GOECP/SEOR radiotheraphy guidelines for non-small-cell lung cancer

Non-small cell lung cancer (NSCLC) is a heterogeneous disease accounting for approximately 85% of all lung cancers. Only 17% of patients are diagnosed at an early stage. Treatment is multidisciplinary and radiotherapy plays a key role in all stages of the disease. More than 50% of patients with NSCLC are treated with radiotherapy (curative-intent or palliative). Technological advances-including highly conformal radiotherapy techniques, new immobilization and respiratory control systems, and precision image verification systems-allow clinicians to individualize treatment to maximize tumor control while minimizing treatment-related toxicity. Novel therapeutic regimens such as moderate hypofractionation and advanced techniques such as stereotactic body radiotherapy (SBRT) have reduced the number of radiotherapy sessions. The integration of SBRT into routine clinical practice has radically altered treatment of early-stage disease. SBRT also plays an increasingly important role in oligometastatic disease. The aim of the present guidelines is to review the role of radiotherapy in the treatment of localized, locally-advanced, and metastatic NSCLC. We review the main radiotherapy techniques and clarify the role of radiotherapy in routine clinical practice. These guidelines are based on the best available evidence. The level and grade of evidence supporting each recommendation is provided.

Has Hypofractionated Whole-Breast Radiation Therapy Become the Standard of Care in the United States? An Updated Report from National Cancer Database.

INTRODUCTION/BACKGROUND: We aimed to update the previous evaluation of hypofractionated whole-breast irradiation (HF-WBI) use over time in the United States and factors related to its adoption for patients undergoing a lumpectomy from 2004 to 2016. MATERIALS AND METHODS: Among the patients who underwent a lumpectomy, we identified 688,079 patients with early-stage invasive breast cancer and 248,218 patients with ductal carcinoma in situ in the National Cancer Database from 2004 to 2016. We defined HF-WBI as 2.5 to 3.33 Gy/fraction to the breast and conventional fractionated whole-breast irradiation as 1.8 to 2.0 Gy/fraction. We evaluated the trend of HF-WBI use and examined factors associated with HF-WBI use using logistic regression models. RESULTS: Among invasive cancer patients, the use of HF-WBI increased exponentially from 0.7% in 2004 to 15.6% in 2013 and then to 38.1% in 2016. Among patients with ductal carcinoma in situ, the use of HF-WBI has increased significantly from 0.42% in 2004 to 13.4% in 2013 and then to 34.3% in 2016. Factors found to be associated with HF-WBI use included age, patient geographical location, race/ethnicity, tumor stage, grade, treating facility type, and volume. CONCLUSION: HF-WBI use in the United States has more than doubled from 2013 to 2016. Although its use is close to that of conventional fractionated whole-breast irradiation, HF-WBI is still far from the preferred standard of care in the United States. We identified several patient and facility factors that can impact the uptake of HF-WBI treatment. Microabstract Using the National Cancer Database from 2004 to 2016, we evaluated the trend of hypofractionated whole-breast radiation therapy use and factors associated with use. Use in the United States has more than doubled from 2013 to 2016, but it has not become the standard of care. We identified several patient and facility factors that impact the uptake of hypofractionated whole-breast radiation therapy treatment.

Hypofractionated radiotherapy for newly diagnosed elderly glioblastoma patients: A systematic review and network meta-analysis.

OBJECTIVE: To evaluate different hypofractionated radiotherapy (HRT) regimens for newly diagnosed elderly glioblastoma (GBM) patients. METHODS: We performed a systematic review with network meta-analysis (NMA), including searches on CENTRAL, Medline, EMBASE, CINAHL, clinical trial databases and manual search. Only randomized clinical trials (RCTs) were included. Primary outcomes: overall survival (OS) and adverse events (AE). Secondary outcomes: progression-free-survival (PFS) and quality of life (QoL). We used the Cochrane Risk of Bias (RoB) table for assessing individual studies and CINeMA for evaluating the certainty of the final body of evidence. RESULTS: Four RCTs (499 patients) were included. For OS, the estimates from NMA did not provide strong evidence of a difference between the HRTs: 40 Gray (Gy) versus 45 Gy (HR: 0.89; CI 95%: 0.42, 1.91); 34 Gy versus 45 Gy (HR: 0.85; CI 95% 0.43, 1.70); 25 Gy versus 45 Gy (HR: 0.81; CI 95% 0.32, 2.02); 34 Gy versus 40 Gy (HR: 0.95; CI 95% 0.57, 1.61); and 25 Gy versus 34 Gy (HR: 0.95; CI 95% 0.46, 1.97). We performed qualitative synthesis for AE and QoL due to data scarcity and clinical heterogeneity among studies. The four studies reported a similar QoL (assessed by different methods) between arms. One RCT reported grade ≥ 3 AE, with no evidence of a difference between arms. PFS was reported in one study (25 Gy versus 40 Gy), with no evidence of a difference between arms. CONCLUSION: This review found no evidence of a difference between the evaluated HRTs for efficacy and safety.

Comparative radiobiological analysis and preliminary results of Ultra hypofractionated accelerated radiotherapy for low-risk prostate cancer patients.

PURPOSE: Moderately accelerated hypofractionation (HypoAR) has been recently established as a standard radiotherapy scheme for low-risk prostate cancer. The application of ultra-hypofractionated regimens (ultra-HypoAR), with fraction size above 5 Gy, is also widely tested. METHODS: We applied Image Guided Radiation Therapy (IGRT) ultra-HypoAR delivered with Volumetric Modulated Arc Therapy (VMAT) technique in low-risk prostate cancer patients (5.75 Gy/fraction, 40.25 Gy total dose, two fractions per week). A comparative radiobiological analysis of Dose-Volume Ηistograms (DVH) obtained for target volumes and organs at risk was performed, investigating the advantages and disadvantages of ultra-HypoAR and conventional radiotherapy regimens (CRT). Early clinical results on efficacy and toxicity are also reported. RESULTS: We calculated the Normalized Total Dose (NTD) and NTD with time correction (NTD_T)-based biological Dose- Volume Histograms (bDVH) for bladder and rectum tissue late effects (α/ß=4 Gy) and early effects (α/ß=10 Gy). Ultra-HypoAR produced a significantly lower biological dose burden than CRT, for both early and late responding tissue components of the bladder and rectum, whether calculated for time-correction or not (p<0.0001). Our clinical experience showed that the ultra-HypoAR regimen produced minimal early and late radiation sequelae. The median PSA levels dropped from 9.1 to 0.75 and 0.45 ng/ml at 6 and 12 months, respectively, after the end of therapy. CONCLUSIONS: In conclusion, radiobiological analysis of DVHs and preliminary clinical experience predict a better efficacy and low early and late toxicity profile for the tested seven-fraction VMAT ultra-HypoAR regimen with IGRT.

Hypofractionated Radiotherapy With Simultaneous-integrated Boost After Breast-conserving Surgery Compared to Standard Boost-applications Using Helical Tomotherapy With TomoEdge.

BACKGROUND/AIM: This comparative plan study examines a range of boost-radiation methods in adjuvant radiotherapy of breast cancer using helical intensity-modulated radiotherapy with TomoEdge-technique. Impact of hypofractionated radiation with simultaneous-integrated boost (SIB) and influence of differing assumed α/ß-values were examined. PATIENTS AND METHODS: For 10 patients with left-sided breast cancer each four helical IMRT-plans with TomoEdge-technique were created: hypofractionated+SIB (H-SIB) (42.4/54.4 Gy, 16 fractions), normofractionated+SIB (N-SIB) (50.4/64.4 Gy, 28 fractions), hypofractionated+sequential-boost (H-SB) (42.4 Gy/16 fractions+16 Gy/8 fractions), normofractionated+ sequential-boost (N-SB) (50.4 Gy/28 fractions+16 Gy/8 fractions). Equivalent doses (EQD2) to organs-at-risk (OAR) and irradiated mammary-gland were analysed for different assumed α/ß-values. RESULTS: The mean EQD2 to OAR was significantly lower using hypofractionated radiation-techniques. H-SIB and H-SB were not significantly different. H-SIB and N-SIB conformed significantly better to the breast planning-target volume (PTV) and boost-volume (BV) than H-SB and N-SB. Regarding BV, mean EQD2 was significantly higher for all α/ß-values investigated when using H-SIB and N-SIB. Regarding PTV, there were no clinically relevant differences. CONCLUSION: Relating to dosimetry, H-SIB is effective compared to standard-boost-techniques.

Optimizing proton minibeam radiotherapy by interlacing and heterogeneous tumor dose on the basis of calculated clonogenic cell survival.

Proton minibeam radiotherapy (pMBRT) is a spatial fractionation method using sub-millimeter beams at center-to-center (ctc) distances of a few millimeters to widen the therapeutic index by reduction of side effects in normal tissues. Interlaced minibeams from two opposing or four orthogonal directions are calculated to minimize side effects. In particular, heterogeneous dose distributions applied to the tumor are investigated to evaluate optimized sparing capabilities of normal tissues at the close tumor surrounding. A 5 cm thick tumor is considered at 10 cm depth within a 25 cm thick water phantom. Pencil and planar minibeams are interlaced from two (opposing) directions as well as planar beams from four directions. An initial beam size of σ0 = 0.2 mm (standard deviation) is assumed in all cases. Tissue sparing potential is evaluated by calculating mean clonogenic cell survival using a linear-quadratic model on the calculated dose distributions. Interlacing proton minibeams for homogeneous irradiation of the tumor has only minor benefits for the mean clonogenic cell survival compared to unidirectional minibeam irradiation modes. Enhanced mean cell survival, however, is obtained when a heterogeneous dose distribution within the tumor is permitted. The benefits hold true even for an elevated mean tumor dose, which is necessary to avoid cold spots within the tumor in concerns of a prescribed dose. The heterogeneous irradiation of the tumor allows for larger ctc distances. Thus, a high mean cell survival of up to 47% is maintained even close to the tumor edges for single fraction doses in the tumor of at least 10 Gy. Similar benefits would result for heavy ion minibeams with the advantage of smaller minibeams in deep tissue potentially offering even increased tissue sparing. The enhanced mean clonogenic cell survival through large ctc distances for interlaced pMBRT with heterogeneous tumor dose distribution results in optimum tissue sparing potential. The calculations show the largest enhancement of the mean cell survival in normal tissue for high-dose fractions. Thus, hypo-fractionation or even single dose fractions become possible for tumor irradiation. A widened therapeutic index at big cost reductions is offered by interlaced proton or heavy ion minibeam therapy.

A retrospective study of hypofractionated radiotherapy for keloids in 100 cases.

At present, the consensus on the best treatment for keloids is the combination of clinical and surgical therapies, if necessary, associated with adjuvant radiotherapy like brachytherapy. Whereas, the uniform scheme of radiotherapy in keloids is unclear. Here, we conducting a retrospective analysis to assess the efficacy and safety of a specific treatment regimen (20 Gy in 5 fractions) in keloid patients. We retrospectively analysed the medical records of keloid patients receiving auxiliary postoperative radiotherapy (PORT) treatment from 2009 to 2019. The patients were treated with the hypofractionation method of 20 Gy in 5 fractions. We compared the local control rate and complications, using the chi-square test and logistic regression analyses. After screening, we identified 100 keloid patients in this study, with a median follow-up of 59 months. In this study, the overall local control rate of keloid lesions was 84.8%. After multivariate analyses (primary keloid or not, family history, interval from surgery to irradiation and site), our research showed that primary keloid, site and interval from surgery to irradiation were significantly related to recurrence. Acute radiation injury and late radiation injury accounted for 3% (erythema) and 1% (skin sclerosis) of the total cases, respectively. Our results indicate that a postoperative hypofractionation with radiation dose of 20 Gy in 5 fractions may be effective, easy to accept and safe for keloid patients.

Hypofractionated radiotherapy in locally advanced bladder cancer: an individual patient data meta-analysis of the BC2001 and BCON trials.

BACKGROUND: Two radiotherapy fractionation schedules are used to treat locally advanced bladder cancer: 64 Gy in 32 fractions over 6·5 weeks and a hypofractionated schedule of 55 Gy in 20 fractions over 4 weeks. Long-term outcomes of these schedules in several cohort studies and case series suggest that response, survival, and toxicity are similar, but no direct comparison has been published. The present study aimed to assess the non-inferiority of 55 Gy in 20 fractions to 64 Gy in 32 fractions in terms of invasive locoregional control and late toxicity in patients with locally advanced bladder cancer. METHODS: We did a meta-analysis of individual patient data from patients (age ≥18 years) with locally advanced bladder cancer (T1G3 [high-grade non-muscle invasive] or T2-T4, N0M0) enrolled in two multicentre, randomised, controlled, phase 3 trials done in the UK: BC2001 (NCT00024349; assessing addition of chemotherapy to radiotherapy) and BCON (NCT00033436; assessing hypoxia-modifying therapy combined with radiotherapy). In each trial, the fractionation schedule was chosen according to local standard practice. Co-primary endpoints were invasive locoregional control (non-inferiority margin hazard ratio [HR]=1·25); and late bladder or rectum toxicity, assessed with the Late Effects Normal Tissue Task Force-Subjective, Objective, Management, Analytic tool (non-inferiority margin for absolute risk difference [RD]=10%). If non-inferiority was met for invasive locoregional control, superiority could be considered if the 95% CI for the treatment effect excluded the null effect (HR=1). One-stage individual patient data meta-analysis models for the time-to-event and binary outcomes were used, accounting for trial differences, within-centre correlation, randomised treatment received, baseline variable imbalances, and potential confounding from relevant prognostic factors. FINDINGS: 782 patients with known fractionation schedules (456 from the BC2001 trial and 326 from the BCON trial; 376 (48%) received 64 Gy in 32 fractions and 406 (52%) received 55 Gy in 20 fractions) were included in our meta-analysis. Median follow-up was 120 months (IQR 99-159). Patients who received 55 Gy in 20 fractions had a lower risk of invasive locoregional recurrence than those who received 64 Gy in 32 fractions (adjusted HR 0·71 [95% CI 0·52-0·96]). Both schedules had similar toxicity profiles (adjusted RD -3·37% [95% CI -11·85 to 5·10]). INTERPRETATION: A hypofractionated schedule of 55 Gy in 20 fractions is non-inferior to 64 Gy in 32 fractions with regard to both invasive locoregional control and toxicity, and is superior with regard to invasive locoregional control. 55 Gy in 20 fractions should be adopted as a standard of care for bladder preservation in patients with locally advanced bladder cancer. FUNDING: Cancer Research UK.

External beam radiotherapy for prostate cancer: What are the current research trends and hotspots?

BACKGROUND: The external beam radiotherapy (EBRT) applied for prostate cancer (PCa) has been one of the most important and hottest research fields over recent decades. This study aimed to explore the research hotspots of EBRT in PCa and help the researchers have a clear and intuitive reference basis for later researches. METHODS: The literature scientometric analysis related to "EBRT applied for PCa" was conducted via the Web of Science Core Collection from 2010 to 2019. The Microsoft Office Excel 2019 and CiteSpace V. 5.7.R1 software were introduced for visualizing and analyzing the data. RESULTS: A total of 7860 relevant papers were extracted and downloaded. A total of 7828 papers were extracted and analyzed after data cleansing by CiteSpace. The tendency of published papers was comprehensively increasing from 2010 to 2019. Among all 73 countries/regions, USA published the most papers, accounting for 39%, which was the most active contributor with most publications. Australia (Centrality: 0.18), England (Centrality: 0.12) were cooperating most cohesively with other countries. Univ Toronto was the most productive institute (229), while Harvard Univ (Centrality: 0.67) had extensive collaborations with other institutes. The International journal of Radiation Oncology Biology Physics had the largest number of publications and the highest number of co-citations. Briganti A had the largest volume of publications. D'Amico AV had the highest number of co-citations. Four latest and largest clusters were identified as oligometastases, salvage therapy (SRT), prostate-specific membrane antigen (PSMA), and hypofractionation. Thirteen references became strongest burst citations lasting until 2019. The studies of "oligometastases," "SRT," "PSMA," "hypofractionation," "postoperative radiotherapy," and "dose and fraction regimen changes" were prevailing in the recent years. CONCLUSION: The "oligometastases," "SRT," "PSMA," "hypofractionation," "postoperative radiotherapy," and "dose and fraction regimen changes" may be the state-of-art research frontiers, and related studies will advance in this field over time.

Is hypofractionated whole pelvis radiotherapy (WPRT) as well tolerated as conventionally fractionated WPRT in prostate cancer patients? The HOPE trial.

BACKGROUND: Patients with high-risk prostate cancer are at increased risk of lymph node metastasis and are thought to benefit from whole pelvis radiotherapy (WPRT). There has been recent interest in the use of hypofractionated radiotherapy in treating prostate cancer. However, toxicity and cancer outcomes associated with hypofractionated WPRT are unclear at this time. This phase II study aims to investigate the impact in quality of life associated with hypofractionated WPRT compared to conventionally fractionated WPRT. METHODS: Fifty-eight patients with unfavourable intermediate-, high- or very high-risk prostate cancer will be randomized in a 1:1 ratio between high-dose-rate brachytherapy (HDR-BT) + conventionally fractionated (45 Gy in 25 fractions) WPRT vs. HDR-BT + hypofractionated (25 Gy in 5 fractions) WPRT. Randomization will be performed with a permuted block design without stratification. The primary endpoint is late bowel toxicity and the secondary endpoints include acute and late urinary and sexual toxicity, acute bowel toxicity, biochemical failure-, androgen deprivation therapy-, metastasis- and prostate cancer-free survival of the hypofractionated arm compared to the conventionally fractionated arm. DISCUSSION: To our knowledge, this is the first study to compare hypofractionated WPRT to conventionally fractionated WPRT with HDR-BT boost. Hypofractionated WPRT is a more attractive and convenient treatment approach, and may become the new standard of care if demonstrated to be well-tolerated and effective. TRIAL REGISTRATION: This trial was prospectively registered in ClinicalTrials.gov as NCT04197141 on December 12, 2019.

[Retrospective study on the intensification of hypofractionated radiotherapy: The organizational change]. / Étude rétrospective sur l'intensification des pratiques de radiothérapie hypofractionnée : le virage organisationnel.

PURPOSE: External radiotherapy process is a chain of steps in which each of them is carried out only if the previous one has been completed. The development of hypofractionation practices in recent years tends to increase the workload of the stages of preparation for irradiation and to decrease the number of fractions per patient. The purpose of this retrospective study is to analyze the evolution of these practices in a single centre and to assess the organizational issues involved. MATERIAL AND METHODS: All radiation therapy records management data were extracted from the Radiation Therapy Information System. Radiotherapy sessions were identified by patient and by ICD (International Classification of Diseases) code. The filling rate of the treatment equipment was calculated using actual data from the radiotherapy department. RESULTS: From 2015 to 2019, there was an increase in the number of scans (+16%), the number of patients treated (+11.6%) and the volume of hours available for treatment (+12%). Also, there was a decrease in the total number of fractions (-5%), in the average number of fractions performed per treatment sequence (-19%), in the occupancy rate of the machines (-7%) and in the average number of fractions performed per patient treated for malignant tumours of the bronchi and lung (-38%), digestive organs (-37%), secondary (-19%) breast (-15%) and prostate (-15%). The number of fractions administered per treatment sequence between 2015 and 2019 decreased significantly for patients in age groups [20-69] (P<0.001) and [>70] (P<0.001). CONCLUSION: A paradox appears between the increase in the total number of patients treated and the decrease in the loading rate of linacs. This shift of workload has an impact on the quality and safety of care and on the organizational and investment strategies. It also has an economic impact where the model of reimbursement is based on per fraction pricing. A reorganization of radiotherapy services is inevitable.

Predictors of Whole Breast Radiation Therapy Completion in Early Stage Breast Cancer Following Lumpectomy.

BACKGROUND: Whole breast radiation therapy (RT) has become standard of care in early stage breast cancer treatment following lumpectomy. Predictors of RT completion have been sparsely studied, with no previous nationwide examination of the impact of fractionation regimen on completion rate. PATIENTS AND METHODS: The National Cancer Database identified patients with early stage breast cancer having undergone lumpectomy and RT from 2004 through 2015. Fraction size of 1.8-2.0 Gray (Gy) was defined as standard fractionation (SFRT); 2.66-2.70 Gy/fraction as hypofractionation (HFRT). RT completion was defined as receipt of at least 46 Gy for SFRT and 40 Gy for HFRT. A multivariable logistic regression model characterized RT completion predictors. RESULTS: A total of 100,734 patients were identified where fraction size could be reliably characterized as above; more than 87% completed RT. Of these, 66.8% received SFRT, yet HFRT use significantly increased over time (5.2% increase/year; P < .0001). RT completion rates were significantly greater following HFRT (99.3%) versus SFRT (79.7%); patients receiving SFRT had higher odds of not completing RT (odds ratio, 41.5; 95% confidence interval, 36.6-47.1; P < .0001). Multivariable analysis revealed that African-American and Caucasian patients treated with SFRT versus HFRT had 22 and 43 times the odds of not completing RT, respectively (P < .0001). CONCLUSIONS: SFRT remained the majority of RT fractionation in the studied time period, although HFRT use has increased over time. Patients residing > 10 miles from a treatment facility or of African-American race had lower odds of completing RT, as were patients treated with SFRT versus HFRT. These findings suggest compliance advantages of HFRT for patients with early stage breast cancer having undergone lumpectomy.

Synergistic effects of anti-PDL-1 with ablative radiation comparing to other regimens with same biological effect dose based on different immunogenic response.

INTRODUCTION: Irradiation can induce multiple inhibitory and stimulatory effects on the immune system. In recent studies, it has been noted that administration of radiation with various doses and fractionation plans may influence on immune responses in microenvironment of tumor. But in radiobiology, the Biologically Effective Dose (BED) formula has been designed for calculating isoeffect doses in different regimens of daily clinical practice. In other words, BED has also been used to predict the effects of fractionation schedules on tumor cells. METHODS: In our study, three different regimens with BEDs of 40 gray (Gy) were analyzed in BALB/c mice. These included conventional fractionated radiotherapy (RT) (3Gyx10), high-dose hypofractionated RT (10Gyx2), and single ablative high-dose RT (15Gyx1). RESULTS: As BED predicts, all three similarly decreased tumor volumes and increased survival times relative to controls, but after high dose exposure in ablative group, the expression of IFNγ was increased following high infiltration of CD8 cells into the tumor microenvironment. When anti-PDL-1 was combined with RT, single ablative high-dose radiation enhanced antitumor activity by increasing IFNγ in tumors and CD8+ tumor-infiltrating lymphocytes; as a result, this combining therapy had enhanced antitumor activity and lead to control tumor volume effectively and improve significantly survival rate and finally the recurrence of tumor was not observed. CONCLUSION: Results show distinct radiation doses and fractionation schemes with same BED have different immunogenic response and these findings can provide data helping to design regimens of radiation combined with immune checkpoint blockers (ICBs).

Elective Pelvic Nodal Irradiation With a Simultaneous Hypofractionated Integrated Prostate Boost for Localised Prostate Cancer: Ready for Prime Time?

External beam radiotherapy is a standard treatment option for localised prostate cancer and hypofractionation has become an alternative to conventionally fractionated radiotherapy. In patients who receive external beam radiotherapy, elective pelvic nodal irradiation is sometimes delivered, especially in patients with unfavourable disease who are at risk of micrometastatic spread of cancer into the regional nodes. One elegant approach to combine prostate hypofractionation with elective pelvic nodal irradiation is with a simultaneous integrated boost technique, where a radical hypofractionated dose is delivered to the prostate while the regional pelvic nodes receive a lower microscopic dose simultaneously in a single radiotherapy plan over the same number of treatment fractions. This article reviews the existing published literature evaluating such an approach.

Adjuvant Irradiation in Carcinoma Breast Patients: Comparison of 3DCRT and Semi-automated Complex VMAT Hypofractionated Plans.

OBJECTIVE: Adjuvant radiotherapy is required for most post MRM breast cancer patients. Aim of treatment is to target radiation to region of interest while sparing Organs at Risk (OARs). Attempts are being made to decrease dose to OARs without compromising target coverage by evolving radiation techniques. In this study, a comparison of traditional 3DCRT plans is done with semi-automated complex VMAT plans for dose received by OARs namely Contralateral Breast (CLB), Ipsilateral lung (I/LL), and Contralateral Lung (C/LL). MATERIALS AND METHODS: It was planned for 30 post MRM breast cancer patients for chest wall, ipsilateral axilla and supraclavicular lymph node. The PTV dose was 42.5 Gy in 16 fractions, 2.66 Gy/fraction, 5 days a week. For each patient traditional 3DCRT and semi-automated complex VMAT plans (conventional + tangential VMAT plans) were prepared and evaluated by radiation oncologists. RESULTS: Dose evaluation of CLB shows higher Dmax for 3DCRT plans, while, Dmean was lower for the 3DCRT plan. Difference between D2 was not significant. V2.5 was significantly less in 3DCRT, while, difference between V5 and V10 were not significant. For C/LL Dmean, V2.5, V5, and V10 were higher for the VMAT plan. For I/LL Dmean, V5 and V10 were higher, while V20 and V30 were lower for VMAT plans. DISCUSSION AND CONCLUSION: The VMAT technique described here is a useful treatment option available for difficult planning situations. OARs stated above had a mixed result showing VMAT plans to be inferior at lower dose metrics, while, superior at higher dose metrics.

The Association Between Use of Hypofractionation and Treatment Completion Among Recipients of Radiation Therapy Post-Mastectomy.

PURPOSE: Although there is some evidence to support the use of hypofractionated (HF) radiation therapy (RT) postmastectomy, it is not currently the standard of care. RT noncompletion and delayed completion have been shown to lead to inferior outcomes. This study assesses the association between the choice of an HF versus conventionally fractionated regimen and completion. METHODS AND MATERIALS: RT orders placed in 2016 and 2017 for patients with a national health plan, along with the associated claims, were extracted. Each order was assigned a target date for timely completion, as well as a date 30 days after the target, which was used to assess delayed completion. Univariate analyses and logistic regressions were conducted to test for an association between regimen and completion. A Poisson regression was used to examine the association between regimen and length of treatment delay among patients completing RT. RESULTS: Of the 743 orders meeting inclusion criteria, 56 (7.5%) were for HF. Unadjusted analyses found that the timely and delayed completion rates were significantly (P < .001) higher for patients receiving HF. The adjusted odds ratios (HF order versus CF order) were 3.96 (95% confidence interval, 2.23-7.01) for timely completion and 2.64 (95% confidence interval, 1.43-5.15) for completion within 30 days of the target. Among completers, an order for HF was significantly (P < .001) associated with less delay. CONCLUSIONS: When an HF regimen was ordered, patients were more likely to complete therapy without a delay, to complete therapy overall, and, if experiencing a delay, to experience a shorter delay.