Postoperative radiotherapy of NSCLC--outcome after 3-D treatment planning

Risk of cardiac-related mortality in stage IIIA-N2 non-small cell lung cancer: Analysis of the Surveillance, Epidemiology, and End Results (SEER) database

Background

In this study, we aimed to investigate the association between postoperative radiotherapy (PORT) and cardiac‐related mortality in patients with stage IIIA‐N2 non‐small cell lung cancer (NSCLC) using the Surveillance, Epidemiology, and End Results (SEER) database.

Methods

The United States (US) population based on the SEER database was searched for cardiac‐related mortality among patients with stage IIIA‐N2 NSCLC. Cardiac‐related mortality was compared between the PORT and Non‐PORT groups. Accounting for mortality from other causes, Fine and Gray's test compared cumulative incidences of cardiac‐related mortality between both groups. Univariate and multivariate analysis were performed using the competing risk model.

Results

From 1988 to 2016, 7290 patients met the inclusion criteria: 3386 patients were treated with PORT and 3904 patients with Non‐PORT. The five‐year overall incidence of cardiac‐related mortality was 3.01% in the PORT group and 3.26% in the Non‐PORT group. Older age, male sex, squamous cell lung cancer, earlier year of diagnosis and earlier T stage were independent adverse factors for cardiac‐related mortality. However, PORT use was not associated with an increase in the hazard for cardiac‐related mortality (subdistribution hazard ratio [SHR] = 0.99, 95% confidence interval [CI]: 0.78–1.24, p = 0.91). When evaluating cardiac‐related mortality in each time period, the overall incidence of cardiac‐related mortality was decreased over time. There were no statistically significant differences based on PORT use in all time periods.

Conclusions

With a median follow‐up of 25 months, no significant differences were found in cardiac‐related mortality between the PORT and Non‐PORT groups in stage IIIA‐N2 NSCLC patients.

Delineation of clinical target volume for postoperative radiotherapy in stage IIIA-pN2 non-small-cell lung cancer

With the high locoregional relapse rate and the improvement of radiation technology, postoperative radiotherapy (PORT) has been widely used in the treatment of completely resected stage IIIA-pN2 non-small-cell lung cancer (NSCLC). However, there is still no definitive consensus on clinical target volume for the pN2 subgroup. This review will discuss how to delineate the clinical target volume (CTV) for pN2 subgroups of IIIA-N2 NSCLC based on the published literature and to investigate the optimal PORT CTV in this cohort of patients. Besides overall survival (OS), locoregional recurrence (LR), and radiotherapy-related toxicity of this subset of the population in the modern PORT era, selection of proper patients will also be considered in this review. In summary, it is appropriate to include involved lymph node stations and uninvolved stations at high risk in PORT CTV for patients with pN2 disease when PORT is administered. PORT can reduce LR and has the potential to improve OS. In the current era of modern radiation technology, PORT can be administered safely with well-tolerated toxicity. Clinicopathological characteristics may be helpful in selecting proper candidates for PORT.

Association Between Radiation Dose and Outcomes With Postoperative Radiotherapy for N0-N1 Non-Small Cell Lung Cancer

PURPOSE

To review trends in the use of postoperative radiotherapy (PORT) in the modern era for N0-N1 margin-negative non-small cell lung cancer (NSCLC) following surgical resection and evaluate the association between PORT dose and overall survival.

MATERIALS AND METHODS

We performed a retrospective study of nonmetastatic stage II and III N0-N1 margin-negative NSCLC surgically treated patients within the National Cancer Data Base from 2003 to 2011. Cox proportional hazards regression was performed for multivariable analyses of overall survival and PORT dose. Radiation modalities included nonconformal beam radiation, 3-dimensional conformal radiation (3D-CRT), and intensity-modulated radiation therapy.

RESULTS

We identified 2167 (6.7%) and 30,269 (93.3%) patients with surgically resected stage II or III N0-N1 margin-negative NSCLC who were treated with and without PORT, respectively. The proportion of patients treated with PORT (dose range, 45 to 74 Gy) decreased from 8.9% in 2003 to 2006 to 4.1% in 2010 to 2011. Among patients receiving PORT, the use of high-dose (60 to 74 Gy) PORT rose throughout the study period, starting at 34.8% in 2003 to 2006 and rising to 49.3% in 2010 to 2011.Overall, patients who received PORT had worse survival (hazards ratio=1.30; 95% confidence interval, 1.20-1.40) compared with those not receiving PORT. This association was unchanged when limited to patients receiving modern treatment with 3-CRT or intensity-modulated radiation therapy (hazards ratio=1.35; 95% confidence interval, 1.10-1.65).

CONCLUSIONS

The use of PORT for N0-N1 margin-negative NSCLC decreased from 2003 to 2011. We found no evidence of benefit from PORT for resected N0-N1 margin-negative NSCLC, regardless of dose or technique. PORT should be approached with caution in this group of patients, regardless of radiotherapy technique.

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.

Modern post-operative radiotherapy for stage III non-small cell lung cancer may improve local control and survival: a meta-analysis

BACKGROUND

We hypothesized that modern postoperative radiotherapy (PORT) could decrease local recurrence (LR) and improve overall survival (OS) in patients with stage IIIA-N2 non-small-cell lung cancer (NSCLC).

METHODS

To investigate the effect of modern PORT on LR and OS, we identified published phase III trials for PORT and stratified them according to use or non-use of linear accelerators. Non-individual patient data were used to model the potential benefit of modern PORT in stage IIIA-N2 NSCLC treated with induction chemotherapy and resection.

RESULTS

Of the PORT phase III studies, eleven trials (2387 patients) were included for OS analysis and eight (1677 patients) for LR. PORT decreased LR, whether given with cobalt, cobalt and linear accelerators, or with linear accelerators only. An increase in OS was only seen when PORT was given with linear accelerators, along with the most significant effect on LR (relative risk for LR and OS 0.31 (p=0.01) and 0.76 (p=0.02) for PORT vs. controls, respectively). Four trials (357 patients) were suitable to assess LR rates in stage III NSCLC treated with surgery, in most cases after induction chemotherapy. LR as first relapse was 30% (105/357) after 5 years. In the modeling part, PORT with linear accelerators was estimated to reduce LR rates to 10% as first relapse and to increase the absolute 5-year OS by 13%.

CONCLUSIONS

This modeling study generates the hypothesis that modern PORT may increase both LR and OS in stage IIIA-N2 NSCLC even in patients being treated with induction chemotherapy and surgery.

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.