Post-Operative Radiation Therapy (PORT) in Completely Resected Non-Small-Cell Lung Cancer

Impacts of Positive Margins and Surgical Extent on Outcomes After Early-Stage Lung Cancer Resection

BACKGROUND

Sublobar resection of early-stage non-small cell lung cancer (NSCLC) is increasingly considered appropriate but may compromise margins compared with lobectomy. This study evaluated resection extent, margin status, and survival in patients with clinical stage I NSCLC.

METHODS

Patients with clinical T1-2 N0 M0 NSCLC in the National Cancer Database (2006-2020) who were treated with primary surgery were compared stratified by margin status. The potential benefit of radiation was explored in subgroup analysis of patients who underwent sublobar resection with positive margins.

RESULTS

Positive margins occurred in 5089 (2.8%) of 181,824 patients and were more common in sublobar resections compared with lobectomy (4.3% vs 2.4%; P < .001). Sublobar resection had the strongest association with positive margins in multivariable analysis (odds ratio, 2.06; 95% CI, 1.91-2.23; P < .001). Patients with positive margins were more likely to undergo both adjuvant chemotherapy (16% vs 13%; P < .001) and radiation (17% vs 1%; P < .001) but had worse survival in univariate analysis (44.0% 5-year overall survival vs 69.2%; P < .001) and multivariable Cox analysis (hazard ratio, 1.71; 95% CI, 1.63-1.78; P < .001) in the entire cohort, as well as in a univariate subset analysis of lobectomy (46.9% vs 70.4%; P < .001) and sublobar resection (37.5% vs 64.1%; P < .001). Postoperative radiation for patients who underwent sublobar resection with positive margins did not improve 5-year overall survival (36.3% for irradiated patients vs 38.3% for nonirradiated patients; P = .57), and patients who underwent sublobar resection with positive margins who were treated with radiation had survival inferior to that of patients who underwent lobectomy with negative margins.

CONCLUSIONS

Positive margins occur more frequently after sublobar resection of clinical stage I NSCLC compared with lobectomy. Patients with positive margins have worse survival than patients who undergo complete resection and are not rescued by postoperative radiation.

Radiotherapy in Lung Cancer: Current and Future Role

Lung cancer is divided into two subgroups concerning its natural course and treatment strategies as follows: non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). In this review, for NSCLC, the role of stereotactic body radiation therapy (SBRT) in early-stage, chemoradiation in the locally advanced stage, post-operative radiotherapy for patients with high risk after surgery and radiotherapy for metastatic disease will be discussed. Also, for SCLC, the role and timing of thoracic irradiation and prophylactic cranial irradiation (PCI) for the limited and extensive stages will be discussed.

How Histopathologic Tumor Extent and Patterns of Recurrence Data Inform the Development of Radiation Therapy Treatment Volumes in Solid Malignancies

The ability to deliver highly conformal radiation therapy using intensity-modulated radiation therapy and particle therapy provides for new opportunities to improve patient outcomes by reducing treatment-related morbidities following radiation therapy. By reducing the volume of normal tissue exposed to radiation therapy (RT), while also allowing for the opportunity to escalate the dose of RT delivered to the tumor, use of conformal RT delivery should also provide the possibility of expanding the therapeutic index of radiotherapy. However, the ability to safely and confidently deliver conformal RT is largely dependent on our ability to clearly define the clinical target volume for radiation therapy, which requires an in-depth knowledge of histopathologic extent of different tumor types, as well as patterns of recurrence data. In this article, we provide a comprehensive review of the histopathologic and radiographic data that provide the basis for evidence-based guidelines for clinical tumor volume delineation.

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.

Comparison of risk and predictors for early radiation pneumonitis in patients with locally advanced non-small cell lung cancer treated with radiotherapy with or without surgery

OBJECTIVES

To investigate risk and predictors for radiation pneumonitis (RP) and tolerance of lung to radiation in patients treated with thoracic radiotherapy (RT) with or without surgery.

METHODS AND MATERIALS

A total of 433 consecutive patients with locally advanced non-small cell lung cancer were followed after three-dimensional conformal radiotherapy. Among them 284 received RT without surgical intervention and 149 received postoperative radiotherapy (PORT). RP was graded according to Common Terminology Criteria for Adverse Events version 4.0.

RESULTS

The rate of grade ≥ 2 and grade ≥ 3 RP was 50 and 16% in the PORT group compared with 38 and 9% in the non-surgical group (p < 0.05 for each comparison). The lung volume was significantly smaller in PORT group than in no-surgical group (3181 ± 915 cm(3) vs. 4010 ± 1120 cm(3), p<0.05). Age, chemotherapy, mean lung dose (MLD) and planning target volume (PTV) were predictors of RP for both non-surgical group and PORT group. Mean heart dose (MHD) predicted RP in PORT group only (OR = 1.28, p = 0.003). Among patients who developed RP, V20, MLD, and MHD were significantly lower in PORT group than in no-surgical group (p < 0.05 for each comparison).

CONCLUSIONS

Except MHD predicting RP in PORT group only, most of predictors for RP were consistent in patients treated with RT with or without surgery. Patients receiving PORT had a higher risk of RP than patients receiving RT without surgery did, possibly due to decreased lung volume and lower tolerance of lung to chemoradiotherapy.

Adjuvant chemotherapy and radiotherapy in the treatment of non-small cell lung cancer (NSCLC)

Lung cancer is one of the most common human malignancies and remains the leading cause of cancer related deaths worldwide. Many recent technological advances led to improved diagnostics and staging of lung cancer. With development of new treatment options such as targeted therapies there might be improvement in progression free survival of patients with advanced stage non-small cell lung cancer (NSCLC). Improvement in overall survival is still reserved for selected patients and selected treatments. One of the mostly investigated therapeutic options is adjuvant treatment. There are many open issues in selection of patients and administration of appropriate adjuvant treatment.

Treatment of stage I and II non-small cell lung cancer: Diagnosis and management of lung cancer, 3rd ed: American College of Chest Physicians evidence-based clinical practice guidelines

BACKGROUND

The treatment of stage I and II non-small cell lung cancer (NSCLC) in patients with good or low surgical risk is primarily surgical resection. However, this area is undergoing many changes. With a greater prevalence of CT imaging, many lung cancers are being found that are small or constitute primarily ground-glass opacities. Treatment such as sublobar resection and nonsurgical approaches such as stereotactic body radiotherapy (SBRT) are being explored. With the advent of minimally invasive resections, the criteria to classify a patient as too ill to undergo an anatomic lung resection are being redefined.

METHODS

The writing panel selected topics for review based on clinical relevance to treatment of early-stage lung cancer and the amount and quality of data available for analysis and relative controversy on best approaches in stage I and II NSCLC: general surgical care vs specialist care; sublobar vs lobar surgical approaches to stage I lung cancer; video-assisted thoracic surgery vs open resection; mediastinal lymph node sampling vs lymphadenectomy at the time of surgical resection; the use of radiation therapy, with a focus on SBRT, for primary treatment of early-stage NSCLC in high-risk or medically inoperable patients as well as adjuvant radiation therapy in the sublobar and lobar resection settings; adjuvant chemotherapy for early-stage NSCLC; and the impact of ethnicity, geography, and socioeconomic status on lung cancer survival. Recommendations by the writing committee were based on an evidence-based review of the literature and in accordance with the approach described by the Guidelines Oversight Committee of the American College of Chest Physicians.

RESULTS

Surgical resection remains the primary and preferred approach to the treatment of stage I and II NSCLC. Lobectomy or greater resection remains the preferred approach to T1b and larger tumors. The use of sublobar resection for T1a tumors and the application of adjuvant radiation therapy in this group are being actively studied in large clinical trials. Every patient should have systematic mediastinal lymph node sampling at the time of curative intent surgical resection, and mediastinal lymphadenectomy can be performed without increased morbidity. Perioperative morbidity and mortality are reduced and long-term survival is improved when surgical resection is performed by a board-certified thoracic surgeon. The use of adjuvant chemotherapy for stage II NSCLC is recommended and has shown benefit. The use of adjuvant radiation or chemotherapy for stage I NSCLC is of unproven benefit. Primary radiation therapy remains the primary curative intent approach for patients who refuse surgical resection or are determined by a multidisciplinary team to be inoperable. There is growing evidence that SBRT provides greater local control than standard radiation therapy for high-risk and medically inoperable patients with NSCLC. The role of ablative therapies in the treatment of high-risk patients with stage I NSCLC is evolving. Radiofrequency ablation, the most studied of the ablative modalities, has been used effectively in medically inoperable patients with small (&lt; 3 cm) peripheral NSCLC that are clinical stage I.

Clinical significance in the number of involved lymph nodes in patients that underwent surgery for pathological stage III-N2 non-small cell lung cancer

Purpose

This study investigated whether the number of involved lymph nodes is associated with the prognosis in patients that underwent surgery for pathological stage (p-stage) III/N2 NSCLC.

Subjects

This study evaluated 121 patients with p-stage III/N2 NSCLC.

Results

The histological types included 65 adenocarcinomas, 39 squamous cell carcinomas and 17 others. The average number of dissected lymph nodes was 23.8 (range: 6-55). The average number of involved lymph nodes was 5.9 (range: 1-23). The 5-year survival rate of the patients was 51.0% for single lymph node positive, 58.9% for 2 lymph nodes positive, 34.2% for 3 lymph nodes positive, and 30.0% for 4 lymph nodes positive, and 20.4% for more than 5 lymph nodes positive. The patients with either single or 2 lymph nodes positive had a significantly more favorable prognosis than the patients with more than 5 lymph nodes positive. A multivariate analysis revealed that the number of involved lymph nodes was a significant independent prognostic factor.

Conclusion

Surgery appears to be preferable as a one arm of multimodality therapy in p-stage III/N2 patients with single or 2 involved lymph nodes. The optimal incorporation of surgery into the multimodality approach therefore requires further clinical investigation.