Benefits of postoperative radiotherapy in multimodality treatment of resected small-cell lung cancer with lymph node metastasis

Application of postoperative adjuvant radiotherapy in limited-stage small cell lung cancer: A systematic review and meta-analysis

BACKGROUND AND PURPOSE

One of the most important treatments for small cell lung cancer (SCLC) is radiation therapy. Currently, the criteria for administering postoperative adjuvant radiotherapy (PORT) in SCLC remain uncertain. Therefore, we conducted a meta-analysis to investigate the influence of PORT on the prognosis of limited-stage SCLC (LS-SCLC).

METHODS

We conducted a comprehensive search across three databases, PubMed, Embase, and the Cochrane Library. Data analysis involved utilizing both random-effects and fixed-effects models for pooling the results. A comparative analysis was performed to assess the prognostic outcomes of patients with LS-SCLC who did and did not undergo PORT. The primary outcome assessed was overall survival (OS), while the secondary outcome was disease-free survival (DFS).

RESULTS

This analysis included 11 retrospective studies comprising 7694 eligible participants. Among the entire population of LS-SCLC patients, the OS was superior in those receiving PORT than in those not receiving it (hazard ratio [HR]: 0.79, 95 % confidence interval [CI]: 0.71-0.87; P < 0.0001). In pN0 stage LS-SCLC patients, PORT was associated with a detrimental effect on OS (HR: 1.22, 95 % CI: 1.04-1.43; P = 0.01). In pN1 stage LS-SCLC patients, additionally administering PORT did not provide a significant OS advantage as compared to not administering it (HR: 0.82, 95 % CI: 0.60-1.12; P = 0.21). In pN2 stage LS-SCLC patients, those receiving PORT demonstrated a significant improvement in OS (HR: 0.59; 95 % CI: 0.50-0.70; P < 0.0001) as compared to those not receiving it. Regarding DFS in LS-SCLC patients, the difference in the protective effect with and without the administration of PORT was less pronounced (HR: 0.76, 95 % CI: 0.58-1.00; P = 0.053).

CONCLUSIONS

With respect to OS, PORT is not advisable in patients with pN0 or pN1 stage LS-SCLC but is highly recommended in pN2 stage LS-SCLC. Further research is warranted to confirm these findings.

Construction and validation of a nomogram based on the log odds of positive lymph nodes to predict cancer-specific survival in patients with small cell lung cancer after surgery

Background

The lymph node ratio (LNR) is useful for predicting survival in patients with small cell lung cancer (SCLC). The present study compared the effectiveness of the N stage, number of positive LNs (NPLNs), LNR, and log odds of positive LNs (LODDS) to predict cancer-specific survival (CSS) in patients with SCLC.

Materials and methods

674 patients were screened using the Surveillance Epidemiology and End Results database. The Kaplan-Meier survival and receiver operating characteristic (ROC) curves were performed to address optimal estimation of the N stage, NPLNs, LNR, and LODDS to predict CSS. The optimal LN status group was incorporated into a nomogram to estimate CSS in SCLC patients. The ROC curve, decision curve analysis, and calibration plots were utilized to test the discriminatory ability and accuracy of this nomogram.

Results

The LODDS model showed the highest accuracy compared to the N stage, NPLNs, and LNR in predicting CSS for SCLC patients. LODDS, age, sex, tumor size, and radiotherapy status were included in the nomogram. The results of calibration plots provided evidences of nice consistency. The ROC and DCA plots suggested a better discriminatory ability and clinical applicability of this nomogram than the 8th TNM and SEER staging systems.

Conclusions

LODDS demonstrated a better predictive power than other LN schemes in SCLC patients after surgery. A novel LODDS-incorporating nomogram was built to predict CSS in SCLC patients after surgery, proving to be more precise than the 8th TNM and SEER staging.

Pathological Stage N1 Limited-Stage Small-Cell Lung Cancer Patients Can Benefit From Surgical Resection

PURPOSE

Surgery is controversial in limited-stage small-cell lung cancer (LS-SCLC) (except for T1-2, N0M0). This study aimed to analyze the survival of LS-SCLC patients with proximal lobe (N1) lymph node metastases after surgery and appropriate postoperative adjuvant treatment.

PATIENTS AND METHODS

We reviewed and followed up medical history and survival data of LS-SCLC patients from June 2007 to June 2016, and a total of 68 pathological stage N1 (p-N1) patients who underwent surgical resection and 71 clinical-stage N1 (c-N1) patients who received chemoradiotherapy were included in the final analysis.

RESULTS

The median follow-up of all the patients was 99.30 months. The median disease-free survival (DFS) of the surgery group was 13.567 months, and the median overall survival (OS) of the surgery and chemoradiotherapy groups were 29.600 months and 21.133 months (P-value < .001), respectively. The 2- and 5-year survival rates of the surgery group were 55.9% and 33.7%, and the 2- and 5-year survival rates of the chemoradiotherapy group were 39.8% and 9.4%, respectively. Meanwhile, postoperative thoracic radiotherapy appeared to be associated with a good prognosis (median OS 36.400 vs. 21.333 months, P-value .048), as did prophylactic cranial irradiation (median OS 50.867 vs. 22.600 months, P-value .007) in the surgery group.

CONCLUSIONS

Surgery may benefit patients with p-N1 SCLC, and in combination with appropriate postoperative adjuvant treatment, surgery may be a new therapeutic modality for SCLC.

The Construction and Validation of Nomogram to Predict the Prognosis with Small-Cell Lung Cancer Followed Surgery

This study constructed and validated a prognostic model to evaluate the survival of small-cell lung cancer (SCLC) patients following surgery, and shed light on the strategy of postoperative radiotherapy. A total of 882 patients from Shanghai Pulmonary Hospital and the Surveillance, Epidemiology and End Results database after lung resection were selected. Multivariable Cox analysis was used to identify the indicators affecting long-term survival in patients. A nomogram was constructed to predict the prognosis of eligible patients. Indices of concordance (C-index) was used to access the predictive ability of cancer-specific survival (CSS) for the prognostic model. CSS discrimination in the prognostic model was comparable in the training and validation cohorts (C-index = 0.637[NORAD-T], 0.660[NORAD-V], 0.656[RAD] and 0.627[our hospital], respectively. Stratification based on the cutoff value of the nomogram yielded low- and high-risk subgroups in four cohorts. For patients in the high-risk group, postoperative radiotherapy was considered a survival-promoting strategy (unadjusted HR 0.641, 95% CI 0.469-0.876, p = 0.0046). In the low-risk group, however, the implementation of radiotherapy barely had an influence on CSS. In conclusion, the nomogram we constructed and validated could predict the prognosis of SCLC patients followed surgery and identify high-risk patients who were likely to benefit from postoperative radiotherapy.

Radiotherapy for small cell lung cancer in current clinical practice guidelines

Several guidelines including radiotherapy recommendations exist worldwide for the treatment of small cell lung cancer (SCLC). To evaluate the differences in radiotherapy recommendations we conducted a systematic review. PubMed and the sites of medical societies were searched for SCLC guidelines published in either English, Chinese, or Dutch. This was limited to January 2018 till February 2021 to only include up-to-date recommendations. Data was extracted and compared regarding the guideline's development method and radiotherapy recommendations. Eleven guidelines were identified (PubMed n=4, societies n=7) from Spain (n=1), Canada (n=1), America (n=3), United Kingdom (n=1), the Netherlands (n=1), and China (n=3), respectively. Nine guidelines assessed the strength of evidence (SOE) and specified the strength of recommendation (SOR), although methods were different. The major radiotherapy recommendations are similar although differences exist in thoracic radiotherapy (TRT) dose, time, and volume. Controversial areas are TRT in resected stage I-IIA (pN1), prophylactic cranial irradiation (PCI) in resected as well as unresected stage I-IIA, stereotactic body radiation therapy (SBRT) in unresected stage I-IIA, PCI time, and PCI versus magnetic resonance imaging (MRI) surveillance in stage IV. The existence of several overlapping guidelines for SCLC treatment indicates that guideline development is (unnecessarily) repeated by different organizations or societies. Improvement could be made by better international collaboration to avoid duplicating unnecessary work, which would spare a lot of time and resources. Efforts should be made to work together on controversial or unknown fields.

The prognostic value of lymph node ratio in patients with surgically resected stage I-III small-cell lung cancer: a propensity score matching analysis of the SEER database

OBJECTIVES

Due to the lack of prospective studies, the role of the lymph node ratio (LNR) in small-cell lung cancer (SCLC) remains unknown. This study aimed to assess the prognostic effect of LNR in surgically resected stage I-III SCLC patients.

METHODS

Clinical data of stage I-III (excluding N3 and NX) SCLC patients diagnosed between 1998 and 2016 were extracted from the Surveillance, Epidemiology and End Results database. Patients were divided into low-risk and high-risk subsets based on the LNR cut-off value of 0.15 using X-tile software. Propensity score matching analysis was employed to reduce bias in baseline characteristics. Kaplan-Meier analysis was performed to determine the overall survival (OS) and lung cancer-specific survival (LCSS). Cox regression analysis was performed to evaluate the effects of multiple variables.

RESULTS

A total of 978 patients were identified, of whom 669 (68.40%) had LNR ≤0.15. Patients with LNR ≤0.15 showed better OS (P < 0.001) and LCSS (P < 0.001) both before and after propensity score matching. Multivariable analyses of the matched population confirmed LNR as an independent prognostic factor. Patients with LNR >0.15 showed poorer OS [hazard ratio (HR) 1.55, 95% confidence interval (CI) 1.09-2.19; P = 0.015] and LCSS (HR 1.65, 95% CI 1.13-2.43; P = 0.010). Subgroup analyses revealed that LNR ≤0.15 was associated with favourable OS (P = 0.009 and 0.197, respectively) and LCSS (P = 0.010 and 0.169, respectively) in N1 and N2 patients.

CONCLUSIONS

LNR was determined as an independent predictor for surgically resected stage I-III SCLC, indicating that higher LNR is associated with reduced survival. The predictive value of LNR should to be further validated in prospective studies.

GOECP/SEOR radiotherapy guidelines for small-cell lung cancer

Small cell lung cancer (SCLC) accounts for approximately 20% of all lung cancers. The main treatment is chemotherapy (Ch). However, the addition of radiotherapy significantly improves overall survival (OS) in patients with non-metastatic SCLC and in those with metastatic SCLC who respond to Ch. Prophylactic cranial irradiation reduces the risk of brain metastases and improves OS in both metastatic and non-metastatic patients. The 5-year OS rate in patients with limited-stage disease (non-metastatic) is slightly higher than 30%, but less than 5% in patients with extensive-stage disease (metastatic). The present clinical guidelines were developed by Spanish radiation oncologists on behalf of the Oncologic Group for the Study of Lung Cancer/Spanish Society of Radiation Oncology to provide a current review of the diagnosis, planning, and treatment of SCLC. These guidelines emphasise treatment fields, radiation techniques, fractionation, concomitant treatment, and the optimal timing of Ch and radiotherapy. Finally, we discuss the main indications for reirradiation in local recurrence.

The role of postoperative radiotherapy (PORT) in combined small cell lung cancer (C-SCLC)

Purpose

To explore the value of radiotherapy in C-SCLC patients, especially in those receiving a radical resection.

Results

The differences of survivals between the postoperative radiotherapy (PORT) and non-PORT groups were not statistically significant. But analyzing the benefits in subgroups, PORT significantly improved OS (p = 0.015), DFS (p = 0.026), LRFS (p = 0.008) and DMFS (p = 0.030) in stage III patients. For the patients with N2 stage, all survivals of the PORT group were also statistically significantly higher than non-PORT group (p = 0.018, 0.032, 0.008, 0.042). Patients with more than 10% of metastatic lymph nodes could get a significant benefit survivals by receiving PORT (p = 0.033, 0.030, 0.025, 0.031). Having a systematic dissection of more than 17 lymph nodes was a subset which could get better OS and LRFS by receiving PORT (p = 0.045, 0.048).

Methods

Between Jan. 2004 to Dec. 2012, fifty-five patients diagnosed as C-SCLC after complete surgical resection in our center were retrospectively analyzed. The overall survival (OS), disease free survival (DFS), loco-regional recurrence free survival (LRFS), and distant metastasis free survival (DMFS) were calculated by Kaplan-Meier method.

Conclusions

PORT can significantly improve the survival of C-SCLC patients with resected pathological pN2 stage. For the patients with a large percent of metastatic lymph nodes, PORT can also improve survivals.

Prognostic Value of Metabolic Parameters of Metastatic Lymph Nodes on 18F-FDG PET/CT in Patients With Limited-stage Small-cell Lung Cancer With Lymph Node Involvement

INTRODUCTION

We assessed the prognostic value of the metabolic parameters of different lesions, including primary tumors and metastatic lymph nodes (LNs), measured by fluorine-18 fluorodeoxyglucose positron emission tomography (PET)/computed tomography in patients with limited-stage small-cell lung cancer (LS-SCLC) with LN metastasis.

MATERIALS AND METHODS

The present retrospective study included 46 patients with clinical stage II-III N1-N2 LS-SCLC who had undergone pretreatment fluorine-18 fluorodeoxyglucose PET/computed tomography scanning from January 2011 to December 2014. All patients underwent complete first-line therapy (concurrent chemoradiotherapy and prophylactic cranial irradiation). The metabolic parameters, including maximal standardized uptake value, mean standardized uptake value, metabolic tumor volume (MTV), and total lesion glycolysis (TLG) values of the PTs and metastatic LNs were measured on PET. Kaplan-Meier survival curves were used for evaluation of progression-free survival (PFS) and overall survival (OS). Univariate and multivariate Cox proportional hazards models were used to analyze the prognostic factors.

RESULTS

The median OS and PFS were 25.9 months (range, 8.2-63.5 months) and 21 months (range, 6.4-55.3 months), respectively. Univariate analysis demonstrated that the Eastern Cooperative Oncology Group performance status, N1 station involvement, subcarinal LN metastasis, LN MTV, LN TLG, sum of the MTV, and summary of the TLG were significant predictive factors (P < .05). The Eastern Cooperative Oncology Group performance status, subcarinal nodal metastasis, LN MTV, and LN TLG were independent predictive factors of PFS and OS on multivariate analysis.

CONCLUSION

The metabolic parameters of metastatic LNs, other than lung lesions, are independent prognostic factors in patients with LS-SCLC with LN metastasis. These parameters could further stratify the prognosis of these patients, and these findings might provide functional imaging evidence for the future study of the mechanisms of metastasis.

Effect of LINAC-based postoperative radiotherapy on local control and survival in patients with non-small cell lung cancer

Aim

To perform a retrospective analysis of survival, local–regional control and the effect of prognostic factors in 61 non-small cell lung cancer patients who were treated with postoperative radiotherapy (PORT) by a linear accelerator (LINAC).

Material and methods

A total of 50–66 Gy PORT with a fractional dose of 1·8–2 Gy was administered to 24 patients (24·5%) for surgical margin positivity, 33 patients (54%) for mediastinal lymph node involvement and 13 patients (21·5%) for both mediastinal lymph node involvement and positive surgical margins.

Results

Median follow-up was 17 months, and the median survival and median distant metastasis-free survival were 25 and 19 months, respectively. Local-regional progression was observed in 10 patients (16·4%). Treatment modality (2D/3D) (p=0·021), tumour size >4 cm (p=0·004), surgical margin positivity (p=0·001), and left lung localisation of the tumour (p≤0·05) were the prognostic factors in terms of survival.

Conclusions

A survey of the literature shows that, without PORT, local recurrence or progression rates increase while overall survival rates decrease. In this study, only patients with PORT are studied and the results show that the local progression and overall survival rates are comparable with literature of LINAC-based PORT. In the case of overall survival, 3D treatment shows better results than 2D treatment modality.

Benefits of postoperative thoracic radiotherapy for small cell lung cancer subdivided by lymph node stage: a systematic review and meta-analysis

BACKGROUND

Whether postoperative thoracic radiotherapy (PORT) is beneficial for small cell lung cancer (SCLC) of different lymph node stages remains uncertain; therefore, the purpose of this meta-analysis was to explore the clinical significance of PORT for SCLC patients subdivided by lymph node status.

METHODS

The PubMed, OVID, Web of SCI, EMBASE, Google Scholar, Cochrane Library, Chinese National Knowledge Infrastructure and Wanfang databases were systematically searched to identify eligible studies where SCLC patients received PORT based on lymph node stage. The main outcome measures were 1-, 3- and 5-year overall survival (OS) rates, as well as 1-, 2- and 3-year local regional recurrence (LRR) rates. All data were analyzed using STATA 12.0 and expressed as risk ratios (RR) with their corresponding 95% confidence intervals (95% CI).

RESULTS

Five cohort studies, including 3,497 SCLC patients (578 receiving PORT and 2,919 not) were included in this study. PORT significantly decreased the 1-, 2- and 3-year LRR rates (RR =0.14, 0.28 and 0.27, respectively; P_all<0.05), but did not improve the 1-, 3- or 5-year OS rates when all patients were analyzed together. However, subgroup analysis showed that in the pN0 group PORT did not improve the 1-, 3- or 5-year OS rates or decrease the 1-, 2- or 3-year LRR rates; in the pN1 group PORT reduced the 1-, 2- and 3-year LRR rates (RR =0.11, 0.16 and 0.17, respectively; P_all<0.05) and improved the 1-year OS rate (RR =0.40; P<0.001), but not the 3- or 5-year OS rates; in the pN2 group PORT significantly reduced the 1-, 2- and 3-year LRR rates (RR =0.14, 0.15 and 0.15 respectively; P_all<0.05) and improved the 1-, 3- and 5-year OS rates (RR =0.46, 0.72 and 0.85, respectively; P_all<0.05).

CONCLUSIONS

This is the first meta-analysis of the benefits of PORT for SCLC patients. Although derived from retrospective cohort studies, the data showed that PORT significantly reduced the risk of recurrence and improved survival for patients with pN2-SCLC; however, patients with pN0-SCLC did not benefit from PORT, whereas for patients with pN1-SCLC, PORT reduced the LRR rates and improved the 1-year survival rate. The long-term survival benefits of PORT remain unclear and will require further prospective studies.

Timing of thoracic radiotherapy in the treatment of extensive-stage small-cell lung cancer: important or not?

Background

This study evaluated the prognosis of patients with extensive-stage small-cell lung cancer (ES-SCLC) that may be associated with timing of thoracic radiotherapy (TRT).

Methods

ES-SCLC patients (n = 232) without progression were retrospectively analyzed after first-line induction chemotherapy. Patients in the TRT group were stratified as early-TRT (ERT; ≤3 cycles of induction chemotherapy received prior to TRT, n = 65) or late-TRT (LRT; >3 cycles, n = 122). To avoid selection bias, we conducted Propensity Score Matching (PSM) for patients. Overall survival (OS), progression-free survival (PFS), and locoregional recurrence-free survival (LRRFS) were assessed and compared.

Results

Overall, the median survival time, PFS, and LRRFS were 13.2, 8.7, and 14.6 months, respectively. After matching by PSM, there were 45 patients total in the TRT/non-TRT groups, and 56 patients total in the ERT/LRT groups. OS, PFS, and LRRFS were significantly longer in the TRT group than the non-TRT group (P < 0.001, all). However, between the ERT and LRT groups these survival parameters were similar (P > 0.05, all).

Conclusion

For ES-SCLC patients without progression, the addition of TRT after first-line chemotherapy benefited survival greatly. Early TRT showed no significant benefit over late TRT.

[Postoperative radiotherapy for non-small cell lung cancer: Efficacy, target volume, dose]

The rate of local failure of stage IIIA-N2 non-small cell lung cancer is 20 to 40%, even if they are managed with surgery and adjuvant chemotherapy. Postoperative radiotherapy improves local control, but its benefit on global survival remains to be demonstrated. Considered for many years as an adjuvant treatment option for pN2 cancers, it continues nevertheless to be deemed too toxic. What is the current status of postoperative radiotherapy? The Lung Adjuvant Radiotherapy Trial (Lung ART) phase III trial should give us a definitive, objective response on global survival, but inclusion of patients is difficult. The results are consequently delayed. The aim of this review is to show all the results about efficacy and tolerance of postoperative radiotherapy and to define the target volume and dose to prescribe.

Assessing the Impact of Postoperative Radiation Therapy for Completely Resected Limited-Stage Small Cell Lung Cancer Using the National Cancer Database

INTRODUCTION

Surgical resection is being increasingly used for early-stage small cell lung cancer (SCLC). However, there are sparse data regarding the role of adjuvant therapies, particularly postoperative radiation therapy (PORT). We investigated the impact of PORT on survival after complete surgical resection for SCLC using the National Cancer Database.

METHODS

There were 3017 patients diagnosed with nonmetastatic SCLC between 1998 and 2011 who underwent R0 sublobar resection, lobectomy, or pneumonectomy. Patients were stratified by the use of PORT, and only those who received a minimum dose of 45 Gy were included. The overall survival (OS) of patients based on PORT use were analyzed by Kaplan-Meier analysis and compared using the log-rank test. Multivariate Cox regression analysis was used to identify factors associated with survival.

RESULTS

For the entire study population, the 5-year OS was significantly poorer with the addition of PORT (33.9% versus 40.6%; p = 0.005). When analyzed by subgroup, patients with pN0 stage had significantly decreased OS with PORT (39.3% versus 46.3%; p = 0.07) and patients with pN2 stage had significantly improved OS with PORT (29.0% versus 18.6%; p < 0.001). No differences in OS were observed in patients with pN1 stage. On multivariate analysis, the hazard ratio for PORT in pN0 disease was 1.36 (95% confidence interval, 1.09-1.70; p < 0.001) and the hazard ratio for PORT in pN2 disease was 0.60 (95% confidence interval, 0.45-0.80; p < 0.001).

CONCLUSION

The use of PORT was associated with a deleterious effect on OS in patients with pN0 disease but significantly improved OS in patients with pN2 disease.