Purpose

To characterize radiation therapy patient breathing patterns based on measured external surrogate information.

Methods

Breathing surrogate data were collected during 4DCT from a cohort of 50 patients including 28 patients with lung cancer and 22 patients without lung cancer. A spirometer and an abdominal pneumatic bellows were used as the surrogates. The relationship between these measurements was assumed to be linear within a small phase difference. The signals were correlated and drift corrected using a previously published method to convert the signal into tidal volume. The airflow was calculated with a first order time derivative of the tidal volume using a window centered on the point of interest and with a window length equal to the CT gantry rotation period. The airflow was compared against the tidal volume to create ellipsoidal patterns that were binned into 25 ml × 25 ml∕s bins to determine the relative amount of time spent in each bin. To calculate the variability of the maximum inhalation tidal volume within a free-breathing scan timeframe, a metric based on percentile volume ratios was defined. The free breathing variability metric (κ) was defined as the ratio between extreme inhalation tidal volumes (defined as >93 tidal volume percentile of the measured tidal volume) and normal inhalation tidal volume (defined as >80 tidal volume percentile of the measured tidal volume).

Results

There were three observed types of volume-flow curves, labeled Types 1, 2, and 3. Type 1 patients spent a greater duration of time during exhalation with κ = 1.37 ± 0.11. Type 2 patients had equal time duration spent during inhalation and exhalation with κ = 1.28 ± 0.09. The differences between the mean peak exhalation to peak inhalation tidal volume, breathing period, and the 85th tidal volume percentile for Type 1 and Type 2 patients were statistically significant at the 2% significance level. The difference between κ and the 98th tidal volume percentile for Type 1 and Type 2 patients was found to be statistically significant at the 1% significance level. Three patients did not display a breathing stability curve that could be classified as Type 1 or Type 2 due to chaotic breathing patterns. These patients were classified as Type 3 patients.

Conclusions

Based on an observed volume-flow curve pattern, the cohort of 50 patients was divided into three categories called Type 1, Type 2, and Type 3. There were statistically significant differences in breathing characteristics between Type 1 and Type 2 patients. The use of volume-flow curves to classify patients has been demonstrated as a physiological characterization metric that has the potential to optimize gating windows in radiation therapy.

Purpose

To determine if and by how much the commercial 4DCT protocols under- and overestimate tumor breathing motion.

Methods

1D simulations were conducted that modeled a 16-slice CT scanner and tumors moving proportionally to breathing amplitude. External breathing surrogate traces of at least 5-min duration for 50 patients were used. Breathing trace amplitudes were converted to motion by relating the nominal tumor motion to the 90th percentile breathing amplitude, reflecting motion defined by the more recent 5DCT approach. Based on clinical low-pitch helical CT acquisition, the CT detector moved according to its velocity while the tumor moved according to the breathing trace. When the CT scanner overlapped the tumor, the overlapping slices were identified as having imaged the tumor. This process was repeated starting at successive 0.1 s time bin in the breathing trace until there was insufficient breathing trace to complete the simulation. The tumor size was subtracted from the distance between the most superior and inferior tumor positions to determine the measured tumor motion for that specific simulation. The effect of the scanning parameter variation was evaluated using two commercial 4DCT protocols with different pitch values. Because clinical 4DCT scan sessions would yield a single tumor motion displacement measurement for each patient, errors in the tumor motion measurement were considered systematic. The mean of largest 5% and smallest 5% of the measured motions was selected to identify over- and underdetermined motion amplitudes, respectively. The process was repeated for tumor motions of 1-4 cm in 1 cm increments and for tumor sizes of 1-4 cm in 1 cm increments.

Results

In the examined patient cohort, simulation using pitch of 0.06 showed that 30% of the patients exhibited a 5% chance of mean breathing amplitude overestimations of 47%, while 30% showed a 5% chance of mean breathing amplitude underestimations of 36%; with a separate simulation using pitch of 0.1 showing, respectively, 37% overestimation and 61% underestimation.

Conclusions

The simulation indicates that commercial low-pitch helical 4DCT processes potentially yield large tumor motion measurement errors, both over- and underestimating the tumor motion.

Background and purpose

To quantify the benefit of motion-specific internal target volumes for FDG-avid mediastinal and hilar lymph nodes generated using 4D-PET, vs. conventional internal target volumes generated using non-respiratory gated PET and 4D-CT scans.

Materials and methods

Five patients with FDG-avid tumors metastatic to 11 hilar or mediastinal lymph nodes were imaged with respiratory-correlated FDG-PET (4D-PET) and 4D-CT. FDG-avid nodes were contoured by a radiation oncologist in two ways. Standard-of-care volumes were contoured using conventional un-gated PET, 4D-CT, and breath-hold CT. A second, motion-specific, set of volumes were contoured using 4D-PET.Contours based on 4D-PET corresponded directly to an internal target volume (ITV(4D)), whereas contours based on un-gated PET were expanded by a series of exploratory isotropic margins (from 5 to 13 mm) based on literature recommendations on lymph node motion to form internal target volumes (ITV(3D)).

Results

A 13 mm expansion of the un-gated PET nodal volume was needed to cover the ITV(4D) for 10 of 11 nodes studied. The ITV(3D) based on a 13 mm expansion included on average 45 cm(3) of tissue that was not included in the ITV(4D).

Conclusions

Motion-specific lymph-node internal target volumes generated from 4D-PET imaging could be used to improve accuracy and/or reduce normal-tissue irradiation compared to the standard-of-care un-gated PET based internal target volumes.

Purpose: To demonstrate that a mathematical model can be used to quantitatively understand tumor cellular dynamics during a course of radiotherapy and to predict the likelihood of local control as a function of dose and treatment fractions.Experimental Design: We model outcomes for early-stage, localized non-small cell lung cancer (NSCLC), by fitting a mechanistic, cellular dynamics-based tumor control probability that assumes a constant local supply of oxygen and glucose. In addition to standard radiobiological effects such as repair of sub-lethal damage and the impact of hypoxia, we also accounted for proliferation as well as radiosensitivity variability within the cell cycle. We applied the model to 36 published and two unpublished early-stage patient cohorts, totaling 2,701 patients.Results: Precise likelihood best-fit values were derived for the radiobiological parameters: α [0.305 Gy^-1; 95% confidence interval (CI), 0.120-0.365], the α/β ratio (2.80 Gy; 95% CI, 0.40-4.40), and the oxygen enhancement ratio (OER) value for intermediately hypoxic cells receiving glucose but not oxygen (1.70; 95% CI, 1.55-2.25). All fractionation groups are well fitted by a single dose-response curve with a high χ² P value, indicating consistency with the fitted model. The analysis was further validated with an additional 23 patient cohorts (n = 1,628). The model indicates that hypofractionation regimens overcome hypoxia (and cell-cycle radiosensitivity variations) by the sheer impact of high doses per fraction, whereas lower dose-per-fraction regimens allow for reoxygenation and corresponding sensitization, but lose effectiveness for prolonged treatments due to proliferation.Conclusions: This proposed mechanistic tumor-response model can accurately predict overtreatment or undertreatment for various treatment regimens. Clin Cancer Res; 23(18); 5469-79. ©2017 AACR.

INTRODUCTION:Concurrent chemoradiotherapy (CRT) is standard therapy for locally advanced NSCLC (LA-NSCLC) patients. This study was performed to examine thoracic radiotherapy (TRT) parameters and their impact on patient survival. METHODS:We collected individual patient data from 3600 LA-NSCLC patients participating in 16 cooperative group trials of concurrent CRT. The primary TRT parameters examined included field design strategy (elective nodal irradiation [ENI] compared to involved-field TRT (IF-TRT)), total dose, and biologically effective dose (BED). Hazard ratios (HRs) for overall survival were calculated with univariable and multivariable Cox models. RESULTS:TRT doses ranged from 60 Gy to 74 Gy with most treatments administered once-daily. ENI was associated with poorer survival than IF-TRT (univariable HR = 1.37, 95% confidence interval [CI]: 1.24-1.51, p < 0.0001; multivariable HR = 1.31, 95% CI: 1.08-1.59, p = 0.002). The median survival times of the IF and ENI patients were 24 months and 16 months, respectively. Patients were divided into three dose groups: low total dose (60 Gy), medium total dose (>60 Gy to 66 Gy), and high total dose (>66 Gy to 74 Gy). With reference to the low-dose group, the multivariable HRs were 1.08 for the medium-dose group (95% CI: 0.93-1.25) and 1.12 for the high-dose group (95% CI: 0.97-1.30).The univariate p = 0.054 and multivariable p = 0.17. BED was grouped as follows: low (<55.5 Gy10), medium (55.5 Gy10), or high (>55.5 Gy10). With reference to the low-BED group, the HR was 1.00 (95% CI: 0.85-1.18) for the medium-BED group and 1.10 (95% CI: 0.93-1.31) for the high-BED group. The univariable p = 0.076 and multivariable p = 0.16. CONCLUSIONS:For LA-NSCLC patients treated with concurrent CRT, IF-TRT was associated with significantly better survival than ENI-TRT. TRT total and BED dose levels were not significantly associated with patient survival. Future progress will require research focusing on better systemic therapy and TRT.

Radiation Therapy Oncology Group (RTOG) 3505 is a randomized phase 3 study of concurrent chemoradiation followed by immune checkpoint inhibitor therapy or placebo in patients with locally advanced non-small-cell lung cancer (NSCLC). Patients with surgically unresectable stage 3 NSCLC will receive thoracic radiotherapy to 60 Gy with concurrent cisplatin 50 mg/m² intravenously (I.V.) on days 1, 8, 29, and 36, and etoposide 50 mg/m² I.V. on days 1 to 5 and days 29 to 33. Between 4 and 12 weeks after completion of concurrent chemoradiation, eligible patients will be randomized to the anti-programmed death 1 (PD-1) monoclonal antibody nivolumab 240 mg I.V. or placebo every 2 weeks for up to 1 year. The primary end points are overall survival (OS) and progression-free survival (PFS), as determined by central independent radiology review. Secondary objectives include toxicity assessment, patient-reported outcomes and quality of life, and OS and PFS in programmed death ligand 1 (PD-L1) expressors (≥ 1%) and PD-L1 nonexpressors (< 1%). Assuming a rate of 16.7% due to ineligibility and dropout before randomization, a total of 660 patients will be enrolled to ensure 550 patients will be randomized after completion of chemoradiation. This sample size will provide ≥ 90% power to detect a hazard ratio of 0.7 for OS with 2-sided type I error of 0.04, and to detect a hazard ratio of 0.667 for PFS 2-sided type I error of 0.01. (NCT02768558).

Objective

Concurrent chemoradiotherapy (CRT) was the standard treatment for locally advanced NSCLC (LA-NSCLC). This study was performed to examine thoracic radiotherapy (TRT) parameters and their impact on adverse events (AEs).

Methods

We collected individual patient data from 3600 patients with LA-NSCLC who participated in 16 cooperative group trials of concurrent CRT. The TRT parameters examined included field design strategy (elective nodal irradiation [ENI] versus involved-field [IF] TRT [IF-TRT]) and TRT dose (60 Gy versus ≥60 Gy). The primary end point of this analysis was the occurrence of AEs. ORs for AEs were calculated with univariable and multivariable logistic models.

Results

TRT doses ranged from 60 to 74 Gy. ENI was not associated with more grade 3 or higher AEs than IF-TRT was (multivariable OR = 0.77, 95% confidence interval [CI]: 0.543-1.102, p = 0.1545). Doses higher than 60 Gy (high-dose TRT) were associated with significantly more grade 3 or higher AEs (multivariable OR = 1.82, 95% CI: 1.501-2.203, p < 0.0001). In contrast, ENI was associated with significantly more grade 4 or higher AEs (multivariable OR = 1.33, 95% CI: 1.035-1.709, p = 0.0258). Doses higher than 60 Gy were also associated with more grade 4 or higher AEs (multivariate OR = 1.42, 95% CI: 1.191-1.700, p = 0.0001). Grade 5 AEs plus treatment-related deaths were more frequent with higher-dose TRT (p = 0.0012) but not ENI (p = 0.099).

Conclusions

For patients with LA-NSCLC treated with concurrent CRT, IF-TRT was not associated with the overall risk of grade 3 or higher AEs but was associated with significantly fewer grade 4 or higher AEs than ENI TRT. This is likely the result of irradiation of a lesser amount of adjacent critical normal tissue. Higher TRT doses were associated significantly with grade 3 or higher and grade 4 or higher AEs. On the basis of these findings and our prior report on survival, CRT using IF-TRT and 60 Gy (conventionally fractionated) were associated with more favorable patient survival and less toxicity than was the use of ENI or higher radiotherapy doses.

Background

S1400D is a biomarker-driven therapeutic substudy of Lung-MAP evaluating the fibroblast growth factor (FGF) receptor (FGFR) inhibitor AZD4547 in patients with FGF pathway-activated squamous cell. This is the first phase II trial to evaluate AZD4547 as a targeted approach in patients with previously treated FGFR-altered squamous cell NSCLC and is the first demonstration of successful implementation and conduct of a national umbrella protocol in this disease setting.

Methods

Eligible patients had tumoral FGFR alteration or mutation and had progressive disease after at least one line of platinum-based systemic therapy. Patients received AZD4547 80 mg twice daily orally. Primary endpoint was response by Response Evaluation Criteria in Solid Tumors version 1.1; secondary endpoints included progression-free survival, overall survival, and duration of response (DoR).

Results

Ninety-two patients were assigned to S1400D, 43 were enrolled, and 27 AZD4547-treated patients were evaluable. Evaluable patients were predominantly white (n = 24, 89%), median age 66 years (range, 49-88 years old), and female (n = 7, 26%). FGFR alterations included FGFR1 amplification (n = 23; 85%), FGFR3 amplification (n = 2; 7%), FGFR3 S249C (n = 2; 7%), and FGFR3 fusion (n = 1; 4%). Treatment with ADZ4547 was well tolerated; grade 3 adverse events occurred in six patients, and one patient had grade 4 sepsis. Of 27 response-evaluable patients, 1 patient with FGFR3 S249C had unconfirmed partial response with a DoR of 1.5 months and 1 patient with FGFR1 amplification had a confirmed partial response with a DoR of 2.9 months (7%, 95% confidence interval [CI]: 0%-17%). Median progression-free survival and overall survival for the AZD4547-treated cohort were 2.7 months (95% CI: 1.4- 4.5 months) and 7.5 months (95% CI: 3.7-9.3 months).

Conclusions

AZD4547 had an acceptable safety profile but minimal activity in this predominantly FGFR1/FGFR3-amplified cohort. Evaluation of other targeted agents in Lung-MAP is ongoing.

Background

Patients undergoing surgery for early stage non-small cell lung cancer (NSCLC) may be at high risk for postoperative mortality. Access to stereotactic body radiation therapy (SBRT) may facilitate more appropriate patient selection for surgery.

Research question

Is postoperative mortality associated with early stage NSCLC lower at facilities with higher use of SBRT?

Study design and methods

Patients with early stage NSCLC reported to the National Cancer Database between 2004 and 2015 were included. Use of SBRT was defined by each facility's SBRT experience (in years) and SBRT to surgery volume ratios. Multivariate logistic regression was used to test for the associations between SBRT use and postoperative mortality.

Results

The study cohort consisted of 202,542 patients who underwent surgical resection of cT1-T2N0M0 NSCLC tumors. The 90-day postoperative mortality rate declined during the study period from 4.6% to 2.6% (P < .001), the proportion of facilities that used SBRT increased from 4.6% to 77.5% (P < .001), and the proportion of patients treated with SBRT increased from 0.7% to 15.4% (P < .001). On multivariate analysis, lower 90-day postoperative mortality rates were observed at facilities with > 6 years of SBRT experience (OR, 0.84; 95% CI, 0.76-0.94; P = .003) and SBRT to surgery volume ratios of more than 17% (OR, 0.85; 95% CI, 0.79-0.92; P < .001). Ninety-day mortality also was associated with surgical volume, region, year, age, sex, and race, among other covariates. Interaction testing between these covariates showed negative results.

Interpretation

Patients who underwent resection for early stage NSCLC at facilities with higher SBRT use showed lower rates of postoperative mortality. These findings suggest that the availability and use of SBRT may improve the selection of patients for surgery who are predicted to be at high risk of postoperative mortality.

Background

S1400B is a biomarker-driven Lung-MAP substudy evaluating the phosphatidylinositol 3-kinase (PI3K) inhibitor taselisib (GDC-0032) in patients with PI3K pathway-activated squamous NSCLC (sqNSCLC).

Methods

Eligible patients had tumoral phosphatidylinositol-4,5-biphosphate 3 kinase catalytic subunit alpha (PIK3CA) alterations by next-generation sequencing and disease progression after at least one line of platinum-based therapy. Patients received 4-mg taselisib orally daily. The primary analysis population (PAP) was a subset of patients having substitution mutations believed to be associated with clinical benefit of PI3K inhibitors. Primary endpoint was response by Response Evaluation Criteria in Solid Tumors version 1.1; secondary endpoints included progression-free survival, overall survival and duration of response.

Results

Twenty-six patients treated with taselisib comprised the full evaluable population (FEP); 21 patients comprised the PAP. Median age for patients in the FEP was 68 years (range: 53-83 years), 19 were male (73%). The study was closed for futility at interim analysis with one responder in the PAP (5% response rate, 95% confidence interval [CI]: 0%-24%). Two possibly treatment-related deaths (one respiratory failure, one cardiac arrest) were observed; one patient had grades 4 and 11 had grade 3 adverse events. Median progression-free survival and overall survival in the PAP group were 2.9 months (95% CI: 1.8-4.0 mo) and 5.9 months (95% CI: 4.2-7.8 mo), respectively. These numbers were nearly the same in the FEP.

Conclusions

Study S1400B evaluating taselisib in PIK3CA-altered sqNSCLC failed to meet its primary endpoint and was closed after an interim futility analysis. The trial is unique in cataloguing the diversity of PIK3CA mutations in sqNSCLC.