A target definition based on electroanatomic maps for stereotactic arrhythmia radioablation

PURPOSE

Identifying the target region is critical for successfully treating ventricular tachycardia (VT) with single fraction stereotactic arrhythmia radioablation (STAR). We report the feasibility of target definition based on direct co-registration of electroanatomic maps (EAM) and radioablation planning images.

MATERIALS AND METHODS

The EAM consists of 3D cardiac anatomy representation with electrical activity at endocardium and is acquired by a cardiac electrophysiologist (CEP) during electrophysiology study. The CEP generates an EAM using a 3D cardiac mapping system anticipating radioablation planning. Our in-house software read these non-DICOM EAMs, registered them to a planning image set, and converted them to DICOM structure files. The EAM based target volume was finalized based on a consensus of CEPs, radiation oncologists and medical physicists, then expanded to ITV and PTV. The simulation, planning, and treatment is performed with a standard STAR technique: a single fraction of 25 Gy using volumetric-modulated arc therapy or dynamic conformal arc therapy depending on the target shape.

RESULTS

Seven patients with refractory VT were treated by defining the target based on registering EAMs on the planning images. Dice similarity indices between reference map and reference contours after registration were 0.814 ± 0.053 and 0.575 ± 0.199 for LV and LA/RV, respectively.

CONCLUSIONS

The quality of the transferred EAMs on the MR/CT images was sufficient to localize the treatment region. Five of 7 patients demonstrated a dramatic reduction in VT events after 6 weeks. Longer follow-up is required to determine the true safety and efficacy of this therapy using EAM-based direct registration method.

Dosimetric benefits of dynamic conformal arc therapy-combined with active breath-hold in lung stereotactic body radiotherapy

To test the hypothesis that dynamic conformal arc therapy (DCAT) in Monaco, compared with volumetric modulated arc therapy (VMAT), maintains plan quality with higher delivery efficiency for lung stereotactic body radiotherapy (SBRT) and to investigate dosimetric benefits of DCAT with active breath-hold (DCAT+ABH), compared with free-breathing (DCAT+FB) for varying tumor sizes and motions. Fifty DCAT plans were used for lung SBRT. Randomly selected 17 DCAT plans were evaluated with respect to the retrospectively generated volumetric modulated arc therapy (VMAT) plans. The maximum dose at 2 cm from planning target volume (PTV) in any direction (D2cm/Rx), the ratio of 50% prescription isodose volume to the PTV (R50%), conformity index (CI), the lung volume receiving ≥20 Gy (V20), and monitor unit (MU) were evaluated. A t-test was used to evaluate the difference of plan quality between DCAT and VMAT. Internal target volume (ITV)/integrated-gross target volume (GTV) attributed by intra-fraction motion and lung V20 were stratified for DCAT+ABH and DCAT+FB across varying GTVs. DCAT maintained plan quality (p = 0.154 for D2cm/Rx, p = 0.089 for R50%, p = 0.064 for CI, and p = 0.780 for lung V20) while reducing MUs up to 30% (p <0.001) from 2748 MU (VMAT) to 1868 MU (DCAT). DCAT+ABH, compared to DCAT+FB, reduced tumor motion, resulting in 19% volume reduction of PTV and 60% reduction in lung V20, on average. The difference in lung V20 between DCAT+ABH and DCAT+FB increased as the target size increased. The DCAT is a favorable approach compared with VMAT. These results support the utility of DCAT as a routine planning platform for lung SBRT, especially when utilized with respiratory motion management using the ABH.

COVD-01. ADAPTATION OF A GAMMA KNIFE ICON STEREOTACTIC RADIOSURGERY PROGRAM IN THE FACE OF A GLOBAL PANDEMIC

PURPOSE

The COVID-19 pandemic necessitated drastic and rapid changes throughout the field of radiation oncology, some of which were unique to the discipline of radiosurgery. Available guidelines called for reduced frame use, postponing non-urgent cases, and reducing the number of fractions delivered. Our institution enacted many of these guidelines, and herein we show the resultant effect on patient treatments on our Gamma Knife Icon system.

METHODS & MATERIALS

In early to mid-March of 2020 our institution rapidly implemented suggested changes according to ASTRO and other consensus guidelines as they relate specifically to stereotactic radiosurgery in the COVID-19 era. We reviewed the GK Icon schedule at our institution between January 01 and April 30, 2020. We documented age, condition treated, technique (frame vs. mask), and number of fractions. We then tabulated and graphed the number of patients, framed cases, and fractions across that time period.

RESULTS

Seventy-seven patients were treated on the GK Icon between January and April 2020, for a total of 231 fractions. The number of unique patients per month varied from 18 (April) to 22 (January). Of the 77 patients only 5 were treated using a frame. The number of fractions per month decreased significantly over time, from 70 in January to 36 in April. Likewise, the percentage of single fraction cases increased from 4.5% per month in January to 67% in April.

CONCLUSIONS

The results presented here show that it is possible to quickly and efficiently change work flows to allow for reduced fractionation and frame use in the time of a global pandemic. Multidisciplinary cooperation and ongoing communication are integral to the success of such programs.

Patterns of Care and Outcomes in Verrucous Carcinoma of the Larynx Treated in the Modern Era

Background: Verrucous carcinoma of the larynx (VCL) is a rare form of laryngeal squamous cell carcinoma. We analyzed the National Cancer Database (NCDB) to examine national treatment pattern, identify factors associated with primary radiation therapy (RT), and compare outcomes in patients with Tis-T2 N0 VCL treated primary surgery and primary RT. Methods: We accessed the NCDB from 2004 to 2015 for patients with Tis-T2 N0 VCL and recorded the treatment modality employed. Multivariable logistic regression was used to identify predictors for radiation therapy. Cox regression was used to calculate hazard ratios for survival. A propensity score matched Kaplan-Meier analysis compared primary surgical treatment to definitive radiation. Results: We identified 732 patients with laryngeal verrucous carcinoma from the NCDB. The majority were cTis-T2 (87%) N0 (96%). We identified 286 vs. 110 Tis-T2N0 patients treated primary surgery and with definitive radiation, respectively, for the purpose of this study. Predictors of radiation were treatment at a community center, no insurance, and higher T stage. Cox regression identified increased age, higher comorbidity score, and government insurance as predictive of worse survival. Propensity matching revealed a trend toward worse survival with definitive radiation, with a median survival of 98 months compared to 143 months (p = 0.02). When including only T1-2 lesions, that is, invasive disease, the trend toward increased survival with surgery [98 months vs. 135 months (p = 0.08)] persisted. Conclusion: The results of the present study support the use of surgery in the management of Tis-T2 N0 VCL when organ preservation is possible.

Predictors of chemotherapy and its effects in early stage squamous cell carcinoma of the larynx

BACKGROUND

Squamous cell carcinoma (SCC) of larynx is a common head and neck cancer. For cases that are node negative, the role of definitive concurrent chemoradiation is unclear and not supported by guidelines but used at provider discretion. To address this knowledge gap, we examined the oncological outcomes with additional chemotherapy and factors correlated with the chemotherapy administration.

METHODS

We queried the National Cancer Database for patients with early stage (T2N0M0) laryngeal SCC treated nonsurgically. Multivariable logistic regression identified predictors of chemotherapy. Multivariable Cox regression evaluated predictors of survival. Propensity matching accounted for indication biases.

RESULTS

We identified 7181 patients meeting the eligibility criteria, of which 1568 (22%) patients received chemotherapy in addition to radiation. Predictors of chemotherapy use included younger age, Caucasian race, more remote year of treatment, higher grade, sites other than glottis, treatment at a community cancer center, and use of intensity-modulated radiation therapy. Median overall survival was not significantly different in the two arms analyzed-65 months (95% confidence interval [CI] 60, 72months) with chemotherapy compared to 70 months without chemotherapy (95% CI 66, 75 months, P<.37). Predictors for survival on propensity-matched multivariable analysis were increased age, male sex, less education, lower income, higher comorbidity score, receipt of treatment at a community center, and nonglottic sites.

CONCLUSIONS

This study shows no clear survival benefit with chemotherapy in early stage disease. Although this implies that chemotherapy should not be routinely delivered, individualized judgment and prospective studies are recommended as the biology behind this interesting finding is undefined.

LEVEL OF EVIDENCE

2C (Outcomes Research).

Trends in management of locally advanced large cell neuroendocrine carcinoma of the lung

e21073

Background: Large cell neuroendocrine carcinoma (LCNEC) is a rare pulmonary malignancy with clinicopathologic features of both non-small cell lung cancer (NSCLC) and small-cell lung cancer (SCLC). The optimal treatment approach for LCNEC is not well established, likely a result of the histology’s underrepresentation in randomized clinical trials. Given the paucity of available data regarding LCNEC management, we queried the National Cancer Database (NCDB) to describe trends in management, identify predictors of treatment receipt, and compare outcomes in patients receiving chemotherapy (ChT) and chemoradiotherapy (CRT). Methods: We identified patients with locally advanced (Stage III) LCNEC of the lung treated with definitive ChT or CRT between the years of 2004-2015. Odds ratios were calculated to determine predictors of CRT receipt. Multivariable cox regression was used to determine predictors of overall survival. Results: Using the above criteria, 6,802 patients were identified, 46% of whom received CRT (n = 3,153) while 39% (n = 2,644) received ChT alone. Median age of the entire cohort was 68 years old. Most patients had T4 (35%) and N2 (59%) disease. Median overall survival was 11.9 months (11.3-12.6) in patients receiving ChT compared to 16.1 months (15.4-16.9) in patients receiving CRT (p < 0.0001). Overall survival at 1, 3, and 5 years was 50%, 20%, and 13% versus 60%, 27%, and 18%, in patients receiving ChT and CRT, respectively. Older patients and those with higher comorbidity scores were less likely to receive CRT; whereas patients with higher education level, treatment receipt at an academic/research program facility, N2 disease, and later treatment year were more likely to receive CRT. On multivariable analysis, older age, greater comorbidity score, presence of N2 disease, and presence of T4 disease were all associated with decreased OS, whereby female sex, private insurance, higher income, lower T stage, and more recent treatment were associated with increased overall survival. CRT receipt was an independent predictor of increased overall survival. Conclusions: Definitive CRT was an independent predictor of increased overall survival in patients with locally advanced LCNEC of the lung. Findings from our study may help guide potential areas of future investigation to help define an ideal treatment approach for LCNEC.

Stereotactic ablative body radiotherapy versus conventionally fractionated radiotherapy for early stage large cell neuroendocrine carcinoma of the lung

Aim

Some patients with early stage large cell neuroendocrine carcinoma (LCNEC) of the lung are not surgical candidates and will be managed with radiotherapy. We used the national cancer database to identify predictors of stereotactic radiotherapy and compare outcomes.

Materials & methods

We queried national cancer database for T1-2N0 LCNEC treated with radiation. Logistic regression and Cox regression identified predictors of stereotactic ablative body radiotherapy (SABR) and survival, respectively.

Results

We identified 754 patients, with 238 (32%) treated with SABR. Predictors of SABR were distance to facility, no chemotherapy, academic center, T1 and recent year. After propensity matching, median survival was 34.7 months compared with 23.7 months in favor of SABR (p = 0.02).

Conclusion

SABR for LCNEC has increased over time and was associated with improved survival.

Intensity-modulated radiation therapy in early stage squamous cell carcinoma of the larynx: treatment trends and outcomes

Purpose

Definitive radiotherapy remains a primary treatment option for early stage glottic cancer. Intensity-modulated radiation therapy (IMRT) has emerged as the standard treatment technique for advanced head and neck cancers, whereas three-dimensional conformal radiotherapy (3D-CRT) has remained standard for early glottic cancers. We used the National Cancer Database (NCDB) to identify predictors of IMRT use and effect on outcome in these patients.

Materials and Methods

We queried the NCDB from 2004–2015 for squamous cell carcinoma of the glottic larynx staged Tis-T2N0 treated with radiation alone. Logistic regression was used to identify predictors of IMRT. Cox regression was used to identify factors predictive of overall survival. Propensity matching was conducted to account for indication bias.

Results

We identified 15,627 patients, of which 11% received IMRT. IMRT use rose from 2% in 2004 to 16% in 2015. Predictors of IMRT include: increased comorbidity, T2 stage, urban location, chemotherapy, treatment at an academic center, and later treatment year. Predictors of improved survival were female gender, higher income, lower stage, no chemotherapy, academic facility, and more remote year. There was no difference in survival between 3D-CRT and IMRT across all stages.

Conclusions

The rate of IMRT use for early stage glottic laryngeal cancer has increased over time. There was no difference in outcome in patients receiving IMRT versus 3D-CRT across the cohort.

Adaptation of a Gamma Knife Icon stereotactic radiosurgery program in the face of the COVID-19 pandemic

Objective: The COVID-19 pandemic necessitated drastic and rapid changes throughout the field of radiation oncology, some of which were unique to the discipline of radiosurgery. Guidelines called for reduced frame use and reducing the number of fractions. Our institution implemented these guidelines, and herein we show the resultant effect on patient treatments on our Gamma Knife Icon program. Methods: In early March 2020 we rapidly implemented suggested changes according to ASTRO and other consensus guidelines as they relate to stereotactic radiosurgery in the COVID-19 era. We reviewed the GK Icon schedule at our institution between January 01 and April 30, 2020. We documented age, condition treated, technique (frame vs. mask), and number of fractions. We then tabulated and graphed the number of patients, framed cases, and fractions delivered. Results: Seventy-seven patients were treated on the GK Icon over that period, for a total of 231 fractions. The number of unique patients varied from 18 (April) to 22 (January). Of the 77 patients only 5 were treated using a frame. The number of fractions per month decreased significantly over time, from 70 in January to 36 in April. Likewise, the percentage of single fraction cases increased from 4.5% per month in January to 67% in April. Conclusions: The results presented here show that it is possible to quickly and efficiently change work flows to allow for reduced fractionation and frame use in the time of a global pandemic. Multidisciplinary cooperation and ongoing communication are integral to the success of such programs.

Surgical resection versus stereotactic body radiation therapy in early stage bronchopulmonary large cell neuroendocrine carcinoma

Background

Surgery is the standard of care for early stage non‐small cell lung cancer (NSCLC). Stereotactic body radiotherapy (SBRT) is another definitive treatment option for those patients who have not been treated surgically. Comparison of approaches is being explored in NSCLC, but has yet to be compared exclusively in large cell neuroendocrine carcinoma (LCNEC) of the lung. We used the National Cancer Database (NCDB) to conduct such a comparison.

Methods

We accessed the NCDB for patients with LCNEC who were recorded as having lung stage T1‐2N0M0 treated with lobectomy/pneumonectomy or SBRT. Multivariable logistic regression identified predictors of SBRT. Multivariable Cox regression was used to identify predictors of survival propensity matching and account for indication bias.

Results

A total of 3209 patients met the criteria, of which 238 (7%) received SBRT. The median SBRT dose was 50 Gy (48–60) in four fractions (3–5). Predictors of SBRT were age >68, T1 disease, and most recent year of treatment. Predictors of survival were younger age, surgical treatment, female sex, and T1 disease. After propensity matching, median survival was 57 months versus 35 months in favor of surgical resection, P < 0.0001.

Conclusion

Surgical resection in comparison to SBRT has improved survival for patients with early stage LCNEC of the lung. SBRT represents a viable treatment alternative for those patients who do not meet the criteria for surgery.

Drivers of 30- and 90-day Postoperative Death After Neoadjuvant Chemoradiation for Esophageal Cancer

BACKGROUND

Neoadjuvant chemoradiation, followed by esophagectomy, is a standard of care for locally advanced esophageal cancers. The ChemoRadiOtherapy plus Surgery versus Surgery alone (CROSS) trial reported a 30-day mortality rate of 6%. We sought to evaluate 30- and 90-day mortality in similar patients in the United States and identify predictors of higher mortality rates.

METHODS

The National Cancer Database was used to identify patients with cT3-4/N+ esophageal cancers treated with neoadjuvant chemoradiation followed by esophagectomy. Bivariate univariable and multivariable regression analysis was used to identify predictors of 30- and 90-day mortality.

RESULTS

We identified 7691 patients. Readmission within 30 days of surgery occurred in 6.0% of patients. Mortality was 2.9% at 30 days and 7.2% at 90 days. Positive surgical margins conferred a more than doubled risk of 30- and 90-day mortality, 5.5% vs 2.7% and 14.6% vs 6.8% (both P < .001). Facility surgical volume impacted 30-day mortality, whereas readmission was associated with 90-day mortality, both exceeding 10% (P = .004 and P = .001, respectively). In patients undergoing minimally invasive surgery converted to open, 90-day mortality was 12.1% (P < .01). For patients 69 years and older, 90-day mortality was also 12.1% (P < .001). Patients who underwent esophagectomy more than 45 days from completion of chemoradiation also had higher 90-day mortality at 8.3% vs 6.2% (P < .001).

CONCLUSIONS

Postoperative death at 30 and 90 days after neoadjuvant chemoradiation and esophagectomy appears to be on par with randomized data. Positive surgical margins, squamous cell carcinomas, age 69 and older, readmission within 30 days, and conversion from a minimally invasive operation to an open operation all carry a 90-day mortality risk exceeding 10%.

Stereotactic body radiation therapy versus fractionated radiation therapy for early-stage bronchopulmonary carcinoid

Aim

To compare trends and outcomes in early stage bronchopulmonary carcinoid (BPC) tumors treated nonoperatively with conventionally fractionated radiotherapy (CFRT) and stereotactic body radiotherapy (SBRT).

Methods/materials

We queried the National Cancer Database for primary (typical) BPC staged cT1-2N0M0 and treated nonsurgically with lung-directed radiation and ≥1 month of follow-up. Odds ratios were used to predict likelihood of SBRT treatment and multivariable Cox regression determined predictors of survival.

Results

Out of 154 patients, 84 (55%) were treated with SBRT and the remainder were treated with CFRT. Although SBRT use was 0% from 2004 to 2007, it varied from 50 to 70% per year thereafter. Propensity-matched Kaplan-Meier analysis revealed improved survival with lung SBRT (median: 66 vs 58 months; p = 0.034).

Conclusion

SBRT for early stage, primary BPC has increased over time and was associated with higher survival than CFRT.

Practice patterns and outcomes following radiation dose de-escalation for oropharyngeal cancer

OBJECTIVES/HYPOTHESIS

Numerous trials are evaluating radiotherapy (RT) de-escalation for human papillomavirus (HPV)-mediated (HPV+) oropharyngeal squamous cell carcinoma (OPSCC). Herein, we evaluated the degree to which de-escalated RT is delivered in the United States, as well as comparative outcomes with full-dose RT as stratified for HPV status.

STUDY DESIGN

Retrospective database review.

METHODS

We identified patients diagnosed with OPSCC in the National Cancer Database, excluding those with stage I/II disease, unknown HPV status, receiving surgery or not receiving external beam radiation therapy to the primary site, receipt of radiation doses >75 or <54 Gy, radiation treatment course duration <25 or >75 days, and unknown or inadequate (<2 months) follow-up. Multivariable logistic regression analysis identified variables associated with delivery of de-escalated RT (<66 Gy). Overall survival of HPV+ and non-HPV-mediated (HPV-) disease was compared between full-dose and de-escalated approaches.

RESULTS

Altogether, 617 and 551 patients were HPV+ and HPV-, respectively. De-escalated RT was delivered in 16.9% HPV+ and 15.2% of HPV- disease, respectively. Older patients and omission of systemic therapy were more likely to receive de-escalated RT. In HPV+ patients, 3- and 5-year survival rates were 83% and 80% in the de-escalated cohort versus 83% and 78% in the full-dose group (P = .83). In HPV- patients, corresponding 3- and 5-year survival rates were 29% and 23% versus 61% and 51% (P = .001).

CONCLUSIONS

National utilization of de-escalated RT for OPSCC is low (15%-20%), but does not seem to impact overall survival in HPV+ (but not HPV-) patients. The caveats of this heterogeneous, retrospective analysis require corroboration from a number of ongoing randomized trials.

LEVEL OF EVIDENCE

2c Laryngoscope, 130:E171-E176, 2020.

Trends in immunotherapy use and survival impact in stage IV non-small cell lung cancer

e20715

Background: Lung cancer is the leading cause of cancer-related mortality in the United States and worldwide. 5-year survival rate for metastatic non-small cell lung cancer (NSCLC) is estimated at 4%. For patients who lack a driver mutation, platinum based chemotherapy had been the cornerstone treatment, but the addition of immunotherapy has altered the treatment landscape for many advanced NSCLC patients. Immunotherapy, with or without chemotherapy, has been demonstrated in many clinical trials to extend survival in both the first-line setting as well as subsequent lines of therapy. While the clinical trial data over the past several years has been robust, less is known about how these agents have fared in routine clinical practice. To understand this better, we utilized the National Cancer Data Base (NCDB) to examine the survival of patients who received immunotherapy for stage IV NSCLC. Methods: We queried the NCDB from 2004-2015 for patients with stage IV NSCLC treated with chemotherapy and at least 3 months of follow-up. Multivariable logistic regression was used to determine predictors of immunotherapy use. Multivariable cox regression was used to determine predictors of overall survival. A propensity score was calculated and used to mitigate indication bias. Results: Of 203,069 eligible patients, 5,877 received immunotherapy. The median age was 65 years (40-90). The median follow up was 10.6 months (3-154). Patients were more likely to receive immunotherapy if they were younger, had a lower comorbidity score, received treatment at an academic facility, had adenocarcinoma histology, private insurance, Caucasian race, and a more recent treatment year. The use of immunotherapy rose steadily across the dataset years, rising from 1% to 12%. Predictors of survival were younger age, lower comorbidity score, lower grade tumor, treatment at an academic facility, higher education, higher income, private insurance, metropolitan location, immunotherapy use, adenocarcinoma histology, and more recent year of treatment. On propensity-matched Kaplan-Meier analysis patients treated with immunotherapy in addition to chemotherapy had improved survival, 13.7 months compared to 11.8 months, p < 0.0001. Conclusions: This analysis demonstrates improved overall survival in stage IV NSCLC patients who received immunotherapy. There are inherent limitations of retrospective analyses of data from large databases, however the survival improvement noted in this study is concordant with the more robust prospective clinical research published to date.

Practice patterns and outcomes following radiation dose de-escalation for oropharyngeal cancer: A National Cancer Database analysis

e17508

Background: Numerous trials are evaluating radiotherapy (RT) de-escalation for HPV-mediated (HPV+) oropharyngeal squamous cell carcinoma (OPSCC). Herein, we evaluated the degree to which de-escalated RT is delivered in the United States, as well as, comparative outcomes with full-dose RT, as stratified for HPV status. Methods: We identified patients diagnosed with OPSCC in the National Cancer Database, excluding those with stage I/II disease, unknown HPV status, receiving surgery or not receiving EBRT to the primary site, receipt of radiation doses > 75 or < 54 Gy, radiation treatment course duration < 25 or > 75 days, and unknown or inadequate ( < 2 months) follow-up. Multivariable logistic regression analysis identified variables associated with delivery of de-escalated RT ( < 66 Gy). Overall survival of HPV+ and HPV- disease was compared between full-dose and de-escalated approaches. Results: Altogether, 617 and 551 patients were HPV+ and HPV-, respectively. De-escalated RT was delivered in 16.9% HPV+ and 15.2% of HPV- disease, respectively. Older patients and those not receiving systemic therapy were more likely to receive de-escalated RT. In HPV+ patients, 3- and 5-year survival rates were 83% and 80% in the de-escalated cohort versus 83% and 78% in the full-dose group (p = 0.83). In HPV- patients, corresponding 3- and 5-year survival rates were 29% and 23% versus 61% and 51% (p = 0.001). Conclusions: National utilization of de-escalated RT for OPSCC is low (15-20%), but does not seem to impact overall survival in HPV+ (but not HPV-) patients. The caveats of this heterogeneous, retrospective analysis require corroboration from a number of ongoing randomized trials.

Time from stereotactic body radiotherapy to immunotherapy as a predictor for outcome in metastatic non small cell lung cancer

9024

Background: Immunotherapy has changed the face of treatment for stage IV non small cell lung cancer (NSCLC), quickly becoming the standard of care. The appropriate timing of immunotherapy in the setting of other ablative therapies, namely stereotactic radiosurgery (SRS) and stereotactic body radiotherapy (SBRT), remains to be determined. We sought to use the National Cancer Database to examine trends in immunotherapy use as well as timing as it relates to SBRT/SRS in stage IV NSCLC patients. Methods: We queried the NCDB for patients with Stage IV NSCLC diagnosed between 2004-2015 that were treated with SRS or SBRT techniques (to any site) and had at least three months of follow up. Multivariable logistic regression was used to identify predictors of immunotherapy use. Receiver operator curve analysis was used to identify the optimal timepoint between SBRT and immunotherapy correlating with overall survival. Kaplan-meier curves were generated to determine overall survival. Multivariable cox regression was used to determine factors predictive of survival. A propensity score was generated and incorporated into Kaplan-meier and cox regressions to account for indication bias. Results: We identified 13,862 patients meeting the above eligibility criteria, 371 being treated with immunotherapy. The vast majority (75%) had chemotherapy as well. Patients with adenocarcinoma, treatment with chemotherapy, and more recent year of treatment were more likely to receive immunotherapy. Univariable Kaplan-meier analysis showed improved median survival with immunotherapy, 17 months vs. 13 months, p < 0.0001. On multivariable propensity-adjusted cox regression significant predictors for improved overall survival were younger age, lower comorbidity score, lower grade, private insurance, and female gender. Using a cutoff of 21 days after start of SBRT, patients treated thereafter were more likely to survive longer, median survival of 19 months vs 15 months, p = 0.0335. Conclusions: Immunotherapy use in Stage IV NSCLC after SBRT has increased over time, mostly in patients with adenocarcinoma and in the setting of chemotherapy. In this analysis, outcomes were improved when immunotherapy was given at least three weeks after start of SBRT.

Update: Implementation of a multidisciplinary quality improvement initiative to improve molecular testing rates in advanced non-squamous non-small cell lung cancer

e18085

Background: EGFR mutations and ALK rearrangements are key targets in nonsquamous nonsmall cell lung carcinoma (nsNSCLC). Treatment with targeted therapy has been shown to improve progression-free survival and overall survival in many lung cancer patients. Current guidelines recommend evaluating all advanced nsNSCLC patients for these targets; however, previous work within our institution revealed that we were not testing a large segment of eligible patients. In order to improve testing rates, we utilized multidisciplinary meetings aimed at direct physician education and process/work-flow enhancement in order to improve our testing rates. We found a significant improvement in testing rates following this intervention, however, whether or not this improved rates were durable/sustainable was unclear. To determine whether this improvements were sustained we analyzed an additional two years of data from our registry. Methods: Utilizing the Association of Community Cancer Centers (ACCC) molecular testing framework, we launched a lean six sigma initiative aimed at improving our molecular profiling rates in 2014. A series of multidisciplinary meetings were conducted addressing key action items as outlined by the ACCC. Since this intervention, a total of 419 advanced nsNSCLC patients were identified from our tumor registry (2014-2017). Testing rates for EGFR and ALK were determined by individual chart review and compared to our previously published testing rates (2011-2013). Results: We found 81.1% (340/419) and 69.0% (289/419) of patients were tested for EGFR mutations and ALK rearrangements, respectively. We utilized a chi-square test of homogeneity to determine whether there was an increased EGFR and ALK testing rate post-intervention. Our EGFR testing rate increased 87.7%, from 43.2% (2011-2013) to 81.1% (2014-2017), p < 0.00001, and our ALK testing rate increased 189.9%, from 23.8% (2011-2013) to 69.0% (2014-2017), p < 0.00001. Further, the rates testing were comparable or even improved year-over-year post intervention indicating a sustained improvement following the quality improvement initiative. Conclusions: Multidisciplinary educational and process enhancement meetings help to improve molecular testing rates in nsNSCLC. In addition, the updated analysis suggests these improvements were durable year-over-year.

Tumor localization accuracy for high-precision radiotherapy during active breath-hold

BACKGROUND

Conventionally fractionated and stereotactic body radiation therapy (SBRT) for thoracoabdominal tumors may utilize breath-hold techniques. However, there are concerns that differential amounts of inspired airflow may result in unplanned tumor dislocation and underdosing. Thus, we investigated tumor localization accuracy associated with lung volume variations during breath-hold treatment via an automated-gating interface.

METHODS

Twelve patients received breath-hold treatment with the active breathing coordinator (ABC) through an automated-gating interface. All breath-hold volumes were recorded at CT simulation, setup imaging, and during treatment, and analyzed as a function of airflow rate into the ABC. The variation of breath-hold volumes was calculated for each fraction over entire course. Intrafraction target motion related to the breathing variation was investigated based on daily imaging acquired before the breath-hold treatment. Correlation between target location and breath-hold variation was statistically analyzed.

RESULTS

The air volume held by the ABC increased as the airflow rate increased on inhalation and decreased on exhalation. The mean range of airflow rate was 0.77 L/s and 0.29 L/s in the conventionally fractionated and SBRT patients, respectively. The maximum air volume difference with respect to the reference volume at the CT simulation was 1.0 L for conventional fractionation and 0.16 L for SBRT. The target dislocation caused by 0.25 L of air volume difference was 6 mm for SBRT. Three patients showed significant correlation between the target location and breath-hold variations.

CONCLUSIONS

This investigation shows that because variations in the breath-hold volume may cause target dislocation, patient-specific breath-hold setting is required to improve tumor localization accuracy.

Stereotactic Body Radiotherapy (SBRT) for Oligometastatic Lung Nodules: A Single Institution Series

Aim: Lung metastases from an extra-pulmonary origin occasionally present with a limited metastatic disease burden. In cases where metastatectomy is not feasible, stereotactic body radiation therapy (SBRT) represents a non-invasive, efficacious option. We report the outcomes of patients treated with lung SBRT in cases of limited metastatic disease.

Methods: We retrospectively reviewed outcomes in 44 patients with 50 lung nodules from various extra-pulmonary malignancies treated with SBRT. Fifty percent of the patients were male and median age was 64. The median number of nodules was 1 and 90% of patients had oligometastatic disease. Thirty-four percent of patients had extra-thoracic disease.

Results: Fifty lung nodules were treated with SBRT in 44 patients. Median dose was 48 Gy in 5 fractions with a median biological effective dose (BED) of 100 Gy₁₀. Follow-up imaging was available for review in 96% of nodules. Median follow-up was 17.5 months. One year local control was 82%. BED >72 Gy₁₀ predicted improved local control (90 vs. 57% at 1 year). One year overall survival following SBRT was 66%. There was no difference in overall survival if patients had extra-thoracic disease.

Conclusion: Lung SBRT is a safe, effective tool for treatment of limited lung metastases. Dose selection remains important for local control.

Grover’s Disease Treated With Total Skin Electron Beam Radiotherapy

Persistent Grover's disease can cause significant symptoms of pruritus thereby decreasing quality of life. Many patients undergo successful conservative management of their disease; however, a subset of patients is recalcitrant despite multiple lines of therapy. Accordingly, we present, to our knowledge, the first reported case of recalcitrant Grover's disease treated successfully with radiotherapy. J Drugs Dermatol. 2019;18(4):392-393.

Management of brain metastases from large cell neuroendocrine carcinoma of the lung: improved outcomes with radiosurgery

OBJECTIVES

Large cell neuroendocrine carcinoma (LCNEC) of the lung is a rare pulmonary tumor, having similar natural history and management strategy as small cell lung cancer. Therefore, the management of brain metastases in these patients has mirrored that of SCLC through the use of whole brain radiation therapy (WBRT). We used the National Cancer Database (NCDB) to look at predictors of stereotactic radiosurgery (SRS) and any potential differences in outcomes for patients with brain metastases from LCNEC.

MATERIAL AND METHODS

We queried the NCDB from 2004 to 2015 for patients with LCNEC of the lung with brain metastases that received brain radiation. Univariable and multivariable analyses were performed to identify factors predictive of SRS use and overall survival (OS). Propensity-adjusted Cox proportional hazard ratios for survival were used to account for indication bias.

RESULTS

Out of 9970 patients with LCNEC of the lung we identified 348 with brain metastases. Sixty-eight patients were treated with upfront SRS and 280 were treated with WBRT. Patients that were treated at an academic facility or received chemotherapy as part of upfront treatment were more likely to receive SRS. Univariable analysis revealed improved outcomes with SRS compared to WBRT, with a median OS of 11 months compared to 6 months, respectively (p = .007). Multivariable Cox regression with propensity score confirmed SRS to have improved survival (HR: 0.68, 95%CI: 0.51-0.91, p = .0093). Multivariable Cox regression with propensity score also identified younger age, receipt of chemotherapy, absence of extracranial disease and non-rural locations as additional predictors of improved OS.

CONCLUSIONS

Treatment of brain metastases from LCNEC of the lung with SRS was associated with improved survival. For the appropriate patients, upfront treatment of limited brain metastases with SRS may be appropriate.

Lung stereotactic body radiotherapy after past ablative therapy: a single institution case series

Aim

Non-small-cell lung cancer recurs locally 10-40% of the time after local therapy, presenting a therapeutic challenge given poor pulmonary reserve. Herein, we seek to evaluate the safety and efficacy of stereotactic body radiotherapy (SBRT) for retreatment of such patients.

Methods

We identified and reviewed clinical outcomes in ten patients with recurrent non-small-cell lung cancer after past vicryl mesh brachytherapy.

Results

Ten patients with a median age of 77 were treated to a median dose of 48 Gy in five fractions. Local control at 1 year was 88%. There was one distant failure at 29 months. There was no significant toxicity after SBRT.

Conclusion

SBRT is safe and effective when used for re-irradiation after past ablative therapies.

Stereotactic body radiation therapy in early-stage NSCLC: historical review, contemporary evidence and future implications

Clinical use of stereotactic body radiation therapy (SBRT) has increased dramatically over the last 2 decades and is the current standard-of-care in cases of inoperable early stage non-small-cell lung cancer. While surgical resection remains the standard-of-care for operable patients, several ongoing clinical trials are investigating the role of SBRT in these operative candidates as well. Taking into consideration the expanding role and utility of SBRT, this paper will: review the historical basis of SBRT; examine landmark trials establishing the framework for the current body of evidence; discuss areas of active and future research; and identify epidemiological trends that are likely to further increase the use of SBRT.

Stereotactic ablative radiation therapy versus conventionally fractionated radiation therapy for stage I small cell lung cancer

BACKGROUND

The National Comprehensive Cancer Network (NCCN) recently revised recommendations for inoperable stage I small cell lung cancer (SCLC), having added stereotactic ablative radiotherapy (SABR)/chemotherapy to the historical paradigm of concurrent conventionally-fractionated radiation therapy (CFRT)/chemotherapy. Despite the conformality, convenience, and cost-effectiveness of SABR, the NCCN continues to recommend both CFRT/chemotherapy and SABR/chemotherapy primarily because these approaches have not been comparatively analyzed to date.

METHODS

The National Cancer Database was queried for histologically-confirmed T1-2N0M0 SCLC; all patients received chemotherapy. Multivariable logistic regression ascertained factors associated with SABR/chemotherapy. Kaplan-Meier analysis assessed overall survival (OS); multivariable Cox proportional hazards modeling examined factors associated with OS. Survival was also calculated following propensity matching.

RESULTS

Of 2,107 patients, 7.1% underwent SABR/chemotherapy, and 92.9% received CFRT/chemotherapy. The median (interquartile range) dose of SABR was 50 (48-54) Gy in 4 (3-5) fractions, and 55.8 (45-60) Gy in 30 (30-33) fractions for CFRT. Patients receiving SABR/chemotherapy were more often older, had T1 disease, treated at academic/integrated network facilities, and managed in more recent years (p < 0.05 for all). Respective median survival figures were 29.2 versus 31.2 months (p = 0.77), which persisted following propensity matching (25.4 versus 34.3 months, p = 0.85). On multivariable analysis, radiotherapeutic technique was not associated with OS (p = 0.95).

CONCLUSIONS

For stage I SCLC, SABR/chemotherapy affords statistically equivalent outcomes to CFRT/chemotherapy. Because randomized studies addressing this uncommon scenario would almost certainly suffer from inadequate accrual, these retrospective data should be strongly considered in efforts to institute SABR/chemotherapy as the preferred option for this population.

Stereotactic ablative radiotherapy (SABR) in early stage non-small cell lung cancer: Comparing survival outcomes in adenocarcinoma and squamous cell carcinoma

PURPOSE

Recent retrospective studies have demonstrated mixed results regarding the histologic association of squamous cell carcinoma (SCC) with reduced overall survival in patients with early-stage non-small cell lung cancer (ES-NSCLC) treated with stereotactic ablative radiotherapy (SABR).

METHODS

We queried the National Cancer Database (NCDB) for ES-NSCLC (T1-2N0, Stage I-IIA) patients with SCC or adenocarcinoma (ADC) treated with SABR. Univariable and multivariable analyses identified characteristics predictive of overall survival. Cox proportional hazard ratios with propensity adjustment were used to mitigate indication bias between the two histologic arms.

RESULTS

Ultimately 15,110 ES-NSCLC patients with either ADC (n = 8,924) or SCC (n = 6,186) were eligible for analysis. Univariable analysis demonstrated a median overall survival of 44 months and 33 months (p < 0.0001) and 5-year overall survival of 36% and 24% (p < 0.0001) in patients diagnosed with ADC and SCC, respectively. SCC histology, remained an independent predictor of worse survival on propensity score matched multivariable comparison (p < 0.0001). Patients with SCC were more likely to have T2 lesions and poorly differentiated grade. Females, African American race, T1 lesions, and age <75 years were also associated with improved survival. Conclusion SCC histology was an independent prognosticator of worse survival in patients with ES-NSCLC treated with SABR, thus corroborating the results of previous studies. Randomized, prospective studies are needed to further validate these findings.

Stereotactic body radiotherapy for central lung tumors: Finding the balance between safety and efficacy in the "no fly" zone

BACKGROUND

Stereotactic body radiotherapy (SBRT) has emerged as a highly effective technique to treat medically inoperable non-small cell lung cancer (NSCLC). Doses must be chosen carefully when treating central lesions because of the potential for significant toxicity. This study reviews the outcomes of a cohort of patients with central lung tumors treated with SBRT.

METHODS

We identified 18 patients (12 women, 6 men) with central lesions that were treated with SBRT at our institution. Overall survival and local, regional, and distant control rates were assessed by Kaplan-Meier methodology. Correlations with outcomes were determined by multivariate analysis via Cox regression models.

RESULTS

Eighty-nine percent of patients had a pathological diagnosis of NSCLC. The median dose to the planning target volume was 40 Gy (range: 30-50) in five fractions, yielding a median biologic equivalent dose (BED₁₀ ) of 72 (range: 48-100). The median planning target volume was 34 cc (range: 13.3-89). Local control was 87% at one year. Median overall survival was 45 months, with a two-year rate of 61%. The two-year regional control rate was 87%. BED₁₀ > 72 predicted improved progression-free survival, with one-year rates of 100% versus 40% with increased BED (P = 0.012). No grade 3 or higher acute or late toxicity was observed.

CONCLUSIONS

Lung SBRT to central lesions is safe and effective when using five fraction regimens. BED₁₀ < 72 predicted disease progression, highlighting the importance of choosing an effective dose fractionation scheme, which must in turn be balanced with potential toxicity.

Stereotactic body radiotherapy for lung metastases from colorectal cancer: a single institution experience

Aim: Stereotactic body radiotherapy (SBRT) has been used as an alternative to surgical intervention to treat primary malignanices of the lung as well as lesions from other primaries. In this study, we evaluate the safety and efficacy of SBRT in treating lung metastases from colorectal cancer (CRC). Materials & methods: We reviewed 22 patients that underwent lung SBRT for metastases from CRC. Almost all patients received chemotherapy before and after undergoing SBRT. Outcomes that were analyzed included overall survival, distant failure and progression-free survival, as well as the effects of biologically effective dose (BED) and KRAS status on local control. Results: Seven females and 15 males underwent SBRT to lung metastases from CRC. The median Eastern Cooperative Oncology Group status was one (0–2). The median dose was 48 Gy (40–54 Gy) in 5 fx (4–8 fx) and the median number of nodules treated with SBRT was one (1–3). Median follow-up was 28.5 months from SBRT and 79 months (9–145) from primary diagnosis. Local control at 1 and 3 years was 75 and 58%, respectively. There was a trend toward improved local control with increasing biologically effective dose (BED10 > 100; p = 0.07). Cancers that were positive for the KRAS mutation had increased local control at 12 months, 100 versus 75% (p = 0.0199). Median OS from the primary diagnosis of CRC and from SBRT was 79 and 31 months, respectively. There were no predictors for OS. There were no episodes of acute or late grade 3 or higher toxicity. Conclusion: The results of this study add to the growing body of literature to support SBRT for lung metastases, specifically those patients with limited lung metastases from CRC. The choice of radiation dose remains important, even in metastatic disease, as highlighted by the trend toward improved local control with increasing BED10.

Image-based management of empiric lung stereotactic body radiotherapy (SBRT) without biopsy: Predictors from a 10-year single institution experience

Background

There is emerging reliance on clinical imaging for the diagnosis, prognosis, and treatment evaluation of early stage non‐small cell lung cancer (NSCLC) in patients deemed too high risk for biopsy. We report our experience of clinically diagnosed NSCLC treated empirically with stereotactic body radiotherapy (SBRT) to validate the imaging parameters used for management in this high‐risk population.

Methods

We reviewed 101 empiric lung SBRT cases and profiled imaging specifics of computed tomography and positron emission tomography for diagnosis and follow‐up. Secondarily, we identified potential correlates of disease progression with Cox regression multivariate analysis.

Results

Fifty‐seven men and 43 women aged 45–94 (median 76) were treated with a median dose of 48 Gy in four fractions. The median nodule diameter was 1.6 cm (0.6–4.5 cm) and most were spiculated (n = 58), right‐sided (n = 63), and in the upper lobe (n = 68). Median follow‐up and survival rates were 14 and 28 months, respectively. Local control at three years was 94%. Freedom from any progression at one and three years was 85% and 69%, respectively. Toxicity ≥ grade 3 included two grade 3 dyspneas. A pre‐treatment standard uptake value > 4.1 was the only significant predictor of disease progression.

Conclusion

This study illustrates the instrumental role of modern clinical imaging for the effective management of presumed early stage NSCLC treated with empiric lung SBRT. As lung SBRT without tissue confirmation becomes more common, hopefully these assertions can be prospectively validated.

SBRT for early stage lung cancer: outcomes from biopsy-proven and empirically treated lesions

Aim:

Herein, we compare outcomes in patients treated with lung stereotactic body radiotherapy (SBRT) with and without tissue confirmation.

Methods:

We reviewed 196 patients that underwent lung SBRT for presumed (100 patients) or proven non-small-cell lung cancer (96 patients) over a 10-year period and compared outcomes.

Results:

A total of 196 patients with a median age of 76 underwent lung SBRT to a median dose of 48 Gy in four fractions. Median follow up was 17 months. Local control and overall survival at 3 years was 94 and 58% for the entire group. There was no difference in overall survival, local control, regional control or distant control between the cohorts.

Conclusion:

SBRT is a safe and effective treatment for patients with non-small-cell lung cancer that are medically inoperable with comparable results in empirically treated patients.

Megavoltage conebeam CT cine as final verification of treatment plan in lung stereotactic body radiotherapy

INTRODUCTION

To analyse the clinical impact of megavoltage conebeam computed tomography (MV-CBCT) cine on internal target volume (ITV) coverage in lung stereotactic body radiotherapy (SBRT).

METHODS

One hundred and six patients received lung SBRT. All underwent 4D computed tomography simulation followed by treatment via image guided 3D conformal or intensity modulated radiation. Prior to SBRT, all patients underwent MV-CBCT cine, in which raw projections are displayed as beam's-eye-view fluoroscopic series with the planning target volume (PTV) projected onto each image, enabling verification of tumour motion relative to the PTV and assessment of adequacy of treatment margin.

RESULTS

Megavoltage conebeam computed tomography cine was completed 1-2 days prior to SBRT. Four patients (3.8%) had insufficient ITV coverage inferiorly at cine review. All four plans were changed by adding 5 mm on the PTV margin inferiorly. The mean change in PTV volumes was 3.9 cubic centimetres (cc) (range 1.85-6.32 cc). Repeat cine was performed after plan modification to ensure adequate PTV coverage in the modified plans.

CONCLUSIONS

PTV margin was adequate in the majority of patients with this technique. MV-CBCT cine did show insufficient coverage in a small subset of patients. Insufficient PTV margins may be a function of 4D CT simulation inadequacies or deficiencies in visualizing the ITV inferior border in the full-inhale phase. MV-CBCT cine is a valuable tool for final verification of PTV margins.

Dosimetric comparison of IMRT rectal and anal canal plans generated using an anterior dose avoidance structure

To describe a dosimetric method using an anterior dose avoidance structure (ADAS) during the treatment planning process for intensity-modulated radiation therapy (IMRT) for patients with anal canal and rectal carcinomas. A total of 20 patients were planned on the Elekta/CMS XiO treatment planning system, version 4.5.1 (Maryland Heights MO) with a superposition algorithm. For each patient, 2 plans were created: one employing an ADAS (ADAS plan) and the other replanned without an ADAS (non-ADAS plan). The ADAS was defined to occupy the volume between the inguinal nodes and primary target providing a single organ at risk that is completely outside of the target volume. Each plan used the same beam parameters and was analyzed by comparing target coverage, overall plan dose conformity using a conformity number (CN) equation, bowel dose-volume histograms, and the number of segments, daily treatment duration, and global maximum dose. The ADAS and non-ADAS plans were equivalent in target coverage, mean global maximum dose, and sparing of small bowel in low-dose regions (5, 10, 15, and 20 Gy). The mean difference between the CN value for the non-ADAS plans and ADAS plans was 0.04 ± 0.03 (p < 0.001). The mean difference in the number of segments was 15.7 ± 12.7 (p < 0.001) in favor of ADAS plans. The ADAS plan delivery time was shorter by 2.0 ± 1.5 minutes (p < 0.001) than the non-ADAS one. The ADAS has proven to be a powerful tool when planning rectal and anal canal IMRT cases with critical structures partially contained inside the target volume.