Pulsed low-dose rate radiotherapy has an improved therapeutic effect on abdominal and pelvic malignancies.
Ontology highlight
ABSTRACT:
SUBMITTER: Wen X
PROVIDER: S-EPMC8435343 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:BackgroundMost tumor cell lines exhibited low-dose hyperradiosensitivity (LDHRS) to radiation doses lower than 0.3 Gy. Pulsed low-dose rate radiotherapy (PLDR) took advantage of LDHRS and maximized the tumor control process. In this study, we retrospectively analyzed patients receiving PLDR for refractory malignancies.Patients and methodsIn total, 22 patients were included in our study: 9 females and 13 males. The median age was 61 years old. All the patients previously received multiline treatments and failed with an estimated survival less than 6 months. Thus, palliative PLDR was given. The PLDR was delivered using 10 fractions of 2 Gy/day, with an interval of 3 minutes, for 5 days per week. The dose rate was 6.67 cGy/min. The median follow-up was 1 year (range 8-30 months). Nine patients underwent PLDR for reirradiation due to locally recurrent diseases. The time interval from last irradiation was 11 to 168 months. Ten patients received PLDR due to poor performance status. Three patients were given PLDR for bulky tumor. The irradiated sites included primary disease (seven patients), locally recurrent disease (nine patients), and retroperitoneal adenopathy (six patients).ResultsFive patients developed grade 3 or 4 toxicities. No grade 5 toxicities occurred. All the toxicities recovered after treatments. In general, the 1-year local-regional control rate was approximately 40%, and almost all the patients developed progression at the second year after PLDR. The 6-month survival rate was 76%, and the 1-year survival rate was 69%. For the three patients given PLDR for bulky tumor, all of them achieved partial remission 1 month after the PLDR, and one patient achieved complete response at the fourth month.ConclusionPLDR is an effective and safe option not only for reirradiation but also for patients with poor performance status or bulky tumors. A prospective clinical trial (NCT03061162) is ongoing to validate our results.
| S-EPMC5756059 | biostudies-literature
Project description:A number of studies in model animal systems and in the clinic have established that RANKL promotes bone resorption. Paradoxically, we found that pulsing ovariectomized mice with low-dose RANKL suppressed bone resorption, decreased the levels of proinflammatory effector T cells and led to increased bone mass. This effect of RANKL is mediated through the induction of FoxP3+CD25+ regulatory CD8+ T cells (TcREG) by osteoclasts. Here, we show that pulses of low-dose RANKL are needed to induce TcREG, as continuous infusion of identical doses of RANKL by pump did not induce TcREG. We also show that low-dose RANKL can induce TcREG at 2, 3, 6, and 10 weeks after ovariectomy. Our results show that low-dose RANKL treatment in ovariectomized mice is optimal at once-per-month doses to maintain the bone mass. Finally, we found that treatment of ovariectomized mice with the Cathepsin K inhibitor odanacatib also blocked TcREG induction by low-dose RANKL. We interpret this result to indicate that antigens presented to CD8+ T cells by osteoclasts are derived from the bone protein matrix because Cathepsin K degrades collagen in the bone. Taken together, our studies provide a basis for using low-dose RANKL as a potential therapeutic for postmenopausal osteoporosis.
| S-EPMC4996279 | biostudies-literature
Project description:BackgroundAbdominal/pelvic lymph node (LN) oligometastasis, a pattern of treatment failure, is observed occasionally, and radiotherapy may work as salvage therapy. The optimal prescription dose, however, is yet to be determined. This study assessed the efficacy of high-dose radiotherapy.MethodsThe medical records of 113 patients at 4 institutes were retrospectively analysed who had 1 to 5 abdominal/pelvic LN oligometastases and were treated with definitive radiotherapy between 2008 and 2018. The exclusion criteria included non-epithelial tumours, uncontrolled primary lesions, palliative intent, and re-irradiation. The prescription dose was evaluated by using the equivalent dose in 2 Gy fractions (EQD2). Patients receiving EQD2 ≥ 60 Gy were placed into the high-dose group, and the remaining others the low-dose group. Kaplan-Meier analyses were performed to evaluate overall survival (OS), local control (LC), and progression-free survival (PFS). Univariate log-rank and multivariate Cox proportional hazards model analyses were performed to explore predictive factors. Adverse events were compared between the high-dose and low-dose groups.ResultsThe primary tumour sites included the colorectum (n = 28), uterine cervix (n = 27), endometrium (n = 15), and ovaries (n = 10). The rate of 2-year OS was 63.1%, that of LC 59.7%, and that of PFS 19.4%. On multivariate analyses, OS were significantly associated with solitary oligometastasis (hazard ratio [HR]: 0.48, p = 0.02), LC with high-dose radiotherapy (HR: 0.93, p < 0.001), and PFS with long disease-free interval (HR: 0.59, p = 0.01). Whereas high-dose radiotherapy did not significantly improve 2-year OS in the entire cohort (74.8% in the high-dose vs. 52.7% in the low-dose; p = 0.08), it did in the subgroup of solitary oligometastasis (88.8% in the high-dose vs. 56.3% in the low-dose; p = 0.009). As for Late grade ≥ 3 adverse event, ileus was observed in 7 patients (6%) and gastrointestinal bleeding in 4 (4%). No significant association between the irradiation dose and adverse event incidence was found.ConclusionsAs salvage therapy, high-dose radiotherapy was recommendable for oligometastasis in the abdominal/pelvic LNs. For solitary oligometastasis, LC and OS were significantly better in the high-dose group.
| S-EPMC7285737 | biostudies-literature
Project description:To compare the outcomes of localized prostate cancer treatment with high-dose-rate brachytherapy (HDR-BT) and low-dose-rate brachytherapy (LDR-BT), we examined 924 patients treated with HDR-BT + external beam radiotherapy (EBRT) and 500 patients treated with LDR-BT ± EBRT using multi-institutional retrospective data. The HDR-BT treated advanced disease with more hormonal therapy than LDR-BT. To reduce background selection bias, we performed inverse probability of treatment weighting (IPTW) analysis using propensity scores and excluded patients with T3b-4 disease/ initial prostate-specific antigen (PSA) levels > 50 ng/ml. The actuarial 5-year biochemical control rates (5y-bNED) were 96.3% and 95.7% in the HDR-BT and LDR-BT groups, respectively. The corresponding values were 100% and 96.5% in the low-risk group; 97.4% and 97.1% in the intermediate-risk group (97.2% and 97% in the higher titer group and 97.5% and 94.6% in the lower titer group, respectively); and 95.7% and 94.9% in the selected high-risk group, respectively. IPTW correction indicated no significant difference among the groups. The 5y-bNED in the HDR-BT + EBRT, LDR-BT + EBRT, and LDR-BT alone groups were 96.3%, 95.5%, and 97%, respectively (P = 0.3011). The corresponding values were 97.4%, 94.7%, and 96.6% (P = 0.1004) in the intermediate-risk group (97.5%, 100%, and 94.5% in the lower titer group [P = 0.122] and 97.2%, 96.2%, and 100% [P = 0.664] in the higher titer group, respectively) and 95.7%, 95.5%, and 100% (P = 0.859) in the high-risk group, respectively. The HDR-BT group showed a lower incidence of acute grade ≥ 2 genitourinary toxicities; the incidence of other early and late grade ≥ 2 toxicities were similar between the HDR-BT and LDR-BT groups. Acute genitourinary toxicity predicted the occurrence of late genitourinary toxicity. EBRT increased the risk of grade ≥ 2 gastrointestinal toxicity. HDR-BT + EBRT is a good alternative to LDR-BT ± EBRT for low-, intermediate-, and selected high-risk patients.
| S-EPMC7969770 | biostudies-literature
Project description:PurposeTo evaluate the efficacy and toxicity of external beam reirradiation using a pulsed low-dose-rate (PLDR) technique.Methods and materialsWe evaluated patients treated with PLDR reirradiation from 2009 to 2016 at a single institution. Toxicity was graded using the Common Terminology Criteria for Adverse Events, version 4.0, and local control was assessed using the Response Evaluation Criteria In Solid Tumors, version 1.1. On univariate analysis (UVA), the χ2 and Fisher exact tests were used to assess the toxicity outcomes. Competing risk analysis using cumulative incidence function estimates were used to assess local progression.ResultsA total of 39 patients were treated to 41 disease sites with PLDR reirradiation. These patients had a median follow-up time of 8.8 months (range 0.5-64.7). The targets were the thorax, abdomen, and pelvis, including 36 symptomatic sites. The median interval from the first radiation course and reirradiation was 26.2 months; the median dose of the first and second course of radiation was 50.4 Gy and 50 Gy, respectively. Five patients (13%) received concurrent systemic therapy. Of the 39 patients, 9 (23%) developed grade ≥2 acute toxicity, most commonly radiation dermatitis (5 of 9). None developed grade ≥4 acute or subacute toxicity. The only grade ≥2 late toxicity was late skin toxicity in 1 patient. On UVA, toxicity was not significantly associated with the dose of the first course of radiation or reirradiation, the interval to reirradiation, or the reirradiation site. Of the 41 disease sites treated with PLDR reirradiation, 32 had pre- and post-PLDR scans to evaluate for local control. The local progression rate was 16.5% at 6 months and 23.8% at 12 months and was not associated with the dose of reirradiation, the reirradiation site, or concurrent systemic therapy on UVA. Of the 36 symptomatic disease sites, 25 sites (69%) achieved a symptomatic response after PLDR, including 6 (17%) with complete symptomatic relief.ConclusionReirradiation with PLDR is effective and well-tolerated. The risk of late toxicity and the durability of local control were limited by the relatively short follow-up duration in the present cohort.
| S-EPMC7537409 | biostudies-literature
Project description:Low intensity pulsed ultrasound (LIPUS) has been widely used in clinic for the treatment of repairing pseudarthrosis, bone fractures and of healing in various soft tissues. Some reports indicated that LIPUS accelerated peripheral nerve regeneration including Schwann cells (SCs) and injured nerves. But little is known about its appropriate intensities on autograft nerves. This study was to investigate which intensity of LIPUS improved the regeneration of gold standard postsurgical nerves in experimental rat model. Sprague-Dawley rats were made into 10 mm right side sciatic nerve reversed autologous nerve transplantation and randomly treated with 250 mW/cm(2), 500 mW/cm(2) or 750 mW/cm(2) LIPUS for 2-12 weeks after operation. Functional and pathological results showed that LIPUS of 250 mW/cm(2) significantly induced faster rate of axonal regeneration. This suggested that autograft nerve regeneration was improved.
| S-EPMC4840319 | biostudies-other
Project description:ObjectivesPelvic lymph nodal regions receive an incidental dose from conformal treatment of the prostate. This study was conducted to investigate the doses received by the different pelvic nodal regions with varying techniques used for prostate radiotherapy.Methods and materialsTwenty patients of high-risk node-negative prostate cancer treated with intensity-modulated radiotherapy to the prostate alone were studied. Replanning was done for intensity-modulated radiotherapy, 3-dimensional conformal treatment, and 2-dimensional conventional radiotherapy with additional delineation of the pelvic nodal regions, namely, common iliac (upper and lower), presacral, internal iliac, obturator, and external iliac. Dose-volume parameters such as Dmean, D100%, D66%, D33%, V40, and V50 to each of the nodal regions were estimated for all patients.ResultsThe obturator nodes received the highest dose among all nodal regions. The mean dose received by obturator nodal region was 44, 29, and 22 Gy from 2-dimensional conventional radiotherapy, 3-dimensional conformal treatment, and intensity-modulated radiotherapy, respectively. The mean dose was significantly higher when compared between 2-dimensional conventional radiotherapy and 3-dimensional conformal treatment ( P < .001), 2-dimensional conventional radiotherapy and intensity-modulated radiotherapy ( P < .001), and 3-dimensional conformal treatment and intensity-modulated radiotherapy ( P < .001). The D33% of the obturator region was 64, 39, and 37 Gy from 2-dimensional conventional radiotherapy, 3-dimensional conformal treatment, and intensity-modulated radiotherapy, respectively. The dose received by all other pelvic nodal regions was low and not clinically relevant.ConclusionThe incidental dose received by obturator regions is significant especially with 2-dimensional conventional radiotherapy and 3-dimensional conformal treatment techniques as used in the trials studying elective pelvic nodal irradiation. However, with intensity-modulated radiotherapy, this dose is lower, making elective pelvic irradiation more relevant. Advances in Knowledge: This study highlights that incidental dose received by obturator regions is significant especially with 2-dimensional conventional radiotherapy and 3-dimensional conformal treatment techniques.
| S-EPMC5616032 | biostudies-literature
Project description:Radiation therapy has long played a major role in the treatment of gynecological malignancies. There is increasing interest in the utility of intensity-modulated radiotherapy (IMRT) and its application to treat gynecological malignancies. Herein, we review the state-of-the-art use of IMRT for gynecological malignancies and report how it is being used alone as well as in combination with chemotherapy in both the adjuvant and definitive settings. Based on dosimetric and clinical evidence, IMRT can reduce gastrointestinal, genitourinary, and hematological toxicities compared with 3D-conformal radiotherapy for gynecologic malignancies. We discuss how these attributes of IMRT may lead to improvements in disease outcomes by allowing for dose escalation of radiation therapy, intensification of chemotherapy, and limiting toxicity-related treatment breaks. Currently accruing trials investigating pelvic IMRT for cervical and endometrial cancers are discussed.
| S-EPMC4420646 | biostudies-literature
Project description:BackgroundRadiotherapy is effective in the treatment of cancer but also causes damage to non-cancerous tissue. Pelvic radiotherapy may produce chronic and debilitating bowel symptoms, yet the underlying pathophysiology is still undefined. Most notably, although pelvic radiotherapy causes an acute intestinal inflammation there is no consensus on whether the late-phase pathophysiology contains an inflammatory component or not. To address this knowledge gap, we examined the potential presence of a chronic inflammation in mucosal biopsies from irradiated pelvic cancer survivors.MethodsWe biopsied 24 cancer survivors two to 20 years after pelvic radiotherapy, and four non-irradiated controls. Using tandem mass tag (TMT) mass spectrometry and mRNA sequencing (mRNA-seq), we charted proteomic and transcriptomic profiles of the mucosal tissue previously exposed to a high or a low/no dose of radiation. Changes in the immune cell populations were determined with flow cytometry. The integrity of the protective mucus layers were determined by permeability analysis and 16S rRNA bacterial detection.Findings942 proteins were differentially expressed in mucosa previously exposed to a high radiation dose compared to a low radiation dose. The data suggested a chronic low-grade inflammation with neutrophil activity, which was confirmed by mRNA-seq and flow cytometry and further supported by findings of a weakened mucus barrier with bacterial infiltration.InterpretationOur results challenge the idea that pelvic radiotherapy causes an acute intestinal inflammation that either heals or turns fibrotic without progression to chronic inflammation. This provides a rationale for exploring novel strategies to mitigate chronic bowel symptoms in pelvic cancer survivors.FundingThis study was supported by the King Gustav V Jubilee Clinic Cancer Foundation (CB), The Adlerbertska Research Foundation (CB), The Swedish Cancer Society (GS), The Swedish State under the ALF agreement (GS and CB), Mary von Sydow's foundation (MA and VP).
| S-EPMC10393618 | biostudies-literature
Project description:Radiotherapy (RT) affects anti-tumor immunity. However, the exact impact of RT on anti-tumor immune response differs among cancer types, RT dose and fractions, patients' innate immunity, and many other factors. There are conflicting findings on the optimal radiation dose and fractions to stimulate effective anti-tumor immunity. High-dose radiotherapy (HDRT) acts in the same way as a double-edged sword in stimulating anti-tumor immunity, while low-dose radiotherapy (LDRT) seems to play a vital role in modulating the tumor immune microenvironment. Recent preclinical data suggest that a 'hybrid' radiotherapy regimen, which refers to combining HDRT with LDRT, can reap the advantages of both. Clinical data have also indicated a promising potential. However, there are still questions to be addressed in order to put this novel combination therapy into clinical practice. For example, the selection of treatment site, treatment volume, the sequencing of high-dose radiotherapy and low-dose radiotherapy, combined immunotherapy, and so on. This review summarizes the current evidence supporting the use of HDRT + LDRT, explains possible immune biology mechanisms of this 'hybrid' radiotherapy, raises questions to be considered when working out individualized treatment plans, and lists possible avenues to increase efficiency in stimulating anti-tumor immunity using high-dose plus low-dose radiotherapy.
| S-EPMC9319172 | biostudies-literature