Toxicity and outcome results of RTOG 9311: a phase I-II dose-escalation study using three-dimensional conformal radiotherapy in patients with inoperable non-small-cell lung carcinoma

A Phase 2 Trial of Primary Tumor Stereotactic Body Radiation Therapy Boost Before Concurrent Chemoradiation for Locally Advanced Non-Small Cell Lung Cancer

PURPOSE

Primary tumor failure is common in patients treated with chemoradiation (CRT) for locally advanced NSCLC (LA-NSCLC). Stereotactic body radiation therapy (SBRT) yields high rates of primary tumor control (PTC) in early-stage NSCLC. This trial tested an SBRT boost to the primary tumor before the start of CRT to improve PTC.

METHODS AND MATERIALS

Patients with LA-NSCLC received an SBRT boost in 2 fractions (central location 12 Gy, peripheral location 16 Gy) to the primary tumor, followed by standard CRT (60 Gy in 30 fractions). The primary objective was PTC rate at 1 year, and the hypothesis was that the 1-year PTC rate would be ≥90%. Secondary objectives included objective response rate, regional and distant control, disease-free survival (DFS), and overall survival (OS). Correlative studies included functional magnetic resonance imaging and blood-based miRNA analysis.

RESULTS

The study enrolled 21 patients (10 men and 11 women); the median age was 62 years (range, 52-78). The median pretreatment primary tumor size was 5.0 cm (range, 1.0-8.3). The most common nonhematologic toxicities were pneumonitis, fatigue, esophagitis/dysphagia, dyspnea, and cough. Only 1 treatment-related grade 4 nonhematologic toxicity occurred (respiratory failure/radiation pneumonitis), and no grade 5 toxicities occurred. The objective response rate at 3 and 6 months was 72.7% and 80.0%, respectively, and PTC at 1 and 2 years was 100% and 92.3%, respectively. The 2-year regional and distant control rates were 81.6% and 70.3%, respectively. Disease-free survival and overall survival at 2 years were 46.1% and 50.3%, respectively, and median survival was 37.8 months. Functional magnetic resonance imaging detected a mean relative decrease in blood oxygenation level-dependent signal of -87.1% (P = .05), and miR.142.3p was correlated with increased risk of grade ≥3 pulmonary toxicity (P = .01).

CONCLUSIONS

Dose escalation to the primary tumor using upfront SBRT appears feasible and safe. PTC was high and other oncologic endpoints compared favorably to standard treatment. Functional magnetic resonance imaging suggested changes in oxygenation with the first SBRT boost dose, and miR.142.3p was correlated with pulmonary toxicity.

Cost-effectiveness of stereotactic body radiotherapy versus conventional fractionated radiotherapy for medically inoperable, early-stage non-small cell lung cancer

BACKGROUND

Stereotactic body radiotherapy (SBRT) is a novel radio-therapeutic technique that has recently emerged as standard-of-care treatment for medically inoperable, early-stage non-small cell lung cancer (NSCLC). In this study, we compared the cost-effectiveness of SBRT with that of conventional fractionated radiotherapy (CFRT) in patients with medically inoperable, early-stage NSCLC from the perspective of the Chinese health system.

METHODS

A Markov model was developed to describe health states of patients after treatment with SBRT and CFRT. The recurrence risks, treatment toxicities, and utilities inputs were obtained from the literature. The costs were based on listed prices and real-world evidence. A simulation was conducted to determine the post-treatment lifetime years. For each treatment, the total costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs) per QALY were calculated. Deterministic and probabilistic sensitivity analyses were performed to assess the uncertainty of the model parameters.

RESULTS

In the base case analysis, SBRT was associated with a mean cost of USD16,933 and 2.05 QALYs, whereas CFRT was associated with a mean cost of USD17,726 and 1.61 QALYs. SBRT is a more cost-effective strategy compared with CFRT for medically inoperable, early-stage NSCLC, with USD 1802 is saved for every incremental QALY. This result was validated by DSA and PSA, in which SBRT remained the most cost-effective option.

CONCLUSIONS

The findings suggested that, compared to CFRT, SBRT may be considered a more cost-effective strategy for medically inoperable, early-stage NSCLC.

Stage III Non-Small-Cell Lung Cancer: An Overview of Treatment Options

Lung cancer is the second-most commonly diagnosed cancer and the leading cause of cancer death worldwide. The most common histological type is non-small-cell lung cancer, accounting for 85% of all lung cancer cases. About one out of three new cases of non-small-cell lung cancer are diagnosed at a locally advanced stage—mainly stage III—consisting of a widely heterogeneous group of patients presenting significant differences in terms of tumor volume, local diffusion, and lymph nodal involvement. Stage III NSCLC therapy is based on the pivotal role of multimodal treatment, including surgery, radiotherapy, and a wide-ranging option of systemic treatments. Radical surgery is indicated in the case of hilar lymphnodal involvement or single station mediastinal ipsilateral involvement, possibly after neoadjuvant chemotherapy; the best appropriate treatment for multistation mediastinal lymph node involvement still represents a matter of debate. Although the main scope of treatments in this setting is potentially curative, the overall survival rates are still poor, ranging from 36% to 26% and 13% in stages IIIA, IIIB, and IIIC, respectively. The aim of this article is to provide an up-to-date, comprehensive overview of the state-of-the-art treatments for stage III non-small-cell lung cancer.

Immunotherapy progress and clinical strategy of unresectable locally advanced non-small cell lung cancer

Non-small cell lung cancer negative for actionable molecular markers entered the splendid era of immunotherapy. This review aims to provide an evidence-based summary for immunotherapy for unresectable locally advanced non-small cell lung cancer, and references for clinical strategies of immunotherapy. Through literature review, the standard treatment for unresectable locally advanced non-small cell lung cancer should be radical concurrent radiotherapy and chemotherapy followed by consolidation immunotherapy. However, the efficacy of concurrent radiotherapy, chemotherapy combined with immunotherapy has not been improved, and its safety should be further validated. It is believed that induction immunotherapy plus concurrent radiotherapy and chemotherapy plus consolidation immunotherapy is promising. In clinical practice, the delineation of radiotherapy target should be relatively small. Pemetrexed combined with PD-1 inhibitor induces the strongest immunogenicity in chemotherapy, which is suggested by preclinical pathway study. Although there is no significant difference between PD1 and PD1 for effect, PD-L1 inhibitor is better in the combination treatment of radiotherapy which presents significantly less adverse events.

Variability of Low-Z Inhomogeneity Correction in IMRT/SBRT: A Multi-Institutional Collaborative Study

Dose-calculation algorithms are critical for radiation treatment outcomes that vary among treatment planning systems (TPS). Modern algorithms use sophisticated radiation transport calculation with detailed three-dimensional beam modeling to provide accurate doses, especially in heterogeneous medium and small fields used in IMRT/SBRT. While the dosimetric accuracy in heterogeneous mediums (lung) is qualitatively known, the accuracy is unknown. The aim of this work is to analyze the calculated dose in lung patients and compare the validity of dose-calculation algorithms by measurements in a low-Z phantom for two main classes of algorithms: type A (pencil beam) and type B (collapse cone). The CT scans with volumes (target and organs at risk, OARs) of a lung patient and a phantom build to replicate the human lung data were sent to nine institutions for planning. Doses at different depths and field sizes were measured in the phantom with and without inhomogeneity correction across multiple institutions to understand the impact of clinically used dose algorithms. Wide dosimetric variations were observed in target and OAR coverage in patient plans. The correction factor for collapsed cone algorithms was less than pencil beam algorithms in the small fields used in SBRT. The pencil beam showed ≈70% variations between measured and calculated correction factors for various field sizes and depths. For large field sizes the trends of both types of algorithms were similar. The differences in measured versus calculated dose for type-B algorithms were within ±10%. Significant variations in the target and OARs were observed among various TPS. The results suggest that the pencil beam algorithm does not provide an accurate dose and should not be considered with small fields (IMRT/SBRT). Type-B collapsed-cone algorithms provide better agreement with measurements, but still vary among various systems.

Outcomes Following SBRT vs. IMRT and 3DCRT for Older Patients with Stage IIA Node-Negative Non-Small Cell Lung Cancer > 5 cm

BACKGROUND

To describe outcomes and compare the effectiveness of stereotactic body radiotherapy (SBRT) versus 3-dimensional conformal radiotherapy (3DCRT) or intensity-modulated radiotherapy (IMRT) in patients with stage IIA lymph node-negative (N0) non-small cell lung cancer (NSCLC) tumors > 5 cm.

METHODS

We used the SEER-Medicare database (2005-2015) to identify patients > 65 years with stage IIA (AJCC TNM7) N0 NSCLC > 5 cm tumors who were treated with SBRT, IMRT, and 3DCRT. We used propensity score methods with inverse probability weighting to compare lung cancer-specific survival (LCSS), overall survival (OS), and toxicity.

RESULTS

Of 584 patients, 88 (15%), 140 (24%), and 356 (61%) underwent SBRT, IMRT, and 3DCRT, respectively. The SBRT group was older (P = .004), had more comorbidities (P = .02), smaller tumors (P = .03), and more adenocarcinomas (P < .0001). We found a trend towards higher median unadjusted OS with SBRT compared to IMRT and 3DCRT (19 vs. 13 and 14 months, respectively, P = .37). In our propensity score-adjusted analyses, SBRT was significantly associated with better OS and LCSS compared to IMRT (HR_OS: 0.78, 95% CI: 0.68-0.89, HR_LCSS: 0.70, 95% CI: 0.60-0.81) and 3DCRT (HR_OS: 0.81, 95% CI: 0.72-0.93, HR_LCSS: 0.80, 95% CI: 0.68-0.93). SBRT-treated patients also had lower overall adjusted complication rates compared to IMRT (OR: 0.74, 95% CI: 0.55-0.99) and 3DCRT (OR: 0.53, 95% CI: 0.40-0.71).

CONCLUSION

For patients with NSCLC tumors > 5 cm, SBRT trends towards fewer toxicities and improved survival compared to other forms of radiotherapy. Our findings support SBRT as an appropriate treatment strategy for older patients with larger inoperable NSCLC tumors.

Using inflammatory indexes and clinical parameters to predict radiation esophagitis in patients with small-cell lung cancer undergoing chemoradiotherapy

OBJECTIVE

Radiation esophagitis (RE) is a common adverse effect in small cell lung cancer (SCLC) patients undergoing thoracic radiotherapy. We aim to develop a novel nomogram to predict the acute severe RE (grade≥2) receiving chemoradiation in SCLC patients.

MATERIALS AND METHODS

the risk factors were analyzed by logistic regression, and a nomogram was constructed based on multivariate analysis results. The clinical value of the model was evaluated using the area under the receiver operating curve (ROC) curve (AUC), calibration curves, and decision curve analysis (DCA). The correlations of inflammation indexes were assessed using Spearman correlation analysis.

RESULTS

Eighty-four of 187 patients (44.9%) developed grade ≥2 RE. Univariate analysis indicated that concurrent chemoradiotherapy (CCRT, p < 0.001), chemotherapy cycle (p = 0.097), system inflammation response index (SIRI, p = 0.048), prognostic-nutrition index (PNI, p = 0.073), platelets-lymphocyte radio (PLR, p = 0.026), platelets-albumin ratio (PAR, p = 0.029) were potential predictors of RE. In multivariate analysis, CCRT [p < 0.001; OR, 3.380; 95% CI, 1.767-6.465], SIRI (p = 0.047; OR, 0.436; 95% CI, 0.192-0.989), and PAR (p = 0.036; OR, 2.907; 95% CI, 1.071-7.891) were independent predictors of grade ≥2 RE. The AUC of nomogram was 0.702 (95% CI, 0.626-0.778), which was greater than each independent predictor (CCRT: 0.645; SIRI: 0.558; PAR: 0.559). Calibration curves showed high coherence between the predicted and actual observation RE, and DCA displayed satisfactory clinical utility.

CONCLUSION

In this study, CCRT, SIRI, and PAR were independent predictors for RE (grade ≥2) in patients with SCLC receiving chemoradiotherapy. We developed and validated a predictive model through these factors. The developed nomogram with superior prediction ability can be used as a quantitative model to predict RE.

Personalized mid-course FDG-PET based adaptive treatment planning for non-small cell lung cancer using machine learning and optimization

Objective. Traditional radiotherapy (RT) treatment planning of non-small cell lung cancer (NSCLC) relies on population-wide estimates of organ tolerance to minimize excess toxicity. The goal of this study is to develop a personalized treatment planning based on patient-specific lung radiosensitivity, by combining machine learning and optimization.Approach. Sixty-nine non-small cell lung cancer patients with baseline and mid-treatment [18]F-fluorodeoxyglucose (FDG)-PET images were retrospectively analyzed. A probabilistic Bayesian networks (BN) model was developed to predict the risk of radiation pneumonitis (RP) at three months post-RT using pre- and mid-treatment FDG information. A patient-specific dose modifying factor (DMF), as a surrogate for lung radiosensitivity, was estimated to personalize the normal tissue toxicity probability (NTCP) model. This personalized NTCP was then integrated into a NTCP-based optimization model for RT adaptation, ensuring tumor coverage and respecting patient-specific lung radiosensitivity. The methodology was employed to adapt the treatment planning of fifteen NSCLC patients.Main results. The magnitude of the BN predicted risks corresponded with the RP severity. Average predicted risk for grade 1-4 RP were 0.18, 0.42, 0.63, and 0.76, respectively (p< 0.001). The proposed model yielded an average area under the receiver-operating characteristic curve (AUROC) of 0.84, outperforming the AUROCs of LKB-NTCP (0.77), and pre-treatment BN (0.79). Average DMF for the radio-tolerant (RP grade = 1) and radiosensitive (RP grade ≥ 2) groups were 0.8 and 1.63,p< 0.01. RT personalization resulted in five dose escalation strategies (average mean tumor dose increase = 6.47 Gy, range = [2.67-17.5]), and ten dose de-escalation (average mean lung dose reduction = 2.98 Gy [0.8-5.4]), corresponding to average NTCP reduction of 15% [4-27].Significance. Personalized FDG-PET-based mid-treatment adaptation of NSCLC RT could significantly lower the RP risk without compromising tumor control. The proposed methodology could help the design of personalized clinical trials for NSCLC patients.

Locally advanced NSCLC: a plea for sparing the ipsilateral normal lung-prospective, clinical trial with DART-bid (dose-differentiated accelerated radiation therapy, 1.8 Gy twice daily) by VMAT

Background

In radiation treatment of locally advanced non-small cell lung cancer (LA-NSCLC), ‘margins’ from internal target volumes to planning target volumes in the range of 12 to 23 mm are reported, and avoiding exposure of the contralateral lung is common practice. We investigated prospectively an approach with tight margins (7 mm) and maximal sparing of the ipsilateral normal lung. Mature results for the first endpoint (pneumonitis) and further toxicities are reported.

Methods

Primary tumors were treated by VMAT with 73.8–90.0 Gy in positive correlation to tumor volumes, nodes with 61.2 Gy, a restricted volume of nodes electively with 45 Gy. Fractional doses of 1.8 Gy bid, interval 8 h. Before radiotherapy, two cycles platin-based chemotherapy were given. 12 patients finished maintenance therapy with Durvalumab. Median follow up time for all patients is 19.4 months, for patients alive 27.0 months (3.4–66.5 months).

Results

100 consecutive, unselected patients with LA-NSCLC in stages II through IVA were enrolled (UICC/AJCC, 8th edition). No acute grade 4/5 toxicity occurred. Pneumonitis grade 2 and 3 was observed in 12% and 2% of patients, respectively; lowering the risk of pneumonitis grade ≥ 2 in comparison to the largest study in the literature investigating pneumonitis in LA-NSCLC, is significant (p < 0.0006). Acute esophageal toxicity grade 1, 2 and 3 occurred in 12%, 57% and 3% of patients, respectively. Two patients showed late bronchial stricture/atelectasis grade 2. In two patients with lethal pulmonary haemorrhages a treatment correlation cannot be excluded. Median overall survival for all stage III patients, and for those with ‘RTOG 0617 inclusion criteria’ is 46.6 and 50.0 months, respectively.

Conclusions

Overall toxicity is low. In comparison to results in the literature, maximal sparing the ipsilateral normal lung lowers the risk for pneumonitis significantly.

Trial registration

Ethics committee of Vorarlberg, Austria; EK-0.04-105, Registered 04/09/2017—Retrospectively registered. http://www.ethikkommission-vorarlberg.at

Stereotactic Body Radiation Therapy for the Treatment of Locally Recurrent and Oligoprogressive Non-Small Cell Lung Cancer: A Single Institution Experience

Objectives

To investigate the efficacy and safety of lung stereotactic body radiation therapy (SBRT) for non-small cell lung cancer (NSCLC) including oligorecurrent and oligoprogressive disease.

Methods

Single-institution retrospective analysis of 60 NSCLC patients with 62 discrete lesions treated with SBRT between 2008 and 2017. Patients were stratified into three groups, including early stage, locally recurrent, and oligoprogressive disease. Group 1 included early stage local disease with no prior local therapy. Group 2 included locally recurrent disease after local treatment of a primary lesion, and group 3 included regional or well-controlled distant metastatic disease receiving SBRT for a treatment naive lung lesion (oligoprogressive disease). Patient/tumor characteristics and adverse effects were recorded. Local failure free survival (LFFS), progression free survival (PFS), and overall survival (OS) were estimated using the Kaplan Meier method.

Results

At median follow-up of 34 months, 67% of the study population remained alive. The estimated 3-year LFFS for group 1, group 2, and group 3 patients was 95% (95% CI: 86%-100%), 82%(62% - 100%), and 83% (58-100%), respectively. The estimated 3-year PFS was 59% (42-83%), 40% (21%-78%), and 33% (12%-95%), and the estimated 3-year OS was 58% (41-82%), 60% (37-96%), and 58% (31-100%)), respectively for each group. When adjusted for age and size of lesion, no significant difference in OS, LFFS, and PFS emerged between groups (p > 0.05). No patients experienced grade 3 to 5 toxicity. Eighteen patients (29%) experienced grade 1 to 2 toxicity. The most common toxicities reported were cough and fatigue.

Conclusions

Our data demonstrates control rates in group 1 patients comparable to historical controls. Our study also reveals comparable clinical results for SBRT in the treatment of NSCLC by demonstrating similar rates of LFFS and OS in group 2 and group 3 patients with locally recurrent and treatment naïve lung lesion with well-controlled distant metastatic disease.

Predicting personalised and progressive adaptive dose escalation to gross tumour volume using knowledge-based planning models for inoperable advanced-stage non-small cell lung cancer patients treated with volumetric modulated arc therapy

OBJECTIVES

Increased radiation doses could improve local control and overall survival of lung cancer patients, however, this could be challenging without exceeding organs at risk (OAR) dose constraints especially for patients with advanced-stage disease. Increasing OAR doses could reduce the therapeutic ratio and quality of life. It is therefore important to investigate methods to increase the dose to target volume without exceeding OAR dose constraints.

METHODS

Gross tumour volume (GTV) was contoured on synthetic computerised tomography (sCT) datasets produced using the Velocity adaptive radiotherapy software for eleven patients. The fractions where GTV volume decreased compared to that prior to radiotherapy (reference plan) were considered for personalised progressive dose escalation. The dose to the adapted GTV (GTVAdaptive) was increased until OAR doses were affected (as compared to the original clinical plan). Planning target volume (PTV) coverage was maintained for all plans. Doses were also escalated to the reference plan (GTVClinical) using the same method. Adapted, dose-escalated, plans were combined to estimate accumulated dose, D99 (dose to 99%) of GTVAdapted, PTV D99 and OAR doses and compared with those in the original clinical plans. Knowledge-based planning (KBP) model was developed to predict D99 of the adapted GTV with OAR doses and PTV coverage kept similar to the original clinical plans; prediction accuracy and model verification were performed using further data sets.

RESULTS

Compared to the original clinical plan, dose to GTV was significantly increased without exceeding OAR doses. Adaptive dose-escalation increased the average D99 to GTVAdaptive by 15.1Gy and 8.7Gy compared to the clinical plans. The KBP models were verified and demonstrated prediction accuracy of 0.4% and 0.7% respectively.

CONCLUSION

Progressive adaptive dose escalation can significantly increase the dose to GTV without increasing OAR doses or compromising dose to microscopic disease. This may increase overall survival without increasing toxicities.

Management of Stage III Non-Small-Cell Lung Cancer: ASCO Guideline

PURPOSE

To provide evidence-based recommendations to practicing clinicians on management of patients with stage III non-small-cell lung cancer (NSCLC).

METHODS

An Expert Panel of medical oncology, thoracic surgery, radiation oncology, pulmonary oncology, community oncology, research methodology, and advocacy experts was convened to conduct a literature search, which included systematic reviews, meta-analyses, and randomized controlled trials published from 1990 through 2021. Outcomes of interest included survival, disease-free or recurrence-free survival, and quality of life. Expert Panel members used available evidence and informal consensus to develop evidence-based guideline recommendations.

RESULTS

The literature search identified 127 relevant studies to inform the evidence base for this guideline.

RECOMMENDATIONS

Evidence-based recommendations were developed to address evaluation and staging workup of patients with suspected stage III NSCLC, surgical management, neoadjuvant and adjuvant approaches, and management of patients with unresectable stage III NSCLC.Additional information is available at www.asco.org/thoracic-cancer-guidelines.

Radiation Therapy in Non-Small-Cell Lung Cancer

The management of non-small-cell lung cancer (NSCLC) varies according to stage. Surgical resection is reserved for operable patients with early-stage NSCLC, while high-dose target radiation-stereotactic body radiation therapy (SBRT)-is reserved for patients whose comorbidities prohibit them from a major surgical procedure. The treatment of locally advanced NSCLC (LA-NSCLC) is stratified according to resectability. Those with resectable disease may require additional treatments such as chemotherapy and radiation, while patients with unresectable disease will require definitive chemoradiation therapy with adjuvant durvalumab. Patients with limited metastatic disease benefit from the combination of SBRT and systemic therapy.

Radiation-Induced Lung Injury-Current Perspectives and Management

Radiotherapy plays an important role in the treatment of localized primary malignancies involving the chest wall or intrathoracic malignancies. Secondary effects of radiotherapy on the lung result in radiation-induced lung disease. The phases of lung injury from radiation range from acute pneumonitis to chronic pulmonary fibrosis. Radiation pneumonitis is a clinical diagnosis based on the history of radiation, imaging findings, and the presence of classic symptoms after exclusion of infection, pulmonary embolism, heart failure, drug-induced pneumonitis, and progression of the primary tumor. Computed tomography (CT) is the preferred imaging modality as it provides a better picture of parenchymal changes. Lung biopsy is rarely required for the diagnosis. Treatment is necessary only for symptomatic patients. Mild symptoms can be treated with inhaled steroids while subacute to moderate symptoms with impaired lung function require oral corticosteroids. Patients who do not tolerate or are refractory to steroids can be considered for treatment with immunosuppressive agents such as azathioprine and cyclosporine. Improvements in radiation technique, as well as early diagnosis and appropriate treatment with high-dose steroids, will lead to lower rates of pneumonitis and an overall good prognosis.

Prognostic index for estimating the survival benefit of postoperative radiotherapy in pathologic N2 non-small cell lung cancer: A real-world validation study

OBJECTIVES

This study aimed to evaluate the effect of postoperative radiotherapy (PORT) in patients with resected pathologic N2 (pN2) non-small cell lung cancer (NSCLC) with different locoregional recurrence (LRR) risks.

MATERIALS AND METHODS

The primary cohort and validation cohort were retrieved from two independent medical centres. Data for all consecutive patients with completely resected pathologic stage T1-3N2M0 NSCLC were analysed. Patients without PORT in the primary cohort were identified as a training set. Significant prognostic factors for LRR were identified by the Fine-Gray model to develop a prognostic index (PI) in the training set.

RESULTS

The primary cohort consisted of 357 patients who met the eligibility criteria (training set, 287 patients without PORT). The external validation cohort consisted of 1044 patients who met the eligibility criteria (validation set, 711 patients without PORT). Heavy cigarette smoking history, clinical N2 status (cN2), and the number of positive lymph nodes >4 were identified as independent risk factors. The PI was computed as follows: PI＝0.8*smoking history＋0.5*cN2＋0.7*the number of involved lymph nodes (reference level was assigned the value 1 and risk level the value 2). In the low-risk group (PI score< = 3), PORT showed a trend towards decreased LRR rates but not significantly improved overall survival (OS). In the high-risk group (PI score>3), PORT significantly reduced the risk of LRR and improved OS.

CONCLUSIONS

We constructed and validated a PI to predict individually the effect of PORT in patients with completely resected pN2 NSCLC. Patients with a higher PI score can benefit from PORT in terms of OS.

Concurrent chemoradiotherapy for stage III non-small-cell lung cancer: recent progress and future perspectives (a narrative review)

Concurrent chemoradiotherapy (CHRT) remains the therapeutic standard for locally advanced inoperable non-small-cell lung cancer (NSCLC). The median overall survival (OS) with this approach is in the range of 20–30 months, with five-year survival of approximately 30%. These outcomes have recently been further improved by supplementing CHRT with maintenance durvalumab, a monoclonal anti-PD-L1 agent. The progress in treatment outcomes of locally advanced NSCLC before the era of immunotherapy has been achieved mainly by virtue of developments in diagnostics and radiotherapy techniques. Routine implementation of endoscopic and endobronchial ultrasonography for mediastinal lymph nodes assessment, positron emission tomography/computed tomography and magnetic resonance imaging of the brain allows for more accurate staging of NSCLC and for optimizing treatment strategy. Thorough staging and respiratory motion control allows for higher conformity of radiotherapy and reduction of radiotherapy related toxicity. Dose escalation with prolonged overall treatment time does not improve treatment outcomes of CHRT. In consequence, 60 Gy in 2 Gy fractions or equivalent biological dose remains the standard dose for definitive CHRT in locally advanced NSCLC. However, owing to increased toxicity of CHRT, this option may not be applicable in a proportion of elderly or frail patients. This article summarizes recent developments in curative CHRT for inoperable stage III NSCLC, and presents perspectives for further improvements of this strategy

Dose and fractionation schedules in radiotherapy for non-small cell lung cancer

In the field of radiotherapy (RT), the issues of total dose, fractionation, and overall treatment time for non-small cell lung cancer (NSCLC) have been extensively investigated. There is some evidence to suggest that higher treatment intensity of RT, when given alone or sequentially with chemotherapy (CHT), is associated with improved survival. However, there is no evidence that the outcome is improved by RT at a higher dose and/or higher intensity when it is used concurrently with CHT. Moreover, some reports on the combination of full dose CHT with a higher biological dose of RT warn of the significant risk posed by such intensification. Stereotactic body radiotherapy (SBRT) provides a high rate of local control in the management of early-stage NSCLC through the use of high ablative doses. However, in centrally located tumors the use of SBRT may carry a risk of serious damage to the great vessels, bronchi, and esophagus, owing to the high ablative doses needed for optimal tumor control. There is a similar problem with moderate hypofractionation in radical RT for locally advanced NSCLC, and more evidence needs to be gathered regarding the safety of such schedules, especially when used in combination with CHT. In this article, we review the current evidence and questions related to RT dose/fractionation in NSCLC.

Implications of pneumonitis after chemoradiation and durvalumab for locally advanced non-small cell lung cancer

Background

Consolidation durvalumab improved overall survival (OS) in locally advanced non-small cell lung cancer (LA-NSCLC) treated with chemoradiotherapy (CRT) in the PACIFIC trial; however, pneumonitis was increased with durvalumab. We sought to examine real-world outcomes with the PACIFIC paradigm, especially factors associated with pneumonitis, using a multi-institutional review.

Methods

Patients with LA-NSCLC treated with CRT followed by durvalumab from January 2017–February 2019 were identified at 2 institutions. We characterized demographics, tumor factors, radiotherapy, and duration of durvalumab. We examined pneumonitis outcomes including re-challenge success, with secondary endpoints of progression-free survival (PFS) and OS.

Results

Thirty-four patients were included with median follow-up of 12 months (range, 3 to 20 months); 94% had stage III disease. The cumulative grade >2 pneumonitis rate was 26.5% with 2 patients developing grade 3 pneumonitis and no grade 4/5 events. Median time to pneumonitis after RT was 2.4 months (range, 0 to 4.9 months). Pneumonitis management included median prednisone dose of 60 mg for median taper of 6 weeks with durvalumab held for median of 4.5 weeks (range, 2 to 8 weeks); 70% of pneumonitis patients received durvalumab re-challenge, with pneumonitis recurring in 14% of patients. 3-month and 6-month pneumonitis-free-survival were 76.9% and 73.6%, respectively; 9- and 12-month OS were 96% (75.1–99.8%), 86.6% (63.5–95.5%), respectively; 9- and 12-month PFS were 68% (47.5–82.5%), 48.7% (25.3–68.3%). Pneumonitis development did not significantly impact PFS or OS (P>0.05).

Conclusions

Among LA-NSCLC patients treated with CRT followed by consolidation durvalumab, more than 25% developed symptomatic pneumonitis. In this small case series, pneumonitis did not appear to negatively impact survival, and durvalumab re-challenge appeared feasible after pneumonitis treatment with steroids.

Adverse effects of chemoradiotherapy on invasion and metastasis of tumor cells

The phenomenon of enhanced invasion and metastasis of residual tumor cells has been observed in an increasing number of patients receiving chemoradiotherapy recently, and tumor metastasis will undoubtedly limit patient prognosis. However, the key mechanism by which chemoradiotherapy affects the invasion and metastasis of tumor cells remains unclear. Studies have shown that chemoradiotherapy may directly act on tumor cells and alter the tumor microenvironment, or induce cell apoptosis and autophagy to promote tumor cell survival and metastasis. In this review, we summarize the potential mechanisms by which chemoradiotherapy may affect the biological behavior of tumor cells and open up new avenues for reducing tumor recurrence and metastasis after treatment. These insights will improve the efficacy of chemoradiotherapy.

Dose-volume predictors of early esophageal toxicity in non-small cell lung cancer patients treated with accelerated-hyperfractionated radiotherapy

BACKGROUND AND PURPOSE

Early radiation-induced esophageal toxicity (RIET) is one of the major side effects in patients with non-small cell lung cancer (NSCLC) and can be a reason for treatment interruptions. As the age of patients with NSCLC and corresponding comorbidities continue to increase, primary radiotherapy alone is a commonly used alternative treatment in these cases. The aim of the present study is to compare dosimetric and clinical parameters from the previously reported CHARTWEL trial for their ability to predict esophagitis and investigate potential differences in the accelerated and conventional fractionation arm.

MATERIAL AND METHODS

146 patients of the Dresden cohort of the randomized phase III CHARTWEL trial were included in this post-hoc analysis. Side effects were prospectively scored weekly during the first 8 weeks from start of radiotherapy. To compare both treatment arms, recorded dose-volume parameters were adjusted for the different fractionation schedules. Logistic regression was performed to predict early RIET for the entire study group as well as for the individual treatment arms. Different dosimetric and clinical parameters were tested.

RESULTS

Patients receiving the accelerated CHARTWEL schedule experienced earlier and more severe esophagitis (e.g. 20.5% vs. 9.6% ≥grade 2 at week 3, respectively). In contrast, the median time period for recovery of grade 1 esophagitis was significantly longer for patients with conventional fractionation compared to the CHARTWEL group (median [range]: 21 [12-49] days vs. 15 [7-84] days, p = 0.028). In univariable logistic regression none of the dose-volume parameters showed a significant correlation with early RIET grade ≥ 2 in the conventional irradiation group. In contrast, for patients receiving CHARTWEL, the physical dose-volumes parameters V₄₀ and V₅₀; and re-scaled values V_EQD2,50 and V_EQD2,60 were significant predictors of early RIET grade ≥ 2. Dose-volume parameters remained different between CHARTWEL and conventional fractionation even after biological rescaling.

CONCLUSION

Our results show a more dominant dose-volume effect in the CHARTWEL arm compared to conventional fractionation, especially for higher esophageal doses. These findings support the notion that dose-volume parameters for radiation esophagitis determined in a specific and time dependent setting of field arrangements can not be easily transferred to another setting. In clinical practice esophageal volumes receiving 40 Gy or more should be strictly limited in hyperfractionated-accelerated fraction schemes.

Functional perfusion image guided radiation treatment planning for locally advanced lung cancer

Background and purpose

Functional avoidance radiation therapy (RT) aims at sparing functional lung regions. The purpose of this simulation study was to evaluate the feasibility of functional lung avoidance methodology in RT of lung cancer and to characterize the achievable dosimetry of single photon emission computed tomography (SPECT) guided treatment planning.

Materials and methods

Fifteen consecutive lung cancer patients were included and planned for definitive RT of 60–66 Gy in 2-Gy fractions. Two plans were optimized: a standard CT-plan, and functional SPECT-plan. The objective was to reduce dose to the highly functional lung subvolumes without compromising tumour coverage, and respecting dose to other organs at risk. For each patient a 3D-conformal, intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy plans were created for standard and functional avoidance. Standard versus functional dose-volume parameters for functional lung (FL) subvolumes, organs at risk and tumour coverage were compared.

Results

The largest dose reduction was achieved with IMRT plans. Functional plans resulted in dose reduction from 9.0 Gy to 6.7 Gy (mean reduction of 2.3 Gy or 26%) to the highest functional subvolume FL80% (95%CI 1.1; 3.5). Dose to FL40% was reduced from 13.3 Gy to 11.6 Gy with functional planning. Dose reduction to FL40% was 1.7 Gy (95%CI 0.9; 2.6). Functional volume of lung receiving over 20 Gy improved by 5% (standard 22%, functional 17%). Dose to organs at risk and tumour coverage were not significantly different between plans.

Conclusions

SPECT/CT-guided planning resulted in improved dose-volumetric outcomes for functional lung. This methodology may lead to potential reduction in radiation-induced lung toxicity.

Chemoradiotherapy of locally-advanced non-small cell lung cancer: Analysis of radiation dose-response, chemotherapy and survival-limiting toxicity effects indicates a low α/β ratio

PURPOSE

To analyse changes in 2-year overall survival (OS_2yr) with radiotherapy (RT) dose, dose-per-fraction, treatment duration and chemotherapy use, in data compiled from prospective trials of RT and chemo-RT (CRT) for locally-advanced non-small cell lung cancer (LA-NSCLC).

MATERIAL AND METHODS

OS_2yr data was analysed for 6957 patients treated on 68 trial arms (21 RT-only, 27 sequential CRT, 20 concurrent CRT) delivering doses-per-fraction ≤4.0 Gy. An initial model considering dose, dose-per-fraction and RT duration was fitted using maximum-likelihood techniques. Model extensions describing chemotherapy effects and survival-limiting toxicity at high doses were assessed using likelihood-ratio testing, the Akaike Information Criterion (AIC) and cross-validation.

RESULTS

A model including chemotherapy effects and survival-limiting toxicity described the data significantly better than simpler models (p < 10^-14), and had better AIC and cross-validation scores. The fitted α/β ratio for LA-NSCLC was 4.0 Gy (95%CI: 2.8-6.0 Gy), repopulation negated 0.38 (95%CI: 0.31-0.47) Gy EQD2/day beyond day 12 of RT, and concurrent CRT increased the effective tumour EQD2 by 23% (95%CI: 16-31%). For schedules delivered in 2 Gy fractions over 40 days, maximum modelled OS_2yr for RT was 52% and 38% for stages IIIA and IIIB NSCLC respectively, rising to 59% and 42% for CRT. These survival rates required 80 and 87 Gy (RT or sequential CRT) and 67 and 73 Gy (concurrent CRT). Modelled OS_2yr rates fell at higher doses.

CONCLUSIONS

Fitted dose-response curves indicate that gains of ~10% in OS_2yr can be made by escalating RT and sequential CRT beyond 64 Gy, with smaller gains for concurrent CRT. Schedule acceleration achieved via hypofractionation potentially offers an additional 5-10% improvement in OS_2yr. Further 10-20% OS_2yr gains might be made, according to the model fit, if critical normal structures in which survival-limiting toxicities arise can be identified and selectively spared.

Accelerated hypofractionated radiotherapy plus chemotherapy for inoperable locally advanced non-small-cell lung cancer: final results of a prospective phase-II trial with a long-term follow-up

BACKGROUND

Concurrent chemotherapy and radiation using conventional fractionation is the standard treatment for inoperable, locally advanced non-small-cell lung cancer (NSCLC). We tested accelerated hypofractionated radiotherapy (AHR) and chemotherapy for the treatment of locally advanced NSCLC.

METHODS

Eligible patients with locally advanced NSCLC were treated with induction chemotherapy (cisplatin and docetaxel), followed by AHR using tomotherapy and consolidation chemotherapy. The prescribed doses were 30 Gy/5 daily fractions at the reference isodose (60-70%) to the tumor, and 25 Gy/5 daily fractions to the clinically involved lymph nodes. The primary end-point was response rate (RR); the secondary end-points were acute and late side-effects, local progression-free survival (PFS), metastasis-free survival (MFS) and overall survival (OS). This trial closed before the first planned interim analysis due to poor accrual.

RESULTS

From January 2009 to January 2012, 17 of the 23 enrolled patients were evaluable. Treatment yielded an overall RR of 82%. Median follow-up was 87 months (range: 6-87), local PFS was 19.8 months (95% CI 9.7 - not reached), MFS was 9.7 months (95% CI 5.8-46.0) and OS was 23 months (95% CI 8.4-48.4). 70% of patients experienced acute G4 neutropenia, 24% G4 leukopenia, 24% G3 paresthesia, 4% G3 cardiac arrythmia, 4% underwent death after chemotherapy. Late toxicity was represented by 24% dyspnea G3.

CONCLUSIONS

AHR combined with chemotherapy is feasible with no severe side-effects, and it appears highly acceptable by patients.

TRIAL REGISTRATION

This study is registered with the EudractCT registration 2008-006525-14 . Registered on 9 December 2008.

Phase II study of compensator-based non-coplanar intensity-modulated radiotherapy for Stage I non-small-cell lung cancer

We conducted a Phase II study to evaluate the usefulness of compensator-based non-coplanar intensity-modulated radiotherapy (ncIMRT) for patients with surgically inaccessible Stage I non-small-cell lung cancer (NSCLC). Patients with pathologically proven or clinically diagnosed surgically inaccessible Stage I NSCLC were enrolled in this study from May 2011 to April 2014. These patients underwent ncIMRT of 75 Gy in 30 fractions regardless of the tumor location. The primary end point was 3-year overall survival, and the secondary end points were local control rate and treatment-related toxicities. A total of 48 patients (50 tumors) were enrolled in this study. Of the 50 tumors, the Stage T1 to T2 ratio was 31 to 19, and the ratio of tumors located in the central to peripheral areas was 11 to 39. During the median follow-up time of 35.9 months, the 3-year actuarial local progression-free and overall survival rates were 82.6% and 87.1%, respectively. No patients experienced toxicities of Grade 3 or greater. Standard-fractionated ncIMRT was effective and safe for patients with surgically inaccessible stage I NSCLC, regardless of the tumor location.

Hypo-fractionated boost in locally advanced non-small cell lung cancer: temporal distribution of boost fractions

To propose new schemas for radiation boosting of primary tumors, in locally advanced non-small cell lung cancers (NSCLC), in conjunction with standard chemoradiotherapy. To investigate the effect of temporal distributions of the boost fractions on tumor control. NSCLC cases, previously treated with 60 Gy in 30 fractions, were retrospectively planned by adding a radiation boost (25 Gy in 5 fractions) to the primary tumor. Several integrated and sequential boosting schedules were considered. Biological doses were calculated for targets and organs at risk (OAR). Tumor control probabilities (TCP) were calculated using an empirical model and a stochastic model that accounts more systematically for tumor growth kinetics and cell kill. For heterogeneous patient populations, the TCPs for different boost schedules ranged from 82% to 84% and from 73% to 74% for integrated and sequential boosting respectively. For individual tumors with specific growth parameters, the TCP varied by up to 19% between the different schedules. The TCP for sequential boosting was expected to be up to 67% lower than front integrated boosting. The gap in TCP between schedules was higher for tumors with higher clonogenic cell numbers, lower radio-sensitivity, shorter doubling times and lower cell loss. The proposed boosting schemas are dosimetrically feasible and biologically effective. We suggest that the boosts are most effective when given during the first week of treatment and least effective when given sequentially after the end of treatment. The effect of boost scheduling and the effectiveness of front boosting are expected to be most significant for tumors with high clonogenic cell numbers, fast growing rates, low cell loss and low radio-sensitivity. Ultimately, animal studies and clinical trials, guided by biology modeling as presented in the present work, will be needed to verify the effectiveness of fine tuning temporal distributions of radiotherapy fractions.

Hypofractionated radiation therapy in the management of locally advanced NSCLC: a narrative review of the literature on behalf of the Italian Association of Radiation Oncology (AIRO)-Lung Working Group

A systematic literature was performed to assess the benefit in terms of effectiveness and feasibility of hypofractionated radiotherapy (HypoRT), with or without chemotherapy (CT), in the treatment of locally advanced non-small cell lung cancer (NSCLC). We have identified all studies, published from 2007 onwards, on patients with locally advanced NSCLC treated with HypoRT with radical intent, with a minimal dose per fraction of 2.4 Gy, with or without concurrent chemotherapy. Twenty-nine studies were identified, for a total of 2614 patients. Patients were divided in the concurrent chemo-radiation therapy group (CT-RT) and radiotherapy alone (RT). In RT group, the delivered dose ranged from 45 to 85.5 Gy, with a dose/fraction from 2.4 to 4 Gy. Actuarial 2-year PFS ranged from 13 to 57.8%, and 1, 2- and 3-year overall survival (OS) ranged from 51.3 to 95%, from 22 to 68.7%, and from 7 to 32%, respectively. Acute Grade ≥ 3 esophagitis occurred in 0-15%, while late esophageal toxicity was 0-16%. Acute pneumonitis occured in 0-44%, whereas late pneumonitis occured in 0-47%, most commonly grade ≤ G3. In CT-RT group, the delivered dose ranged from 52.5 to 75 Gy, with a dose/fraction ranging from 2.4 to 3.5 Gy. Actuarial 2-year PFS ranged from 19 to 57.8%, and OS at 1, 2 and 3 years ranged from 28 to 95%, 38.6 to 68.7%, and 31 to 44%, respectively. Acute Grade 2 and 3 esophagitis occurred in 3-41.7%, while late esophageal toxicity occurred in 0-8.3%. Acute pneumonitis ranged from 0 to 23%, whereas late pneumonitis occured 0-47%. HypoRT seems to be safe in patients with locally advanced NSCLC. The encouraging survival results of several studies analyzed suggest that hypofractionated radiation schemes should be further investigated in the future.

Amifostine- and chemoradiotherapy-related esophagitis in small cell lung cancer: a single institutional series and literature update

Objectives

Concurrent chemoradiotherapy is considered a standard option for patients with stage 3 small cell lung carcinoma. A 25% risk of acute esophagitis is experienced by patients as a result of the volume of esophagus encompassed within a conformal radiotherapy technique. We reviewed our institutional experience administering the radioprotectant amifostine prior to daily radiotherapy to determine its effects on the onset of esophagitis.

Materials and methods

From 2005 to 2016, 49 patients diagnosed with stage 3 small cell lung carcinoma received concurrent chemoradiotherapy. Chemotherapy (CT) consisted of cisplatin and etoposide with radiotherapy (RT) encompassing CT-identified gross tumor volume. In 32 patients (group 1), amifostine was delivered (500 mg subcutaneously divided in two injections) prior to the second daily RT fraction. The remaining 17 patients (group 2) did not receive amifostine due to choice or drug intolerance.

Results

Metrics of esophagitis included weight loss and opiate requirement during treatment. About 31% of group 1 required opiates at a median RT dose of 3300 cGy, and 41% of group 2 required opiates at a median dose of 2250 cGy. The dose of radiotherapy delivered to 50% of the esophageal volume for group 1 was significantly greater than that in group 2 (3000 cGy vs 576 cGy).

Conclusion

In this modern retrospective series of thoracic chemoradiotherapy in the treatment of stage 3 small cell lung cancer, amifostine that was delivered subcutaneously postponed the onset of esophagitis.

Dose escalation to 84 Gy with concurrent chemotherapy in stage III NSCLC appears excessively toxic: Results from a prematurely terminated randomized phase II trial

OBJECTIVES

Concurrent chemoradiotherapy is the mainstay treatment for NSCLC stage III disease. To investigate whether radiation dose escalation based on individual normal tissue constraints can improve outcome, the Swedish lung cancer study group launched this randomized phase II trial.

MATERIALS AND METHODS

NSCLC patients with stage III disease, good performance status (0-1) and adequate lung function (FEV1 > 1.0 L and CO diffusion capacity > 40%) received three cycles of cisplatin (75 mg/m² day 1) and vinorelbine (25 mg/m² day 1 and 8) every third week. Radiotherapy started concurrently with the second cycle, with either 2 Gy daily, 5 days a week, to 68 Gy (A) or escalated therapy (B) based on constraints to the spinal cord, esophagus and lungs up to 84 Gy by adding an extra fraction of 2 Gy per week.

RESULTS

A pre-planned safety analysis revealed excessive toxicity and decreased survival in the escalated arm, and the study was stopped. Thirty-six patients were included during 2011-2013 (56% male, 78% with adenocarcinoma, 64% with PS 0 and 53% with stage IIIB). The median progression-free survival (PFS) and overall survival (OS) were 11 and 17 months in arm B compared to the encouraging results of 28 and 45 months in the standard arm. The 1- and 3-year survival rates were 56% and 33% (B) and 72% and 56% (A), respectively. There were seven toxicity-related deaths due to esophageal perforations and pneumonitis: five in the escalated group and two with standard treatment.

CONCLUSION

Dose-escalated concurrent chemoradiotherapy to 84 Gy to primary tumor and nodal disease is hazardous, with a high risk of excessive toxicity, whereas modern standard dose chemoradiotherapy with proper staging given in the control arm shows a promising outcome with a median survival of 45 months and a 3-year survival of 56% (NCT01664663).

Early tumor shrinkage served as a prognostic factor for patients with stage III non-small cell lung cancer treated with concurrent chemoradiotherapy

BACKGROUND

Lung cancer is the most common cause of cancer death. About 80% of patients are diagnosed at stage III in the non-small cell lung cancer (NSCLC). It is extremely important to understand the progression of this disease which has low survival times despite the advancing treatment modalities. We aimed to investigate the relationship between early tumor shrinkage (ETS) after initial concurrent chemoradiotherapy (C-CRT) and survival outcome in patients with stage III (NSCLC).

METHODS

A retrospective review of 103 patients with stage III NSCLC who had received C-CRT from January 2006 to October 2011 was performed. Patients were treated with systemic chemotherapy regimen of Cisplatin/Vp-16 and concurrent thoracic radiotherapy at a median dose of 66 Gy (range 60-70 Gy). All patients received a computed tomography (CT) examination before treatment. Also subsequently, chest CT scans were performed with the same imaging parameters at approximately 5 weeks after the initiation of treatment. ETS is here stratified by a decrease in tumor size ≥30% and <30% in the longest dimension of the target lesion within 5 weeks.

RESULTS

Of the 103 patients, 59 ones showed a 30% decrease in tumor size, and the rest displayed a decrease of <30%. ETS showed no significant correlation with age, T classification, N classification, histological classification, smoking status, G classification, EGFR status, or acute pulmonary toxicity. In the current retrospective clinical study, Kaplan-Meier curves showed that patients with ETS ≥ 30% had a better progression-free survival and overall survival. The univariate and multivariate Cox regression analyses indicated that ETS < 30% was associated with a significantly increased risk of cancer-related death (P < .05) in stage IIINSCLC.

CONCLUSIONS

ETS may be served as a useful prognostic factor to predict the outcome of stage III NSCLC patients treated with CCRT.

Dosimetric feasibility of 4DCT-ventilation imaging guided proton therapy for locally advanced non-small-cell lung cancer

Background

The principle aim of this study is to incorporate 4DCT ventilation imaging into functional treatment planning that preserves high-functioning lung with both double scattering and scanning beam techniques in proton therapy.

Methods

Eight patients with locally advanced non-small-cell lung cancer were included in this study. Deformable image registration was performed for each patient on their planning 4DCTs and the resultant displacement vector field with Jacobian analysis was used to identify the high-, medium- and low-functional lung regions. Five plans were designed for each patient: a regular photon IMRT vs. anatomic proton plans without consideration of functional ventilation information using double scattering proton therapy (DSPT) and intensity modulated proton therapy (IMPT) vs. functional proton plans with avoidance of high-functional lung using both DSPT and IMPT. Dosimetric parameters were compared in terms of tumor coverage, plan heterogeneity, and avoidance of normal tissues.

Results

Our results showed that both DSPT and IMPT plans gave superior dose advantage to photon IMRTs in sparing low dose regions of the total lung in terms of V5 (volume receiving 5Gy). The functional DSPT only showed marginal benefit in sparing high-functioning lung in terms of V5 or V20 (volume receiving 20Gy) compared to anatomical plans. Yet, the functional planning in IMPT delivery, can further reduce the low dose in high-functioning lung without degrading the PTV dosimetric coverages, compared to anatomical proton planning. Although the doses to some critical organs might increase during functional planning, the necessary constraints were all met.

Conclusions

Incorporating 4DCT ventilation imaging into functional proton therapy is feasible. The functional proton plans, in intensity modulated proton delivery, are effective to further preserve high-functioning lung regions without degrading the PTV coverage.

Robust optimization in lung treatment plans accounting for geometric uncertainty

Robust optimization generates scenario‐based plans by a minimax optimization method to find optimal scenario for the trade‐off between target coverage robustness and organ‐at‐risk (OAR) sparing. In this study, 20 lung cancer patients with tumors located at various anatomical regions within the lungs were selected and robust optimization photon treatment plans including intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) plans were generated. The plan robustness was analyzed using perturbed doses with setup error boundary of ±3 mm in anterior/posterior (AP), ±3 mm in left/right (LR), and ±5 mm in inferior/superior (IS) directions from isocenter. Perturbed doses for D₉₉, D₉₈, and D₉₅ were computed from six shifted isocenter plans to evaluate plan robustness. Dosimetric study was performed to compare the internal target volume‐based robust optimization plans (ITV‐IMRT and ITV‐VMAT) and conventional PTV margin‐based plans (PTV‐IMRT and PTV‐VMAT). The dosimetric comparison parameters were: ITV target mean dose (D_mean), R₉₅(D₉₅/D_prescription), Paddick's conformity index (CI), homogeneity index (HI), monitor unit (MU), and OAR doses including lung (D_mean, V_{20 Gy} and V_{15 Gy}), chest wall, heart, esophagus, and maximum cord doses. A comparison of optimization results showed the robust optimization plan had better ITV dose coverage, better CI, worse HI, and lower OAR doses than conventional PTV margin‐based plans. Plan robustness evaluation showed that the perturbed doses of D₉₉, D₉₈, and D₉₅ were all satisfied at least 99% of the ITV to received 95% of prescription doses. It was also observed that PTV margin‐based plans had higher MU than robust optimization plans. The results also showed robust optimization can generate plans that offer increased OAR sparing, especially for normal lungs and OARs near or abutting the target. Weak correlation was found between normal lung dose and target size, and no other correlation was observed in this study.

Using gEUD based plan analysis method to evaluate proton vs. photon plans for lung cancer radiation therapy

The goal of this study was to exam the efficacy of current DVH based clinical guidelines draw from photon experience for lung cancer radiation therapy on proton therapy. Comparison proton plans and IMRT plans were generated for 10 lung patients treated in our proton facility. A gEUD based plan evaluation method was developed for plan evaluation. This evaluation method used normal lung gEUD(a) curve in which the model parameter "a" was sampled from the literature reported value. For all patients, the proton plans delivered lower normal lung V5 Gy with similar V20 Gy and similar target coverage. Based on current clinical guidelines, proton plans were ranked superior to IMRT plans for all 10 patients. However, the proton and IMRT normal lung gEUD(a) curves crossed for 8 patients within the tested range of "a", which means there was a possibility that proton plan would be worse than IMRT plan for lung sparing. A concept of deficiency index (DI) was introduced to quantify the probability of proton plans doing worse than IMRT plans. By applying threshold on DI, four patients' proton plan was ranked inferior to the IMRT plan. Meanwhile if a threshold to the location of curve crossing was applied, 6 patients' proton plan was ranked inferior to the IMRT plan. The contradictory ranking results between the current clinical guidelines and the gEUD(a) curve analysis demonstrated there is potential pitfalls by applying photon experience directly to the proton world. A comprehensive plan evaluation based on radio-biological models should be carried out to decide if a lung patient would really be benefit from proton therapy.

Evaluation of MLC leaf transmission on IMRT treatment plan quality of patients with advanced lung cancer

The purpose of this paper was to evaluate the impact of leaf treatment of multileaf collimator (MLC) in plan quality of intensity-modulated radiotherapy (IMRT) of patients with advanced lung cancer. Five MLCs with different leaf transmissions (0.01%, 0.5%, 1.2%, 1.8%, and 3%) were configured for an accelerator in a treatment planning system. Correspondingly, 5 treatment plans with the same optimization setting were created and evaluated quantitatively for each patient (11 patients total) who was diagnosed with advanced lung cancer. All of the 5 plans for each patient met the dose requirement for the planning treatment volumes (PTVs) and had similar target dose homogeneity and conformity. On average, the doses to selected organs were as follows: (1) V₅, V₂₀, and the mean dose of total lung; (2) the maximum and mean dose to spinal cord planning organ-at-risk volume (PRV); and (3) V₃₀ and V₄₀ of heart, decreased slightly when MLC transmission was decreased, but with no statistical differences. There is a clear grouping of plans having total quality score (S_D) value, which is used to evaluate plan quality: (1) more than 1 (patient nos. 1 to 3, 5, and 8), and more than 2.5 (patient no. 6); (2) less than 1 (patient nos. 7 and 10); (3) around 1 (patient nos. 4, 9, and 11). As MLC transmission increased, overall S_D values increased as well and plan dose requirement was harder to meet. The clinical requirements were violated increasingly as MLC transmission became large. Total S_D with and without normal tissue (NT) showed similar results, with no statistically significant differences. Therefore, decrease of MLC transmission did have minimum impact on plan, and it improved target coverage and reduced normal tissue radiation slightly, with no statistical significance. Plan quality could not be significantly improved by MLC transmission reduction. However, lower MLC transmission may have advantages on lung sparing to low- and intermediate-dose exposure. Besides conventional fraction, hyperfraction, or stereotactic body radiotherapy (SBRT), the reduction on lung sparing is still essential because it is highly relevant to radiation pneumonitis (RP). It has potential to diminish incidence of RP and improve patient's quality of life after irradiation with lowered MLC transmission.

Is a clinical target volume (CTV) necessary for locally advanced non-small cell lung cancer treated with intensity-modulated radiotherapy? -a dosimetric evaluation of three different treatment plans

Background

The aim of this study was to determine the feasibility of omitting the clinical target volume (CTV) in patients with locally advanced non-small cell lung cancer (NSCLC) treated with intensity-modulated radiotherapy (IMRT) by comparing dosimetric characteristics of three different IMRT plans with or without CTV implementation.

Methods

Thirteen patients with stage III NSCLC were reviewed. Target volumes were contoured such that the planning target volume (PTV) derived from the gross tumor volume (GTV) directly was named PTV_g and that from GTV plus CTV margin was named PTV_c. The PTV margin to generate PTV_g or PTV_c was the same within each case. Three IMRT plans were retrospectively generated to deliver: (I) 60 Gy to PTV_g in plan_routine; (II) 60 Gy to PTV_c in plan_CTV, and (III) 50 Gy to PTV_c while the dose was simultaneously escalated to 60 Gy to PTV_g in plan_SIB, achieved using the simultaneous integrated boost (SIB) technique. Optimization was performed to minimize the dose volumes of the irradiated normal lung, heart, esophagus, and spinal cord. Dose distributions and dosimetric indexes for the target volumes and critical structures in the three plans were computed and compared.

Results

In plan_routine, the 50-Gy isodose line covered at least 95% of the GTV plus CTV margins in all 13 patients. The statistics showed better sparing of the organs at risk (OAR) in plan_routine than in plan_CTV, and the best OAR sparing in plan_SIB.

Conclusions

In patients with locally advanced lung cancer, IMRT planning without CTV implementation provides sufficient dose coverage of subclinical disease while reducing the dose to normal tissues. The omission of CTV was feasible in our cohort of patients. However, when CTV was implemented, IMRT planning that included the SIB technique had further dosimetric benefits to the patients. This strategy thus merits further evaluation in clinical trials.

Radiation toxicity in patients with collagen vascular disease and intrathoracic malignancy treated with modern radiation techniques

BACKGROUND AND PURPOSE

There is concern that patients with collagen vascular disease (CVD) are at higher risk of developing radiation toxicity. We analyzed radiation toxicities in patients with intrathoracic malignancy and CVD treated using modern radiotherapy.

MATERIALS AND METHODS

This single-institution retrospective study included 31 patients with CVD and 825 patients without CVD treated from 1998 to 2014. Radiation esophagitis (RE) and radiation pneumonitis (RP) were scored by RTOG scales. RE was analyzed with logistic regression and RP with Cox regression.

RESULTS

CVD patients experienced similar grade ≥3 RE compared to control patients (23% vs. 19%, p = 0.64) but more grade ≥3 RP (26% vs. 10%, p = 0.01). There was no significant association between CVD subtype and toxicities. In multivariate analysis, CVD and lung V20 >30% were associated with grade ≥3 RP. We identified V20 ≤30%, V5 ≤50%, and MLD ≤18 Gy as dose thresholds in patients with CVD. CVD patients with mild severity disease and only 1 organ system involved were at low risk for RP.

CONCLUSIONS

Patients with CVD may be at higher risk of RP. However, CVD patients may be offered curative thoracic RT with particular attention to risk-reduction strategies and maintaining recommended dose constraints as described in this study.

Effect of Midtreatment PET/CT-Adapted Radiation Therapy With Concurrent Chemotherapy in Patients With Locally Advanced Non-Small-Cell Lung Cancer: A Phase 2 Clinical Trial

Importance

Our previous studies demonstrated that tumors significantly decrease in size and metabolic activity after delivery of 45 Gy of fractionated radiatiotherapy (RT), and that metabolic shrinkage is greater than anatomic shrinkage. This study aimed to determine whether 18F-fludeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) acquired during the course of treatment provides an opportunity to deliver higher-dose radiation to the more aggressive areas of the tumor to improve local tumor control without increasing RT-induced lung toxicity (RILT), and possibly improve survival.

Objective

To determine whether adaptive RT can target high-dose radiation to the FDG-avid tumor on midtreatment FDG-PET to improve local tumor control of locally advanced non-small-cell lung cancer (NSCLC).

Design, Setting, and Participants

A phase 2 clinical trial conducted at 2 academic medical centers with 42 patients who had inoperable or unresectable stage II to stage III NSCLC enrolled from November 2008, to May 2012. Patients with poor performance, more than 10% weight loss, poor lung function, and/or oxygen dependence were included, providing that the patients could tolerate the procedures of PET scanning and RT.

Intervention

Conformal RT was individualized to a fixed risk of RILT (grade >2) and adaptively escalated to the residual tumor defined on midtreatment FDG-PET up to a total dose of 86 Gy in 30 daily fractions. Medically fit patients received concurrent weekly carboplatin plus paclitaxel followed by 3 cycles of consolidation.

Main Outcomes and Measures

The primary end point was local tumor control. The trial was designed to achieve a 20% improvement in 2-year control from 34% of our prior clinical trial experience with 63 to 69 Gy in a similar patient population.

Results

The trial reached its accrual goal of 42 patients: median age, 63 years (range, 45-83 years); male, 28 (67%); smoker or former smoker, 39 (93%); stage III, 38 (90%). Median tumor dose delivered was 83 Gy (range, 63-86 Gy) in 30 daily fractions. Median follow-up for surviving patients was 47 months. The 2-year rates of infield and overall local regional tumor controls (ie, including isolated nodal failure) were 82% (95% CI, 62%-92%) and 62% (95% CI, 43%-77%), respectively. Median overall survival was 25 months (95% CI, 12-32 months). The 2-year and 5-year overall survival rates were 52% (95% CI, 36%-66%) and 30% (95% CI, 16%-45%), respectively.

Conclusions and Relevance

Adapting RT-escalated radiation dose to the FDG-avid tumor detected by midtreatment PET provided a favorable local-regional tumor control. The RTOG 1106 trial is an ongoing clinical trial to validate this finding in a randomized fashion.

Trial Registration

clinicaltrials.gov Identifier: NCT01190527.

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

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

Induction chemoradiotherapy using docetaxel and cisplatin with definitive-dose radiation followed by surgery for locally advanced non-small cell lung cancer

Background

Induction chemoradiotherapy (CRT) followed by surgery is a therapeutic option for locally advanced non-small cell lung cancer (LA-NSCLC). Typically, around 40-50 Gy of radiation is applied as the induction-dose; however, a definitive-dose (DD) of radiation (60 Gy or higher) is occasionally applied to increase local control. We investigated the impact of induction CRT with DD radiation in LA-NSCLC patients treated with a single regimen of docetaxel and cisplatin.

Methods

We reviewed 110 patients with LA-NSCLC who underwent induction CRT followed by surgery using a single regimen (docetaxel and cisplatin) between January 1999 and December 2014 at our hospital. The clinical outcomes of a DD group (60 Gy or higher, n=11) and a non-DD group (less than 60 Gy, n=99) were investigated using a propensity score (PS)-matched analysis.

Results

An advanced clinical stage was significantly more common in the DD group than in the non-DD group (P=0.033). Before and after the PS-matching based on seven factors including clinical stage, there was no significant difference in the rates of postoperative (PO) complication, mortality, 5-year overall survival (OS), or 5-year recurrence-free survival (RFS) between the two groups. After the PS-matching, the pathological complete response (CR) rate was significantly higher in the DD group than in the non-DD group [50% (n=5/10) vs. 0% (n=0/10), P=0.033].

Conclusions

Induction CRT followed by surgery using docetaxel and cisplatin with DD radiation can be performed safely and is associated with a higher pathological CR rate than that attained using non-DD radiation in LA-NSCLC patients.

An individualized radiation dose escalation trial in non-small cell lung cancer based on FDG-PET imaging

AIM

The aim of the study was to assess the feasibility of an individualized 18F fluorodeoxyglucose positron emission tomography (FDG-PET)-guided dose escalation boost in non-small cell lung cancer (NSCLC) patients and to assess its impact on local tumor control and toxicity.

PATIENTS AND METHODS

A total of 13 patients with stage II-III NSCLC were enrolled to receive a dose of 62.5 Gy in 25 fractions to the CT-based planning target volume (PTV; primary turmor and affected lymph nodes). The fraction dose was increased within the individual PET-based PTV (PTV_PET) using intensity modulated radiotherapy (IMRT) with a simultaneous integrated boost (SIB) until the predefined organ-at-risk (OAR) threshold was reached. Tumor response was assessed during follow-up by means of repeat FDG-PET/computed tomography. Acute and late toxicity were recorded and classified according to the CTCAE criteria (Version 4.0). Local progression-free survival was determined using the Kaplan-Meier method.

RESULTS

The average dose to PTV_PET reached 89.17 Gy for peripheral and 75 Gy for central tumors. After a median follow-up period of 29 months, seven patients were still alive, while six had died (four due to distant progression, two due to grade 5 toxicity). Local progression was seen in two patients in association with further recurrences. One and 2-year local progression free survival rates were 76.9% and 52.8%, respectively. Three cases of acute grade 3 esophagitis were seen. Two patients with central tumors developed late toxicity and died due to severe hemoptysis.

CONCLUSION

These results suggest that a non-uniform and individualized dose escalation based on FDG-PET in IMRT delivery is feasible. The doses reached were higher in patients with peripheral compared to central tumors. This strategy enables good local control to be achieved at acceptable toxicity rates. However, dose escalation in centrally located tumors with direct invasion of mediastinal organs must be performed with great caution in order to avoid severe late toxicity.

Identifying the Optimal Radiation Dose in Locally Advanced Non-Small-cell Lung Cancer Treated With Definitive Radiotherapy Without Concurrent Chemotherapy

INTRODUCTION

The optimal radiation dose for locally advanced non-small-cell lung cancer (NSCLC) is not known for patients who receive sequential chemoradiation (CRT) or definitive radiotherapy (RT) only. Our objective was to determine whether a benefit exists for radiation dose escalation for these patients.

MATERIALS AND METHODS

The patients included in our retrospective analysis had undergone RT for NSCLC from 2004 to 2013, had not undergone surgery, and received a dose ≥ 50.0 Gy. Patients who received concurrent CRT were excluded from the analysis, leaving 336 patients for analysis. The primary outcomes were overall survival (OS), local failure (LF), and distant failure (DF).

RESULTS

On multivariate analysis, after adjusting for age, Karnofsky performance status, gross tumor volume, and treatment modality, patients treated with a radiation dose > 66 Gy had significantly improved OS compared with those treated with < 60 Gy (hazard ratio [HR], 0.58; 95% confidence interval [CI], 0.39-0.87; P = .008). After adjusting for smoking history and radiologic tumor size, patients treated with a radiation dose > 66 Gy had a significantly decreased risk of LF compared with those treated with < 60 Gy (HR, 0.59; 95% CI, 0.38-0.91; P = .02). The radiation dose was not an independent prognostic factor of DF on multivariate analysis.

CONCLUSION

When controlling for tumor volume and/or dimensions and other independent prognostic factors, patients with locally advanced NSCLC who were not candidates for concurrent CRT benefited from a radiation dose > 66 Gy versus < 60 Gy with improved OS and reduced LF. An increased radiation dose did not appear to affect the incidence of DF.

Assessment of pulmonary 18F-FDG-PET uptake and cytokine profiles in non-small cell lung cancer patients treated with radiotherapy and erlotinib

Purpose

To investigate effects of radiotherapy (RT) and erlotinib on pulmonary glucose uptake using 2-deoxy-2-(18F)fluoro-D-glucose (¹⁸F-FDG) positron emission tomography (PET) during and after treatment of non-small cell lung cancer (NSCLC) and to identify associations between serum cytokine levels and lung glucose uptake.

Material and methods

Twenty-seven patients with advanced NSCLC, receiving RT alone or concomitant RT and erlotinib therapy, were examined by ¹⁸F-FDG PET before, during, and after treatment. A total of 57 ¹⁸F-FDG PET scans were analyzed. Pulmonary ¹⁸F-FDG uptake and radiotherapy dose mapping were used to acquire dose-response curves for each patient, where subsequent linear regression gave a glucose uptake level in the un-irradiated parts of the lungs (SUV₀) and a response slope (ΔSUV). Serum cytokine levels at corresponding time points were assessed using a multiplex bioassay. Correlations between the most robust cytokines and lung ¹⁸F-FDG dose response parameters were further investigated.

Results

From the dose response analysis, SUV₀ at post-therapy was significantly higher (P < 0.001) than at mid- and pre-therapy (45% and 58%, respectively) for the group receiving RT + erlotinib. Also, SUV₀ at post-therapy was higher for patients receiving RT + erlotinib compared to RT alone (42%; P < 0.001). No differences in ΔSUV were seen with treatments or time. SUV₀ was positively associated (r = 0.47, P = 0.01) with serum levels of the chemokine C-C motif ligand 21 (CCL21) for patients receiving RT + erlotinib.

Conclusions

Concomitant RT and erlotinib causes an elevation in pulmonary ¹⁸F-FDG uptake post treatment compared to RT alone. Pulmonary glucose uptake is associated with an upregulation of a chemokine (CCL21) involved in inflammatory reactions.

Evaluating the Toxicity Reduction With Computed Tomographic Ventilation Functional Avoidance Radiation Therapy

PURPOSE

Computed tomographic (CT) ventilation imaging is a new modality that uses 4-dimensional (4D) CT information to calculate lung ventilation. Although retrospective studies have reported on the reduction in dose to functional lung, no work to our knowledge has been published in which the dosimetric improvements have been translated to a reduction in the probability of pulmonary toxicity. Our work estimates the reduction in toxicity for CT ventilation-based functional avoidance planning.

METHODS AND MATERIALS

Seventy previously treated lung cancer patients who underwent 4DCT imaging were used for the study. CT ventilation maps were calculated with 4DCT deformable image registration and a density change-based algorithm. Pneumonitis was graded on the basis of imaging and clinical presentation. Maximum likelihood methods were used to generate normal tissue complication probability (NTCP) models predicting grade 2 or higher (2+) and grade 3+ pneumonitis as a function of dose (V5 Gy, V10 Gy, V20 Gy, V30 Gy, and mean dose) to functional lung. For 30 patients a functional plan was generated with the goal of reducing dose to the functional lung while meeting Radiation Therapy Oncology Group 0617 constraints. The NTCP models were applied to the functional plans and the clinically used plans to calculate toxicity reduction.

RESULTS

By the use of functional avoidance planning, absolute reductions in grade 2+ NTCP of 6.3%, 7.8%, and 4.8% were achieved based on the mean fV20 Gy, fV30 Gy, and mean dose to functional lung metrics, respectively. Absolute grade 3+ NTCP reductions of 3.6%, 4.8%, and 2.4% were achieved with fV20 Gy, fV30 Gy, and mean dose to functional lung. Maximum absolute reductions of 52.3% and 16.4% were seen for grade 2+ and grade 3+ pneumonitis for individual patients.

CONCLUSION

Our study quantifies the possible toxicity reduction from CT ventilation-based functional avoidance planning. Reductions in grades 2+ and 3+ pneumonitis were 7.1% and 4.7% based on mean dose-function metrics, with reductions as high as 52.3% for individual patients. Our work provides seminal data for determining the potential toxicity benefit from incorporating CT ventilation into thoracic treatment planning.

Advances in radiotherapy techniques and delivery for non-small cell lung cancer: benefits of intensity-modulated radiation therapy, proton therapy, and stereotactic body radiation therapy

The 21st century has seen several paradigm shifts in the treatment of non-small cell lung cancer (NSCLC) in early-stage inoperable disease, definitive locally advanced disease, and the postoperative setting. A key driver in improvement of local disease control has been the significant evolution of radiation therapy techniques in the last three decades, allowing for delivery of definitive radiation doses while limiting exposure of normal tissues. For patients with locally-advanced NSCLC, the advent of volumetric imaging techniques has allowed a shift from 2-dimensional approaches to 3-dimensional conformal radiation therapy (3DCRT). The next generation of 3DCRT, intensity-modulated radiation therapy and volumetric-modulated arc therapy (VMAT), have enabled even more conformal radiation delivery. Clinical evidence has shown that this can improve the quality of life for patients undergoing definitive management of lung cancer. In the early-stage setting, conventional fractionation led to poor outcomes. Evaluation of altered dose fractionation with the previously noted technology advances led to advent of stereotactic body radiation therapy (SBRT). This technique has dramatically improved local control and expanded treatment options for inoperable, early-stage patients. The recent development of proton therapy has opened new avenues for improving conformity and the therapeutic ratio. Evolution of newer proton therapy techniques, such as pencil-beam scanning (PBS), could improve tolerability and possibly allow reexamination of dose escalation. These new progresses, along with significant advances in systemic therapies, have improved survival for lung cancer patients across the spectrum of non-metastatic disease. They have also brought to light new challenges and avenues for further research and improvement.