV maximum dose constraints for HIPOurethra plans, TCPs were found to be in agreement with IPSA without affecting the urethral NTCPs.PACS numbers: 87.55.‐x, 87.55.de, 87.55.dh, 87.53.Jw

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α / β

value of 1.5 Gy and clonogen density of 10 5 appeared to reproduce, on average, the observed control of 70%–80%, confirming the hypothesis that a lower

α / β

ratio could be more appropriate to model its TCP (26) .…”

Section: Discussionmentioning

confidence: 99%

α / β

ratio was varied between 5 and 1.5 Gy.…”

Section: Methodsmentioning

confidence: 99%

Comparison of IPSA and HIPO inverse planning optimization algorithms for prostate HDR brachytherapy

Panettieri

Smith

Mason

et al. 2014

J Applied Clin Med Phys

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“…As HypoARC seems to overcome both intrinsic radioresistance and accelerated repopulation, taking also into account the promising low early and late side effects of the regimen, its role in clinical radiotherapy should be thoroughly examined. Prostate cancer, recently shown to have an a/b ratio lower than 2 Gy (Fowler et al, 2001), and also tumours with low intrinsic radiosensitivity (e.g. sarcomas, melanomas and pancreatic carcinoma) are expected to benefit from HypoARC regimens.…”

Section: Discussionmentioning

confidence: 99%

Molecular analysis of local relapse in high-risk breast cancer patients: can radiotherapy fractionation and time factors make a difference?

et al. 2003

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Large primary breast tumours and extensive lymph node involvement are linked to a high rate of local recurrence after surgery. In 10 -20% of such high-risk breast cancer patients, local relapse will occur despite postoperative radiotherapy. In the present study, we investigated whether molecular features, such as angiogenesis, cancer cell proliferation, steroid receptor expression, c-erbB-2 oncoprotein overexpression, p53 protein nuclear accumulation or bcl-2 antiapoptotic protein expression, can predict failure of local therapy. We further examined as to which subgroups of patients could benefit from altered fractionation schemes of radiotherapy. In univariate analysis, high intratumoural angiogenesis, c-erbB overxpression and mutant-p53 nuclear accumulation were significantly associated with increased relapse rate (P ¼ 0.0002, 0.009 and 0.05, respectively). In multivariate analysis, the microvessel density and the c-erbB-2 status were independent and significant factors related to local relapse (P ¼ 0.001, t-ratio 3.36 and P ¼ 0.02, t-ratio 2.26, respectively). Hypofractionated and accelerated radiotherapy supported with amifostine (HypoARC regimen) was significantly more effective than standard radiotherapy in cases with high cancer cell proliferation index, c-erbB-2 and p53 overexpression. High angiogenesis, however, was linked with local relapse regardless of the radiotherapy regimen.

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“…It may, therefore, prove advantageous to use larger daily fractions of 42.0 Gy (hypofractionation), rather than conventional 1.8 -2.0 Gy fractions commonly employed, when treating most other tumour types. Using linear quadratic formulation, one can predict an improved ratio of tumour control to normal tissue toxicity (the therapeutic ratio) for prostate cancer by using hypofractionation (Fowler et al, 2001). Cleveland Clinic investigators have carried out a trial of hypofractionation consisting of 28 fractions of 2.5 Gy for a total dose of 70 Gy (Kupelian et al, 2002).…”

Section: Clinical Applications In Prostate Cancermentioning

confidence: 99%

Intensity-modulated radiation therapy: emerging cancer treatment technology

et al. 2005

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The use of intensity-modulated radiation therapy (IMRT) is rapidly advancing in the field of radiation oncology. Intensity-modulated radiation therapy allows for improved dose conformality, thereby affording the potential to decrease the spectrum of normal tissue toxicities associated with IMRT. Preliminary results with IMRT are quite promising; however, the clinical data is relatively immature and overall patient numbers remain small. High-quality IMRT requires intensive physics support and detailed knowledge of threedimensional anatomy and patterns of tumour spread. This review focuses on basic principles, and highlights the clinical implementation of IMRT in head and neck and prostate cancer.

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Is α/β for prostate tumors really low?

Cited by 612 publications

References 33 publications

Comparison of IPSA and HIPO inverse planning optimization algorithms for prostate HDR brachytherapy

Comparison of IPSA and HIPO inverse planning optimization algorithms for prostate HDR brachytherapy

Molecular analysis of local relapse in high-risk breast cancer patients: can radiotherapy fractionation and time factors make a difference?

Intensity-modulated radiation therapy: emerging cancer treatment technology

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