Impact of invasive nodal staging on regional and distant recurrence rates after SBRT for inoperable stage I NSCLC

Invasive Nodal Staging via Endobronchial Ultrasound and Outcome in Patients Treated with Stereotactic Body Radiation Therapy for Early-Stage Non-Small Cell Lung Cancer - Results from a Single Institution Study

INTRODUCTION

Stereotactic body radiation therapy (SBRT) is an effective treatment for medically inoperable early-stage non-small cell lung cancer (NSCLC). The prognostic value of invasive nodal staging (INS) for patients undergoing SRBT has not been studied extensively. Herein, we report the impact of INS in addition to 18F-FDG-PET on treatment outcome for patients with NSCLC undergoing SBRT.

MATERIALS AND METHODS

Patients with stage I/ II NSCLC who underwent SBRT were included with IRB approval. Clinical, dosimetric, and radiological data were obtained. Overall survival (OS), regional recurrence free survival (RRFS), local recurrence free survival (LRFS), and distant recurrence free survival (DRFS) were analyzed using Kaplan Meyer method. Univariable analysis (UVA) and multivariable analysis (MVA) were performed to assess the relationship between the variables and the outcomes.

RESULTS

A total of 376 patients were included in the analysis. Median follow up was 43 months (IQ 32.6-45.8). Median OS, LRFS, RRFS, DRFS were 40, 32, 32, 33 months, respectively. The 5-year local, regional, and distant failure rates were 13.4%, 23.5% and 25.3%, respectively. The 1-year, 3-year and 5-year OS were 83.8%, 55.6%, and 36.3%, respectively. On MVA, INS was not a predictor of either improved overall or any recurrence free survival endpoints while larger tumor size, age, and adjusted Charleston co-morbidity index (aCCI) were significant for inferior LRFS, RRFS, and DRFS.

CONCLUSION

Invasive nodal staging did not improve overall or recurrence free survival among patients with early-stage NSCLC treated with SBRT whereas older age, aCCI, and larger tumor size were significant predictors of LRFS, RRFS, and DRFS.

What is new in mediastinal staging?

PURPOSE OF REVIEW

Appropriate staging is of utmost importance in nonsmall cell lung cancer (NSCLC), as the pathologic stage dictates both overall prognosis and appropriate therapeutic pathways. This article seeks to review the current recommendations for mediastinal staging of NSCLC and available modalities to achieve this. Landmark publications pertaining to recent advancements in NSCLC treatments are also highlighted and the role of specific bronchoscopic modalities for tissue acquisition are reviewed.

RECENT FINDINGS

Recent advancements in the treatment of NSCLC have made accurate mediastinal staging more important than ever. Guidelines and recommendations outlining patients that warrant invasive mediastinal staging are available and a systematic approach should be utilized when sampling is performed. Ensuring the adequacy of tissue for the growing number of molecular biomarkers that must be tested has been the focus of many recent studies.

SUMMARY

Appropriate mediastinal staging is crucial for the management of patients with NSCLC as is obtaining adequate tissue for diagnostic and therapeutic purposes. EBUS-TBNA is sufficient for the diagnosis of nonsmall cell and small cell lung carcinomas, but EBUS-guided intranodal forceps and cryobiopsy may provide more optimal specimen for patients with benign disease, such as sarcoidosis, or in cases of lymphoma. Further studies are necessary to better delineate the role of these techniques in the diagnosis and staging of mediastinal diseases before they become the primary diagnostic modalities.

Lung cancer staging, the established role of bronchoscopy

PURPOSE OF REVIEW

Lung cancer is the leading cause of cancer-related deaths worldwide. In the absence of distant metastases, accurate mediastinal nodal staging determines treatment approaches to achieve most favourable outcomes for patients. Mediastinal staging differentiates N0/N1 disease from N2/N3 in surgical candidates. Likewise, presence of nodal involvement in nonsurgical candidates who are being considered for stereotactic body radiation therapy is also critical. This review article seeks to discuss the current options available for mediastinal staging in nonsmall cell lung cancer (NSCLC), particularly the role of bronchoscopy.

RECENT FINDINGS

Although several techniques are available to stage the mediastinum, bronchoscopy with EBUS-TBNA with or without EUS-FNA appears to be superior in most clinical situations based on its ability to concomitantly diagnose and stage at once, safety, accessibility to the widest array of lymph node stations, cost and low risk of complications. However, training and experience are required to achieve consistent diagnostic accuracy with EBUS-TBNA.

SUMMARY

EBUS-TBNA with or without EUS-FNA is considered the modality of choice in the diagnosis and staging of NSCLC in both surgical and nonsurgical candidates.

Nodal recurrences after stereotactic body radiotherapy for early stage non-small-cell lung cancer

Lobectomy is considered the standard of care for early stage non-small-cell lung cancer. However, for those patients who remain unfit to undergo surgery due to advanced age, poor performance status, comorbidities, poor pulmonary reserve or a combination of these are now treated with stereotactic body radiation therapy (SBRT). Due to its noninvasive nature, lower cost, lower toxicity, reduced recovery time and equivalent efficacy, even medically operable patients are attracted to the option of SBRT despite the lack of level I evidence. Thus, studying the incidence and patterns of recurrence after SBRT help in understanding the magnitude of the problem, risk factors associated with the different patterns of recurrence, and aid in devising strategies to prevent them in future. Nodal recurrences are not uncommon after SBRT and can potentially lead to further seeding for distant metastases and ultimately poor survival. This review is aimed at reviewing the published data on the incidence of nodal recurrences after SBRT and compare it to surgery, identify potential risk factors for recurrence, salvage treatment options and prevention strategies.