Conventional radiation therapy for brain metastases

Yuan³

et al. 2020

Preprint

BackgroundTo pursue high precision in tumor and steeper dose fall-off in healthy tissues of brain metastases stereotactic radiosurgery (SRS), this study investigated an opitimized planning by comparison only one multiple-lesions-plan (MLP) and multiple single-lesion-plans (SLP) in the treatment of brain metastases using Cyberknife (CK) Robotic Radiosurgery System. MethodsFifty non-small cell lung cancer (NSCLC) patients (28 males and 22 females) with 2-4 multiple brain metastases were retrospectively replanned with 12 to 32 Gy prescription dose in 1 to 3 fractions. Two different clinical SRS plans (SLP and MLP) for the same patients were generated, under the same collimator and prescription isodose line (62-68%) by CK Multiplan System. Both the SLP and MLP were able to get ＞95% PTV volume covered prescription isodose and meet the Timmerman 2011 OAR (brainstem, optic nerve and pituitary) constraints.ResultsCompared with the SLP, the maximum dose (Dmax) and mean dose (Dmean) of brainstem in the MLP decreased 0.22-3.13% (2.62%) and 2.71-12.56% (5.57%), over all P＜0.05. While the volumes of whole brain minus the tumors received a single dose equivalence of 8-16Gy (V8Gy-V16Gy) could effectively reduce in the MLP. And the treatment time parameters (the total number of beams and monitor units (MU)) of the MLP declined 3.31% and 1.47% (P＜0.05) respectively. Although there were a few differences of conformity index (CI) and homogeneity index (HI) between two treatment plans, it was no statistical significance (P = 2.94 and 1.08＞ 0.05). ConclusionOne multiple-lesions-plan for brain metastases could achieve higher precision in target and lower dose in healthy tissue, while shorten the treatment time and improve the treatment efficiency.

Section: Resultsmentioning

confidence: 99%

Benefit of dosimetry distribution for patients with brain metastases from non-small cell lung cancer by Cyberknife Stereotactic radiosurgery (SRS) system

YU¹,

Yuan³

et al. 2020

Preprint

“…Chung C et al indicated that 68% of radiation oncologists believed 1-3 brain metastases were ideal quantities to be treated with stereotactic radioactive surgery (SRS) [21]. Murovic Judith et al performed a comparison and analysis on patients with 1-3 brain metastases and on the curative effect for patients with more than 4 brain metastases who only received CK SRS.…”

Section: Discussionmentioning

confidence: 99%

“…Rades Dirk et al performed a retrospective comparison and analysis on patients with brain metastases treated by SRS or WBRT (number of tumours< 3 and tumour diameter < 4 cm), and the results showed that the median survival and one-year local control rate in the SRS group were superior to those in the WBRT group [ 19 , 20 ]. Chung C et al indicated that 68% of radiation oncologists believed 1–3 brain metastases were ideal quantities to be treated with stereotactic radioactive surgery (SRS) [ 21 ]. Murovic Judith et al performed a comparison and analysis on patients with 1–3 brain metastases and on the curative effect for patients with more than 4 brain metastases who only received CK SRS.…”

Section: Discussionmentioning

confidence: 99%

Benefit of dosimetry distribution for patients with multiple brain metastases from non-small cell lung cancer by a Cyberknife stereotactic radiosurgery (SRS) system

et al. 2020

BMC Cancer

Background In order to obtain a high dose conformal index of tumor and steep dose fall-off in healthy tissues for brain metastasis stereotactic radiosurgery (SRS), the aim of this study was to investigate SRS planning optimization by comparing one multiple-lesions plan (MLP) with multiple single-lesion plans (SLPs) for patients with multiple brain metastases using the Cyberknife (CK) system. Methods Fifty non-small cell lung cancer (NSCLC) patients (28 males and 22 females) with 2–4 brain metastases, inter-tumour distances less than 3 cm, were retrospectively replanned with the original prescription dose (12–32 Gy) in the original fractions (1–3). Two different clinical CK SRS plans (SLPs and MLP) were generated for the same patients with the same collimator and prescription isodose line (62–68%) by the CK Multiplan System. Both SLPs and MLP were able to achieve > 95% PTV volume covered prescription dose and met the Timmerman 2011 organs at risk (brainstem, optic nerve and pituitary) constraints. Results Compared with those in the SLPs, the maximum dose (Dmax) and mean dose (Dmean) of brainstem in the MLP were reduced 0.22–3.13% (2.62%) and 2.71–12.56% (5.57%), respectively, all P < 0.05. Meanwhile, the volumes of the whole brain minus the tumors that received a single dose equivalent of 8–16 Gy (V8Gy-V16Gy) were effectively reduced in the MLP. The treatment time parameters, the total number of beams and monitor units, of the MLP were reduced by 3.31 and 1.47% (P < 0.05), respectively. Although there were a few differences in the conformity index (CI) and homogeneity index (HI) between the two treatment plans, the differences were not statistically significant (P = 2.94 and 1.08 > 0.05). Conclusion One multiple-lesions plan for brain metastases could achieve higher precision in the target and lower doses in healthy tissue while shortening the treatment time and improving the treatment efficiency over multiple single-lesion plans.

“…Rades Dirk et al performed a retrospective comparison and analysis on patients with brain metastases treated by SRS or WBRT (number of tumours<3 and tumour diameter<4 cm), and the results showed that the median survival and one-year local control rate in the SRS group were superior to those in the WBRT group [19,20]. Chung C et al indicated that 68% of radiation oncologists believed 1-3 brain metastases were ideal quantities to be treated with stereotactic radioactive surgery (SRS) [21]. Murovic Judith et al performed a comparison and analysis on patients with 1-3 brain metastases and on the curative effect for patients with more than 4 brain metastases who only received CK SRS.…”

Section: Discussionmentioning

confidence: 99%

Benefit of dosimetry distribution for patients with multiple brain metastases from non-small cell lung cancer by a Cyberknife stereotactic radiosurgery (SRS) system

YU¹,

Yuan³

et al. 2020

Preprint

Background: To achieve high precision in treating tumors and a steep dose fall-off in healthy tissues for brain metastasis stereotactic radiosurgery (SRS), this study investigated SRS planning optimization by comparing one multiple-lesions plan (MLP) with multiple single-lesion plans (SLPs) for patients with multiple brain metastases using the Cyberknife (CK) system.Methods: Fifty non-small cell lung cancer (NSCLC) patients (28 males and 22 females) with 2-4 brain metastases, inter-tumour distances less than 3 cm, were retrospectively replanned with the original prescription dose (12-32 Gy) in the original fractions (1-3). Two different clinical CK SRS plans (SLPs and MLP) were generated for the same patients with the same collimator and prescription isodose line (62-68%) by the CK Multiplan System. Both SLPs and MLP were able to achieve >95% PTV volume covered prescription dose and met the Timmerman 2011 organs at risk (brainstem, optic nerve and pituitary) constraints.Results: Compared with those in the SLPs, the maximum dose (Dmax) and mean dose (Dmean) of brainstem in the MLP were reduced 0.22-3.13% (2.62%) and 2.71-12.56% (5.57%), respectively, all P<0.05. Meanwhile, the volumes of the whole brain minus the tumors that received a single dose equivalent of 8-16 Gy (V8Gy-V16Gy) were effectively reduced in the MLP. The treatment time parameters, the total number of beams and monitor units, of the MLP were reduced by 3.31% and 1.47% (P<0.05), respectively. Although there were a few differences in the conformity index (CI) and homogeneity index (HI) between the two treatment plans, the differences were not statistically significant (P = 2.94 and 1.08>0.05).Conclusion: One multiple-lesions plan for brain metastases could achieve higher precision in the target and lower doses in healthy tissue while shortening the treatment time and improving the treatment efficiency over multiple single-lesion plans.