Stereotactic body radiation therapy and 3-dimensional conformal radiotherapy for stage I non-small cell lung cancer: A pooled analysis of biological equivalent dose and local control

Mehta, Nishank; King, Christopher R.; Agazaryan, Nzhde; Steinberg, Michael L.; Hua, A.P.; Lee, Percy

doi:10.1016/j.prro.2011.10.004

Cited by 82 publications

(68 citation statements)

References 54 publications

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“…2 in Mehta publication). 12 As expected, the curves relating TCP and BED calculated by LQ model or by USC model were different but with minimal clinical significance for high dose per fraction used in SBRT.…”

Section: Tumor Radiosensitivitysupporting

confidence: 57%

“…Recently, Mehta et al reviewed the available clinical tumor control (≥2 years) probability (TCP) data for SBRT (single dose and 3-8 multifractions) and 3-dimensional conformal radiation therapy (3D-CRT) to determine the relationship between TCP and BED in medically inoperable stage I NSCLC. 12 They found a sigmoidal relationship between TCP as a function of BED with TCP ≥ 90% achieved with BED ≥ 159 Gy 8.6 and EQD2 ≥ 125 Gy (Table 1) (Figures 1 and 2 in Mehta publication). Replotted data distinguishing between single fraction SBRT, multifraction SBRT and 3D-CRT showed a monotonic relationship between TCP and BED for SBRT and 3D-CRT data ( Figure 1 in Brown editorial) suggesting that SBRT and 3D-CRT produce the same TCP probability when adjusted for BED.…”

Section: Tumor Radiosensitivitymentioning

confidence: 93%

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Radiobiology of stereotactic body radiation therapy (SBRT)

Garau

2017

Reports of Practical Oncology & Radiotherapy

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a b s t r a c tRecent advances in the technology of radiotherapy have enabled the development of new therapeutic modalities that deliver radiation with very high accuracy, reduced margins and high dose conformation, allowing the reduction of healthy tissue irradiated and therefore minimizing the risk of toxicity. The next step was to increase the total tumor dose using conventional fractionation (which remains the best way to relatively radioprotect healthy tissues when large volumes are treated) or to use new fractionation schemes with greater biological effectiveness. Based on the experience gained in radiosurgery, the latter way was chosen for small and well-defined tumors in the body. Stereotactic body radiotherapy delivers high doses of radiation to small and well-defined targets in an extreme hypofractionated (and accelerated) scheme with a very high biological effectiveness obtaining very good initial clinical results in terms of local tumor control and acceptable rate of late complications.In fact, we realize a posteriori that it was not feasible to administer such biologically equivalent dose in a conventional fractionation because the treatment could last several months.So far, these new therapeutic modalities have been developed due to technologic advances in image guidance and treatment delivery but without a solid biological basis. It is the role of traditional radiobiology (and molecular radiobiology) to explain the effects of high doses of ionizing radiation on tumor and normal tissues. Only through a better understanding of how high doses of ionizing radiation act, clinicians will know exactly what we do, allowing us in the future to refine our treatments. This article attempts to describe through simple and understandable concepts the known aspects of the biological action of high doses of radiation on tumor and normal tissues, but it is clear that we need much more basic research to better understand the biology of high doses of radiation.

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Section: Tumor Radiosensitivitysupporting

confidence: 57%

Section: Tumor Radiosensitivitymentioning

confidence: 93%

Radiobiology of stereotactic body radiation therapy (SBRT)

Garau

2017

Reports of Practical Oncology & Radiotherapy

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“…In NSCLC, BED correlates with the tumour control probability (TCP) over a wide range of fractionated conformal radiotherapy and SBRT regimes. 33 The question remains therefore open, whether oligofractionation can be only justified by the improved physical dose distribution in IGRT and, consequently, very high BED, 34 or it requires a different radiobiological mechanism involving vascular damage and possibly reperfusion. 35 The high conformity granted by the Bragg peak makes CPT ideal for radiosurgery.…”

Section: Hypofractionationmentioning

confidence: 99%

New challenges in high-energy particle radiobiology

Durante

2014

BJR

125

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Densely ionizing radiation has always been a main topic in radiobiology. In fact, a-particles and neutrons are sources of radiation exposure for the general population and workers in nuclear power plants. More recently, high-energy protons and heavy ions attracted a large interest for two applications: hadrontherapy in oncology and space radiation protection in manned space missions. For many years, studies concentrated on measurements of the relative biological effectiveness (RBE) of the energetic particles for different end points, especially cell killing (for radiotherapy) and carcinogenesis (for late effects). Although more recently, it has been shown that densely ionizing radiation elicits signalling pathways quite distinct from those involved in the cell and tissue response to photons. The response of the microenvironment to charged particles is therefore under scrutiny, and both the damage in the target and non-target tissues are relevant. The role of individual susceptibility in therapy and risk is obviously a major topic in radiation research in general, and for ion radiobiology as well. Particle radiobiology is therefore now entering into a new phase, where beyond RBE, the tissue response is considered. These results may open new applications for both cancer therapy and protection in deep space.Biological effects of densely ionizing radiation have been studied since the beginning of radiobiology. As a matter of fact, a-particles deliver the main contribution to the background radiation dose on Earth, owing to inhalation of the indoor radon.1 Neutrons have also been extensively studied because of protection of workers in nuclear power plants; use of fast neutrons in radiotherapy; and of the exposure of the survivors of the atomic bomb in Hiroshima and Nagasaki, where a neutron component was added to g-rays. Bacq and Alexander 2 already elegantly described the radiobiology of a-particles and neutrons in their 1955 seminal book.More recently, radiobiology research has focused on highenergy protons and heavy ions, mostly for two reasons: charged particle therapy (CPT) in oncology and radiation protection in manned space missions. In both cases, charged particles at energies .100 MeV n 21 are involved. The characteristic depth-dose distribution with the sharp Bragg peak at the end of the range can be exploited for killing tumours; on the other hand, densely ionizing radiation can effectively delay tissue morbidity. Notwithstanding the many differences in exposure conditions, CPT and space radiation protection share several research topics, including individual sensitivity, non-targeted effects, late stochastic effects and so forth.3 Research in these fields requires large high-energy accelerators and is often performed by the same research groups with a common interest in particle radiobiology. Research is rapidly moving forward owing to the diffusion of CPT centres in the USA, Europe, and Asia 4 and to the growing interest in manned space exploration, now a priority for all space agencies, 5 but wi...

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“…However, other clinical studies, which have been done by other research groups express that by utilizing an extreme hypofractionation, we could validate the LQ model (23)(24)(25)(26). There is also some clinical research, which has been done 2 Int J Cancer Manag.…”

Section: Possible Cell-killing Scenariosmentioning

confidence: 99%

Effect of Hypofractionation on Prostate Cancer Radiotherapy

Arabpour

Shahbazi‐Gahrouei

2017

Int J Cancer Manag

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Context: Prior research over the past few decades has shown that the hypofractionated external beam radiation therapy could be a valuable method with an outstanding potential to treat the prostate cancer. The alpha-beta ratio (α/β) is an indication of the fractionation sensitivity of a particular cell type. Values of α/β ≥ 10 Gy are responsible for early-responding normal tissues and most tumors, while values of α/β < 5 Gy are for late-responding normal tissues. The α/β ratio could be raised by either a local tumor control increase or a decrease of normal tissue late effects through the application of an unconventional fractionation schedules. Evidence Acquisition: This review article aimed to investigation the details of radiobiological and clinical trials which are reported to highlight the characteristics of hypofractionation for the prostate cancer treatment based on the investigation of clinical results from hypofractionated treatments. Results:With the sufficient radiobiological and physiological research studies, it may be claimed that if α/β value for prostate cancer is less than the adjacent surrounding organs at risk and by applying fewer and larger fractions; a better therapeutic ratio can be achieved for the patient. Conclusions: Radiobiological modeling can play a major role in the design of new protocols. Also, one should be aware that in modeling the hypofractionated treatment, normal tissue iso-effects are significantly important and some assumptions needed to be made regarding α/β values for the critical normal tissue complication endpoint.

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Stereotactic body radiation therapy and 3-dimensional conformal radiotherapy for stage I non-small cell lung cancer: A pooled analysis of biological equivalent dose and local control

Cited by 82 publications

References 54 publications

Radiobiology of stereotactic body radiation therapy (SBRT)

Radiobiology of stereotactic body radiation therapy (SBRT)

New challenges in high-energy particle radiobiology

Effect of Hypofractionation on Prostate Cancer Radiotherapy

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