Search

Abstract The relationship between radiation doses and clinical relapse in patients receiving salvage radiotherapy (SRT) for biochemical recurrence (BCR) after radical prostatectomy (RP) remains unclear. We identified 292 eligible patients treated with SRT between 2005 and 2018 at 15 institutions. Clinical relapse-free survival (cRFS) between the ≥ 66 Gy (n = 226) and

Abstract Background Successful local therapy for oligometastases may lead to longer survival. The purpose of this multicentre retrospective study was to investigate factors affecting the local control (LC) of pulmonary oligometastases treated by stereotactic body radiotherapy (SBRT) and to investigate the impact of LC on survival. Methods The inclusion criteria included 1 to 5 metastases, the primary lesion and other extrathoracic metastases were controlled before SBRT, and the biological effective dose (BED10) of the SBRT was 75 Gy or more. The Cox proportional hazards model was used for analyses. Results Data of 1378 patients with 1547 tumours from 68 institutions were analysed. The median follow-up period was 24.2 months. The one-year, 3-year and 5-year LC rates were 92.1, 81.3 and 78.6%, respectively, and the 1-year, 3-year and 5-year overall survival rates were 90.1, 60.3 and 45.5%, respectively. Multivariate analysis for LC showed that increased maximum tumour diameter (p = 0.011), type A dose calculation algorithm (p = 0.005), shorter overall treatment time of SBRT (p = 0.035) and colorectal primary origin (p

Abstract Background Despite advances in chemotherapy, curing multiple liver metastases is quite rare. Even when response is obtained, regrowth of the tumors is almost inevitable. We aimed to evaluate the efficacy and adverse events of helical tomotherapy for chemo‐refractory multiple liver metastases. Methods Forty‐five patients with chemo‐refractory multiple (3‐10) liver metastases after standard systemic chemotherapy entered the single‐institutional prospective study. Liver metastases were the major disease; however, 31 also had uncontrolled primary lesions and/or other metastases. The prescribed dose was 55 Gy in 25 fractions. The median planning target volume (PTV) and normal liver volume (NLV) of first treatment were 128 cm3 and 1175 cm3, respectively. The median of V15Gy, V30Gy, and mean dose to NLV were 45%, 23%, and 19.4 Gy, respectively. Results Forty‐two patients (93%) completed the planned treatment. Median survival time (MST) for all patients was 8 months, and the 1‐year survival rate was 29%. The median local control (LC) period was 5 months and the 6‐month control rate of irradiated tumors was 33%. A ≥30% decrease in tumor markers was observed in 31%. The most common grade 3 toxicity was lymphocytopenia (40%), followed by fatigue (6%). Radiation‐induced liver disease (RILD) was not observed. Pancreatic cancer as the primary tumor, distant metastases outside the liver, low pretreatment neutrophil‐to‐lymphocyte ratio (NLR), and low pretreatment monocyte‐to‐lymphocyte ratio (MLR) were associated with poorer prognoses. Conclusions Helical tomotherapy for chemo‐refractory multiple liver metastases is a feasible and potentially effective treatment. Incorporating tomotherapy into the first‐line treatment in combination with systemic chemotherapy should be considered. Trial registration number CROG 12005.

Abstract Background Efficacy of stereotactic body radiotherapy (SBRT) in stage I non–small-cell lung cancer (NSCLC) has almost been established. In Japan, the protocol of 48 Gy in 4 fractions over 4 days has been most often employed, but higher doses may be necessary to control large tumors. Previously, we conducted a clinical study using SBRT for stage I NSCLC employing different doses depending on tumor diameter, which was closed in 2008. Thereafter, a new study employing higher doses has been conducted, which is reported here. The purpose of this study was to review the safety and effectiveness of the higher doses. Methods We escalated the total dose for the improvement of local control for large tumors. In this study, 71 patients underwent SBRT between December 2008 and April 2014. Isocenter doses of 48, 50, and 52 Gy were administered for tumors with a longest diameter of 3 cm, respectively. It was recommended to cover 95% of the PTV with at least 90% of the isocenter dose, and in all but one cases, 95% of the PTV received at least 80% of the prescribed dose. Treatments were delivered in 4 fractions, giving 2 fractions per week. SBRT was performed with 6-MV photons using 4 non-coplanar and 3 coplanar beams. Results The median follow-up period was 44 months for all patients and 61 months for living patients. Overall survival (OS) was 65%, progression-free survival (PFS) was 55%, and cumulative incidence of local recurrence (LR) was 15% at 5 years. The 5-year OS was 69% for 57 stage IA patients and 53% for 14 stage IB patients (p = 0.44). The 5-year PFS was 55 and 54%, respectively (p = 0.98). The 5-year cumulative incidence of LR was 11 and 31%, respectively (p = 0.09). The cumulative incidence of Grade ≥ 2 radiation pneumonitis was 25%. Conclusions Our newer SBRT study yielded reasonable local control and overall survival and acceptable toxicity, but escalating the total dose did not lead to improved outcomes. Trial registration UMIN000027231 , registered on 3 May 2017. Retrospectively registered.

A previous study showed that continuous low-dose-rate irradiation promoted the growth of silkworm larvae. This study aimed to confirm that finding, determine the optimal dose rate for growth promotion, and compare low- and high-dose-rate irradiation in silkworms, while also investigating the effects of the radiation-emitting sheet on growth and tumor transplantability in mice. Silkworm eggs were placed on low-dose-emitting sheets with 4 different dose rates (γ-ray rate: 1.7 -22.4 μSv/hour) or on control sheets. The other groups of silkworm larvae received single whole-body X-irradiation (0.1-50 Gy), and subsequent body weight changes were monitored. Starting at 3 weeks old, Balb/c mice were bred on the same sheets, and body weight change was measured. Seven weeks later, the mice were used to investigate the transplantability of EMT6 tumor cells cultured in vitro. The silkworms bred on the 13.4- and 22.4-μSv/hour sheets became larger than the control. Single 50-Gy irradiation suppressed the growth of silkworms. An increase in the time to EMT6 tumor development was observed in low-dose-rate-irradiated mice. This study confirmed growth promotion of silkworms by continuous low-dose radiation and demonstrated growth suppression at a high dose rate. Growth promotion was not observed in mice; further studies using higher dose-rate sheets may be warranted.

Objective: Dynamic jaws (DJ) are expected to be useful in stereotactic radiotherapy (SRT) for brain metastases (BM). The efficacy and optimal dose fractionation were investigated. Methods: In a planning study, 63 treatment plans were generated for the following 3 conditions: 1.0-cm fixed jaws (FJ), 2.5-cmFJ and 2.5-cmDJ. In a clinical study, 30Gy/3 fr, 35Gy/5 fr or 37.5Gy/5fr were prescribed depending on tumour size. Clinical results of groups treated with 2.5-cm DJ plans and 1.0-cm FJ were compared. Results: In the planning study, the treatment times in 2.5-cm DJ and FJ plans were less than that in 1.0-cm FJ plans (p,0.001). The brain doses in 1.0-cm FJ plans and 2.5-cm DJ plans were smaller than those in 2.5-cm FJ plans (p,0.05). In the clinical study, 34 patients with 68 BM were treated with SRT. Of those, 15 patients with 34 BM were treated with 2.5-cm DJ plans and 19 patients with 34 BM were treated with 1.0-cm FJ plans. The overall survival and local tumour control (LC) rates were 52 and 93% at 12 months, respectively. The DJ system achieved favourable LC and 29% shorter treatment time compared with the FJ system (p,0.001). Grade 2 or 3 necrosis occurred more frequently in patients with 15 cc or larger tumour volumes (p50.05). Conclusion: DJ technology enables treatment time to be reduced without worsening the dose distribution and clinical efficacy. The prescribed doses in this study may be acceptable for patients with small tumour volumes. Advances in knowledge: DJ technology enables treatment time to be reduced without worsening the dose. [ABSTRACT FROM AUTHOR]