Clinical Outcomes of Synchronous Lung Stereotactic Body Radiation Therapy Lesions via Single-Isocenter/Multi-Lesion Treatments

PURPOSE/OBJECTIVE(S)

Lung cancer patients with synchronous primary or oligometastatic (< 5 lesions) with associated co-morbidities may not retain their treatment position for the extended stereotactic body radiotherapy (SBRT) treatment times with individual isocenter plans for each lesion due to discomfort or shortness of breath. SBRT using a single-isocenter/multi-lesion (SIML) volumetric arc therapy (VMAT) plan with flattening filter free (FFF) beam could significantly shorten overall treatment time, improve patient comfort and compliance and clinic efficiency. We report clinical results of treating multiple lung metastases or synchronous primary lung cancers with SIML lung SBRT.

MATERIALS/METHODS

Eighty patients with synchronous primary lung cancers or oligometastatic lung tumors (two, n = 61; three, n = 10; four, n = 4; five n = 5; total treated lesions, n = 193) were simulated with abdominal compression and/or 4D-CT MIP images and treated with a highly-conformal SIML VMAT lung SBRT plans via 3-4 non-coplanar arcs. Common prescriptions were 50-55 Gy/5 fractions and 54 Gy/3 fractions prescribed 70-80% isodose line to the each PTV. Acuros dose calculation for 6MV-FFF beam was used for tissue heterogeneity corrections. RTOG-0618/0813 criteria were used to dose constraints to organs at risk (OAR) and target conformality. Treatment was delivered every other day or twice weekly with CBCT-guidance, adjustments made with 6DOF couch corrections on a medical linear accelerator, and treatment delivery time within 15 minutes. Local control rates and toxicity profile was evaluated using CTCAE v. 5.0 grading for pneumonitis, rib fracture and chest wall pain.

RESULTS

All plans met RTOG-0618/0813 requirements for each tumor coverage, dose to OAR including normal lung and ribs. Mean follow up after last fraction of treatment was 16.9 months (range, 1.0-54.2 months). PTV volume ranged from 2.17 to 167.8 cc with mean volume of 16.1 cc. Of the 80 patients treated, 71 had adequate post-treatment thoracic CT imaging to assess local control. Local control was achieved in 167/175 (95.4%) of treated and followed lesions. CTCAE grade 1 asymptomatic pneumonitis was noted on thoracic CT scans in 42/71 (59.2%) of patients and occurred, on average 4.8 months after SBRT. Symptomatic pneumonitis and rib fracture did not occur in any patient. CTCAE grade 2 chest wall pain occurred in 4/80 (5.0%) treated patients and was managed conservatively with over-the-counter NSAIDS or acetaminophen.

CONCLUSION

SIML lung SBRT for synchronous primary lung cancers or multiple lung metastases can be used as a variant to traditional multiple isocenter SBRT or chronologically separate treatment courses, and has excellent local control rates and low toxicity profile in our patient population. It can help improve comfort and compliance of the patients who have difficulty lying still for an extended treatment course, and significantly reduces treatment time via isocenter shifts/repeated CBCTs for image guidance, thus improving clinic efficiency.

Escalating SBRT Dose to Hypoxic Centers of Large Pulmonary Tumors via Simultaneous Integrated Boost Confers Effective Local Control with Minimal Toxicity

PURPOSE/OBJECTIVE(S)

Hypoxia confers radio-resistance to tumor cells and drives malignant disease progression. SBRT treatment of large (>5.0 cm) pulmonary tumors pose significant dosimetric challenges in minimizing dose to adjacent organs at risk (OARs). Here, we detail the use of SBRT with simultaneous integrated boost (SIB) to the hypoxic centers of large pulmonary masses with effective local control and minimal normal tissue toxicity.

MATERIALS/METHODS

Highly conformal treatment plans utilized 3-4 non-coplanar VMAT arcs with 6MV-FFF (1400 MU/min) and 4D-CT on TrueBeam to deliver 50 Gy in 5 fractions to the planning target volume (PTV). SIB dose of 60 Gy was delivered to a 1-cm internal margin from the gross tumor volume (GTV). Dose was calculated using Acuros-based engine. Pre-treatment Conebeam CT imaging was used for patient setup and verification. Treatments were delivered in < 15 minutes. Patients underwent post-treatment clinical evaluation and CT imaging in 3-month intervals to assess changes in tumor size and post-radiation sequelae. Clinical outcomes reported include treatment response and toxicity.

RESULTS

Twenty-six patients with large, centrally (n = 13) or peripherally (n = 13) located tumors were evaluated; this included 16 NSCLC patients with T2-T3N0 disease and 5 with pulmonary metastases from distant sites. One patient had declined surgery, while 25/26 (96.1%) were deemed medically inoperable. All plans met RTOG-0813 requirements for target coverage and dose to OARs. Median follow-up interval was 11 months (0 to 23 months). Twenty-one of 26 (80.7%) patients received post-treatment CT imaging within 6 months of SBRT. Local control was achieved in 20/21 (95.2%) patients; one patient with a peripherally located tumor progressed outside the treatment field. Acute toxicity profile amongst the 25 patients assessed included grade 1 fatigue (n = 2), grade 1 rib pain (n = 1), and grade 2 pulmonary fibrosis (n = 1). Otherwise, 22/25 (88%) patients reported no radiation induced toxicities. Subgroup analysis was performed on patients with centrally located tumors, defined as located <2 cm from the hilum, heart, or bronchial trees. One of 13 (7.6%) patients with central tumors reported grade 1 rib pain; otherwise, no radiation induced adverse effects were observed. All patients with centrally located lung tumors experienced local control on surveillance imaging.

CONCLUSION

SBRT with SIB to the hypoxic centers of large pulmonary masses is a safe, efficacious treatment that confers improved local control while maintaining dose to adjacent OARs. This study demonstrates the feasibility of delivering doses up to 60 Gy to the hypoxic centers of large lung tumors, while decreasing local tumor burden, minimizing treatment mobility, and improving clinic workflow. SBRT with SIB shortens treatment course to 5 fractions (in contrast to the traditional daily 30 fractions), thus improving patient comfort and compliance.

Fast generation of lung SBRT plans with a knowledge-based planning model on ring-mounted Halcyon Linac

Purpose

To demonstrate fast treatment planning feasibility of stereotactic body radiation therapy (SBRT) for centrally located lung tumors on Halcyon Linac via a previously validated knowledge‐based planning (KBP) model to support offline adaptive radiotherapy.

Materials/methods

Twenty previously treated non‐coplanar volumetric‐modulated arc therapy (VMAT) lung SBRT plans (c‐Truebeam) on SBRT‐dedicated C‐arm Truebeam Linac were selected. Patients received 50 Gy in five fractions. c‐Truebeam plans were re‐optimized for Halcyon manually (m‐Halcyon) and with KBP model (k‐Halcyon). Both m‐Halcyon and k‐Halcyon plans were normalized for identical or better target coverage than clinical c‐Truebeam plans and compared for target conformity, dose heterogeneity, dose fall‐off, and dose tolerances to the organs‐at‐risk (OAR). Treatment delivery parameters and planning times were evaluated.

Results

k‐Halcyon plans were dosimetrically similar or better than m‐Halcyon and c‐Truebeam plans. k‐Halcyon and m‐Halcyon plan comparisons are presented with respect to c‐Truebeam. Differences in conformity index were statistically insignificant in k‐Halcyon and on average 0.02 higher (p = 0.04) in m‐Halcyon plans. Gradient index was on average 0.43 (p = 0.006) lower and 0.27 (p = 0.02) higher for k‐Halcyon and m‐Halcyon, respectively. Maximal dose 2 cm away in any direction from target was statistically insignificant. k‐Halcyon increased maximal target dose on average by 2.9 Gy (p < 0.001). Mean lung dose was on average reduced by 0.10 Gy (p = 0.004) in k‐Halcyon and increased by 0.14 Gy (p < 0.001) in m‐Halcyon plans. k‐Halcyon plans lowered bronchial tree dose on average by 1.2 Gy. Beam‐on‐time (BOT) was increased by 2.85 and 1.67 min, on average for k‐Halcyon and m‐Halcyon, respectively. k‐Halcyon plans were generated in under 30 min compared to estimated dedicated 180 ± 30 min for m‐Halcyon or c‐Truebeam plan.

Conclusion

k‐Halcyon plans were generated in under 30 min with excellent plan quality. This adaptable KBP model supports high‐volume clinics in the expansion or transfer of lung SBRT patients to Halcyon.

Addition of Metformin to Concurrent Chemoradiation in Patients With Locally Advanced Non-Small Cell Lung Cancer: The NRG-LU001 Phase 2 Randomized Clinical Trial

Importance

Non-small cell lung cancer (NSCLC) has relatively poor outcomes. Metformin has significant data supporting its use as an antineoplastic agent.

Objective

To compare chemoradiation alone vs chemoradiation and metformin in stage III NSCLC.

Design, Setting, and Participants

The NRG-LU001 randomized clinical trial was an open-label, phase 2 study conducted from August 24, 2014, to December 15, 2016. Patients without diabetes who were diagnosed with unresectable stage III NSCLC were stratified by performance status, histology, and stage. The setting was international and multi-institutional. This study examined prespecified endpoints, and data were analyzed on an intent-to-treat basis. Data were analyzed from February 25, 2019, to March 6, 2020.

Interventions

Chemoradiation and consolidation chemotherapy with or without metformin.

Main Outcomes and Measures

The primary outcome was 1-year progression-free survival (PFS), designed to detect 15% improvement in 1-year PFS from 50% to 65% (hazard ratio [HR], 0.622). Secondary end points included overall survival, time to local-regional recurrence, time to distant metastasis, and toxicity per Common Terminology Criteria for Adverse Events, version 4.03.

Results

A total of 170 patients were enrolled, with 167 eligible patients analyzed after exclusions (median age, 64 years [interquartile range, 58-72 years]; 97 men [58.1%]; 137 White patients [82.0%]), with 81 in the control group and 86 in the metformin group. Median follow-up was 27.7 months (range, 0.03-47.21 months) among living patients. One-year PFS rates were 60.4% (95% CI, 48.5%-70.4%) in the control group and 51.3% (95% CI, 39.8%-61.7%) in the metformin group (HR, 1.15; 95% CI, 0.77-1.73; P = .24). Clinical stage was the only factor significantly associated with PFS on multivariable analysis (HR, 1.79; 95% CI, 1.19-2.69; P = .005). One-year overall survival was 80.2% (95% CI, 69.3%-87.6%) in the control group and 80.8% (95% CI, 70.2%-87.9%) in the metformin group. There were no significant differences in local-regional recurrence or distant metastasis at 1 or 2 years. No significant difference in adverse events was observed between treatment groups.

Conclusions and Relevance

In this randomized clinical trial, the addition of metformin to concurrent chemoradiation was well tolerated but did not improve survival among patients with unresectable stage III NSCLC.

Trial Registration

ClinicalTrials.gov Identifier: NCT02186847.

Automation and integration of a novel restricted single-isocenter stereotactic body radiotherapy (a-RESIST) method for synchronous two lung lesions

Synchronous treatment of two lung lesions using a single-isocenter volumetric modulated arc therapy (VMAT) stereotactic body radiation therapy (SBRT) plan can decrease treatment time and reduce the impact of intrafraction motion. However, alignment of both lesions on a single cone beam CT (CBCT) can prove difficult and may lead to setup errors and unacceptable target coverage loss. A Restricted Single-Isocenter Stereotactic Body Radiotherapy (RESIST) method was created to minimize setup uncertainties and provide treatment delivery flexibility. RESIST utilizes a single-isocenter placed at patient's midline and allows both lesions to be planned separately but treated in the same session. Herein is described a process of automation of this novel RESIST method. Automation of RESIST significantly reduced treatment planning time while maintaining the benefits of RESIST. To demonstrate feasibility, ten patients with two lung lesions previously treated with a single-isocenter clinical VMAT plan were replanned manually with RESIST (m-RESIST) and with automated RESIST (a-RESIST). a-RESIST method automatically sets isocenter, creates beam geometry, chooses appropriate dose calculation algorithms, and performs VMAT optimization using an in-house trained knowledge-based planning model for lung SBRT. Both m-RESIST and a-RESIST showed lower dose to normal tissues compared to manually planned clinical VMAT although a-RESIST provided slightly inferior, but still clinically acceptable, dose conformity and gradient indices. However, a-RESIST significantly reduced the treatment planning time to less than 20 min and provided a higher dose to the lung tumors. The a-RESIST method provides guidance for inexperienced planners by standardizing beam geometry and plan optimization using DVH estimates. It produces clinically acceptable two lesions VMAT lung SBRT plans efficiently. We have further validated a-RESIST on phantom measurement and independent pretreatment dose verification of another four selected 2-lesions lung SBRT patients and implemented clinically. Further development of a-RESIST for more than two lung lesions and refining this approach for extracranial oligometastastic abdominal/pelvic SBRT, including development of automated simulated collision detection algorithm, merits future investigation.

A novel restricted single-isocenter stereotactic body radiotherapy (RESIST) method for synchronous multiple lung lesions to minimize setup uncertainties

Treating multiple lung lesions synchronously using a single-isocenter volumetric modulated arc therapy (VMAT) stereotactic body radiation therapy (SBRT) plan can improve treatment efficiency and patient compliance. However, due to set up uncertainty, aligning multiple lung tumors on a single daily cone beam CT (CBCT) image has shown clinically unacceptable loss of target(s) coverage. Herein, we propose a Restricted Single-Isocenter Stereotactic Body Radiotherapy (RESIST), an alternative treatment that mitigates patient setup uncertainties. Twenty-one patients with two lung lesions were treated with single-isocenter VMAT-SBRT using a 6MV-FFF beam to 54 Gy in 3 fractions (n = 7) or 50 Gy in 5 fractions (n = 14) prescribed to 70-80% isodose line. To minimize setup uncertainties, each plan was re-planned using the RESIST method, utilizing a single-isocenter placed at the patient's mediastinum. It allows for an individual plan to be created for each tumor, using the first plan as the base-dose for the second plan, while still allowing both tumors to be treated in the same session. The technique uses novel features in Eclipse, including dynamic conformal arc (DCA)-based dose and aperture shape controller before each VMAT optimization. RESIST plans provided better target dose conformity (p < 0.001) and gradient indices (p < 0.001) and lower dose to adjacent critical organs. Using RESIST to treat synchronous lung lesions with VMAT-SBRT significantly reduces plan complexity as demonstrated by smaller beam modulation factors (p < 0.001), without unreasonably increasing treatment time. RESIST reduces the chance of a geometric miss due by allowing CBCT matching of one tumor at a time. Placement of isocenter at the mediastinum avoids potential patient/gantry collisions, provides greater flexibility of noncoplanar arcs and eliminates the need for multiple couch movements during CBCT imaging. Efficacy of RESIST has been demonstrated for two lesions and can potentially be used for more lesions. Clinical implementation of this technique is ongoing.

Priming immunotherapy with radiotherapy (RT) in advanced non-small cell lung cancer (NSCLC) and head and neck squamous cell cancer (HNSCC): Interim analysis of phase II clinical trial

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Background: Preclinical models demonstrate that combined RT with immune checkpoint inhibitor (ICI) results in specific CD8+ T-cell phenotype associated with a tumor-reactive population resulting in significant tumor response. Sequential treatment could allow radiation to release tumor antigens from immune inaccessible areas and provide robust anti-tumor immune response with ICI. We report an interim analysis of the phase II clinical trial evaluating the efficacy and safety of the combination. Methods: Advanced NSCLC and HNSCC patients who had initiated on FDA approved single-agent ICI were eligible. Patients were given SBRT (BED>100Gy) or 30 Gy fractionated RT delivered as a 3-dimensional dose to a single metastatic site within 14 days of the first ICI dose. Primary objective was 6-month PFS and secondary objectives were safety and tolerability, 1Y PFS and OS. This interim analysis was done after enrollment of 43 patients. Results: Between 10/2017 to 1/2021, 43 patients were enrolled, and 38 included in this analysis. Median age was 62 years; 26 patients were male. 9 patients received ICI for NSCLC as first-line, 7 for NSCLC second-line and 22 for HNSCC second-line. 24 patients received pembrolizumab and 14 nivolumab; 21 had SBRT and 17 fractionated RT. Median follow up duration was 11.8m (range: 2.7 - 31.4m) for patients without progressive disease (PD). 10 patients were off-study, 7 continuing treatment. 15 died and 26 had PD. 14 patients died of malignancy and cause of death for one patient was unknown. 6-month PFS was 49.19% with median PFS of 5.5 months. (table) Fifty-two grade-3-5 adverse events (AEs) were reported among 21 subjects. Most common were transaminitis (n=15), lymphopenia (n=8), and GI side effects (n=4). Treatment related AEs included 19 grade-3 events, and none were grade 4/5. Two grade-5 AEs were from PD (oral bleeding and unspecified). There were 20 grade-1/2 and 3 grade-3 immune related adverse events (IRAEs). No grade-4/5 IRAEs were reported. Two patients discontinued treatment due to grade 3 transaminitis. Conclusions: Interim analysis shows that 6m PFS was acceptable with majority of patients being second-line metastatic HNSCC who historically had mPFS of 2.1-2.3 months and mOS 7.7-8.4 months in Checkmate-141/KEYNOTE-040 trials. Hence, the combination is of further interest and accrual will continue to reach the goal. The combination therapy was tolerable without unexpected AEs. Majority of deaths were from disease progression. No treatment related grade 4/5 adverse events were reported. Two patients discontinued treatment due to grade-3 IRAE. Clinical trial information: NCT03313804. [Table: see text]

Risk of target coverage loss for stereotactic body radiotherapy treatment of synchronous lung lesions via single-isocenter volumetric modulated arc therapy

Treating multiple lung lesions synchronously via single‐isocenter volumetric modulated arc therapy (VMAT) stereotactic body radiation therapy (SBRT) improves treatment efficiency and patient compliance. However, aligning multiple lung tumors accurately on single pretreatment cone beam CTs (CBCTs) can be problematic. Tumors misaligned could lead to target coverage loss. To quantify this potential target coverage loss due to small, clinically realistic setup errors, a novel simulation method was developed. This method was used on 26 previously treated patients with two metastatic lung lesions. Patients were treated with 4D CT‐based, highly conformal noncoplanar VMAT plans (clinical VMAT) with 6MV‐flattening filter free (FFF) beam using AcurosXB dose calculation algorithm with heterogeneity corrections. A single isocenter was placed approximately between the lesions to improve patient convenience and clinic workflow. Average isocenter to tumor distance was 5.9 cm. Prescription dose was 54 Gy/50 Gy in 3/5 fractions. For comparison, a plan summation (simulated VMAT) was executed utilizing randomly simulated, clinically relevant setup errors, obtained from pretreatment setup, per treatment fraction, in Eclipse treatment planning system for each of the six degrees of freedom within ± 5.0 mm and ± 2°. Simulations yielded average deviations of 27.4% (up to 72% loss) (P < 0.001) from planned target coverage when treating multiple lung lesions using a single‐isocenter plan. The largest deviations from planned coverage and desired biological effective dose (BED10, with α/β = 10 Gy) were seen for the smallest targets (<10 cc), some of which received < 100 Gy BED10. Patient misalignment resulted in substantial decrease in conformity and increase in the gradient index, violating major characteristics of SBRT. Statistically insignificant differences were seen for normal tissue dose. Although, clinical follow‐up of these patients is ongoing, the authors recommend an alternative treatment planning strategy to minimize the probability of a geometric miss when treating small lung lesions synchronously with single‐isocenter VMAT SBRT plans.

Development and clinical validation of a robust knowledge-based planning model for stereotactic body radiotherapy treatment of centrally located lung tumors

PURPOSE

To develop a robust and adaptable knowledge-based planning (KBP) model with commercially available RapidPlan^TM for early stage, centrally located non-small-cell lung tumors (NSCLC) treated with stereotactic body radiotherapy (SBRT) and improve a patient's"simulation to treatment" time.

METHODS

The KBP model was trained using 86 clinically treated high-quality non-coplanar volumetric modulated arc therapy (n-VMAT) lung SBRT plans with delivered prescriptions of 50 or 55 Gy in 5 fractions. Another 20 independent clinical n-VMAT plans were used for validation of the model. KBP and n-VMAT plans were compared via Radiation Therapy Oncology Group (RTOG)-0813 protocol compliance criteria for conformity (CI), gradient index (GI), maximal dose 2 cm away from the target in any direction (D2cm), dose to organs-at-risk (OAR), treatment delivery efficiency, and accuracy. KBP plans were re-optimized with larger calculation grid size (CGS) of 2.5 mm to assess feasibility of rapid adaptive re-planning.

RESULTS

Knowledge-based plans were similar or better than n-VMAT plans based on a range of target coverage and OAR metrics. Planning target volume (PTV) for validation cases was 30.5 ± 19.1 cc (range 7.0-71.7 cc). KBPs provided an average CI of 1.04 ± 0.04 (0.97-1.11) vs. n-VMAT plan'saverage CI of 1.01 ± 0.04 (0.97-1.17) (P < 0.05) with slightly improved GI with KBPs (P < 0.05). D2cm was similar between the KBPs and n-VMAT plans. KBPs provided lower lung V10Gy (P = 0.003), V20Gy (P = 0.007), and mean lung dose (P < 0.001). KBPs had overall better sparing of OAR at the minimal increased of average total monitor units and beam-on time by 460 (P < 0.05) and 19.2 s, respectively. Quality assurance phantom measurement showed similar treatment delivery accuracy. Utilizing a CGS of 2.5 mm in the final optimization improved planning time (mean, 5 min) with minimal or no cost to the plan quality.

CONCLUSION

The RTOG-compliant adaptable RapidPlan model for early stage SBRT treatment of centrally located lung tumors was developed. All plans met RTOG dosimetric requirements in less than 30 min of planning time, potentially offering shorter "simulation to treatment" times. OAR sparing via KBPs may permit tumorcidal dose escalation with minimal penalties. Same day adaptive re-planning is plausible with a 2.5-mm CGS optimizer setting.

An Automated knowledge-based planning routine for stereotactic body radiotherapy of peripheral lung tumors via DCA-based volumetric modulated arc therapy

Purpose

To develop a knowledge‐based planning (KBP) routine for stereotactic body radiotherapy (SBRT) of peripherally located early‐stage non‐small‐cell lung cancer (NSCLC) tumors via dynamic conformal arc (DCA)‐based volumetric modulated arc therapy (VMAT) using the commercially available RapidPlan^TM software. This proposed technique potentially improves plan quality, reduces complexity, and minimizes interplay effect and small‐field dosimetry errors associated with treatment delivery.

Methods

KBP model was developed and validated using 70 clinically treated high quality non‐coplanar VMAT lung SBRT plans for training and 20 independent plans for validation. All patients were treated with 54 Gy in three treatments. Additionally, a novel k‐DCA planning routine was deployed to create plans incorporating historical three‐dimensional‐conformal SBRT planning practices via DCA‐based approach prior to VMAT optimization in an automated planning engine. Conventional KBPs and k‐DCA plans were compared with clinically treated plans per RTOG‐0618 requirements for target conformity, tumor dose heterogeneity, intermediate dose fall‐off and organs‐at‐risk (OAR) sparing. Treatment planning time, treatment delivery efficiency, and accuracy were recorded.

Results

KBPs and k‐DCA plans were similar or better than clinical plans. Average planning target volume for validation was 22.4 ± 14.1 cc (7.1–62.3 cc). KBPs and k‐DCA plans provided similar conformity to clinical plans with average absolute differences of 0.01 and 0.01, respectively. Maximal doses to OAR were lowered in both KBPs and k‐DCA plans. KBPs increased monitor units (MU) on average 1316 (P < 0.001) while k‐DCA reduced total MU on average by 1114 (P < 0.001). This routine can create k‐DCA plan in less than 30 min. Independent Monte Carlo calculation demonstrated that k‐DCA plans showed better agreement with planned dose distribution.

Conclusion

A k‐DCA planning routine was developed in concurrence with a knowledge‐based approach for the treatment of peripherally located lung tumors. This method minimizes plan complexity associated with model‐based KBP techniques and improve plan quality and treatment planning efficiency.

On the use of single‐isocenter VMAT plans for SBRT treatment of synchronous multiple lung lesions: Plan quality, treatment efficiency, and early clinical outcomes

Cone‐beam computed tomography (CT)‐guided volumetric‐modulated arc therapy (VMAT) plans for stereotactic body radiotherapy (SBRT) treatment of synchronous multiple lung lesions with a flattening filter‐free (FFF) beam is a safe and highly effective treatment option for oligometastases lung cancer patients. Fourteen patients with metastatic non–small‐cell lung cancer (NSCLC) lesions (two to five) received a single‐isocenter VMAT SBRT treatment in our clinic. Four‐dimensional (4D) CT‐based treatment plans were generated using advanced AcurosXB‐based dose calculation algorithm using heterogeneity corrections with a single isocenter placed between/among the lesions. Compared to 10X‐FFF and traditional flattened 6X (6X‐FF) beams, 6X‐FFF beam produced highly conformal radiosurgical dose distribution to each target volume, reduced dose to adjacent organs at risk (OAR), and significantly reduced the lung SBRT fraction duration to < 3.5 min/fraction for 54/50 Gy treatments in 3/5 fractions — significantly improving patient convenience and clinic workflow. Early follow‐up CT imaging (mean, 9 months) results show high local control rates (100%) with no acute lung or rib toxicity. Longer clinical follow up in a larger patient cohort is ongoing to further validate the outcomes of this treatment approach.

Clinical evaluation of photon optimizer (PO) MLC algorithm for stereotactic, single-dose of VMAT lung SBRT

Recently implemented photon optimizer (PO) MLC optimization algorithm is mandatory for RapidPlan modeling in Eclipse. This report quantifies and compares the dosimetry and treatment delivery parameters of PO vs its predecessor progressive resolution optimizer (PRO) algorithm for a single-dose of volumetric modulated arc therapy (VMAT) lung stereotactic body radiation therapy (SBRT). Clinical SBRT treatment plans for 12 early-stage non-small-cell lung cancer patients receiving 30 Gy in 1 fraction using PRO-VMAT were re-optimized using the PO-VMAT MLC algorithm with identical planning parameters and objectives. Average planning target volume derived from the 4D CT scans was 13.6 ± 12.0 cc (range: 4.3 to 41.1 cc) Patients were treated with 6 MV flattening filter free beam using Acuros-based calculations and 2.5 mm calculation grid-size (CGS). Both treatment plans were normalized to receive same target coverage and identical CGS to isolate effects of MLC positioning optimizers. Original PRO and re-optimized PO plans were compared via RTOG-0915 protocol compliance criteria for target conformity, gradient indices, dose to organs at risks and delivery efficiency. Additionally, PO-VMAT plans with a 1.25 mm CGS were evaluated. Both plans met RTOG protocol requirements. Conformity indices showed no statistical difference between PO 2.5 mm CGS and PRO 2.5 mm CGS plans. Gradient index (p = 0.03), maximum dose to 2 cm away from planning target volume in any direction (D_2cm) (p < 0.05), and gradient distance (p < 0.05) presented statistically significant differences for both plans with 2.5 mm CGS. Some organs at risks showed statistically significant differences for both plans calculated with 2.5 mm CGS; however, no clinically significant dose differences were observed between the plans. Beam modulation factor was statistically significant for both PO 1.25 mm CGS (p = 0.001) and PO 2.5 mm CGS (p < 0.001) compared to clinical PRO 2.5 mm CGS plans. PO-VMAT plans provided decreased beam-on time by an average of 0.2 ± 0.1 minutes (up to 1.0 minutes) with PO 2.5 mm and 1.2 ± 0.39 minutes (maximum up to 3.22 minutes) with PO 1.25 mm plans compared to PRO 2.5 mm plans. PO-VMAT single-dose of VMAT lung SBRT plans showed slightly increased intermediate-dose spillage but boasted overall similar plan quality with less beam modulation and hence shorter beam-on time. However, PO 1.25 mm CGS had less intermediate-dose spillage and analogous plan quality compared to clinical PRO-VMAT plans with no additional cost of plan optimization. Further investigation into peripheral targets with PO-MLC algorithm is warranted. This study indicates that PO 1.25 mm CGS plans can be used for RapidPlan modeling for a single dose of lung SBRT patients. PO-MLC 1.25 mm algorithm is recommended for future clinical single-dose lung SBRT plan optimization.

Flattening filter free VMAT for a stereotactic, single-dose of 30 Gy to lung lesion in a 15-min treatment slot

Cone‐beam CT‐guided single dose of lung stereotactic body radiotherapy (SBRT) treatment with a flattening filter free (FFF) beam and volumetric modulated arc therapy (VMAT) is a safe and highly effective treatment modality for selective small lung lesions. Four‐dimensional (4D) CT‐based treatment plans were generated using advanced AcurosXB algorithm for heterogeneity corrections. 6X‐FFF beam produced highly conformal radiosurgical dose distribution to the target and reduced lung SBRT fraction duration to less than 10 min for a single dose of 30 Gy, significantly improving patient comfort and clinic workflow. Early follow‐up CT imaging results (mean, 8 months) show high local control rates (100%) with no acute lung or rib toxicity. Longer clinical follow‐up in a larger patient cohort managed in this fashion is underway to further validate this treatment approach.

Stereotactic Body Radiation Therapy for Operable Early-Stage Lung Cancer: Findings From the NRG Oncology RTOG 0618 Trial

Importance

Stereotactic body radiation therapy (SBRT) has become a standard treatment for patients with medically inoperable early-stage lung cancer. However, its effectiveness in patients medically suitable for surgery is unclear.

Objective

To evaluate whether noninvasive SBRT delivered on an outpatient basis can safely eradicate lung cancer and cure selected patients with operable lung cancer, obviating the need for surgical resection.

Design, Setting, and Participants

Single-arm phase 2 NRG Oncology Radiation Therapy Oncology Group 0618 study enrolled patients from December 2007 to May 2010 with median follow-up of 48.1 months (range, 15.4-73.7 months). The setting was a multicenter North American academic and community practice cancer center consortium. Patients had operable biopsy-proven peripheral T1 to T2, N0, M0 non-small cell tumors no more than 5 cm in diameter, forced expiratory volume in 1 second (FEV1) and diffusing capacity greater than 35% predicted, arterial oxygen tension greater than 60 mm Hg, arterial carbon dioxide tension less than 50 mm Hg, and no severe medical problems. The data analysis was performed in October 2014.

Interventions

The SBRT prescription dose was 54 Gy delivered in 3 18-Gy fractions over 1.5 to 2.0 weeks.

Main Outcomes and Measures

Primary end point was primary tumor control, with survival, adverse events, and the incidence and outcome of surgical salvage as secondary end points.

Results

Of 33 patients accrued, 26 were evaluable (23 T1 and 3 T2 tumors; 15 [58%] male; median age, 72.5 [range, 54-88] years). Median FEV1 and diffusing capacity of the lung for carbon monoxide at enrollment were 72.5% (range, 38%-136%) and 68% (range, 22%-96%) of predicted, respectively. Only 1 patient had a primary tumor recurrence. Involved lobe failure, the other component defining local failure, did not occur in any patient, so the estimated 4-year primary tumor control and local control rate were both 96% (95% CI, 83%-100%). As per protocol guidelines, the single patient with local recurrence underwent salvage lobectomy 1.2 years after SBRT, complicated by a grade 4 cardiac arrhythmia. The 4-year estimates of disease-free and overall survival were 57% (95% CI, 36%-74%) and 56% (95% CI, 35%-73%), respectively. Median overall survival was 55.2 months (95% CI, 37.7 months to not reached). Protocol-specified treatment-related grade 3, 4, and 5 adverse events were reported in 2 (8%; 95% CI, 0.1%-25%), 0, and 0 patients, respectively.

Conclusions and Relevance

As given, SBRT appears to be associated with a high rate of primary tumor control, low treatment-related morbidity, and infrequent need for surgical salvage in patients with operable early-stage lung cancer.

Trial Registration

ClinicalTrials.gov Identifier: NCT00551369.

Management of local recurrences and regional failure in early stage non-small cell lung cancer after stereotactic body radiation therapy

Stereotactic body radiation therapy (SBRT) is a very effective way to treat early stage non-small cell lung cancer (NSCLC) and small oligometastatic lung lesions with consistently high rates of local control, but both local and regional/distant recurrences still occur. The management of recurrences remains unsettled and may entail repeat SBRT, conventionally fractionated external beam RT (EF-EBRT), chemotherapy or surgery. Most patients with local recurrences [within the initial planning target volume (PTV)] can be salvaged successfully with good cancer specific survival. Nonetheless, proximity of the initial SBRT delivery to organs at risk (ribs, blood vessels, airways) may make retreatment more difficult. With attention to detail and careful patient selection, both surgery and reirradiation can be performed safely and effectively. Strategies for management of regional (nodal) recurrences may require conventional therapies tailored to the patterns of failure. The role of immunotherapy in salvage has not been elucidated as yet. We review here data on the available literature concerning salvage of SBRT lung patients.

Safety and Efficacy of a Five-Fraction Stereotactic Body Radiotherapy Schedule for Centrally Located Non-Small-Cell Lung Cancer: NRG Oncology/RTOG 0813 Trial

PURPOSE

Patients with centrally located early-stage non-small-cell lung cancer (NSCLC) are at a higher risk of toxicity from high-dose ablative radiotherapy. NRG Oncology/RTOG 0813 was a phase I/II study designed to determine the maximum tolerated dose (MTD), efficacy, and toxicity of stereotactic body radiotherapy (SBRT) for centrally located NSCLC.

MATERIALS AND METHODS

Medically inoperable patients with biopsy-proven, positron emission tomography-staged T1 to 2 (≤ 5 cm) N0M0 centrally located NSCLC were accrued into a dose-escalating, five-fraction SBRT schedule that ranged from 10 to 12 Gy/fraction (fx) delivered over 1.5 to 2 weeks. Dose-limiting toxicity (DLT) was defined as any treatment-related grade 3 or worse predefined toxicity that occurred within the first year. MTD was defined as the SBRT dose at which the probability of DLT was closest to 20% without exceeding it.

RESULTS

One hundred twenty patients were accrued between February 2009 and September 2013. Patients were elderly, there were slightly more females, and the majority had a performance status of 0 to 1. Most cancers were T1 (65%) and squamous cell (45%). Organs closest to planning target volume/most at risk were the main bronchus and large vessels. Median follow-up was 37.9 months. Five patients experienced DLTs; MTD was 12.0 Gy/fx, which had a probability of a DLT of 7.2% (95% CI, 2.8% to 14.5%). Two-year rates for the 71 evaluable patients in the 11.5 and 12.0 Gy/fx cohorts were local control, 89.4% (90% CI, 81.6% to 97.4%) and 87.9% (90% CI, 78.8% to 97.0%); overall survival, 67.9% (95% CI, 50.4% to 80.3%) and 72.7% (95% CI, 54.1% to 84.8%); and progression-free survival, 52.2% (95% CI, 35.3% to 66.6%) and 54.5% (95% CI, 36.3% to 69.6%), respectively.

CONCLUSION

The MTD for this study was 12.0 Gy/fx; it was associated with 7.2% DLTs and high rates of tumor control. Outcomes in this medically inoperable group of mostly elderly patients with comorbidities were comparable with that of patients with peripheral early-stage tumors.

Long-term Follow-up on NRG Oncology RTOG 0915 (NCCTG N0927): A Randomized Phase 2 Study Comparing 2 Stereotactic Body Radiation Therapy Schedules for Medically Inoperable Patients With Stage I Peripheral Non-Small Cell Lung Cancer

PURPOSE

To present long-term results of RTOG 0915/NCCTG N0927, a randomized lung stereotactic body radiation therapy trial of 34 Gy in 1 fraction versus 48 Gy in 4 fractions.

METHODS AND MATERIALS

This was a phase 2 multicenter study of patients with medically inoperable non-small cell lung cancer with biopsy-proven peripheral T1 or T2 N0M0 tumors, with 1-year toxicity rates as the primary endpoint and selected failure and survival outcomes as secondary endpoints. The study opened in September 2009 and closed in March 2011. Final data were analyzed through May 17, 2018.

RESULTS

Eighty-four of 94 patients accrued were eligible for analysis: 39 in arm 1 and 45 in arm 2. Median follow-up time was 4.0 years for all patients and 6.0 years for those alive at analysis. Rates of grade 3 and higher toxicity were 2.6% in arm 1 and 11.1% in arm 2. Median survival times (in years) for 34 Gy and 48 Gy were 4.1 versus 4.6, respectively. Five-year outcomes (95% confidence interval) for 34 Gy and 48 Gy were a primary tumor failure rate of 10.6% (3.3%-23.1%) versus 6.8% (1.7%-16.9%); overall survival of 29.6% (16.2%-44.4%) versus 41.1% (26.6%-55.1%); and progression-free survival of 19.1% (8.5%-33.0%) versus 33.3% (20.2%-47.0%). Distant failure as the sole failure or a component of first failure occurred in 6 patients (37.5%) in the 34 Gy arm and in 7 (41.2%) in the 48 Gy arm.

CONCLUSIONS

No excess in late-appearing toxicity was seen in either arm. Primary tumor control rates at 5 years were similar by arm. A median survival time of 4 years for each arm suggests similar efficacy, pending any larger studies appropriately powered to detect survival differences.

Comparison of outcomes of stereotactic body radiation therapy delivered with three different technologies to the lung

PURPOSE/OBJECTIVES

Since the inception of stereotactic body radiation therapy (SBRT), treatment delivery has been performed with volumetric modulated arc therapy (VMAT), helical tomotherapy (HT) and noncoplanar static fields (SF). The purpose of this study is to compare SBRT delivery among these treatment modalities to the lung.

MATERIALS/METHODS

A retrospective review of SBRT treatments of 30 to 60 Gy in 1 to 5 fractions from 2007 to 2015 was performed. Dosimetric parameters included V5, V20, D2cm, gross tumor volume (GTV) and planning target volume (PTV) size and coverage, rib/esophageal minimum/maximum doses, R30Gy, R50%, and the conformality index (CI). Clinical outcomes evaluated included local control, pneumonitis and other toxicities. ANOVA, Student's t-test and Kruskal-Wallis test were used to compare the parameters among modalities. Kaplan-Meier estimates of time-to-local failure were produced.

RESULTS

176 Treatments included 106 SF, 36 VMAT and 34 HT. HT had better PTV coverage (p=0.0166) but higher lung V5 and esophageal doses (p<0.001 and p=0.0032). R30Gy, R50%, and CI were significantly better with VMAT SBRT (p<0.001). Clinically, Grade 2+ pneumonitis was associated with larger median GTV's of 21.39 cc versus 7.65 cc (p=0.0016), larger median PTV's of 65.62 cc versus 31.75 cc (p=0.0030), and higher V20 6.62% versus 4.08% (p=0.0408). For patients surviving >1 year, overall local failure rate was 9.4%. Actuarial control rates trended toward statistical significance with time to local failure with VMAT being the most favorable group on the Kaplan-Meier curve (p=0.0733).

CONCLUSION

VMAT showed superior conformality compared to the other modalities. Among the modalities examined, HT had higher values for parameters associated with toxicity such as V5 and maximum esophageal dose, but all were within acceptable limits. There was a trend to better local control with VMAT.

Emerging Therapies for Stage III Non-Small Cell Lung Cancer: Stereotactic Body Radiation Therapy and Immunotherapy

The current standard of care for locally advanced non-small cell lung cancer (NSCLC) includes radiation, chemotherapy, and surgery in certain individualized cases. In unresectable NSCLC, chemoradiation has been the standard of care for the past three decades. Local and distant failure remains high in this group of patients, so dose escalation has been studied in both single institution and national clinical trials. Though initial studies showed a benefit to dose escalation, phase III studies examining dose escalation using standard fractionation or hyperfractionation have failed to show a benefit. Over the last 17 years, stereotactic body radiation therapy (SBRT) has shown a high degree of safety and local control for stage I lung cancers and other localized malignancies. More recently, phase I/II studies using SBRT for dose escalation after conventional chemoradiation in locally advanced NSCLC have been promising with good apparent safety. Immunotherapy also offers opportunities to address distant disease and preclinical data suggest immunotherapy in tandem with SBRT may be a rational way to induce an “abscopal effect” although there are little clinical data as yet. By building on the proven concept of conventional chemoradiation for patients with locally advanced NSCLC with a subsequent radiation dose intensification to residual disease with SBRT concurrent with immunotherapy, we hope address the issues of metastatic and local failures. This “quadmodality” approach is still in its infancy but appears to be a safe and rational approach to the improving the outcome of NSCLC therapy.

Update of a Prospective Study of Stereotactic Body Radiation Therapy for Post-Chemoradiation Residual Disease in Stage II/III Non-Small Cell Lung Cancer

PURPOSE

To report long-term outcomes (risk of late toxicities, local control, and survival) of dose escalation by stereotactic radiation therapy boost to residual fluorodeoxyglucose positron emission tomography-positive residual disease after chemoradiation (CRT) in stage III non-small cell lung cancer (NSCLC).

METHODS AND MATERIALS

Patients with stage IIB/III NSCLC underwent computed tomography or positron emission tomography-computed tomography screening approximately 1 month after completion of CRT. Limited residual disease (≤5 cm) within the site of the primary tumor received a stereotactic radiation therapy boost of either 10 Gy × 2 fractions or 6.5 Gy × 3 fractions to the primary tumor, to achieve a total Biologically Equivalent Dose >100 Gy.

RESULTS

Thirty-seven patients received protocol therapy. With a median follow-up of 25.2 months, the crude local control rate for the entire group was 78% (n=29), but 10 patients (29%) and 24 patients (65%) developed regional and metastatic disease, respectively. At last follow-up, 5 patients (13.5%) remain alive, all with no evidence of disease, whereas 27 (73%) died of disease and the remaining 5 (13.5%) died of other causes. Median overall survival (OS) for the entire group was 25.2 months. Predictors for grade 3 pneumonitis included age and mean lung dose. Poorer median OS was associated with histology: median OS 15.6 months for squamous cell versus 34.8 months for other histologies (large cell neuroendocrine tumors excluded) (P=.04). The median progression-free survival was 6 months, with IIIB disease having significantly worse median progression-free survival (stages IIB/IIA being 9.4 months, vs 4.7 months for stage IIIB [P=.03]).

CONCLUSIONS

Stereotactic radiation therapy boost after CRT is a safe treatment resulting in improvements in local control for locally advanced NSCLC. No additional late toxicities were seen. Possible improvement in OS was found, but further study in a larger prospective trial is needed.

Randomized Phase II Study Comparing Prophylactic Cranial Irradiation Alone to Prophylactic Cranial Irradiation and Consolidative Extracranial Irradiation for Extensive-Disease Small Cell Lung Cancer (ED SCLC): NRG Oncology RTOG 0937

INTRODUCTION

NRG Oncology RTOG 0937 is a randomized phase II trial evaluating 1-year overall survival (OS) with prophylactic cranial irradiation (PCI) or PCI plus consolidative radiation therapy (PCI+cRT) to intrathoracic disease and extracranial metastases for extensive-disease SCLC.

METHODS

Patients with one to four extracranial metastases were eligible after a complete response or partial response to chemotherapy. Randomization was to PCI or PCI+cRT to the thorax and metastases. Original stratification included partial response versus complete response after chemotherapy and one versus two to four metastases; age younger than 65 years versus 65 years or older was added after an observed imbalance. PCI consisted of 25 Gy in 10 fractions. cRT consisted of 45 Gy in 15 fractions. To detect an improvement in OS from 30% to 45% with a 34% hazard reduction (hazard ratio = 0.66) under a 0.1 type 1 error (one sided) and 80% power, 154 patients were required.

RESULTS

A total of 97 patients were randomized between March 2010 and February 2015. Eleven patients were ineligible (nine in the PCI group and two in the PCI+cRT group), leaving 42 randomized to receive PCI and 44 to receive PCI+cRT. At planned interim analysis, the study crossed the futility boundary for OS and was closed before meeting the accrual target. Median follow-up was 9 months. The 1-year OS was not different between the groups: 60.1% (95% confidence interval [CI]: 41.2-74.7) for PCI and 50.8% (95% CI: 34.0-65.3) for PCI+cRT (p = 0.21). The 3- and 12-month rates of progression were 53.3% and 79.6% for PCI and 14.5% and 75% for PCI+cRT, respectively. Time to progression favored PCI+cRT (hazard ratio = 0.53, 95% CI: 0.32-0.87, p = 0.01). One patient in each arm had grade 4 therapy-related toxicity and one had grade 5 therapy-related pneumonitis with PCI+cRT.

CONCLUSIONS

OS exceeded predictions for both arms. cRT delayed progression but did not improve 1-year OS.

Influence of Fractionation Scheme and Tumor Location on Toxicities After Stereotactic Body Radiation Therapy for Large (≥5 cm) Non-Small Cell Lung Cancer: A Multi-institutional Analysis

PURPOSE

To describe the impact of fractionation scheme and tumor location on toxicities in stereotactic body radiation therapy (SBRT) for ≥5-cm non-small cell lung cancer (NSCLC), as part of a multi-institutional analysis.

METHODS

Patients with primary ≥5-cm N0 M0 NSCLC who underwent ≤5-fraction SBRT were examined across multiple high-volume SBRT centers. Collected data included clinical/treatment parameters; toxicities were prospectively assessed at each institution according to the Common Terminology Criteria for Adverse Events. Patients treated daily were compared with those treated every other day (QOD)/other nondaily regimens. Stratification between central and peripheral tumors was also performed.

RESULTS

Ninety-two patients from 12 institutions were evaluated (2004-2016), with median follow-up of 12 months. In total there were 23 (25%) and 6 (7%) grade ≥2 and grade ≥3 toxicities, respectively. Grades 2 and 3 pulmonary toxicities occurred in 9% and 4%, respectively; 1 patient treated daily experienced grade 5 radiation pneumonitis. Of the entire cohort, 46 patients underwent daily SBRT, and 46 received QOD (n=40)/other nondaily (n=6) regimens. Clinical/treatment parameters were similar between groups; the QOD/other group was more likely to receive 3-/4-fraction schemas. Patients treated QOD/other experienced significantly fewer grade ≥2 toxicities as compared with daily treatment (7% vs 43%, P<.001). Patients treated daily also had higher rates of grade ≥2 pulmonary toxicities (P=.014). Patients with peripheral tumors (n=66) were more likely to receive 3-/4-fraction regimens than those with central tumors (n=26). No significant differences in grade ≥2 toxicities were identified according to tumor location (P>.05).

CONCLUSIONS

From this multi-institutional study, toxicity of SBRT for ≥5-cm lesions is acceptable, and daily treatment was associated with a higher rate of toxicities.

Multi-institutional experience of stereotactic body radiotherapy for large (≥5 centimeters) non-small cell lung tumors

BACKGROUND

Stereotactic body radiotherapy (SBRT) is the standard of care for patients with nonoperative, early-stage non-small cell lung cancer (NSCLC) measuring < 5 cm, but its use among patients with tumors measuring ≥5 cm is considerably less defined, with the existing literature limited to small, single-institution reports. The current multi-institutional study reported outcomes evaluating the largest such population reported to date.

METHODS

Clinical/treatment characteristics, outcomes, toxicities, and patterns of failure were assessed in patients with primary NSCLC measuring ≥5 cm without evidence of distant/lymph node metastasis who underwent SBRT using ≤5 fractions. Statistics included Kaplan-Meier survival analyses and univariate/multivariate Cox proportional hazards models.

RESULTS

A total of 92 patients treated from 2004 through 2016 were analyzed from 12 institutions. The median follow-up was 12 months (15 months in survivors). The median age and tumor size among the patients were 73 years (range, 50-95 years) and 5.4 cm (range, 5.0-7.5 cm), respectively. The median dose/fractionation was 50 Gray/5 fractions. The actuarial local control rates at 1 year and 2 years were 95.7% and 73.2%, respectively. The disease-free survival rate was 72.1% and 53.5%, respectively, at 1 year and 2 years. The 1-year and 2-year disease-specific survival rates were 95.5% and 78.6%, respectively. The median, 1-year, and 2-year overall survival rates were 21.4 months, 76.2%, and 46.4%, respectively. On multivariate analysis, lung cancer history and pre-SBRT positron emission tomography maximum standardized uptake value were found to be associated with overall survival. Posttreatment failures were most commonly distant (33% of all disease recurrences), followed by local (26%) and those occurring elsewhere in the lung (23%). Three patients had isolated local failures. Grade 3 to 4 toxicities included 1 case (1%) and 4 cases (4%) of grade 3 dermatitis and radiation pneumonitis, respectively (toxicities were graded according to the Common Terminology Criteria for Adverse Events [version 4.0]). Grades 2 to 5 radiation pneumonitis occurred in 11% of patients. One patient with a tumor measuring 7.5 cm and a smoking history of 150 pack-years died of radiation pneumonitis.

CONCLUSIONS

The results of the current study, which is the largest study of patients with NSCLC measuring ≥5 cm reported to date, indicate that SBRT is a safe and efficacious option. Cancer 2017;123:688-696. © 2016 American Cancer Society.

Pulmonary Hilar Stereotactic Body Radiation Therapy in the Rat

Stereotactic Body Radiation therapy (SBRT) is an emerging modality of treatment for early stage non-small cell lung carcinoma. Concerns have arisen related to increased toxicities for medial tumors. We have developed a model of high dose, hypofractionated radiotherapy to the pulmonary hilum using the Leksell Gamma-Knife™. Sprague-Dawley rats received hypofractionated SBRT to the unilateral lung hilum using a custom immobilization device on the Gamma Knife. Each animal was individually scanned, treatment planned, and treated with either two 4 mm or one 8 mm collimated shots at escalating doses of 20, 40, and 80 Gy to the 50% isodose volume, encompassing the right mainstem bronchus. All animals were carefully followed post-treatment and imaged by plain film and CT. In addition, histopathological analysis of all rats was performed at selected time points. Animals treated with 4 mm collimated shots demonstrated no appreciable changes on plain films or sequential, follow-up CT scans, or histopathologically. Animals irradiated with the 8 mm collimator were less active, gained weight at a reduced rate, and demonstrated histopathological changes in 7/34 animals six months post-irradiation. Cellular atypia and interstitial pneumonitis were found, three of the seven of the animals showed clear bronchial damage and two showed vascular damage. Significant volume and time effects were found. Utilizing a novel Gamma Knife based animal model to study SBRT toxicity, it was found that the bronchus will tolerate small volumes of very high dose radiotherapy. It was postulated that radiation of the surrounding support stroma and normal tissue are important in the etiology of bronchial or hilar damage.

Development of three-dimensional lung multicellular spheroids in air- and liquid-interface culture for the evaluation of anticancer therapeutics

Three-dimensional (3D) lung multicellular spheroids (MCS) in liquid-covered culture (LCC) and air-interface culture (AIC) conditions have both been developed for the evaluation of aerosol anticancer therapeutics in solution and aerosols, respectively. The MCS were formed by seeding lung cancer cells on top of collagen where they formed spheroids due to the prevalence of cell-to-cell interactions. LCC MCS were exposed to paclitaxel (PTX) in media whereas AIC MCS were exposed to dry powder PEGylated phospholipid aerosol microparticles containing paclitaxel. The difference in viability for 2D versus 3D culture for both LCC and AIC was evaluated along with the effects of the particles on lung epithelium via transepithelial electrical resistance (TEER) measurements. For LCC and AIC conditions, the 3D spheroids were more resistant to treatment with higher IC50 values for A549 and H358 cell lines. TEER results initially indicated a decrease in resistance upon drug or particle exposure, however, these values increased over the course of several days indicating the ability of the cells to recover. Overall, these studies offer a comprehensive in vitro evaluation of aerosol particles used in the treatment of lung cancer while introducing a new method for culturing lung cancer MCS in both LCC and AIC conditions.

High-performing dry powder inhalers of paclitaxel DPPC/DPPG lung surfactant-mimic multifunctional particles in lung cancer: physicochemical characterization, in vitro aerosol dispersion, and cellular studies

Inhalable lung surfactant-based carriers composed of synthetic phospholipids, dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylglycerol (DPPG), along with paclitaxel (PTX), were designed and optimized as respirable dry powders using organic solution co-spray-drying particle engineering design. These materials can be used to deliver and treat a wide variety of pulmonary diseases with this current work focusing on lung cancer. In particular, this is the first time dry powder lung surfactant-based particles have been developed and characterized for this purpose. Comprehensive physicochemical characterization was carried out to analyze the particle morphology, surface structure, solid-state transitions, amorphous character, residual water content, and phospholipid bilayer structure. The particle chemical composition was confirmed using attenuated total reflectance-Fourier-transform infrared (ATR-FTIR) spectroscopy. PTX loading was high, as quantified using UV-VIS spectroscopy, and sustained PTX release was measured over weeks. In vitro cellular characterization on lung cancer cells demonstrated the enhanced chemotherapeutic cytotoxic activity of paclitaxel from co-spray-dried DPPC/DPPG (co-SD DPPC/DPPG) lung surfactant-based carrier particles and the cytotoxicity of the particles via pulmonary cell viability analysis, fluorescent microscopy imaging, and transepithelial electrical resistance (TEER) testing at air-interface conditions. In vitro aerosol performance using a Next Generation Impactor™ (NGI™) showed measurable powder deposition on all stages of the NGI and was relatively high on the lower stages (nanometer aerodynamic size). Aerosol dispersion analysis of these high-performing DPIs showed mass median diameters (MMADs) that ranged from 1.9 to 2.3 μm with excellent aerosol dispersion performance as exemplified by high values of emitted dose, fine particle fractions, and respirable fractions.

Abstract 5377: Assessing the chemotherapeutic response of nanoliposomal topotecan in conjunction with radiotherapy on tumor and its microenvironment

Topotecan (TPT), a highly active, water soluble analogue of camptothecin, is currently being used in the treatment of various localized cancers from different tissue origin including the breast. Topotecan is classically known for its ability to inhibit topoisomerase I activity as well as accumulation of HIF-1α to block upregulation of pro-angiogenic factors. Despite its known anticancer and antiangiogenic properties the clinical use of TPT is limited owing to its rapid clearance and hematological toxicity. Liposomal encapsulation of TPT can potentially increase its efficacy by shielding it from systemic clearance, allowing greater uptake and extended tissue exposure in solid tumors. We hypothesize that tumor cell biology and treatment response would be more informative when done in the presence of stromal components, like endothelial cells. To that end we have developed a 3D in-vitro/ in-vivo murine model of Triple Negative Breast Cancer where 4T1-GFP tumor cells are co-cultured with their stromal component (2H11 murine endothelial cells) in ‘hanging drops’ of medium. In the present study we have determined the effective dose of radiation and TPT for 4T1 tumor and 2H11 endothelial cells by cell viability and clonogenic assays. Based on the observed toxicity treatment response of actively loaded liposomal topotecan (ALLTs) and free drug with or without radiation exposure (3Gy) in tumor-endothelial spheroids was determined by monitoring the spheroid size and quantitation of apoptotic changes observed.

100nm DSPC and m-PEG DSPE (95:5 mol: mol) nanoliposomes were prepared in ammonium besylate and then TPT was actively loaded by pH gradient method. Tumor-endothelial spheroids grown in hanging drops, were subsequently transferred to cell repellent plates for high throughput in-vitro analysis. Our studies indicate that endothelial cells are more sensitive to TPT treatment (IC50 of 0.13µM) than tumor cells (IC50=63µM). Combinatorial treatment with topotecan loaded nanoliposome (ALLT) and radiation of tumor endothelial spheroid reveals a decrease in spheroid size and severe disruption of the peripheral layers with time. ALLTs based chemotherapy in conjunction with radiation was thus observed to be more efficacious in disrupting the integrity, more specifically the extracellular matrix of tumor-endothelial spheroids. Unlike the free drug which gets hydrolyzed into its relatively inactive carboxylate form, we expect that the ability of ALLTs for extended release of active TPT (more than 24 hours) in a metronomic fashion, may contribute to the therapeutic efficacy of its combined treatment with radiation. Efforts are underway to implant these spheroids in mammary fat pad and dorsal skin fold window chamber and study the effect of ALLTs in combination with radiation on tumor growth and neovascularization and metastasis.

Supported by NCI grants R25CA153954 and CA173609

Citation Format: Amar Jyoti, Pallavi Sethi, Kyle Fugit, Ulrich Langner, William St. Clair, Ronald C. McGarry, Bradley D. Anderson, Meenakshi Upreti. Assessing the chemotherapeutic response of nanoliposomal topotecan in conjunction with radiotherapy on tumor and its microenvironment. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5377. doi:10.1158/1538-7445.AM2014-5377

Abstract 4589: Impact of tumor microenvironment on tumor growth, metastasis and response to combination therapy via microenvironment-responsive dual drug-loaded nanoparticles and radiation

Several studies including our own have made it increasingly clear that genetic alterations of tumor cells alone are not the sole driving force behind tumor development but that tumor initiation, growth, progression and response to combinatorial treatments are rather intimately controlled by the microenvironment. Improved knowledge of cancer biology and investigation of the complex functional interrelation between the cellular and noncellular compartments of the tumor microenvironment have provided an ideal platform for the evolution of novel cancer nanotherapies. In the present study we have developed an in-vitro method to co-culture color coded triple negative breast carcinoma cells and cell types that exist in the tumor/tumor microenvironment in a “hanging drop” of medium to the size of an avascular microtissue (∼800 µm). Changes in the fluorescence intensity of different cell types and spheroid/microtissue sizing is being utilized as a method for high throughput therapeutic evaluation of the combination therapy using nanoparticles. When implanted orthotopically and in the dorsal skin fold window chambers in nude mice they facilitate the imaging of neovascularization and understanding response to therapy. We have also observed that radiation (3Gy) can significantly enhances expression of Galectin-1 in tumor vasculature associated endothelial cells which can serve as a specific ligand for the 33 amino acid antiangiogenic, anginex peptide. Thus Galectin-1 is a promising candidate for actively targeting irradiated tumors with anginex conjugated nanoparticles. The objective of this study is to establish a novel strategy for radiation therapy-amplified delivery of dual drugs for targeting the microenvironment-responsive endothelial component of the tumor vasculature. Use of radiation-guided anginex bound nanoparticles for delivery and controlled release of dual drugs (Arsenic-cisplatin) are expected to simulate metronomic therapy and preferentially target the tumor endothelial cells at the irradiated tumor site via tumor stroma enriched Galectin-1 protein. Our molecular studies indicate differential vulnerability for arsenic and cisplatin in cell types constituting the tumor/tumor microenvironment. This is the first study to understand a novel combinatorial nanotherapeutic system in an in-vitro/ in-vivo breast tumor model which incorporates characteristics of the tumor microenvironment and is thus expected to better predict treatment response in patients.

Supported by NCI grant CA173609 and (CNPP) U01CA151461

Citation Format: Pallavi Sethi, Amar Jyoti, Elden Swindell, Ulrich W. Langner, William H. St. Clair, Ronald C. McGarry, Thomas V. O'Halloran, Meenakshi Upreti. Impact of tumor microenvironment on tumor growth, metastasis and response to combination therapy via microenvironment-responsive dual drug-loaded nanoparticles and radiation. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4589. doi:10.1158/1538-7445.AM2014-4589

Integrating stereotactic body radiation therapy in stage II/III non-small cell lung cancer: is local control important?

Local control for advanced non-small cell lung cancer (NSCLC) remains a significant problem with chemoradiation local failure rates in the chest of 30-50%. Despite attempts at dose escalation with conventional radiation therapy techniques, toxicities limit the amount of radiation that can be delivered. For stage I NSCLC, mounting evidence supports the use of hypofractionated radiation therapy (SBRT) to gain high local control rates with acceptable toxicity. For healthy patients with stage II/III NSCLC, the National Comprehensive Cancer Network guidelines suggest surgery is the preferred standard of care for patients with <N2 nodes or T3 tumors. In select patients who are surgical candidates or have more extensive disease, guidelines may include pre-operative chemoradiation followed by surgery, although this remains controversial and is the subject of a current national clinical trial (RTOG 0839). Dose escalation through conventional radiation therapy planning suggests that we can improve outcomes in stage III patients, but toxicity remains problematic. It follows that with improvements in imaging and delivery of radiotherapy, dose escalation with SBRT incorporation may improve local control in stage II/III NSCLC for medically inoperable patients. The rationale for dose escalation and some of the considerations for incorporation of SBRT dose escalation in stage III lung cancer are reviewed here.

Characterization and aerosol dispersion performance of advanced spray-dried chemotherapeutic PEGylated phospholipid particles for dry powder inhalation delivery in lung cancer

Pulmonary inhalation chemotherapeutic drug delivery offers many advantages for lung cancer patients in comparison to conventional systemic chemotherapy. Inhalable particles are advantageous in their ability to deliver drug deep in the lung by utilizing optimally sized particles and higher local drug dose delivery. In this work, spray-dried and co-spray dried inhalable lung surfactant-mimic PEGylated lipopolymers as microparticulate/nanoparticulate dry powders containing paclitaxel were rationally designed via organic solution advanced spray drying (no water) in closed-mode from dilute concentration feed solution. Dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylethanolamine poly(ethylene glycol) (DPPE-PEG) with varying PEG chain length were mixed with varying amounts of paclitaxel in methanol to produce co-spray dried microparticles and nanoparticles. Scanning electron microscopy showed the spherical particle morphology of the inhalable particles. Thermal analysis and X-ray powder diffraction confirmed the retention of the phospholipid bilayer structure in the solid-state following spray drying, the degree of solid-state molecular order, and solid-state phase transition behavior. The residual water content of the particles was very low as quantified analytically Karl Fisher titration. The amount of paclitaxel loaded into the particles was quantified which indicated high encapsulation efficiencies (43-99%). Dry powder aerosol dispersion performance was measured in vitro using the Next Generation Impactor (NGI) coupled with the Handihaler dry powder inhaler device and showed mass median aerodynamic diameters in the range of 3.4-7 μm. These results demonstrate that this novel microparticulate/nanoparticulate chemotherapeutic PEGylated phospholipid dry powder inhalation aerosol platform has great potential in lung cancer drug delivery.

Design, physicochemical characterization, and optimization of organic solution advanced spray-dried inhalable dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylethanolamine poly(ethylene glycol) (DPPE-PEG) microparticles and nanoparticles for targeted respiratory nanomedicine delivery as dry powder inhalation aerosols

Novel advanced spray-dried and co-spray-dried inhalable lung surfactant-mimic phospholipid and poly(ethylene glycol) (PEG)ylated lipopolymers as microparticulate/nanoparticulate dry powders of biodegradable biocompatible lipopolymers were rationally formulated via an organic solution advanced spray-drying process in closed mode using various phospholipid formulations and rationally chosen spray-drying pump rates. Ratios of dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylethanolamine PEG (DPPE-PEG) with varying PEG lengths were mixed in a dilute methanol solution. Scanning electron microscopy images showed the smooth, spherical particle morphology of the inhalable particles. The size of the particles was statistically analyzed using the scanning electron micrographs and SigmaScan^® software and were determined to be 600 nm to 1.2 μm in diameter, which is optimal for deep-lung alveolar penetration. Differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD) were performed to analyze solid-state transitions and long-range molecular order, respectively, and allowed for the confirmation of the presence of phospholipid bilayers in the solid state of the particles. The residual water content of the particles was very low, as quantified analytically via Karl Fischer titration. The composition of the particles was confirmed using attenuated total-reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy and confocal Raman microscopy (CRM), and chemical imaging confirmed the chemical homogeneity of the particles. The dry powder aerosol dispersion properties were evaluated using the Next Generation Impactor™ (NGI™) coupled with the HandiHaler^® dry powder inhaler device, where the mass median aerodynamic diameter from 2.6 to 4.3 μm with excellent aerosol dispersion performance, as exemplified by high values of emitted dose, fine particle fraction, and respirable fraction. Overall, it was determined that the pump rates defined in the spray-drying process had a significant effect on the solid-state particle properties and that a higher pump rate produced the most optimal system. Advanced dry powder inhalers of inhalable lipopolymers for targeted dry powder inhalation delivery were successfully achieved.

Early PET/CT scans for assessing treatment responses of non-small cell lung cancer for SBRT boost: what to do with scans from multiple scanners

Chemoradiation remains the standard of care for the nonsurgical treatment of advanced non-small cell lung cancer (NSCLC) but local recurrence rates of 30-40% are documented. We examined the early PET/CT responses of NSCLC treated with standard chemoradiation in a prospective single institutional trial of early 18F-2-deoxy-D-glucose-PET/CT scans to help define patients appropriate for dose escalation with SBRT. 48 patients with stage IIA, IIB or IIIA-B NSCLC with no or non-bulky ( Collapse

Key Words

• PET scan
• chemoradiation
• lung cancer
• response to treatment

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MESH Headings Collapse

Grants

• P30 CA177558 NCI NIH HHS

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Affiliation(s)

Ronald C. McGarry Department of Radiation Medicine, University of Kentucky, Lexington, Kentucky, USA
Jonathan Feddock Department of Radiation Medicine, University of Kentucky, Lexington, Kentucky, USA
Partha Sinha Department of Radiology. University of Kentucky, Lexington, Kentucky, USA
Gary Conrad Department of Radiology. University of Kentucky, Lexington, Kentucky, USA
Brent J. Shelton Department of Biostatistics, University of Kentucky, Lexington, Kentucky, USA
Li Chen Department of Biostatistics, University of Kentucky, Lexington, Kentucky, USA
Susanne M. Arnold Department of Medicine, University of Kentucky, Lexington, Kentucky, USA
John Rinehart Department of Medicine, University of Kentucky, Lexington, Kentucky, USA

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Nicotinic modulation of therapeutic response in vitro and in vivo

Tobacco use significantly increases the risk of developing cancer. Moreover, there is growing evidence that tobacco use decreases survival in cancer patients. Nicotine, a systemically available component of tobacco, is associated with tumor promotion and decreased apoptosis in cell culture; however, the role of nicotine on response to radiotherapy (RT) or chemoradiotherapy (CRT) in vivo has not been evaluated. Our study evaluated the effects of nicotine administration on cancer cell survival in cell culture and mouse models. Nicotine increased survival in two cell lines following RT in vitro. Nicotine administration in mice during fractionated RT or CRT increased xenograft regrowth as compared to RT or CRT alone. Nicotine increased hypoxia-inducible factor 1-alpha (HIF-1α) expression in tumor xenografts without altering expression of carbonic-anhydrase, a clinical marker of tumor hypoxia. The effects of nicotine on HIF-1α expression were transient, returning to baseline levels within 2-3 days after nicotine removal. Further mechanistic studies indicated that inhibition of phosphoinositide-3-kinase (PI3K) prevented nicotine-mediated increases in HIF-1α expression as well as the prosurvival effects of nicotine on RT. These findings imply that during tobacco use, nicotine may function as a systemic agent through acute and reversible regulation of HIF-1α expression and a decreased therapeutic response.

A pilot trial of serial 18F-fluorodeoxyglucose positron emission tomography in patients with medically inoperable stage I non-small-cell lung cancer treated with hypofractionated stereotactic body radiotherapy

PURPOSE

Routine assessment was made of tumor metabolic activity as measured by 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in Stage I non-small-cell lung cancer (NSCLC). This report describes PET correlates prospectively collected after stereotactic body radiotherapy (SBRT) for patients with medically inoperable NSCLC.

METHODS AND MATERIALS

14 consecutive patients with medically inoperable Stage I NSCLC were enrolled. All patients received SBRT to 60-66 Gy in three fractions. Patients underwent serial planned FDG-PET/computed tomography fusion imaging before SBRT and at 2, 26, and 52 weeks after SBRT.

RESULTS

With median follow-up of 30.2 months, no patients experienced local failure. One patient developed regional failure, 1 developed distant failure, and 1 developed a second primary. The median tumor maximum standardized uptake value (SUV(max)) before SBRT was 8.70. The median SUV(max) values at 2, 26, and 52 weeks after SBRT were 6.04, 2.80, and 3.58, respectively. Patients with low pre-SBRT SUV were more likely to experience initial 2-week rises in SUV, whereas patients with high pre-SBRT SUV commonly had SUV declines 2 weeks after treatment (p = 0.036). Six of 13 patients had primary tumor SUV(max) >3.5 at 12 months after SBRT but remained without evidence of local disease failure on further follow-up.

CONCLUSIONS

A substantial proportion of patients may have moderately elevated FDG-PET SUV(max) at 12 months without evidence of local failure on further follow-up. Thus, slightly elevated PET SUV(max) should not be considered a surrogate for local treatment failure. Our data do not support routine serial FDG-PET/computed tomography for follow-up of patients receiving SBRT for Stage I NSCLC.

Stereotactic body radiation therapy: a novel treatment modality

Stereotactic body radiation therapy (SBRT) involves the delivery of a small number of ultra-high doses of radiation to a target volume using very advanced technology and has emerged as a novel treatment modality for cancer. The role of SBRT is most important at two cancer stages-in early primary cancer and in oligometastatic disease. This modality has been used in the treatment of early-stage non-small-cell lung cancer, prostate cancer, renal-cell carcinoma, and liver cancer, and in the treatment of oligometastases in the lung, liver, and spine. A large body of evidence on the use of SBRT for the treatment of primary and metastatic tumors in various sites has accumulated over the past 10-15 years, and efficacy and safety have been demonstrated. Several prospective clinical trials of SBRT for various sites have been conducted, and several other trials are currently being planned. The results of these clinical trials will better define the role of SBRT in cancer management. This article will review the radiobiologic, technical, and clinical aspects of SBRT.

Stereotactic body radiation therapy for early-stage non-small-cell lung carcinoma: four-year results of a prospective phase II study

PURPOSE

The 50-month results of a prospective Phase II trial of stereotactic body radiation therapy (SBRT) in medically inoperable patients are reported.

METHODS AND MATERIALS

A total of 70 medically inoperable patients had clinically staged T1 (34 patients) or T2 (36 patients) (< or =7 cm), N0, M0, biopsy-confirmed non-small-cell lung carcinoma (NSCLC) and received SBRT as per our previously published reports. The SBRT treatment dose of 60-66 Gy was prescribed to the 80% isodose volume in three fractions.

RESULTS

Median follow-up was 50.2 months (range, 1.4-64.8 months). Kaplan-Meier local control at 3 years was 88.1%. Regional (nodal) and distant recurrence occurred in 6 (8.6%) and 9 (12.9%) patients, respectively. Median survival (MS) was 32.4 months and 3-year overall survival (OS) was 42.7% (95% confidence interval [95% CI], 31.1-54.3%). Cancer-specific survival at 3 years was 81.7% (95% CI, 70.0-93.4%). For patients with T1 tumors, MS was 38.7 months (95% CI, 25.3-50.2) and for T2 tumors MS was 24.5 months (95% CI, 18.5-37.4) (p = 0.194). Tumor volume (< or =5 cc, 5-10 cc, 10-20 cc, >20 cc) did not significantly impact survival: MS was 36.9 months (95% CI, 18.1-42.9), 34.0 (95% CI, 16.9-57.1), 32.8 (95% CI, 21.3-57.8), and 21.4 months (95% CI, 17.8-41.6), respectively (p = 0.712). There was no significant survival difference between patients with peripheral vs. central tumors (MS 33.2 vs. 24.4 months, p = 0.697). Grade 3 to 5 toxicity occurred in 5 of 48 patients with peripheral lung tumors (10.4%) and in 6 of 22 patients (27.3%) with central tumors (Fisher's exact test, p = 0.088).

CONCLUSION

Based on our study results, use of SBRT results in high rates of local control in medically inoperable patients with Stage I NSCLC.

Stereotactic body radiotherapy for bilateral primary lung cancers: the Indiana University experience

PURPOSE

To review the outcomes of 10 patients treated with stereotactic body radiotherapy for bilateral primary medically inoperable lung cancer.

METHODS AND MATERIALS

Between July 2001 and February 2005, 10 patients were treated at Indiana University with stereotactic body radiotherapy for bilateral multiple primary lung cancers using a stereotactic body frame (Elekta, Stockholm, Sweden). Nine patients had cancers that were deemed inoperable secondary to multiple medical comorbidities. One patient refused surgery. All patients had biopsy proven non-small-cell lung carcinoma of at least one of their masses and presented with either metachronous or synchronous pulmonary nodules. Positron emission tomography scans were done for all patients before treatment. Radiation dose varied between 4800 and 6600 cGy given in 3 fractions prescribed to the 80% line covering at least 95% of the planning target volume. We performed a retrospective review of the outcome of these patients.

RESULTS

The mean follow-up time was 20.7 months and the median time was 18.5 months (range, 7-42 months). At the time of this review, all 10 patients were living. Eight (80%) of 10 patients had no evidence of disease progression. One patient developed distant metastasis 5 months after treatment and a second patient developed a local recurrence within the radiation field 11 months after treatment. Six patients had either acute or late pulmonary toxicity, but all toxicity was < or =Grade 2 as defined by the Radiation Therapy Oncology Group toxicity criteria.

CONCLUSION

Our preliminary results indicate that stereotactic body radiotherapy is a possibly safe and potentially effective treatment option for patients with bilateral multiple primary lung cancers that are deemed medically inoperable.

Randomized phase II trial of high-dose melatonin and radiation therapy for RPA class 2 patients with brain metastases (RTOG 0119)

PURPOSE

To determine if high-dose melatonin for Radiation Therapy Oncology Group (RTOG) recursive partitioning analysis (RPA) Class 2 patients with brain metastases improved survival over historical controls, and to determine if the time of day melatonin was given affected its toxicity or efficacy. RTOG 0119 was a phase II randomized trial for this group of patients.

METHODS AND MATERIALS

RTOG RPA Class 2 patients with brain metastases were randomized to 20 mg of melatonin, given either in the morning (8-9 AM) or in the evening (8-9 PM). All patients received radiation therapy (30 Gy in 10 fractions) in the afternoon. Melatonin was continued until neurologic deterioration or death. The primary endpoint was overall survival time. Neurologic deterioration, as reflected by the Mini-Mental Status Examination, was also measured.

RESULTS

Neither of the randomized groups had survival distributions that differed significantly from the historic controls of patients treated with whole-brain radiotherapy. The median survivals of the morning and evening melatonin treatments were 3.4 and 2.8 months, while the RTOG historical control survival was 4.1 months.

CONCLUSIONS

High-dose melatonin did not show any beneficial effect in this group of patients.