First Clinical Report of Proton Beam Therapy for Postoperative Radiotherapy for Non–Small-Cell Lung Cancer

Adjuvant modern radiotherapy in resected pN2 NSCLC patients: results from a multicentre retrospective analysis on acute and late toxicity on behalf of AIRO thoracic oncology study group: the RAC-TAC study

BACKGROUND

Recently, the PORT-C and LUNG-ART trials, which evaluated the role of postoperative radiation therapy (PORT), have significantly altered the treatment landscape for NSCLC pN2 patients who previously underwent surgery. In response, the Italian Association of Radiotherapy and Oncology Thoracic Oncology study group has initiated an observational multicenter trial to assess both acute and late toxicities of PORT in pN2 NSCLC patients treated with modern techniques.

METHODS

Data on NSCLC patients submitted to PORT after radical surgery treated between 2015 and 2020 in six Italian Centers were collected. Heart, lung, and esophageal acute and late toxicities have been retrospectively analyzed and related to radiation therapy dosimetric parameters. Furthermore, loco-regional control, distant metastasis and overall survival have been analyzed.

RESULTS

A total of 212 patients with a median age of 68 years from six different centers were included in this analysis (142 males and 70 females). Prior to undergoing PORT, 96 patients (45.8%) had a history of heart disease, 110 patients (51.9%) had hypertension, and 51 patients (24%) had COPD. Acute toxicity was observed in 147 patients (69.3%), with lung toxicity occurring in 93 patients (G1 in 70 patients, G2 in 17 patients, and G3 in 4 patients), esophageal toxicity in 114 patients (G1 in 89 patients, G2 in 23 patients, and G3 in 1 patient), and cardiac toxicity in 4 patients (G1 in 2 patients and G3 in 2 patients). Late side effects were found in 60 patients (28.3%), predominantly involving the lungs (51 patients: 32 G1, 11 G2, and 1 G3) and the esophagus (11 patients: 8 G1 and 3 G2), with no reported late cardiac side effects. Various clinical and dosimetric parameters were found to correlate with both acute and chronic toxicities. Over a median follow-up period of 54 months, 48 patients (22.6%) showed locoregional disease relapse, 106 patients (50%) developed distant metastases, and 66 patients (31.1%) died.

CONCLUSIONS

RAC-TAC retrospective multicentric study showed the low toxicity of PORT when advanced technology is used. At the same time, it's noteworthy to underline that 50% of the patients develop distant recurrences in the follow up.

Is there role of adjuvant radiotherapy after complete resection of locally advanced nonsmall cell lung cancer?

PURPOSE OF REVIEW

This review aims to provide a timely and relevant overview of the role of postoperative radiotherapy (PORT) in completely resected stage IIIA-N2 nonsmall cell lung cancer (NSCLC). Given the controversy surrounding the use of PORT and the emergence of advanced radiation techniques and therapies, this review provides valuable insight into current and potential treatment strategies.

RECENT FINDINGS

The Lung ART and PORT-C trials have provided valuable insights into the efficacy of PORT in stage IIIA-N2 NSCLC. While the results have been mixed, studies have shown that advanced radiation techniques, such as intensity-modulated radiotherapy (IMRT) and proton therapy, can reduce cardiopulmonary toxicities associated with PORT. Molecular targeted therapies and immunotherapies have also shown potential in improving NSCLC treatment outcomes.

SUMMARY

The role of radiotherapy becomes smaller and smaller in new era. However, it is too early to abolish radiotherapy for all the patients after complete resection of locally advanced NSCLC. Nowadays, it is recommended to adopt individualized treatment approaches guided by multidisciplinary team consultations. The integration of IMRT, proton therapy, and emerging therapies offers the potential to enhance treatment efficacy while minimizing toxicity. Further research is needed to optimize the use of PORT and explore the method to identify the patients who can really benefit from PORT.

ASTRO Radiation Therapy Summary of the ASCO Guideline on Management of Stage III Non-Small Cell Lung Cancer

PURPOSE

To develop a radiation therapy summary of recommendations on the management of locally advanced non-small cell lung cancer (NSCLC) based on the Management of Stage III Non-Small Cell Lung Cancer: American Society of Clinical Oncology Guideline, which was endorsed by the American Society for Radiation Oncology (ASTRO).

METHODS

The American Society of Clinical Oncology, ASTRO, and the American College of Chest Physicians convened a multidisciplinary panel to develop a guideline based on a systematic review of the literature and a formal consensus process, that has been separately published. A new panel consisting of radiation oncologists from the original guideline as well as additional ASTRO members was formed to provide further guidance to the radiation oncology community. A total of 127 articles met the eligibility criteria to answer 5 clinical questions. This summary focuses on the 3 radiation therapy questions (neoadjuvant, adjuvant, and unresectable settings).

RESULTS

Radiation-specific recommendations are summarized with additional relevant commentary on specific questions regarding the management of preoperative radiation, postoperative radiation, and combined chemoradiation.

CONCLUSIONS

Patients with stage III NSCLC who are planned for surgical resection, should receive either neoadjuvant chemotherapy or chemoradiation. The addition of neoadjuvant treatment is particularly important in patients planned for surgery in the N2 or superior sulcus settings. Postoperatively, patients who did not receive neoadjuvant chemotherapy should be offered adjuvant chemotherapy. The use of postoperative radiation for completely resected N2 disease is not routinely recommended. Unresectable patients with stage III NSCLC should ideally be managed with combined concurrent chemoradiation using a platinum-based doublet with a standard radiation dose of 60 Gy followed by consolidation durvalumab in patients without progression after initial therapy. Patients who cannot tolerate a concurrent chemoradiation approach can be managed either by sequential chemotherapy followed by radiation or by dose-escalated or hypofractionated radiation alone.

Proton versus photon radiation therapy: A clinical review

While proton radiation therapy offers substantially better dose distribution characteristics than photon radiation therapy in certain clinical applications, data demonstrating a quantifiable clinical advantage is still needed for many treatment sites. Unfortunately, the number of patients treated with proton radiation therapy is still comparatively small, in some part due to the lack of evidence of clear benefits over lower-cost photon-based treatments. This review is designed to present the comparative clinical outcomes between proton and photon therapies, and to provide an overview of the current state of knowledge regarding the effectiveness of proton radiation therapy.

Toxicities and Deaths From Intercurrent Disease Following Contemporary Postoperative Radiotherapy in Resected Non-Small-Cell Lung Cancer

INTRODUCTION

The role of postoperative radiotherapy (PORT) in patients with resected locally advanced non-small-cell lung cancer (NSCLC) remains controversial due to the radiation techniques used in randomized trials. We conducted a retrospective cohort study evaluating contemporary PORT techniques to evaluate the safety of PORT and risk of death from intercurrent disease .

MATERIALS AND METHODS

We analyzed consecutive patients with NSCLC treated in a single center that underwent PORT for pN2 disease and/or positive margin, with 3-dimensional conformal radiotherapy (3DRT), intensity modulated radiotherapy , or proton RT (PRT), between 2008 and 2019. Clinical details were collected including intercurrent deaths, defined as death without cancer recurrence. Kaplan-Meier and Cox-Proportional Hazards Models were used.

RESULTS

Of 119 patients, 21 (17.6%) received 3DRT, 47 (39.5%) intensity modulated radiotherapy, and 51 (42.9%) PRT. Median follow-up was 40 months (range 8-136) and median RT dose was 5040cGy. Most patients (65.5%) received sequential adjuvant chemoRT; 18.5% received concurrent chemoRT. The rate of grade 3 toxicities was 9.2%. There were 13 (10.9%) deaths from intercurrent diseases, including 6 from second primary cancers and 2 from cardiopulmonary diseases. There were 2 additional deaths from cardiopulmonary disease in patients with cancer progression at time of death. Mean, V5Gy, V30Gy heart doses and mean lung doses were significantly lower with PRT. Three-year OS and disease-free-survival were 70.1% and 49.9%.

CONCLUSION

PORT using contemporary techniques was well tolerated with acceptable toxicity and low rates of intercurrent deaths. Proton therapy significantly reduced heart and lung doses, but radiotherapy modality was not associated with differences in intercurrent disease.

The Value of Radiotherapy in Patients With Resectable Stage IIIA Non-Small-Cell Lung Cancer in the Era of Individualized Treatment: A Population-Based Analysis

INTRODUCTION

No consensus has been achieved on the benefit of radiotherapy for resected stage IIIA NSCLC patients. The division of stage IIIA has changed significantly in 2017. This study aims to explore the effects of radiotherapy on the survival of patients with resectable stage IIIA NSCLC in the new era.

PATIENTS AND METHODS

Patients diagnosed with NSCLC between 2010 and 2018 were identified in the 8th edition TNM classification from the Surveillance, Epidemiology, and End Results database. A nomogram was developed by integrating all independent predictors for lung cancer-specific survival (LCSS). The Propensity Score Matching (PSM) and subgroup analysis were applied to mitigate potential bias. Survival analyses were conducted using the Kaplan Meier curves and Cox proportional hazards regression.

RESULTS

A total of 2632 stage IIIA NSCLC patients were enrolled. The C-index of the nomogram for the prediction of LCSS was 0.636 (95% CI, 0.616-0.656). In the group of patients with N2 stage who featured more than 5 positive regional lymph nodes, compared with non-PORT, PORT did prolong postoperative survival time (50 vs. 31 months; P= .005). N2 patients with visceral pleural invasion (VPI), older (age >65), or had a larger tumor (size >3 cm) could also benefit from adjuvant radiotherapy.

CONCLUSION

Treatment protocol for stage IIIA NSCLC patients should be individualized. Based on our findings, N2 patients with more than 5 positive regional lymph nodes, VPI, larger tumor size (greater than 3 cm), and older (age above 65) could benefit from adjuvant radiotherapy. Further well-designed randomized trials are warranted.

Postoperative radiotherapy with modern techniques does not improve survival for operable stage IIIA-N2 non-small cell lung cancer

OBJECTIVES

This study aims to evaluate whether postoperative radiotherapy using newer techniques (intensity-modulated radiotherapy [IMRT]) is associated with improved survival for patients with stage IIIA-N2 non-small cell lung cancer (NSCLC) who underwent complete resection.

METHODS

The overall survival of patients with stage IIIA-N2 NSCLC who received postoperative IMRT versus no postoperative IMRT following induction chemotherapy and lobectomy in the National Cancer Database from 2010-2018 was assessed via Kaplan-Meier analysis, Cox proportional hazards analysis and propensity score-matched analysis. Additional survival analyses were also conducted in patients with completely resected stage IIIA-pN2 NSCLC who had upfront lobectomy (without induction therapy) followed by adjuvant chemotherapy alone or adjuvant chemotherapy with postoperative IMRT. Only patients receiving IMRT, which is a newer, more conformal radiotherapy technique, were included. Patients with positive surgical margins were excluded.

RESULTS

A total of 3203 patients with stage IIA-N2 NSCLC who underwent lobectomy were included. Five hundred eighty-eight (18.4%) patients underwent induction chemotherapy followed by lobectomy, and 2615 (82%) underwent lobectomy followed by chemotherapy. In unadjusted, multivariable-adjusted, and propensity score--matched analyses, there were no significant differences in overall survival between the patients who also received postoperative IMRT versus those who did not.

CONCLUSIONS

In this national analysis, the use of postoperative IMRT was not associated with improved survival in patients with completely resected stage IIIA-N2 NSCLC with or without induction chemotherapy.

Trends in Postoperative Intensity-Modulated Radiation Therapy Use and Its Association With Survival Among Patients With Incompletely Resected Non-Small Cell Lung Cancer

IMPORTANCE

National guidelines allow consideration of postoperative radiation therapy (PORT) among patients with incompletely resected non-small cell lung cancer (NSCLC). However, there is a paucity of prospective data because recently completed trials excluded patients with positive surgical margins. In addition, unlike for locally advanced NSCLC, the role of intensity-modulated radiation therapy (IMRT) for PORT remains unclear.

OBJECTIVE

To evaluate trends of IMRT use for PORT in the US and the association of IMRT with survival outcomes among patients with incompletely resected NSCLC.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study used data from the National Cancer Database for patients diagnosed between January 2004 and December 2019 with incompletely resected NSCLC who underwent upfront surgery with positive surgical margins followed by PORT.

EXPOSURES

IMRT vs 3D conformal radiation therapy (3DCRT) for PORT.

MAIN OUTCOMES AND MEASURES

The main outcome was overall survival. Multivariable Cox proportional hazards regression assessed the association of IMRT vs 3DCRT with overall survival. Multivariable logistic regression identified variables associated with IMRT. Propensity score matching (1:1) was performed based on variables of interest.

RESULTS

A total of 4483 patients (2439 men [54.4%]; median age, 67 years [IQR, 60-73 years]) were included in the analysis. Of those, 2116 (47.2%) underwent 3DCRT and 2367 (52.8%) underwent IMRT. Median follow-up was 48.5 months (IQR, 31.1-77.2 months). The proportion of patients who underwent IMRT increased from 14.3% (13 of 91 patients) in 2004 to 70.7% (33 of 471 patients) in 2019 (P < .001). IMRT was associated with improved overall survival compared with 3DCRT (adjusted hazard ratio, 0.84; 95% CI, 0.78-0.91; P < .001). Similar findings were observed for 1463 propensity score-matched pairs; IMRT was associated with improved 5-year overall survival compared with 3DCRT (37.3% vs 32.2%; hazard ratio, 0.88; 95% CI, 0.80-0.96; P = .003). IMRT use was associated with receipt of treatment at an academic facility (adjusted odds ratio [aOR], 1.15; 95% CI, 1.00-1.33; P = .049), having T4 stage tumors (aOR, 1.50; 95% CI, 1.13-1.99; P = .005) or N2 or N3 stage tumors (aOR, 1.25; 95% CI, 1.04-1.51; P = .02), and receipt of pneumonectomy (aOR, 1.35; 95% CI, 1.02-1.80; P = .04).

CONCLUSION AND RELEVANCE

This cohort study found that use of IMRT for PORT among patients with incompletely resected NSCLC increased in the US from 2004 to 2019 and was associated with improved survival compared with 3DCRT. Further studies are warranted to investigate the role of different radiation therapy techniques for PORT.

Imaging Strategies in Proton Therapy for Thoracic Tumors: A Mini Review

Proton beam therapy (PBT) is often more attractive for its high gradient dose distributions than other treatment modalities with external photon beams. However, in thoracic lesions treated particularly with pencil beam scanning (PBS) proton beams, several dosimetric issues are addressed. The PBS approach may lead to large hot or cold spots in dose distributions delivered to the patients, potentially affecting the tumor control and/or increasing normal tissue side effects. This delivery method particularly benefits image-guided approaches. Our paper aims at reviewing imaging strategies and their technological trends for PBT in thoracic lesions. The focus is on the use of imaging strategies in simulation, planning, positioning, adaptation, monitoring, and delivery of treatment and how changes in the anatomy of thoracic tumors are handled with the available tools and devices in PBT. Starting from bibliographic research over the past 5 years, retrieving 174 papers, major key questions, and implemented solutions were identified and discussed; the results aggregated and presented following the methodology of analysis of expert interviews.

Role of Adjuvant Radiotherapy in Non-Small Cell Lung Cancer-A Review

Simple Summary

The role of postoperative radiotherapy (PORT) in completely resected non-small cell lung cancer (NSCLC) with ipsilateral mediastinal lymph node involvement (pN2) is controversial. The aim of our review was to study the literature relating to PORT for completely resected NSCLC patients with pN2 involvement. The Lung ART and PORT-C trials indicate better locoregional control with PORT, but this has not yet translated into survival benefits. Given the conflicting results, guidelines do not recommend the use of PORT routinely. Future research should focus on identifying subgroups of patients who might benefit from PORT.

Abstract

Background: For patients with completely resected non-small cell lung cancer (NSCLC) with ipsilateral mediastinal lymph node involvement (pN2), the administration of adjuvant chemotherapy is the standard of care. The role of postoperative radiation therapy (PORT) is controversial. Methods: We describe the current literature focusing on the role of PORT in completely resected NSCLC patients with pN2 involvement and reflect on its role in current guidelines. Results: Based on the results of the recent Lung ART and PORT-C trials, the authors conclude that PORT cannot be generally recommended for all resected pN2 NSCLC patients. A substantial decrease in the locoregional relapse rate without translating into a survival benefit suggests that some patients with risk factors might benefit from PORT. This must be balanced against the risk of cardiopulmonary toxicity with potentially associated mortality. Lung ART has already changed the decision making for the use of PORT in daily practice for many European lung cancer experts, with lower rates of recommendations for PORT overall. Conclusions: PORT is still used, albeit decreasingly, for completely resected NSCLC with pN2 involvement. High-level evidence for its routine use is lacking. Further analyses are required to identify patients who would potentially benefit from PORT.

Increasing Heart Dose Reduces Overall Survival in Patients Undergoing Postoperative Radiation Therapy for NSCLC

Introduction

Given the concern for cardiopulmonary toxicity in patients with NSCLC undergoing postoperative radiation therapy (PORT), the purpose of this study was to evaluate the association between heart dose and overall survival (OS) in patients undergoing PORT with modern techniques.

Methods

This is a retrospective study of consecutive patients with NSCLC treated with PORT between May 2004 and January 2017. Clinical records were reviewed and radiation dose distributions were analyzed for association with OS.

Results

A total of 284 patients were analyzed. At the time of surgery, most patients had pathologic American Joint Committee on Cancer seventh edition stage III disease (91.2 %) and received either preoperative or adjuvant chemotherapy (92.3 %). Most patients underwent a lobectomy (81.3 %) and had R0 (80.6 %) or R1 (19.4 %) resection. PORT was delivered with a median radiation dose of 54 Gy, and 70.4 % of patients were treated with intensity-modulated radiation therapy. Dosimetric variables across a large range of doses to the heart were highly significant (p < 0.05) for OS. The volume of the heart receiving 8 Gy (HV8) was the most significant dosimetric variable (p < 0.001), and the median HV8 was 35.5 %. The median OS was 33.2 versus 53.6 months (p < 0.005) for patients with HV8 above or below 35.5 %, respectively. On multivariable analysis accounting for other potential prognostic confounders, HV8 remained highly significant (p < 0.001).

Conclusions

The data reveal a strong correlation between increasing heart dose and OS in patients with NSCLC undergoing PORT. Taken together with the recently presented LungART trial, lowering heart dose in PORT patients may help to decrease the risk of morbidity and mortality and improve the therapeutic ratio of PORT.

Postoperative Radiotherapy for Patients With Resectable Stage III-N2 Non-Small Cell Lung Cancer: A Systematic Review and Meta-Analysis

Purpose

For resectable cases of stage III-N2 non-small cell lung cancer (NSCLC), the best treatment after surgery is still uncertain. The effect of postoperative radiotherapy (PORT) is controversial. Thus, we performed this updated meta-analysis to reassess the data of PORT in stage III-N2 NSCLC patients, to figure out whether these patients can benefit from PORT.

Methods

We conducted searches of the published literature in EMBASE, PubMed, and the Cochrane Library for relevant randomized control trials (RCTs) comparing PORT group with the non-PORT group in NSCLC patients at stage III-N2. These studies allowed the prior chemotherapy in the treatment. We extracted the data from these articles and used the hazard ratios (HRs) and their 95% confidence intervals (CIs) as summary statistics for estimating the effect of PORT on overall survival (OS), disease-free survival (DFS), local-regional recurrence-free survival (LRFS).

Result

The analyses of seven randomized controlled trials (1,318 participants) show no benefit of PORT on survival (HR, 0.87; 95% CI, 0.71 to 1.07; p = 0.18) but a significantly different effect of PORT on DFS (HR, 0.83; 95% CI, 0.71 to 0.97; p = 0.02) and LRFS (HR, 0.64; 95% CI, 0.50 to 0.81; p = 0.0003). There is not enough evidence of a difference in the effect on survival by the utility of chemotherapy along with PORT though subgroup analysis of no chemotherapy group, concurrent chemoradiotherapy and sequential chemoradiotherapy group. Even in trials with 3D-CRT radiation technique, the pooled analysis shows no benefit of PORT on survival in patients with stage III-N2 NSCLC (data is not shown).

Conclusion

Our findings illustrate that in the postoperative treatment for patients with stage III-N2 NSCLC, PORT contributes to a significantly increased DFS and LR and may not associate with an improved OS, indicating a cautious selection.

Single Institution Experience of Proton and Photon-based Postoperative Radiation Therapy for Non-small-cell Lung Cancer

INTRODUCTION

Postoperative radiation therapy (PORT) for non-small-cell lung cancer remains controversial with studies showing no overall survival (OS) benefit in the setting of excessive cardiopulmonary toxicity. Proton beam therapy (PBT) can potentially reduce toxicity with improved organ-at-risk sparing. We evaluated outcomes of PORT patients treated with PBT and intensity-modulated radiation therapy (IMRT).

MATERIALS AND METHODS

This is a retrospective review of 136 PORT patients (61 PBT, 75 IMRT) treated from 2003 to 2016. A Kaplan-Meier analysis was performed to assess oncologic outcomes. A Cox regression was conducted to identify associated factors. Total toxicity burden (TTB) was defined as grade ≥ 2 pneumonitis, cardiac, or esophageal toxicity.

RESULTS

Median OS was 76 and 46 months for PBT and IMRT with corresponding 1- and 5-year OS of 85.3%, 50.9% and 89.3%, 37.2% (P = .38), respectively. V30 Gy heart (odds ratio [OR], 144.9; 95% confidence interval [CI], 2.91-7214; P = .013) and V5 Gy lung (OR, 15.8; 95% CI, 1.22-202.7; P = .03) were predictive of OS. Organ-at-risk sparing was improved with PBT versus IMRT; mean heart 2.0 versus 7.4 Gy (P < .01), V30 Gy heart 2.6% versus 10.7% (P < .01), mean lung 7.9 versus 10.4 Gy (P = .042), V5 Gy lung 23.4% versus 42.1% (P < .01), and V10 Gy lung 20.4% versus 29.6% (P < .01). TTB was reduced with PBT (OR, 0.35; 95% CI, 0.15-0.83; P = .017). Rates of cardiac toxicity were 14.7% IMRT and 4.9% PBT (P = .09). Rates of ≥ grade 2 pneumonitis were 17.0% IMRT and 4.9% PBT (P = .104).

CONCLUSION

PBT improved cardiac and lung sparing and reduced toxicity compared with IMRT. Considering the impact of cardiopulmonary toxicity on PORT outcomes, PBT warrants prospective evaluation.

Proton beam radiotherapy for patients with early-stage and advanced lung cancer: a narrative review with contemporary clinical recommendations

Although lung cancer rates are decreasing nationally, lung cancer remains the leading cause of cancer related death. Despite advancements in treatment and technology, overall survival (OS) for lung cancer remains poor. Proton beam therapy (PBT) is an advanced radiation therapy (RT) modality for treatment of lung cancer with the potential to achieve dose escalation to tumor while sparing critical structures due to higher target conformality. In early and late-stage non-small cell lung cancer (NSCLC), dosimetric studies demonstrated reduced doses to organs at risk (OARs) such as the lung, spinal cord, and heart, and clinical studies report limited toxicities with PBT, including hypofractionated regimens. In limited-stage SCLC, studies showed that regimens chemo RT including PBT were well tolerated, which may help optimize clinical outcomes. Improved toxicity profiles may be beneficial in post-operative radiotherapy, for which initial dosimetric and clinical data are encouraging. Sparing of OARs may also increase the proportion of patients able to complete reirradiation for recurrent disease. However, there are various challenges of using PBT including a higher financial burden on healthcare and limited data supporting its cost-effectiveness. Further studies are needed to identify subgroups that benefit from PBT based on prognostic factors, and to evaluate PBT combined with immunotherapy, in order to elucidate the benefit that PBT may offer future lung cancer patients.

Proton therapy for thoracic malignancies: a review of oncologic outcomes

Introduction: Radiotherapy is an integral component in the treatment of the majority of thoracic malignancies. By taking advantage of the steep dose fall-off characteristic of protons combined with modern optimization and delivery techniques, proton beam therapy (PBT) has emerged as a potential tool to improve oncologic outcomes while reducing toxicities from treatment.Areas covered: We review the physical properties and treatment techniques that form the basis of PBT as applicable for thoracic malignancies, including a brief discussion on the recent advances that show promise to enhance treatment planning and delivery. The dosimetric advantages and clinical outcomes of PBT are critically reviewed for each of the major thoracic malignancies, including lung cancer, esophageal cancer, mesothelioma, thymic cancer, and primary mediastinal lymphoma.Expert opinion: Despite clear dosimetric benefits with PBT in thoracic radiotherapy, the improvement in clinical outcomes remains to be seen. Nevertheless, with the incorporation of newer techniques, PBT remains a promising modality and ongoing randomized studies will clarify its role to determine which patients with thoracic malignancies receive the most benefit. Re-irradiation, advanced disease requiring high cardio-pulmonary irradiation volume and younger patients will likely derive maximum benefit with modern PBT.

[Perioperative treatment for resected non-small cell lung cancer: Which option in 2020?]

Surgery is the ultimate curative treatment for resectable non-small cell lung cancer (NSCLC). However, the prognosis for operated patients remains disappointing. Multiple randomized studies have shown that administering perioperative chemotherapy improves the prognosis and increases the cure rate by around 3-5%. The purpose of this article is to take stock of the role of perioperative treatments for NSCLC, which can be completely resected. Six questions were evaluated: 1) What is the place of (neo) adjuvant chemotherapy in 2020, among others in the early stages (IB)? 2) Can new chemotherapy agents be combined with a platinum derivative? 3) What is the place of radiochemotherapy for resectable NSCLC? 4) Is there a place for postoperative radiotherapy (PORT)? 5) Is there a place for targeted therapies for resectable NSCLC? 6) What is the place of immunotherapies in the perioperative period?

Clinical and Dosimetric Predictors of Radiation Pneumonitis in Patients With Non-Small Cell Lung Cancer Undergoing Postoperative Radiation Therapy

PURPOSE

Radiation pneumonitis (RP) is a common and potentially life-threatening toxicity from lung cancer radiation therapy. Data sets reporting RP rates after postoperative radiation therapy (PORT) have historically been small and with predominantly outdated field designs and radiation techniques. We examined a large cohort of patients in this context to assess the incidence and causes of RP in the modern era.

METHODS AND MATERIALS

We reviewed 285 patients with non-small cell lung cancer treated with PORT at our institution from May 2004 to January 2017. Complete dosimetric data and clinical records were reviewed and analyzed with grade 2 or higher RP as the endpoint (RP2+) (Common Terminology Criteria for Adverse Events v4.0). Patients were a median of 67 years old (range, 28-87), and most had pathologic stage III non-small cell lung cancer (91%) and received trimodality therapy (90%). Systematic dosimetric analyses using Dx increments of 5% and Vx increments of 2 Gy were performed to robustly evaluate dosimetric variables. Lung V₅ was also evaluated.

RESULTS

The incidence of RP2+ after PORT was 12.6%. Dosimetric factors most associated with RP2+ were total lungV₄ (hazard ratio [HR] 1.04, P < .001) and heart V₁₆ (HR 1.03, P = .001). On univariate analysis, the clinical factors of age (HR 1.05, P = .006) and carboplatin chemotherapy (HR 2.32, P = .012) were correlated with RP2+. On step-up multivariate analysis, only bivariate models remained significant, including lungV₅ (HR 1.037, P < .001) and age (HR 1.052, P = .011).

CONCLUSIONS

The incidence of RP after PORT is consistent with the literature. Factors correlated with RP include lung and heart doses, age, and carboplatin chemotherapy. These data also suggest that elderly patients may be more susceptible to lower doses of radiation to the lung. Based on these data, dose constraints to limit the risk of RP2+ to <5% in the setting of PORT include lungV₅ ≤65% in patients <65 years old and lungV₅ ≤36% in patients 65 years or older.

Proton beam re-irradiation for gastrointestinal malignancies: a systematic review

Background

Radiotherapy (RT) is part of the standard of care management of most gastrointestinal (GI) cancers. Even with advanced RT, systemic therapy, and surgical techniques, locoregional recurrences or second primary cancers can still occur within previously irradiated fields, which can present challenges in delivering effective and safe treatment. Options for reirradiation are often limited, but given the favorable dosimetric aspects of proton-beam RT, it may provide an effective and safe re-irradiation option for patients with recurrent or second primary GI cancers.

Methods

We conducted a systematic review as per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement protocol, assessing for reports of proton-beam reirradiation for recurrent or second primary GI cancers, primarily via PubMed. From the initial 373 articles identified, 7 articles were ultimately included in the analysis.

Results

The 7 included studies reported on proton-beam re-irradiation for the following disease sites: esophageal (n=2), pancreas (n=1), liver (n=2), rectal (n=1), and anal (n=1). Study sizes varied from as few as 1 to as many as 83 patients. Across studies, in patients who presented with tumor-related symptoms, palliation (stability/improvement) was achieved in 80-100% of the cases. Local control rates, with variable follow-up, ranged from 36-100%. All median overall survival values, when reported, were greater than 1 year. Across both liver studies, there were no cases of radiation-induced liver disease (RILD) from proton-beam re-irradiation. Across all studies, there were 2 acute (esophagopleural fistula in esophageal cancer, small bowel perforation in pancreatic cancer) and 1 late (esophageal ulcer in esophageal cancer) grade 5 toxicities, all favored to be due to progressive disease, rather than proton-beam re-irradiation. Two studies (1 esophageal, 1 rectal) generated comparison photon plans. One found that proton therapy reduced mean heart and lung doses, spinal cord dose, and lung V5Gy as compared to photon treatment, while resulting in higher lung V20Gy and V30Gy. The other found that protons decreased bowel V10Gy, V20Gy, and the dose to 200 and 150 cc of bowel, as compared to photons.

Conclusions

Based upon the published experiences, proton-beam re-irradiation for recurrent or second primary GI cancers appears effective for palliation, with good disease-control, limited toxicity, favorable dosimetry, and overall compares well with published non-proton-beam experiences. Given short follow-up, additional studies are warranted to determine if dosimetric advantages from proton therapy will translate into comparative toxicity benefits.

The Use of Radiation Therapy for the Treatment of Malignant Pleural Mesothelioma: Expert Opinion from the National Cancer Institute Thoracic Malignancy Steering Committee, International Association for the Study of Lung Cancer, and Mesothelioma Applied Research Foundation

INTRODUCTION

Detailed guidelines regarding the use of radiation therapy for malignant pleural mesothelioma (MPM) are currently lacking because of the rarity of the disease, the wide spectrum of clinical presentations, and the paucity of high-level data on individual treatment approaches.

METHODS

In March 2017, a multidisciplinary meeting of mesothelioma experts was cosponsored by the U.S. National Cancer Institute, International Association for the Study of Lung Cancer Research, and Mesothelioma Applied Research Foundation. Among the outcomes of this conference was the foundation of detailed, multidisciplinary consensus guidelines.

RESULTS

Here we present consensus recommendations on the use of radiation therapy for MPM in three discrete scenarios: (1) hemithoracic radiation therapy to be used before or after extrapleural pneumonectomy; (2) hemithoracic radiation to be used as an adjuvant to lung-sparing procedures (i.e., without pneumonectomy); and (3) palliative radiation therapy for focal symptoms caused by the disease. We discuss appropriate simulation techniques, treatment volumes, dose fractionation regimens, and normal tissue constraints. We also assess the role of particle beam therapy, specifically, proton beam therapy, for MPM.

CONCLUSION

The recommendations provided in this consensus statement should serve as important guidelines for developing future clinical trials of treatment approaches for MPM.

Quantification of global lung inflammation using volumetric 18F-FDG PET/CT parameters in locally advanced non-small-cell lung cancer patients treated with concurrent chemoradiotherapy: a comparison of photon and proton radiation therapy

INTRODUCTION

Radiation pneumonitis is a major dose-limiting complication in thoracic radiation therapy (RT) and presents clinically in the first few months after RT. We evaluated the feasibility of quantifying pulmonary parenchymal glycolysis (PG) as a surrogate of global lung inflammation and radiation-induced pulmonary toxicity using a novel semiautomatic lung segmentation technique in non-small-cell lung cancer (NSCLC) patients and compared PG in patients treated with photon or proton RT.

PATIENTS AND METHODS

We evaluated 18 consecutive locally advanced NSCLC patients who underwent pretreatment and post-treatment F-FDG PET/CT treated with definitive (median: 66.6 Gy; 1.8 Gy fractions) photon or proton RT between 2010 and 2014. Lung volume segmentation was conducted using 3D Slicer by performing simple thresholding. Pulmonary PG was calculated by summing F-FDG uptake in the whole lung.

RESULTS

In nine patients treated with photon RT, significant increases in PG in both ipsilateral (mean difference: 1400±510; P=0.02) and contralateral (mean difference: 1200±450; P=0.03) lungs were noted. In nine patients treated with proton therapy, no increase in pulmonary PG was observed in either the ipsilateral (P=0.30) or contralateral lung (P=0.98).

CONCLUSION

We observed a significant increase in global lung inflammation bilaterally as measured by quantification of PG. However, no significant change in global lung inflammation was noted after proton therapy. Future larger studies are needed to determine whether this difference correlates with lower risks of radiation pneumonitis in NSCLC patients treated with proton therapy.

The Dosimetric Comparisons of CRT, IMRT, ARC, CRT+IMRT, and CRT+ARC of Postoperative Radiotherapy in IIIA-N2 Stage Non-Small-Cell Lung Cancer Patients

Currently, studies about PORT in stage IIIA-N2 NSCLC patients in recent years have mostly adopted the conformal radiation therapy (CRT) technique, while other modern techniques such as intensity modulated radiation therapy (IMRT), volumetric modulated arc therapy (VMAT, hereinafter referred to as ARC), helical tomotherapy (HT), and so forth are also developing quickly. In this paper, we intended to compare the dosimetric characteristics of CRT, IMRT, ARC, CRT+IMRT, and CRT+ARC of PORT in stage IIIA-N2 NSCLC patients. Ten patients with stage IIIA-N2 completely resected NSCLC, whom were treated by PORT in the radiotherapy department of our hospital from January 1, 2017, to January 1, 2018, were randomly selected in this study. For each patient, the CRT plan, IMRT plan, ARC plan, CRT+IMRT plan, and CRT+ARC plan were designed separately on the same set of CT images. The isodose distribution and dose-volume histogram (DVH) of the five plans were compared to determine the dosimetric parameters of the targets, OAR (organs at risk), and the normal tissue (defined as body subtracted to PTV (planning target volume), B-P). No plan had absolute dosimetry advantages than any other plans. In clinical practice, the plans could be chosen according to their dosimetry characteristics.

Proton Therapy in Non-small Cell Lung Cancer

OPINION STATEMENT

Non-small cell lung cancer (NSCLC) accounts for 85% of new lung cancer cases and has 5-year survival rates ranging from 92% in early-stage disease to as low as 13% in locally advanced cases. Radiation therapy is a key component in the treatment repertoire for NSCLC, where it is currently used alone or in combinations with chemotherapy and surgery. Despite the broad use of modern photon radiation techniques, as many as 25% of patients experience isolated locoregional recurrences, and toxicity has been proven to be a limiting factor in many cases. Proton beam therapy (PBT) has emerged as a potential solution to improve upon clinical outcomes in both early-stage and locally advanced disease. The proton beam allows for a sharp dose build-up and drop-off, which is particularly important in lung cancer where nearby structures include the heart, spinal cord, esophagus, and uninvolved lung. There are now numerous studies showing dosimetric advantages of PBT in early and locally advanced NSCLC, particularly in the heart and lung doses. Randomized data comparing clinical outcomes between proton and photon radiation are limited to a small number of studies. Despite early results suggesting improvements or at least comparable outcomes with PBT, the most recent randomized comparisons have failed to show significant differences in toxicity and local control between photon and proton therapy. As newer PBT techniques (e.g., intensity-modulated proton therapy) are increasingly utilized, more dramatic improvements in tumor control and toxicity may be demonstrated. It is also important to recognize that there may be certain subpopulations in which the benefits of proton therapy are greater, such as central early-stage tumors, previously irradiated tumors, and locally advanced tumors, while others may best be treated with traditional photon techniques. As immunotherapy becomes more prevalent in the treatment of NSCLC, improving local control and limiting the toxicity contributed by radiation will be increasingly important. The unique dosimetric advantages of PBT may allow for tumor dose escalation while maintaining normal tissue doses to improve local control, or treating the tumor to the standard dose while decreasing normal tissue doses to improve toxicity. Finally, given the high costs of proton therapy, where low insurance approval rates have limited trial enrollment, it will be important to determine the overall cost-benefit ratio.

Proton Beam Therapy for Bronchogenic Adenoid Cystic Carcinoma: Dosimetry, Toxicities, and Outcomes

Purpose

Bronchogenicadenoid cystic carcinoma (ACC) is a rare malignancy particularly challenging to irradiate, largely owing to anatomic location and associated toxicities. Proton beam therapy (PBT) can reduce doses to nearby organs at risk, but only one case report has been published detailing PBT for this neoplasm.

Patients and Methods

This study was an institutional review board-approved retrospective chart review of all patients at one institution with bronchogenic ACC treated with PBT. Toxicities were assessed per Common Toxicity Criteria for Adverse Events, version 4.0.

Results

Five patients, median age 67 years (range = 40-97 years), were all symptomatic before PBT. Two patients were debulked before PBT, which was delivered at a median 66.6 Gy (RBE) (range, 57.5-80 Gy (RBE)). Two patients received concurrent platinum-based chemotherapy. Symptoms improved in all patients. Acute toxicities included the following: grade 1 fatigue (n = 3), grade 1 dermatitis (n = 2), grade 1 esophagitis (n = 1), grade 2 fatigue (n = 1), grade 2 dermatitis (n = 1), grade 2 esophagitis (n = 2). There was one case of late radiation fibrosis causing bronchial stenosis and requiring a stent, and another of late grade 1 dysphagia. All grade 2 toxicities occurred in patients receiving concurrent chemoradiotherapy. At median follow-up of 10 months (range = 5-47 months), no patient experienced tumor recurrence and none had symptoms impairing daily functioning or quality of life. Although statistically nonsignificant owing to low sample sizes, dosimetric data revealed that PBT numerically reduced doses, most notably to the heart and to low-dose volumes of the lung.

Conclusions

This is the largest series to date evaluating PBT for bronchogenic ACC. PBT is associated with low rates of acute and late toxicities and excellent early local control.

Particle therapy in non-small cell lung cancer

The finite range of proton beams in tissues offers unique dosimetric advantages that theoretically allow the dose to the target to be escalated while minimizing exposure of surrounding tissues and thereby minimizing radiation-induced toxicity. These theoretical advantages have led to widespread adoption of proton therapy around the world for a wide variety of tumors at different anatomic sites. Many treatment-planning comparisons have shown that proton therapy has substantial dosimetric advantages over conventional photon (X-ray) radiation therapy. However, given the typically significant difference in cost between proton therapy versus conventional photon therapy, strong evidence of proton therapy's clinical benefits in terms of toxicity and survival is warranted. Some findings from retrospective studies, single-arm prospective studies, and a very few randomized clinical trials comparing these modalities are beginning to emerge. In this review, we examine the available data on proton therapy for (non-small cell lung cancer NSCLC). We begin by discussing the unique challenges involved in treating moving targets with significant tissue heterogeneity and the technologic efforts underway to overcome these challenges. We then discuss the rationale for minimizing normal tissue toxicity, particularly pulmonary, cardiac, and hematologic toxicity, within the context of previously unsuccessful attempts at dose escalation for lung cancer. Finally, we explore strategies for accelerating the development of trials aimed at measuring meaningful clinical endpoints and for maximizing the value of proton therapy by personalizing its use for individual patients.

Proton beam therapy for malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a rare disease with a poor prognosis. Surgical techniques have made incremental improvements over the last few decades while new systemic therapies, including immunotherapies, show promise as potentially effective novel therapies. Radiation therapy has historically been used only in the palliative setting or as adjuvant therapy after extrapleural pneumonectomy, but recent advances in treatment planning and delivery techniques utilizing intensity-modulated radiation therapy and more recently pencil-beam scanning (PBS) proton therapy, have enabled the delivery of radiation therapy as neoadjuvant or adjuvant therapy after an extended pleurectomy and decortication or as definitive therapy for patients with recurrent or unresectable disease. In particular, PBS proton therapy has the potential to deliver high doses of irradiation to the entire effected pleura while significantly reducing doses to nearby organs at risk. This article describes the evolution of radiation therapy for MPM and details how whole-pleural PBS proton therapy is delivered to patients at the Maryland Proton Treatment Center.

Proton therapy for post-operative radiation therapy of non-small cell lung cancer

Post-operative radiation therapy (PORT) is typically recommended for patients with locally advanced non-small cell lung cancer (NSCLC) with N2 mediastinal nodal involvement after surgical resection. The routine use of PORT, however, is controversial as older data demonstrated a detriment in overall survival in patients who received PORT. This detriment was thought to be due to older, more toxic radiation techniques. More recent data with modern radiation techniques demonstrates a local-regional and overall survival benefit with PORT in patients with N2 nodal involvement. Due to the competing risks of local-regional recurrence and cardiopulmonary toxicity in patients who are candidates for PORT, methods to widen the therapeutic window are needed. The physical characteristics of proton beam therapy allow for less radiation dose to the heart and lungs. Therefore, proton beam therapy has great potential in patients undergoing PORT. Initial dosimetric and clinical data have been published and are encouraging, but prospective data is needed to further understand the true benefit of proton therapy in patients undergoing PORT.

Quality of Life and Patient-Reported Outcomes Following Proton Radiation Therapy: A Systematic Review

Background

As costs of cancer care rise, the importance of documenting value in oncology increases. Proton beam radiotherapy (PBT) has the potential to reduce toxicities in cancer patients, but is relatively expensive and unproven. Evaluating quality of life (QOL) and patient-reported outcomes (PROs) is essential to establishing PBT's "value" in oncologic therapy. The goal of this systematic review was to assess QOL and PROs in patients treated with PBT.

Methods

Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-guided systematic searches were conducted. The PubMed search engine was the primary data source, along with publications found from references of selected articles, and articles known to the authors published through 2017. Seventeen original investigations were found to have sufficient focus and relevance to be incorporated into the systematic review.

Results

Studies of skull base (n = 1), brain (n = 1), head/neck (n = 1), lung (n = 1), breast (n = 2), prostate (n = 8), and pediatric (n = 3) malignancies treated with PBT that met eligibility criteria were included. QOL did not deteriorate during PBT for skull base and after PBT for brain tumors, respectively. PROs were higher for PBT than photon-based radiotherapy for both head/neck and lung cancer. Patient-reported breast cosmesis was appropriate after PBT and comparable to photon modalities. PBT in various settings of prostate cancer displayed an expected post-therapy decline; one study showed improved PROs (rectal urgency, bowel frequency) for PBT, and two others showed PROs/QOL comparable with other modalities. Pediatric studies demonstrated improvements in QOL during therapy, with additional increases thereafter.

Conclusions

Based on limited data, PBT provides favorable QOL/PRO profiles for select brain, head/neck, lung, and pediatric cancers; measures for prostate and breast cancers were more modest. These results have implications for cost-effective cancer care and prudently designed QOL evaluation in ongoing trials, which are discussed. Future data could substantially change the conclusions of this review.

Advances in proton therapy in lung cancer

Lung cancer remains the leading cause of cancer deaths in the United States (US) and worldwide. Radiation therapy is a mainstay in the treatment of locally advanced non-small cell lung cancer (NSCLC) and serves as an excellent alternative for early stage patients who are medically inoperable or who decline surgery. Proton therapy has been shown to offer a significant dosimetric advantage in NSCLC patients over photon therapy, with a decrease in dose to vital organs at risk (OARs) including the heart, lungs and esophagus. This in turn, can lead to a decrease in acute and late toxicities in a population already predisposed to lung and cardiac injury. Here, we present a review on proton treatment techniques, studies, clinical outcomes and toxicities associated with treating both early stage and locally advanced NSCLC.

Proceedings of the National Cancer Institute Workshop on Charged Particle Radiobiology

In April 2016, the National Cancer Institute hosted a multidisciplinary workshop to discuss the current knowledge of the radiobiological aspects of charged particles used in cancer therapy to identify gaps in that knowledge that might hinder the effective clinical use of charged particles and to propose research that could help fill those gaps. The workshop was organized into 10 topics ranging from biophysical models to clinical trials and included treatment optimization, relative biological effectiveness of tumors and normal tissues, hypofractionation with particles, combination with immunotherapy, "omics," hypoxia, and particle-induced second malignancies. Given that the most commonly used charged particle in the clinic currently is protons, much of the discussion revolved around evaluating the state of knowledge and current practice of using a relative biological effectiveness of 1.1 for protons. Discussion also included the potential advantages of heavier ions, notably carbon ions, because of their increased biological effectiveness, especially for tumors frequently considered to be radiation resistant, increased effectiveness in hypoxic cells, and potential for differentially altering immune responses. The participants identified a large number of research areas in which information is needed to inform the most effective use of charged particles in the future in clinical radiation therapy. This unique form of radiation therapy holds great promise for improving cancer treatment.

Synthetic Secoisolariciresinol Diglucoside (LGM2605) Protects Human Lung in an Ex Vivo Model of Proton Radiation Damage

Radiation therapy for the treatment of thoracic malignancies has improved significantly by directing of the proton beam in higher doses on the targeted tumor while normal tissues around the tumor receive much lower doses. Nevertheless, exposure of normal tissues to protons is known to pose a substantial risk in long-term survivors, as confirmed by our work in space-relevant exposures of murine lungs to proton radiation. Thus, radioprotective strategies are being sought. We established that LGM2605 is a potent protector from radiation-induced lung toxicity and aimed in the current study to extend the initial findings of space-relevant, proton radiation-associated late lung damage in mice by looking at acute changes in human lung. We used an ex vivo model of organ culture where tissue slices of donor living human lung were kept in culture and exposed to proton radiation. We exposed donor human lung precision-cut lung sections (huPCLS), pretreated with LGM2605, to 4 Gy proton radiation and evaluated them 30 min and 24 h later for gene expression changes relevant to inflammation, oxidative stress, and cell cycle arrest, and determined radiation-induced senescence, inflammation, and oxidative tissue damage. We identified an LGM2605-mediated reduction of proton radiation-induced cellular senescence and associated cell cycle changes, an associated proinflammatory phenotype, and associated oxidative tissue damage. This is a first report on the effects of proton radiation and of the radioprotective properties of LGM2605 on human lung.

Incorporation of pre-therapy 18 F-FDG uptake data with CT texture features into a radiomics model for radiation pneumonitis diagnosis

PURPOSE

To determine whether the addition of standardized uptake value (SUV) from PET scans to CT lung texture features could improve a radiomics-based model of radiation pneumonitis (RP) diagnosis in patients undergoing radiotherapy.

METHODS AND MATERIALS

Anonymized data from 96 esophageal cancer patients (18 RP-positive cases of Grade ≥ 2) were collected including pre-therapy PET/CT scans, pre-/post-therapy diagnostic CT scans and RP status. Twenty texture features (first-order, fractal, Laws' filter and gray-level co-occurrence matrix) were calculated from diagnostic CT scans and compared in anatomically matched regions of the lung. Classifier performance (texture, SUV, or combination) was assessed by calculating the area under the receiver operating characteristic curve (AUC). For each texture feature, logistic regression classifiers consisting of the average change in texture feature value and the pre-therapy SUV standard deviation (SUV_SD ) were created and compared with the texture feature as a lone classifier using ANOVA with correction for multiple comparisons (P < 0.0025).

RESULTS

While clinical parameters (mean lung dose, smoking history, tumor location) were not significantly different among patients with and without symptomatic RP, SUV and texture parameters were significantly associated with RP status. AUC for single-texture feature classifiers alone ranged from 0.58 to 0.81 and 0.53 to 0.71 in high-dose (≥ 30 Gy) and low-dose (< 10 Gy) regions of the lungs, respectively. AUC for SUV_SD alone was 0.69 (95% confidence interval: 0.54-0.83). Adding SUV_SD into a logistic regression model significantly improved model fit for 18, 14 and 11 texture features and increased the mean AUC across features by 0.08, 0.06, and 0.04 in the low-, medium-, and high-dose regions, respectively.

CONCLUSIONS

Addition of SUV_SD to a single-texture feature improves classifier performance on average, but the improvement is smaller in magnitude when SUV_SD is added to an already effective classifier using texture alone. These findings demonstrate the potential for more accurate assessment of RP using information from multiple imaging modalities.