Report From the International Atomic Energy Agency (IAEA) Consultants' Meeting on Elective Nodal Irradiation in Lung Cancer: Non–Small-Cell Lung Cancer (NSCLC)

The treatment in patients with unresectable locally advanced non-small cell lung cancer: Explorations on hot issues

The treatment efficacy for patients with unresectable, locally advanced non-small-cell lung cancer (LA-NSCLC) stagnated for a long time until the advent of immunotherapy. Immune checkpoint inhibitors, particularly programmed cell death protein 1/programmed death-ligand 1 inhibitors, have thrived, reshaping the treatment landscape for patients with lung cancer. Based on the results of the PACIFIC trial, concurrent chemoradiotherapy followed by durvalumab has become the standard of care for patients with unresectable LA-NSCLC; however, numerous issues are yet to be resolved. Currently, several clinical trials are exploring an optimal treatment paradigm, and we have summarized them for comparison to eliminate barriers. In addition, we discuss better predictive biomarkers, therapeutic options for specific populations, and other challenges to identify directions for future research design.

Evolving target volume concepts in locally advanced non-small cell lung cancer

Radiotherapy (RT) target volume concepts for locally advanced lung cancer have been under discussion for years. Although they may be as important as treatment doses, many aspects of them are still based on conventions, which, due to the paucity of prospective data, rely on long-term practice or on clinical knowledge and experience (e.g., on patterns of spread or recurrence). However, in recent years, large improvements have been made in medical imaging and molecular imaging methods have been implemented, which are of great interest in RT. For lung cancer, in recent years, 18F-fluoro-desoxy-glucose (FDG)-positron-emission tomography (PET)/computed tomography (CT) has shown a superior diagnostic accuracy as compare to conventional imaging and has become an indispensable standard tool for diagnostic workup, staging and response assessment. This offers the chance to optimize target volume concepts in relation to modern imaging. While actual recommendations as the EORTC or ESTRO-ACROP guidelines already include imaging standards, the recently published PET-Plan trial prospectively investigated conventional versus imaging guided target volumes in relation to patient outcome. The results of this trial may help to further refine standards. The current review gives a practical overview on procedures for pre-treatment imaging and target volume delineation in locally advanced non-small cell lung cancer (NSCLC) in synopsis of the procedures established by the PET-Plan trial with the actual EORTC and ACROP guidelines.

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.

Comparison of Involved Field Radiotherapy versus Elective Nodal Irradiation in Stage IIIB/C Non-Small-Cell Lung Carcinoma Patients Treated with Concurrent Chemoradiotherapy: A Propensity Score Matching Study

Background

We retrospectively compared the incidence of isolated elective nodal failure (IENF) and toxicity rates and survival outcomes after elective nodal irradiation (ENI) versus involved-field RT (IFRT) by employing the propensity score matching (PSM) methodology in stage IIIB/C inoperable non-small-cell lung cancer (NSCLC) patients treated with definitive concurrent chemoradiotherapy (C-CRT).

Methods

Our PSM examination included 1048 stage IIIB/C NSCLC patients treated with C-CRT from January 2007 to December 2016: a total dose of 66 Gy (2 Gy/fraction) radiotherapy and 1–3 cycles of platinum-based doublet chemotherapy concurrently. The primary and secondary endpoints were the IENF and toxicity rates and survival outcomes after ENI versus IFRT, respectively. Propensity scores were calculated for each group to adjust for confounding variables and facilitate well-balanced comparability by creating 1 : 1 matched study groups.

Results

The median follow-up was 26.4 months for the whole study accomplice. The PSM analysis unveiled 1 : 1 matched 646 patients for the ENI (N = 323) and IFRT (N = 323) cohorts. Intergroup comparisons discovered that the 5-year isolated ENF incidence rates (3.4% versus 4.3%; P=0.52) and median overall survival (25.2 versus 24.6 months; P=0.69), locoregional progression-free survival (15.3 versus 15.1 months; P=0.52), and progression-free survival (11.7 versus 11.2 months; P=0.57) durations were similar between the ENI and IFRT cohorts, separately. However, acute grade 3-4 leukopenia (P=0.0012), grade 3 nausea-vomiting (P=0.006), esophagitis (P=0.003), pneumonitis (P=0.002), late grade 3-4 esophageal toxicity (P=0.038), and the need for hospitalization (P < 0.001) were all significantly higher in the ENI than in the IFRT group, respectively.

Conclusion

Results of the present large-scale PSM cohort established the absence of meaningful IENF or survival differences between the IFRT and ENI cohorts and, consequently, counseled the IFRT as the elected RT technique for such patients since ENI increased the toxicity rates.

Imaging-based target volume reduction in chemoradiotherapy for locally advanced non-small-cell lung cancer (PET-Plan): a multicentre, open-label, randomised, controlled trial

BACKGROUND

With increasingly precise radiotherapy and advanced medical imaging, the concept of radiotherapy target volume planning might be redefined with the aim of improving outcomes. We aimed to investigate whether target volume reduction is feasible and effective compared with conventional planning in the context of radical chemoradiotherapy for patients with locally advanced non-small-cell lung cancer.

METHODS

We did a multicentre, open-label, randomised, controlled trial (PET-Plan; ARO-2009-09) in 24 centres in Austria, Germany, and Switzerland. Previously untreated patients (aged older than 18 years) with inoperable locally advanced non-small-cell lung cancer suitable for chemoradiotherapy and an Eastern Cooperative Oncology Group performance status of less than 3 were included. Undergoing ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) PET and CT for treatment planning, patients were randomly assigned (1:1) using a random number generator and block sizes between four and six to target volume delineation informed by ¹⁸F-FDG PET and CT plus elective nodal irradiation (conventional target group) or target volumes informed by PET alone (¹⁸F-FDG PET-based target group). Randomisation was stratified by centre and Union for International Cancer Control stage. In both groups, dose-escalated radiotherapy (60-74 Gy, 2 Gy per fraction) was planned to the respective target volumes and applied with concurrent platinum-based chemotherapy. The primary endpoint was time to locoregional progression from randomisation with the objective to test non-inferiority of ¹⁸F-FDG PET-based planning with a prespecified hazard ratio (HR) margin of 1·25. The per-protocol set was included in the primary analysis. The safety set included all patients receiving any study-specific treatment. Patients and study staff were not masked to treatment assignment. This study is registered with ClinicalTrials.gov, NCT00697333.

FINDINGS

From May 13, 2009, to Dec 5, 2016, 205 of 311 recruited patients were randomly assigned to the conventional target group (n=99) or the ¹⁸F-FDG PET-based target group (n=106; the intention-to-treat set), and 172 patients were treated per protocol (84 patients in the conventional target group and 88 in the ¹⁸F-FDG PET-based target group). At a median follow-up of 29 months (IQR 9-54), the risk of locoregional progression in the ¹⁸F-FDG PET-based target group was non-inferior to, and in fact lower than, that in the conventional target group in the per-protocol set (14% [95% CI 5-21] vs 29% [17-38] at 1 year; HR 0·57 [95% CI 0·30-1·06]). The risk of locoregional progression in the ¹⁸F-FDG PET-based target group was also non-inferior to that in the conventional target group in the intention-to-treat set (17% [95% CI 9-24] vs 30% [20-39] at 1 year; HR 0·64 [95% CI 0·37-1·10]). The most common acute grade 3 or worse toxicity was oesophagitis or dysphagia (16 [16%] of 99 patients in the conventional target group vs 17 [16%] of 105 patients in the ¹⁸F-FDG PET-based target group); the most common late toxicities were lung-related (12 [12%] vs 11 [10%]). 20 deaths potentially related to study treatment were reported (seven vs 13).

INTERPRETATION

¹⁸F-FDG PET-based planning could potentially improve local control and does not seem to increase toxicity in patients with chemoradiotherapy-treated locally advanced non-small-cell lung cancer. Imaging-based target volume reduction in this setting is, therefore, feasible, and could potentially be considered standard of care. The procedures established might also support imaging-based target volume reduction concepts for other tumours.

FUNDING

German Cancer Aid (Deutsche Krebshilfe).

The dosimetric effects of limited elective nodal irradiation in volumetric modulated arc therapy treatment planning for locally advanced non-small cell lung cancer

Objective

Contemporary radiotherapy guidelines for locally advanced non-small cell lung carcinoma (LA-NSCLC) recommend omitting elective nodal irradiation, despite the fact that evidence supporting this came primarily from older reports assessing comprehensive nodal coverage using 3D conformal techniques. Herein, we evaluated the dosimetric implications of the addition of limited elective nodal irradiation (LENI) to standard involved field irradiation (IFI) using volumetric modulated arc therapy (VMAT) planning.

Method

Target volumes and organs-at-risk (OARs) were delineated on CT simulation images of 20 patients with LA-NSCLC. Two VMAT plans (IFI and LENI) were generated for each patient. Involved sites were treated to 60 Gy in 30 fractions for both IFI and LENI plans. Adjacent uninvolved nodal regions, considered high risk based on the primary tumor site and extent of nodal involvement, were treated to 51 Gy in 30 fractions in LENI plans using a simultaneous integrated boost approach.

Results

All planning objectives for PTVs and OARs were achieved for both IFI and LENI plans. LENI resulted in significantly higher esophagus D_mean (15.3 vs. 22.5 Gy, p < 0.01), spinal cord D_max (34.9 vs. 42.4 Gy, p = 0.02) and lung D_mean (13.5 vs. 15.9 Gy, p = 0.02), V₂₀ (23.0 vs. 27.9%, p = 0.03), and V₅ (52.6 vs. 59.4%, p = 0.02). No differences were observed in heart parameters. On average, only 32.2% of the high-risk nodal volume received an incidental dose of 51 Gy when untargeted in IFI plans.

Conclusion

The addition of LENI to VMAT plans for LA-NSCLC is feasible, with only modestly increased doses to OARs and marginal expected increase in associated toxicity.

Early postoperative radiotherapy is associated with improved outcomes over late postoperative radiotherapy in the management of completely resected (R0) Stage IIIA-N2 non-small cell lung cancer

Aims

The aim of this study was to evaluate the ideal timing of PORT in the management of completely resected (R0) Stage IIIA-N2 NSCLC.

Patients and Methods

Between January 2008 and December 2015, patients with known histologies of pathologic Stage IIIA-N2 NSCLC who underwent R0 resection and received PORT concurrent with or prior to two sequential cycles of chemotherapy (“early PORT”) or with PORT administered after two cycles of chemotherapy (“late PORT”) at multiple hospitals. The primary endpoint was OS; secondary end points included pattern of the first failure, LRRFS, and DMFS. Kaplan–Meier OS, LRRFS, and DMFS curves were compared with the log-rank test. Cox regression analysis was used to determine prognosticators for OS, LRRFS, and DMFS.

Results

Of 112 included patients, 41 (36.6%) and 71 (63.4%) patients received early PORT and late PORT, respectively. The median OS, LRRFS, and DMFS were longer for those who received early PORT than for those who received late PORT at the median follow-up of 29.6 months (all p < 0.05). Uni- and multi-variate analyses showed that number of POCT cycles and the combination schedule of PORT and POCT were independent prognostic factors for OS, LRRFS, and DMFS.

Conclusions

Early PORT is associated with improved outcomes in pathologic Stage IIIA-N2 R0 NSCLC patients.

[Role of functional imaging in the definition of target volumes for lung cancer radiotherapy]

Functional imaging with positron emission tomography (PET) is interesting to optimize lung radiotherapy planning, and probably to deliver a heterogeneous dose or adapt the radiation dose during treatment. Only fluorodeoxyglucose (FDG) PET-computed tomography (CT) is validated for staging lung cancer and planning radiotherapy. The optimal segmentation methods remain to be defined as well as the interest of "dose painting" from pre-treatment PET (metabolism: FDG) or hypoxia (fluoromisonidazole: FMISO) and the interest of replanning based on pertherapeutic PET.

PET-CT limitations in early stage non-small cell lung cancer: to whom more aggressive approach in radiotherapy and surgery should be directed?

This editorial comments on the study by Paravati et al., which reported on the incidence of occult regional lymph node metastases in PET-CT T1T2N0 non-small cell lung cancer (NSCLC) patients. A central location and the size of the tumor were shown to be the strongest predictors of the risk of occult nodal disease. Authors comment that in view of limitations of modern imaging, as well as the reported negative predictive value (NPV) of invasive staging methods, the choice of therapeutic options as the extent of surgery (lobectomy or sublobar resection) or radiotherapy [stereotactic body radiation therapy (SBRT) or conformal radiotherapy (RT) with some forms of elective nodal irradiation (ENI)] should consider tumor's characteristics and not be based only on imaging and invasive staging modalities.

IMRT and 3D conformal radiotherapy with or without elective nodal irradiation in locally advanced NSCLC: A direct comparison of PET-based treatment planning

AIM

The potential of intensity-modulated radiation therapy (IMRT) as opposed to three-dimensional conformal radiotherapy (3D-CRT) is analyzed for two different concepts of fluorodeoxyglucose positron emission tomography (FDG PET)-based target volume delineation in locally advanced non-small cell lung cancer (LA-NSCLC): involved-field radiotherapy (IF-RT) vs. elective nodal irradiation (ENI).

METHODS

Treatment planning was performed for 41 patients with LA-NSCLC, using four different planning approaches (3D-CRT-IF, 3D-CRT-ENI, IMRT-IF, IMRT-ENI). ENI included a boost irradiation after 50 Gy. For each plan, maximum dose escalation was calculated based on prespecified normal tissue constraints. The maximum prescription dose (PD), tumor control probability (TCP), conformal indices (CI), and normal tissue complication probabilities (NTCP) were analyzed.

RESULTS

IMRT resulted in statistically significant higher prescription doses for both target volume concepts as compared with 3D-CRT (ENI: 68.4 vs. 60.9 Gy, p < 0.001; IF: 74.3 vs. 70.1 Gy, p < 0.03). With IMRT-IF, a PD of at least 66 Gy was achieved for 95 % of all plans. For IF as compared with ENI, there was a considerable theoretical increase in TCP (IMRT: 27.3 vs. 17.7 %, p < 0.00001; 3D-CRT: 20.2 vs. 9.9 %, p < 0.00001). The esophageal NTCP showed a particularly good sparing with IMRT vs. 3D-CRT (ENI: 12.3 vs. 30.9 % p < 0.0001; IF: 15.9 vs. 24.1 %; p < 0.001).

CONCLUSION

The IMRT technique and IF target volume delineation allow a significant dose escalation and an increase in TCP. IMRT results in an improved sparing of OARs as compared with 3D-CRT at equivalent dose levels.

Dose distribution and tumor control probability in out-of-field lymph node stations in intensity modulated radiotherapy (IMRT) vs 3D-conformal radiotherapy (3D-CRT) of non-small-cell lung cancer: an in silico analysis

Background

The advent of IMRT and image-guided radiotherapy (IGRT) in combination with involved-field radiotherapy (IF-RT) in inoperable non-small-cell lung cancer results in a decreased incidental dose deposition in elective nodal stations. While incidental nodal irradiation is considered a relevant by-product of 3D-CRT to control microscopic disease this planning study analyzed the impact of IMRT on dosimetric parameters and tumor control probabilities (TCP) in elective nodal stations in direct comparison with 3D-CRT.

Methods and materials

The retrospective planning study was performed on 41 patients with NSCLC (stages II-III). The CTV was defined as the primary tumor (GTV + 3 mm) and all FDG-PET-positive lymph node stations. As to the PTV (CTV + 7 mm), both an IMRT plan and a 3D-CRT plan were established. Plans were escalated until the pre-defined dose-constraints of normal tissues (spinal cord, lung, esophagus and heart) were reached. Additionally, IMRT plans were normalized to the total dose of the corresponding 3D-CRT. For two groups of out-of-field mediastinal node stations (all lymph node stations not included in the CTV (LN_{all_el}) and those directly adjacent to the CTV (LN_{adj_el})) the equivalent uniform dose (EUD) and the TCP (for microscopic disease a D50 of 36.5 Gy was assumed) for the treatment with IMRT vs 3D-CRT were calculated.

Results

In comparison, a significantly higher total dose for the PTV could be achieved with the IMRT planning as opposed to conventional 3D-CRT planning (74.3 Gy vs 70.1 Gy; p = 0.03). In identical total reference doses, the EUD of LN_{adj_el} is significantly lower with IMRT than with 3D-CRT (40.4 Gy vs. 44.2 Gy. P = 0.05) and a significant reduction of TCP with IMRT vs 3D-CRT was demonstrated for LN_{all_el} and LN_{adj_el} (12.6 % vs. 14.8 %; and 23.6 % vs 27.3 %, respectively).

Conclusions

In comparison with 3D-CRT, IMRT comes along with a decreased EUD in out-of-field lymph node stations. This translates into a statistically significant decrease in TCP-values. Yet, the combination of IF-RT and IMRT leads to a significantly better sparing of normal tissues and higher total doses whereas the potential therapeutic drawback of decreased incidental irradiation of elective lymph nodes is moderate.

2nd ESMO Consensus Conference in Lung Cancer: locally advanced stage III non-small-cell lung cancer

To complement the existing treatment guidelines for all tumour types, ESMO organises consensus conferences to focus on specific issues in each type of tumour. The 2nd ESMO Consensus Conference on Lung Cancer was held on 11-12 May 2013 in Lugano. A total of 35 experts met to address several questions on non-small-cell lung cancer (NSCLC) in each of four areas: pathology and molecular biomarkers, first-line/second and further lines of treatment in advanced disease, early-stage disease and locally advanced disease. For each question, recommendations were made including reference to the grade of recommendation and level of evidence. This consensus paper focuses on locally advanced disease.

Role of adjuvant radiotherapy in completely resected non-small-cell lung cancer

Most long-term survivors of non-small-cell lung cancer (NSCLC) are patients who have had a completely resected tumour. However, this is only achievable in about 30% of the patients. Even in this highly selected group of patients, there is still a high risk of both local and distant failure. Adjuvant treatments such as chemotherapy (CT) and radiotherapy (RT) have therefore been evaluated in order to improve their outcome. In patients with stage II and III, administration of adjuvant platinum-based chemotherapy is now considered the standard of care, based on level 1 evidence. The role of postoperative radiation therapy (PORT) remains controversial. In the PORT meta-analysis published in 1998, the conclusions were that if PORT was detrimental to patients with stage I and II completely resected NSCLC, the role of PORT in the treatment of tumours with N2 involvement was unclear and further research was warranted. Thus at present, after complete resection, adjuvant radiotherapy should not be administered in patients with early lung cancer. Recent retrospective and non-randomised studies, as well as subgroup analyses of recent randomised trials evaluating adjuvant chemotherapy, provide evidence of the possible benefit of PORT in patients with mediastinal nodal involvement. The role of PORT needs to be evaluated also for patients with proven N2 disease who undergo neoadjuvant chemotherapy followed by surgery. The risk of local recurrence for N2 patients varies between 20% and 60%. Based on currently available data, PORT should be discussed for fit patients with completely resected NSCLC with N2 nodal involvement, preferably after completion of adjuvant chemotherapy or after surgery if patients have had preoperative chemotherapy. There is a need for new randomised evidence to reassess PORT using modern three-dimensional conformal radiation technique, with attention to normal organ sparing, particularly lung and heart, to reduce the possible over-added toxicity. Quality assurance of radiotherapy as well as quality of surgery – and most particularly nodal exploration modality – should both be monitored. A new large multi-institutional randomised trial Lung ART evaluating PORT in this patient population is needed and is now under way.

Target volume for postoperative radiotherapy in non-small cell lung cancer: results from a prospective trial

BACKGROUND AND PURPOSE

A previous prospective trial reported that three-dimensional conformal postoperative radiotherapy (PORT) for pN2 NSCLC patients using a limited clinical target volume (CTV) had a late morbidity rate and pulmonary function that did not differ from those observed in pN1 patients treated with surgery without PORT. The aim of this study was to assess locoregional control and localization of failure in patients treated with PORT.

MATERIALS AND METHODS

The pattern of locoregional failure was evaluated retrospectively in 151 of 171 patients included in the PORT arm. The CTV included the involved lymph node stations and those with a risk of invasion >10%. Competing risk analysis was used to assess the incidence of locoregional failure and its location outside the CTV.

RESULTS

Overall survival at 5years was 27.1% with a median follow-up of 67months for 40 living patients. The 5-year cumulative incidence of locoregional failure was 19.4% (95% CI: 18.2-20.5%) including a failure rate of 2% (95% CI: 0-17%) in locations outside or at the border of the CTV.

CONCLUSIONS

The use of limited CTV was associated with acceptable risk of geographic miss. Overall locoregional control was similar to that reported by other studies using PORT for pN2 patients.

Involved-field radiotherapy versus elective nodal irradiation in combination with concurrent chemotherapy for locally advanced non-small cell lung cancer: a prospective randomized study

This prospective randomized study is to evaluate the locoregional failure and its impact on survival by comparing involved field radiotherapy (IFRT) with elective nodal irradiation (ENI) in combination with concurrent chemotherapy for locally advanced non-small cell lung cancer. It appears that higher dose could be delivered in IFRT arm than that in ENI arm, and IFRT did not increase the risk of initially uninvolved or isolated nodal failures. Both a tendency of improved locoregional progression-free survival and a significant increased overall survival rate are in favor of IFRT arm in this study.

Optimal radiotherapy for non-small-cell lung cancer: current progress and future challenges

Radiotherapy has a key role in treating lung cancer. Advances in physics and computer technology have improved radiation delivery systems. With innovations in the radiation therapy of non-small-cell lung cancer (NSCLC), new strategies have emerged, such as intensity-modulated radiation therapy, stereotactic body radiation therapy, and particle therapy. Compared with previous methods, these newer technologies can deliver even higher doses precisely to the tumor while minimizing doses to normal tissues, which should lead to better tumor control with less toxicity. In patients with stage I NSCLC, stereotactic body radiation therapy is highly effective and may achieve local control and survival equivalent to that achieved with surgery. In patients with stage III NSCLC, dose escalation has been investigated using three-dimensional conformal radiation therapy, intensity-modulated radiation therapy, and particle therapy. The results from ongoing randomized trials on both patient populations are awaited. It is important to generate new hypotheses and to explore newer radiotherapy approaches to overcome NSCLC.

Multidisciplinary approach in stage III non-small-cell lung cancer: standard of care and open questions

Lung cancer is the most frequent cause of cancer death worldwide and its global incidence has been steadily increasing during recent decades. A third of patients with newly diagnosed non-small-cell lung cancer (NSCLC) present with locally advanced disease. There is not a single widely accepted standard of care for these patients because of the wide spectrum of presentation of the disease. Although feasible and safe in experienced hands, evidence that surgical resection after induction treatment improves overall survival (OS) is lacking. For resectable or potentially resectable stage III, the findings of two phase III trials suggest that surgical resection should not be considered a standard of care but rather reserved for selected patients after critical multidisciplinary assessment, in whom surgery improves survival after downstaging if pneumonectomy can be avoided or in some T4N0-1 resectable tumours. For unresectable stage III NSCLC the standard of care is a combination of chemotherapy and radiotherapy. In those patients with good performance status and minimal weight loss, the concurrent approach has resulted in a statistically significant improvement in OS rates compared with a sequential approach in randomised clinical trials, although several questions remain unresolved.

[Radiotherapy of lung cancer: Any room left for elective mediastinal irradiation in 2011?]

Traditionally, the target volumes of curative-intent radiotherapy for non-small cell lung cancer include all uninvolved mediastinal nodes. However, an improvement in tumour control requires an increase of the total dose to the macroscopic target volume. This is only achievable if the irradiation of the organs at risk is reduced, i.e. elective irradiation of the mediastinum is omitted. The available data suggest that elective mediastinal irradiation may be safely omitted, provided that an adequate staging procedure, including FDG PET-CT, has been performed.

Role of postoperative radiotherapy in resected non-small cell lung cancer: a reassessment based on new data

In completely resected non-small cell lung cancer (NSCLC) patients with pathologically involved mediastinal lymph nodes (N2), administration of adjuvant platinum-based chemotherapy is now considered the standard of care, based on level 1 evidence. The role of postoperative radiation therapy (PORT) in this group of patients remains controversial. The PORT meta-analysis published in 1998 concluded that adjuvant radiotherapy was detrimental to patients with early-stage completely resected NSCLC, but that the role of PORT in the treatment of tumors with N2 involvement was unclear, and that further research was warranted. Recent retrospective and nonrandomized studies, as well as subgroup analyses of recent randomized trials evaluating adjuvant chemotherapy, provide evidence of the possible benefit of PORT in patients with mediastinal nodal involvement. The role of PORT is also a valid question in patients with proven N2 disease who have undergone only induction chemotherapy followed by surgery, because the local recurrence rate for such patients varies in the range of 20%-60%. Based on the currently available data, PORT should be discussed for fit patients with completely resected NSCLC with N2 nodal involvement, preferably after completion of adjuvant chemotherapy. There is a need for new randomized evidence to evaluate PORT using the modern three-dimensional conformal radiation technique, with attention paid to reducing the risk for, particularly, pulmonary and cardiac toxicity. A new large multi-institutional randomized trial evaluating PORT in this patient population is needed and now under way.

Therapeutic implications of molecular imaging with PET in the combined modality treatment of lung cancer

Molecular imaging with PET, and certainly integrated PET-CT, combining functional and anatomical imaging, has many potential advantages over anatomical imaging alone in the combined modality treatment of lung cancer. The aim of the current article is to review the available evidence regarding PET with FDG and other tracers in the combined modality treatment of locally advanced lung cancer. The following topics are addressed: tumor volume definition, outcome prediction and the added value of PET after therapy, and finally its clinical implications and future perspectives. The additional value of FDG-PET in defining the primary tumor volume has been established, mainly in regions with atelectasis or post-treatment effects. Selective nodal irradiation (SNI) of FDG-PET positive nodal stations is the preferred treatment in NSCLC, being safe and leading to decreased normal tissue exposure, providing opportunities for dose escalation. First results in SCLC show similar results. FDG-uptake on the pre-treatment PET scan is of prognostic value. Data on the value of pre-treatment FDG-uptake to predict response to combined modality treatment are conflicting, but the limited data regarding early metabolic response during treatment do show predictive value. The FDG response after radical treatment is of prognostic significance. FDG-PET in the follow-up has potential benefit in NSCLC, while data in SCLC are lacking. Radiotherapy boosting of radioresistant areas identified with FDG-PET is subject of current research. Tracers other than (18)FDG are promising for treatment response assessment and the visualization of intra-tumor heterogeneity, but more research is needed before they can be clinically implemented.

European Organisation for Research and Treatment of Cancer Recommendations for Planning and Delivery of High-Dose, High-Precision Radiotherapy for Lung Cancer

Purpose

To derive recommendations for routine practice and clinical trials for techniques used in high-dose, high-precision thoracic radiotherapy for lung cancer.

Methods

A literature search was performed to identify published articles considered both clinically relevant and practical to use. Recommendations were categorized under the following headings: patient selection, patient positioning and immobilization, tumor motion, computed tomography and [18F]fluorodeoxyglucose–positron emission technology scanning, generating target volumes, radiotherapy treatment planning, treatment delivery, and scoring of response and toxicity. The American College of Chest Physicians grading of recommendations was used.

Results

Recommendations were identified for each of the recommendation categories. Although most of the recommended techniques have not been evaluated in multicenter clinical trials, their use in high-precision thoracic radiotherapy and stereotactic body radiotherapy (SBRT) appears to be justified on the basis of available evidence.

Conclusion

Recommendations to facilitate the clinical implementation of high-precision conformal radiotherapy and SBRT for lung tumors were identified from the literature. Some techniques that are considered investigational at present were also highlighted.

Initial evaluation of the nonsmall cell lung cancer patient: diagnosis and staging

PURPOSE OF REVIEW

The initial diagnosis and staging of nonsmall cell lung cancer patients is complex and involves multiple technologies. This review evaluates the recent literature and integrates it into a systematic method for evaluating patients.

RECENT FINDINGS

The goal of the initial diagnosis and staging of nonsmall cell lung cancer is to provide sufficient information to allow definitive treatment. Initial steps should include a history and physical, basic laboratory tests, pulmonary functions, and PET-computed tomography (CT) imaging. If there is evidence of metastatic disease, then biopsy of the most advanced lesion is warranted. If there is no evidence of metastatic disease, the evaluation should focus on evaluation of the mediastinal lymph nodes. If there is evidence of nodal involvement by PET-CT, then endobronchial ultrasound-guided transbronchial needle aspiration is warranted. If there is no evidence of nodal involvement on PET-CT, then either surgery or CT-guided fine needle aspiration is warranted. Other factors that should be kept in mind when selecting a diagnostic strategy include whether or not the patient is a surgical candidate, the impact of comorbidities, the type of cancer, the need for predictive biomarker analysis, and the range of possible treatment options.

SUMMARY

Integrating new technologies such as PET-CT and endobronchial ultrasound into the initial evaluation of patients can save unnecessary diagnostic procedures and lead to more rapid and accurate staging.

Involved field radiotherapy for locally advanced non-small cell lung cancer: isolated mediastinal nodal relapse

The current standard of care for locally advanced inoperable non-small cell lung cancer is high dose radiotherapy with concurrent chemotherapy. We report on a patient with stage IIIA NSCLC treated with concurrent chemoradiotherapy on the primary tumor and the 18-fluorodeoxyglucose positron emission tomography ((18)FDG-PET) positive hilar and mediastinal lymph nodes. Six months after treatment this patient developed a single isolated contralateral mediastinal nodal relapse outside but in the proximity of the irradiated target volume. This patient was successfully re-irradiated to this isolated nodal relapse after reconstruction of the dose given to the localisation of this regional recurrence. This case describes the clinical problem of a regional recurrence after involved field radiotherapy that occasionally occurs. A possible explanation for those regional recurrences is an under staging of extension of the disease because the time-interval between the staging (18)FDG-PET-CT scan and the start of the irradiation was too long. If the time-interval is 4 weeks or more, we strongly recommend a new (18)FDG-PET-CT because of the possibility of upstaging of the disease.

Comparison of positron emission tomography (PET) and computed tomography (CT) for better target volume definition in radiation therapy planning

BACKGROUND

In cancer patients, positron emission tomography/ computed tomography (PET/CT) fused images present less variability in target contouring, respect to use only CT images, respectively. However, the gold standard has not yet been clearly established between radiation oncologists with regard to PET images and the methodology of contouring targets with confidence using PET/CT fused images. The aim of this study was to determine whether integrated PET/CT fused images provide advantages in virtual simulation compared with morphological contouring only with CT.

MATERIAL AND METHODS

Thirty cancer patients were evaluated in an adapted PET/CT hybrid in radiotherapy (RT) setup position, with 20 of them being suitable for RT: 17 were suitable for curative intent, which was the group of interest in this study. All image series were sent to the RT work station (WS) where CT and PET series were automatically fused by Digital Imaging and Communications in Medicine (DICOM) in each case. PET series were threshold and were subjected to source-to-background contrast algorithms to fi nally redefine the original tumour description. Three different radiotherapy plans (RTP) for each patient were compared after targets were contoured: [1] planning over metabolic (PET) contoured targets, [2] planning over only morphologic (CT) targets, and [3] planning over targets obtained for treatment based on fused PET/CT images.

RESULTS

PET/CT findings altered initial-stage planning in four patients (23.5%) because they had been undergoing chemotherapy. Gross target volume (GTV) and planning target volume (PTV) based only on PET showed more homogeneity to obtain mean doses (p = 0.025) with respect to those based on PET/CT, respectively. However, no percentage differences were observed in median PTV doses between the planning methods, although there was higher variability in PET/CT planning. Morphological (CT) and PET/ CT target volumes were more voluminous than metabolic (PET) volumes. On the other hand, 20% of metabolic (PET) PTV were out of those defined by PET/CT. Thoracic RT plans based on PET preserved better bilateral lung [percentage volume of lung irradiated with a dose of 20 Gy (V20); significance, R(2) = 0.559, p = 0.006].

CONCLUSIONS

For our physicians, PET/CT fused images allowed better contouring of primary tumours in 40% of head and neck cancers and 34% of thoracic cancers. PET/CT provides useful information for virtual simulation therapy. Image treatment and planning in an RT workstation is mandatory.

Potential of adaptive radiotherapy to escalate the radiation dose in combined radiochemotherapy for locally advanced non-small cell lung cancer

PURPOSE

To evaluate the potential of adaptive radiotherapy (ART) for advanced-stage non-small cell lung cancer (NSCLC) in terms of lung sparing and dose escalation.

METHODS AND MATERIALS

In 13 patients with locally advanced NSCLC, weekly CT images were acquired during radio- (n=1) or radiochemotherapy (n=12) for simulation of ART. Three-dimensional (3D) conformal treatment plans were generated: conventionally fractionated doses of 66 Gy were prescribed to the planning target volume without elective lymph node irradiation (Plan_3D). Using a surface-based algorithm of deformable image registration, accumulated doses were calculated in the CT images acquired during the treatment course (Plan_4D). Field sizes were adapted to tumor shrinkage once in week 3 or 5 and twice in weeks 3 and 5.

RESULTS

A continuous tumor regression of 1.2% per day resulted in a residual gross tumor volume (GTV) of 49%±15% after six weeks of treatment. No systematic differences between Plan_3D and Plan_4D were observed regarding doses to the GTV, lung, and spinal cord. Plan adaptation to tumor shrinkage resulted in significantly decreased lung doses without compromising GTV coverage: single-plan adaptation in Week 3 or 5 and twice-plan adaptation in Weeks 3 and 5 reduced the mean lung dose by 5.0%±4.4%, 5.6%±2.9% and 7.9%±4.8%, respectively. This lung sparing with twice ART allowed an iso-mean lung dose escalation of the GTV dose from 66.8 Gy±0.8 Gy to 73.6 Gy±3.8 Gy.

CONCLUSIONS

Adaptation of radiotherapy to continuous tumor shrinkage during the treatment course reduced doses to the lung, allowed significant dose escalation and has the potential of increased local control.

Palliative thoracic radiotherapy for lung cancer

Despite an increasing use of chemotherapy in the palliative setting for lung cancer, the role of palliative thoracic radiotherapy should not be disregarded. It offers quick and efficient palliation, with improvement observed in approximately two-thirds of treated patients. There is evidence that the short and long radiotherapy schedules are equally effective for poor performance patients. Higher radiation doses delivered via protracted schedules give a modest survival benefit for good performance patients. The current review covers the issues related to the use of palliative thoracic radiotherapy, such as total dose, fractionation, delayed versus immediate use, external-beam radiotherapy versus endobronchial brachytherapy, combination with chemotherapy, re-irradiation and palliation with radiation in small-cell lung cancer.

Meta-analysis of concomitant versus sequential radiochemotherapy in locally advanced non-small-cell lung cancer

PURPOSE

The previous individual patient data meta-analyses of chemotherapy in locally advanced non-small-cell lung cancer (NSCLC) showed that adding sequential or concomitant chemotherapy to radiotherapy improved survival. The NSCLC Collaborative Group performed a meta-analysis of randomized trials directly comparing concomitant versus sequential radiochemotherapy.

METHODS

Systematic searches for trials were undertaken, followed by central collection, checking, and reanalysis of updated individual patient data. Results from trials were combined using the stratified log-rank test to calculate pooled hazard ratios (HRs). The primary outcome was overall survival; secondary outcomes were progression-free survival, cumulative incidences of locoregional and distant progression, and acute toxicity.

RESULTS

Of seven eligible trials, data from six trials were received (1,205 patients, 92% of all randomly assigned patients). Median follow-up was 6 years. There was a significant benefit of concomitant radiochemotherapy on overall survival (HR, 0.84; 95% CI, 0.74 to 0.95; P = .004), with an absolute benefit of 5.7% (from 18.1% to 23.8%) at 3 years and 4.5% at 5 years. For progression-free survival, the HR was 0.90 (95% CI, 0.79 to 1.01; P = .07). Concomitant treatment decreased locoregional progression (HR, 0.77; 95% CI, 0.62 to 0.95; P = .01); its effect was not different from that of sequential treatment on distant progression (HR, 1.04; 95% CI, 0.86 to 1.25; P = .69). Concomitant radiochemotherapy increased acute esophageal toxicity (grade 3-4) from 4% to 18% with a relative risk of 4.9 (95% CI, 3.1 to 7.8; P < .001). There was no significant difference regarding acute pulmonary toxicity.

CONCLUSION

Concomitant radiochemotherapy, as compared with sequential radiochemotherapy, improved survival of patients with locally advanced NSCLC, primarily because of a better locoregional control, but at the cost of manageable increased acute esophageal toxicity.

Combination of radiotherapy and chemotherapy in locally advanced NSCLC

The combination of radiotherapy and chemotherapy is considered to be a standard approach for patients with locally advanced, stage III non-small-cell lung cancer. The current state of the art of combined radiochemotherapy supported by evidence-based data is presented. As shown in the meta-analyses, the concurrent radiochemotherapy gives a superior outcome in terms of survival compared with sequential delivery of both modalities. This is obtained at the expense of higher toxicity, which makes further intensification of radiochemotherapy challenging. Eligibility of patients with non-small-cell lung cancer for such an approach is limited. The new methods to improve treatment results, such as selection of proper strategies, incorporation of molecular agents into combined treatment and radiotherapy technique modifications are discussed.

Radiochemotherapy in the elderly with lung cancer

Lung cancer is the leading cause of cancer mortality with the median age of incidence being 69 years in males and 67 years in females. Radiochemotherapy (RT-CHT) is indicated in locally advanced non-small-cell lung cancer and limited-stage small-cell lung cancer; however, a significant under-representation of the elderly has been observed in patient recruitment in cancer treatment trials. In the last decades of the 20th Century, studies showed that elderly patients achieved the best quality-adjusted survival with radiotherapy alone, but recent trials have found that fit elderly patients benefit from concurrent RT-CHT, although with more short-term toxicity. Age alone should not exclude fit patients and deprive them of the standard treatment. Using tools, such as comprehensive geriatric assessment, a patient's tolerance to therapy can be assessed and monitoring can be performed. This review will focus on RT-CHT treatment in elderly patients with nonoperable stage III non-small-cell lung cancer and limited-stage small-cell lung cancer exclusively.

Impact of incidental irradiation on clinically uninvolved nodal regions in patients with advanced non-small-cell lung cancer treated with involved-field radiation therapy: does incidental irradiation contribute to the low incidence of elective nodal failure?

PURPOSE

To evaluate the incidental irradiation dose to elective nodal regions in the treatment of advanced non-small-cell lung cancer with involved-field radiation therapy (IF-RT) and the pattern of elective nodal failure (ENF).

METHODS AND MATERIALS

Fifty patients with advanced non-small-cell lung cancer, who received IF-RT at Kagawa University were enrolled. To evaluate the dose of incidental irradiation, we delineated nodal regions with a Japanese map and the American Thoracic Society map (levels 1-11) in each patient retrospectively and calculated the dose parameters such as mean dose, D95, and V95 (40 Gy as the prescribed dose of elective nodal irradiation).

RESULTS

Using the Japanese map, the median mean dose was more than 40 Gy in most of the nodal regions, except at levels 1, 3, and 7. In particular, each dosimetric parameter of level 1 was significantly lower than those at other levels, and each dosimetric parameter of levels 10 to 11 ipsilateral (11I) was significantly higher than those in other nodal regions. Using the American Thoracic Society map, basically, the results were similar to those of the Japanese map. ENF was observed in 4 patients (8%), five nodal regions, and no mean dose to the nodal region exceeded 40 Gy. On the Japanese map, each parameter of these five nodal region was significantly lower than those of the other nodal regions.

CONCLUSIONS

These results show that a high dose of incidental irradiation may contribute to the low incidence of ENF in patients who have received IF-RT.

Exclusion of elective nodal irradiation is associated with minimal elective nodal failure in non-small cell lung cancer

BACKGROUND

Controversy still exists regarding the long-term outcome of patients whose uninvolved lymph node stations are not prophylactically irradiated for non-small cell lung cancer (NSCLC) treated with definitive radiotherapy. To determine the frequency of elective nodal failure (ENF) and in-field failure (IFF), we examined a large cohort of patients with NSCLC staged with positron emission tomography (PET)/computed tomography (CT) and treated with 3-dimensional conformal radiotherapy (3D-CRT) that excluded uninvolved lymph node stations.

METHODS

We retrospectively reviewed the records of 115 patients with non-small cell lung cancer treated at our institution with definitive radiation therapy with or without concurrent chemotherapy (CHT). All patients were treated with 3D-CRT, including nodal regions determined by CT or PET to be disease involved. Concurrent platinum-based CHT was administered for locally advanced disease. Patients were analyzed in follow-up for survival, local regional recurrence, and distant metastases (DM).

RESULTS

The median follow-up time was 18 months (3 to 44 months) among all patients and 27 months (6 to 44 months) among survivors. The median overall survival, 2-year actuarial overall survival and disease-free survival were 19 months, 38%, and 28%, respectively. The majority of patients died from DM, the overall rate of which was 36%. Of the 31 patients with local regional failure, 26 (22.6%) had IFF, 5 (4.3%) had ENF and 2 (1.7%) had isolated ENF. For 88 patients with stage IIIA/B, the frequencies of IFF, any ENF, isolated ENF, and DM were 23 (26%), 3 (9%), 1 (1.1%) and 36 (40.9%), respectively. The comparable rates for the 22 patients with early stage node-negative disease (stage IA/IB) were 3 (13.6%), 1(4.5%), 0 (0%), and 5 (22.7%), respectively.

CONCLUSION

We observed only a 4.3% recurrence of any ENF and a 1.7% recurrence of isolated ENF in patients with NSCLC treated with definitive 3D-CRT without prophylactic irradiation of uninvolved lymph node stations. Thus, distant metastasis and IFF remain the primary causes of treatment failure and cancer death in such patients, suggesting little value of ENI in this cohort.