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

COX-2/PTGS2-targeted herbal-derived oligonucleotide drug HQi-sRNA-2 was effective in spontaneous mouse lung cancer model

In 2020, the number of deaths caused by lung cancer worldwide reached 1,796,144, making it the leading cause of cancer-related deaths. Cyclooxygenase-2/prostaglandin endoperoxide synthase 2 (COX-2/PTGS2) is overexpressed in lung cancer, which promotes tumor proliferation, invasion, angiogenesis, and resistance to apoptosis. Here, we report that the oligonucleotide drug HQi-sRNA-2 from Traditional Chinese Medicine Huangqin targeting COX-2/PTGS2 significantly inhibited proliferation, migration, and invasion and induced apoptosis in the human lung cancer cell line NCI-H460. Oral delivery of HQi-sRNA-2 bencaosomes prolonged survival, reduced tumor burden, and maintained weight in a spontaneous mouse lung cancer model. Compared with paclitaxel, HQi-sRNA-2 may be less toxic and have approximately equal efficacy in reducing tumor burden. Our previous studies reported that herbal small RNAs (sRNAs) are functional medical components. Our data suggest that sphingosine (d18:1)-HQi-sRNA-2 bencaosomes, targeting COX-2/PTGS2 and downregulating the PI3K and AKT signaling pathways, may provide novel therapeutics for lung cancer.

Impact of examined lymph node count on survival outcomes in patients with stage T1-2N0M0 small cell lung cancer undergoing surgery: A retrospective cohort study

To explore the relationship between the count of examined lymph nodes (ELNs) and survival outcomes in patients with stage T1-2N0M0 small cell lung cancer (SCLC) after surgical treatment. We analyzed data from patients with SCLC in the Surveillance, Epidemiology, and End Results database. The study focused on examining the correlation between the ELN count and both cancer-specific survival (CSS) and overall survival (OS). This relationship was investigated using restricted cubic spline curves within the framework of multivariable Cox regression models. The cutoff value for both CSS and OS was 7 ELN counts. Patients with ELN < 7 had a median CSS of 64 months, significantly lower than 123 months of patients with ELN ≥ 7 (P = .012). Multivariable Cox regression analysis indicated that ELN ≥ 7 was an independent prognostic factor for CSS (hazard ratio = 0.50, 95% confidence interval: 0.30-0.83; P = .007). Similarly, Patients with ELN < 7 had a median OS of 41 months for patients with ELN < 7, compared to 103 months for those with ELN ≥ 7 (P = .004). Multivariable Cox regression analysis confirmed that ELN ≥ 7 was an independent prognostic factor for OS (hazard ratio = 0.54, 95% confidence interval: 0.36-0.81; P = .003). ELN ≥ 7 is recommended as the threshold for evaluating the quality of postoperative lymph node examination and for prognostic stratification in patients with stage T1-2N0M0 SCLC undergoing surgery.

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.

Treatment Patterns and Survival Outcomes in Patients With Stage T1-2N0M0 Small Cell Lung Cancer Undergoing Surgery: A Retrospective Cohort Study

Background

The aim of the study was to delineate the treatment modalities and survival outcomes in patients with stage T1-2N0M0 small cell lung cancer (SCLC) who underwent surgery.

Methods

SCLC patients from the Surveillance, Epidemiology, and End Results databases between 2000 and 2020 were investigated. Kaplan-Meier survival analysis was employed to assess cancer-specific survival (CSS) and overall survival (OS) across diverse therapeutic strategies.

Results

The study included 190 patients. Treatment modalities included surgery alone in 65 patients (34.2%), surgery + chemotherapy in 70 patients (36.8%), surgery + radiotherapy in three patients (1.6%), and surgery + chemoradiotherapy in 52 patients (27.4%). The median CSS remained undetermined for the surgery alone group, whereas it was 123 and 113 months for the surgery + chemotherapy and surgery + chemoradiotherapy groups. Median OS was 47, 84, and 50 months for these groups. Multivariate Cox regression analysis revealed that patients receiving surgery + chemotherapy exhibited a significantly enhanced OS (hazard ratio (HR) = 0.60, 95% confidence interval (CI): 0.38 - 0.94; P = 0.028) compared to those undergoing surgery alone. However, the integration of radiotherapy did not improve OS compared to surgery alone (HR = 0.72, 95% CI: 0.44 - 1.15; P = 0.170).

Conclusion

Adjuvant chemotherapy improved OS compared to surgery alone. However, the addition of radiotherapy did not prolong OS.

Survival of small-cell lung cancer patients after surgery: A single-center retrospective cohort study

This study summarized and analyzed the clinical characteristics and prognosis of small-cell lung cancer (SCLC) patients after surgical treatment. The clinical data of 130 patients (99 males and 31 females) with SCLC treated by surgery and confirmed by postoperative pathological examination at Peking Union Medical College Hospital from April 2004 to April 2019 were retrospectively analyzed. Clinical characteristics, surgery, pathological stage, and perioperative treatment were summarized. Kaplan-Meier survival curve and Cox regression analysis were performed. Pathological examination revealed that 36 (27.69%) patients had stage I SCLC, 22 (16.92%) patients had stage II SCLC, 65 (50.00%) patients had stage III SCLC, and 7 (5.39%) patients had stage IV SCLC. The overall median survival time was 50 months (95% confidence interval, 10.8-89.2 months). The median survival time of stage I, II, III and IV SCLC patients was 148, 42, 32, and 10 months, respectively. In patients who underwent surgical treatment, postoperative adjuvant therapy and tumor stage were independent prognostic factors for survival (p < 0.05).Lobectomy and lymph nodes resection combined with adjuvant therapy were cautiously recommended for stage I-IIIa SCLC patients.

Long-term results of postoperative unsuspected small cell lung cancer on real-world data

BACKGROUND

In traditional opinion, solid pulmonary nodule suspected lung cancer should be confirmed by pathology before the operation to exclude small cell lung cancer (SCLC), considering SCLC tends to be aggressive and surgical effect in the management of SCLC remains controversial. The aim of this study was to evaluate the survival result and risk factors of postoperative unsuspected SCLC.

METHODS

A total of 120 patients with postoperative unsuspected SCLC who were confirmed by pathology and referred to Chinese PLA General Hospital between 2000 and 2021 were retrospectively analyzed (surgery group). Additionally, 120 patients with limited-stage SCLC who underwent chemotherapy and radiotherapy in the same period were enrolled in the chemoradiotherapy group.. Kaplan-Meier method was used to estimate survival; the Log-Rank test was used to compare survival rates between different groups; a COX stepwise regression model was used for multivariate analysis.

RESULTS

Among 120 patients in the surgery group, 28 were with central type and other 92 with peripheral type. The median survival (OS) was 44.85 months, and the 5-year survival rate was 46%. The 5-year survival rates for stage I, II, and III were 52.1%, 45.4%, and 27.8%, respectively. The mean disease-free survival time (DFS) was 30.63 ± 4.38 months, and the 5-year DFS rate was 31.5%. In the chemoradiotherapy group, the mean OS was 21.4 ± 4.26 months, and the 5-year survival rate was 28.3%. The 5-year survival rates for clinical stage I, II, and III were 42.5%, 39.8%, and 20.5%, respectively. The mean progression-free survival (PFS) was 10.63 ± 3.6 months. In the surgery group, one-way ANOVA revealed that the gender, symptoms, smoking history, tumor location, and postoperative radiotherapy were not associated with OS (P ≥ 0.05), while age, surgical approach, surgical method, N stage, TNM stage, and vascular tumor thrombus were related to OS (P < 0.05). Multivariate analysis indicated that the N stage was associated with OS (HR = 1.86 P = 0.042).

CONCLUSION

Surgery and adjuvant therapy were found to have encouraging outcomes in postoperative unsuspected SCLC. Patients with stage I, stage II and part of stage IIIA SCLC could benefit from surgery and the standard lobectomy, and systematic lymph node dissection, is also recommended for these patients.

Development and validation of nomogram prognostic model for early-stage T1-2N0M0 small cell lung cancer: A population-based analysis

Background

Survival outcomes of early-stage T1-2N0M0 small cell lung cancer (SCLC) patients differ widely, and the existing Veterans Administration Lung Study Group (VALSG) or TNM staging system is inefficient at predicting individual prognoses. In our study, we developed and validated nomograms for individually predicting overall survival (OS) and lung cancer-specific survival (LCSS) in this special subset of patients.

Methods

Data on patients diagnosed with T1-2N0M0 SCLC between 2000 and 2015 were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. All enrolled patients were split into a training cohort and a validation cohort according to the year of diagnosis. Using multivariable Cox regression, significant prognostic factors were identified and integrated to develop nomograms for 1-, 3-, and 5-year OS and LCSS prediction. The prognostic performance of our new model was measured by the concordance index (C-index) and calibration curve. We compared our latest model and the 8th AJCC staging system using decision curve analyses (DCA). Kaplan-Meier survival analyses were applied to test the application of the risk stratification system.

Results

A total of 1,147 patients diagnosed from 2000 to 2011 were assigned to the training cohort, and 498 cases that were diagnosed from 2012 to 2015 comprised the validation cohort. Age, surgery, lymph node removal (LNR), and chemotherapy were independent predictors of LCSS. The variables of sex, age, surgery, LNR, and chemotherapy were identified as independent predictors of OS. The above-mentioned prognostic factors were entered into the nomogram construction of OS and LCSS. The C-index of this model in the training cohort was 0.663, 0.702, 0.733, and 0.658, 0.702, 0.733 for predicting 1-, 3-, and 5-year OS and LCSS, respectively. Additionally, in the validation cohort, there were 0.706, 0.707, 0.718 and 0.712, 0.691, 0.692. The calibration curve showed accepted prediction accuracy between nomogram-predicted survival and actual observed survival, regardless of OS or LCSS. In addition, there were significant distinctions in the survival curves of OS and LCSS between different risk groups stratified by prognostic scores. Compared with the 8th AJCC staging system, our new model also improved net benefits.

Conclusions

We developed and validated novel nomograms for individual prediction of OS and LCSS, integrating the characteristics of patients and tumors. The model showed superior reliability and may help clinicians make treatment strategies and survival predictions for early-stage T1-2N0M0 SCLC patients.

Different clinical characteristics and survival between surgically resected pure and combined small cell lung cancer

BACKGROUND

Small cell lung cancer (SCLC) is the most malignant and common form of neuroendocrine lung cancer with pure (P-SCLC) and combined subtypes (C-SCLC). However, little is known about the differences between these two groups and in this study we aimed to provide a more comprehensive insight into SCLC.

METHODS

Data from 580 postoperative patients with pathologically confirmed SCLC in Shanghai Chest Hospital from January 2010 to December 2020 were collected retrospectively. The clinical characteristics and prognosis were analyzed.

RESULTS

A total of 357 P-SCLC patients and 223 C-SCLC patients were included. The results indicated that P-SCLC appeared to have a higher proportion of being located in the middle lobe than C-SCLC. The incidences of P-SCLC in patients with visceral pleural invasion (VPI) and in stage II were higher than C-SCLC, while C-SCLC was more likely to be accompanied by higher incidences of epidermal growth factor receptor (EGFR) mutation, anaplastic lymphoma kinase (ALK) rearrangement, and higher levels of CEA, SCCA and CYFRA21-1 than P-SCLC. The most common were SCLC combined with large cell neuroendocrine components among 223 C-SCLCs. Survival analysis confirmed a more favorable disease-free survival (DFS) (p = 0.016) and overall survival (OS) (p = 0.024) in patients with P-SCLCs compared with C-SCLCs. Histological type, tumor location, pN stage, adjuvant chemotherapy, serum NSE and CA125 levels were independent risk factors for survival rate in SCLC. In addition, adjuvant chemotherapy was beneficial in improving stage I P-SCLC and C-SCLC DFS and OS rates, and similar results were not seen in adjuvant radiation therapy.

CONCLUSIONS

Patients with C-SCLC have a poorer prognosis than P-SCLC patients. We determined that large cell neuroendocrine carcinoma was the most common additional component of C-SCLC, and patients with this component appeared to have a longer DFS and OS than other combined components.

Additional Postoperative Radiotherapy Prolonged the Survival of Patients with I-IIA Small Cell Lung Cancer: Analysis of the SEER Database

Purpose

Complete resection and adjuvant chemotherapy are recommended as the standard strategy for patients with stage I-IIA small cell lung cancer (SCLC). However, the role of additional postoperative radiotherapy (PORT) in treatment remains controversial.

Methods

Patients with stage I-IIA SCLC undergoing surgery and adjuvant chemotherapy were extracted from the Surveillance, Epidemiology, and End Results database. Stage I-IIA, defined as T1-2N0M0, was recalculated according to the 8th AJCC TNM staging system. Propensity score matching (PSM) was conducted to identify the therapeutic impact of PORT. Univariate Cox hazards regression and least absolute shrinkage and selection operator regression were utilized for primary screening of prognostic variables for I-IIA SCLC disease. A nomogram to predict overall survival (OS) was constructed based on the multivariate Cox proportional hazards model, evaluated with area under the curve, calibration curve, and decision curve analysis, and validated with bootstrap resampling.

Results

Our results demonstrated that compared with no PORT, PORT significantly prolonged the median OS (8.58 vs. 5.17 years, HR = 0.61 [0.39–0.96], P = 0.032) and median cancer-specific survival (11.33 vs. 8.08, HR = 0.47 [0.27–0.82], P = 0.0086) after PSM. The 5-year OS rate was 61.56% vs. 46.60%. Five variables including age at diagnosis, gender, T stage, surgical type, and PORT were elucidated to impact on prognosis and included in a nomogram to predict 3-/5-/10-year OS probability. The area under the curve values were 0.72, 0.71, and 0.81, respectively. The nomogram also exhibited satisfactory accuracy and clinical usefulness.

Conclusion

PORT was verified to improve the OS of patients with T1-2N0M0 SCLC after surgery and chemotherapy. A prognostic nomogram was developed and validated for OS prediction for these patients.

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.

Radiation and Systemic Therapy for Limited-Stage Small-Cell Lung Cancer

Progress in the overall treatment of small-cell lung cancer (SCLC) has moved at a slower pace than non-small-cell lung cancer. In fact, the standard treatment regimen for limited stage SCLC has not appreciably shifted in more than 20 years, consisting of four to six cycles of cisplatin and etoposide chemotherapy concurrent with thoracic radiotherapy (TRT) followed by prophylactic cranial irradiation (PCI) for responsive disease. Nevertheless, long-term outcomes have improved with median survival approaching 25-30 months, and approximately one third of patients now survive 5 years. This is likely attributable in part to improvements in staging, including use of brain magnetic resonance imaging and fluorodeoxyglucose-positron emission tomography imaging, advances in radiation treatment planning, and supportive care. The CONVERT and CALGB 30610 phase III trials failed to demonstrate a survival advantage for high-dose, once-daily TRT compared with standard 45 Gy twice-daily TRT, although high-dose, once-daily TRT remains common in practice. A phase III comparison of high-dose 60 Gy twice-daily TRT versus 45 Gy twice-daily TRT aims to confirm the provocative outcomes reported with 60 Gy twice daily in the phase II setting. Efforts over time have shifted from intensifying PCI, to attempting to reduce treatment-related neurotoxicity, to more recently questioning whether careful magnetic resonance imaging surveillance may obviate the routine need for PCI. The addition of immunotherapy has resulted in mixed success in extensive-stage SCLC with modest benefit observed with programmed death-ligand 1 inhibitors, and several ongoing trials assess programmed death-ligand 1 inhibition concurrent or adjuvant to chemoradiotherapy in limited-stage SCLC. Major advances in future treatment will likely depend on a better understanding and exploiting of molecular characteristics of SCLC with increasing personalization of therapy.

Patterns of Recurrence and Survival Rate After Complete Resection of Pathological Stage N2 Small-Cell Lung Cancer

The benefits of surgical resection for patients with stage N2 limited-disease small-cell lung cancer (LD-SCLC) remain controversial. This retrospective study analyzed the survival and recurrence patterns of the patients diagnosed with pathological N2 (p-N2) LD-SCLC after radical resection. A total of 171 p-N2 LD-SCLC patients who underwent radical pulmonary resection and systematic lymphadenectomies at Shanghai Chest Hospital from July 2005 to June 2015 were enrolled. The influence of the mediastinal lymph node status (single or multiple nodes, single- or multiple-station) on the survival and recurrence patterns was retrospectively analyzed. The main recurrence sites were outside the chest cavity (54.8%) and hematogenous metastasis (67.4%). The bone and liver as initial recurrence sites had a poor prognosis, with a median overall survival (OS) of 13.100 months and 11.900 months, respectively. The median disease-free survival (DFS) of patients diagnosed with single and multiple p-N2 after surgery were 19.233 and 9.367 months (P = 0.001), and the median OS were 43.033 and 17.100 months (P < 0.001), respectively. In conclusion, recurrence occurred in the form of hematogenous metastasis mostly in the extra-thoracic part. Interestingly, patients diagnosed with single p-N2 benefited from radical resection. Surgery may be a treatment option regardless of the T stage if N2 SCLC with a single metastatic lymph node can be identified preoperatively.

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.

[Surgery for small-cell lung cancer]

Small-cell lung cancer (SCLC) is a high-grade neuroendocrine carcinoma, metastatic at the time of initial diagnosis in 70% of cases. Within the 30% of localised tumours only 5% of patients are eligible for surgical treatment according to the recommendations of learned societies. These recommendations are mainly based on old phase II and III randomised prospective trials and more recent registry studies. Surgical care is only possible within a multimodal treatment and essentially concerns small-sized tumours without involvement of hilar or mediastinal lymph nodes. As with non-small cell lung cancer (NSCLC), lobectomy with radical lymph node removal is the recommended procedure to achieve complete tumour resection. Patient selection for surgery includes age, performance status and comorbidity factors. Adjuvant chemotherapy combining Platinum salts and Etoposide for resected stage I tumours is recommended by ASCO, ACCP and NCCN. The precise sequence of neo-adjuvant or adjuvant treatments remains controversial because of the large heterogeneity in clinical practice reported in the studies and the context at the time of SCLC discovery. The 5-year survival rate of patients with early stage disease (pT1-2N0M0) treated by lobectomy and adjuvant chemotherapy is between 30% and 58%, which validates the primary place that surgery must have in these early forms. There is certainly little or even no place for such a therapeutic sequence in locally advanced stages (T3-T4 or N2). However, the stage heterogeneity, as in NSCLC, makes final conclusions difficult. In fact, some registry studies with pairing scores reported a median survival of more than 20 months in N2 SCLC. So, all files of SCLC must be evaluated in a multidisciplinary meeting in order to find the optimal solution for patients with rare and heterogeneous tumours.

[Small Cell Lung Cancer]

Small cell lung cancer is an aggressive cancer entity and characterized by rapid progression, early distant metastasis and poor prognosis. Only the minority of patients presents with a non-metastatic stage disease where chemo-radiotherapy or - in very selected cases - even surgical resection may be discussed. For most patients, the efficacy of systemic therapy is crucial. However, although most patients respond to platinum doublet chemotherapy, virtually all patients with metastatic disease eventually develop tumor progression for which there are limited treatment options. Recently and for the first time since decades, the systemic approaches have been enriched by the implementation of immunotherapy. Moreover, novel therapeutic approaches such as new cytotoxic agents or further immune modulatory strategies are being tested in clinical studies that might broaden our treatment options in the future even further.

Thoracic radiotherapy in small cell lung cancer-a narrative review

Small-cell lung cancer (SCLC) represents 10–15% of all lung cancers and has a poor prognosis. Thoracic radiotherapy plays a central role in current SCLC management. Concurrent chemoradiotherapy (CTRT) is the standard of care for localised disease (stage I−III, limited-stage, LS). Definitive thoracic radiotherapy may be offered in metastatic patients (stage IV, extensive stage, ES-SCLC) after chemotherapy. For LS-SCLC, the gold standard is early accelerated hyperfractionated twice-daily CTRT (4 cycles of cisplatin etoposide, starting with the first or second chemotherapy cycle). Modern radiation techniques should be used with involved-field radiotherapy based on baseline CT and PET/CT scans. In ES-SCLC, thoracic radiotherapy should be discussed in cases of initial bulky mediastinal disease/residual thoracic disease not progressing after induction chemotherapy. This strategy was however not assessed in recent trials establishing chemo-immunotherapy as the standard first line treatment in ES-SCLC. Future developments include technical radiotherapy advances and the incorporation of new drugs. Thoracic irradiation is delivered more precisely given technical developments (IMRT, image-guided radiotherapy, stereotactic radiotherapy), reducing the risks of severe adverse events. Stereotactic ablative radiotherapy may be discussed in rare early stage (T1 to 2, N0) inoperable patients. A number of current clinical trials are investigating immunoradiotherapy. In this review, we highlight the current role of thoracic radiotherapy and describe ongoing research in the integration of biological surrogate markers, advanced radiotherapy technologies and novel drugs in SCLC patients.

Optimal Surgery Type and Adjuvant Therapy for T1N0M0 Lung Large Cell Neuroendocrine Carcinoma

Background

The appropriate treatment strategy for T1N0M0 lung large cell neuroendocrine carcinoma (LCNEC) was not well illustrated. We evaluated the efficacy of different surgery types and adjuvant therapy on patients with T1N0M0 LCNEC.

Methods

Patients diagnosed T1N0M0 LCNEC from 2004 to 2016 were identified in the surveillance, epidemiology, and end results (SEER) database. Clinical characteristics, treatment and survival data were collected. The efficacy of surgery type and adjuvant therapy stratified by tumor size was assessed. Overall survival(OS) was evaluated by the Kaplan-Meier method, and relevant survival variables were identified by the Cox proportional hazard model.

Results

From 2004 to 2016, 425 patients were included in this study, 253 (59.5%) patients received lobectomy, and 236 (55.5%) patients had 4 or more lymph nodes removed. Patients received lobectomy had better survival than those received sublobar resection(P=0.000). No matter tumor size less than 2 cm or 2 to 3 cm, lobectomy was significantly prolonged survival. Compared with no lymph nodes removed, lymph nodes dissection was associated with more remarkable OS(P<0.000). 4 or more regional lymph nodes dissection predicted better OS compared with 1 to 3 regional lymph nodes dissection(P=0.014). After surgery, adjuvant chemotherapy did not contribute to extended survival in patients with tumor less than 2 cm(P=0.658), and possibly for tumor 2 to 3 cm(P=0.082). Multivariate analysis showed that age and lobectomy were independent prognostic factors(P=0.000).

Conclusion

Our results suggest that lobectomy and lymph nodes dissection were associated with significantly better survival. Extensive regional lymph node dissection(4 or more) was more effective in prolonging survival than 1 to 3 lymph nodes dissection. Adjuvant chemotherapy was not associated with extended survival for tumor less than 2 cm, and possibly for tumor 2 to 3 cm.

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.

Development and Validation of a Nomogram Prognostic Model for Resected Limited-Stage Small Cell Lung Cancer Patients

Background

In this study, we developed and validated nomograms for predicting the survival in surgically resected limited-stage small cell lung cancer (SCLC) patients.

Methods

The SCLC patients extracted from the Surveillance, Epidemiology, and End Results database between 2000 and 2014 were reviewed. Significant prognostic factors were identified and integrated to develop the nomogram using multivariable Cox regression. The model was then validated internally by bootstrap resampling, and externally using an independent SCLC cohort diagnosed between 2000 and 2015 at our institution. The prognostic performance was measured by the concordance index (C-index) and calibration curve.

Results

A total of 1006 resected limited-stage SCLC patients were included in the training cohort. Overall, 444 cases from our institution constituted the validation cohort. Seven prognostic factors were identified and entered into the nomogram construction. The C-indexes of this model in the training cohort were 0.723, 0.722, and 0.746 for predicting 1-, 3-, and 5-year overall survival (OS), respectively, and 0.816, 0.710, and 0.693, respectively, in the validation cohort. The calibration curve showed optimal agreement between nomogram-predicted survival and actual observed survival. Additionally, significant distinctions in survival curves between different risk groups stratified by prognostic scores were also observed. The proposed nomogram was then deployed into a website server for convenient application.

Conclusions

We developed and validated novel nomograms for individual prediction of survival for resected limited-stage SCLC patients. These models perform better than the previously widely used staging system and may offer clinicians instructions for strategy making and the design of clinical trials.

Supplementary Information

The online version of this article (10.1245/s10434-020-09552-w) contains supplementary material, which is available to authorized users.

Development and validation of a prognostic model of resectable small-cell lung cancer: a large population-based cohort study and external validation

Background

Survival outcomes of patients with resected SCLC differ widely. The aim of our study was to build a model for individualized risk assessment and accurate prediction of overall survival (OS) in resectable SCLC patients.

Methods

We collected 1052 patients with resected SCLC from the Surveillance, Epidemiology, and End Results (SEER) database. Independent prognostic factors were selected by COX regression analyses, based on which a nomogram was constructed by R code. External validation were performed in 114 patients from Shandong Provincial Hospital. We conducted comparison between the new model and the AJCC staging system. Kaplan–Meier survival analyses were applied to test the application of the risk stratification system.

Results

Sex, age, T stage, N stage, LNR, surgery and chemotherapy were identified to be independent predictors of OS, according which a nomogram was built. Concordance index (C-index) of the training cohort were 0.721, 0.708, 0.726 for 1-, 3- and 5-year OS, respectively. And that in the validation cohort were 0.819, 0.656, 0.708, respectively. Calibration curves also showed great prediction accuracy. In comparison with 8th AJCC staging system, improved net benefits in decision curve analyses (DCA) and evaluated integrated discrimination improvement (IDI) were obtained. The risk stratification system can significantly distinguish the ones with different survival risk. We implemented the nomogram in a user-friendly webserver.

Conclusions

We built a novel nomogram and risk stratification system integrating clinicopathological characteristics and surgical procedure for resectable SCLC. The model showed superior prediction ability for resectable SCLC.

Radiation Therapy for Small Cell Lung Cancer: An ASTRO Clinical Practice Guideline

PURPOSE

Several sentinel phase III randomized trials have recently been published challenging traditional radiation therapy (RT) practices for small cell lung cancer (SCLC). This American Society for Radiation Oncology guideline reviews the evidence for thoracic RT and prophylactic cranial irradiation (PCI) for both limited-stage (LS) and extensive-stage (ES) SCLC.

METHODS

The American Society for Radiation Oncology convened a task force to address 4 key questions focused on indications, dose fractionation, techniques and timing of thoracic RT for LS-SCLC, the role of stereotactic body radiation therapy (SBRT) compared with conventional RT in stage I or II node negative SCLC, PCI for LS-SCLC and ES-SCLC, and thoracic consolidation for ES-SCLC. Recommendations were based on a systematic literature review and created using a consensus-building methodology and system for grading evidence quality and recommendation strength.

RESULTS

The task force strongly recommends definitive thoracic RT administered once or twice daily early in the course of treatment for LS-SCLC. Adjuvant RT is conditionally recommended in surgically resected patients with positive margins or nodal metastases. Involved field RT delivered using conformal advanced treatment modalities to postchemotherapy volumes is also strongly recommended. For patients with stage I or II node negative disease, SBRT or conventional fractionation is strongly recommended, and chemotherapy should be delivered before or after SBRT. In LS-SCLC, PCI is strongly recommended for stage II or III patients who responded to chemoradiation, conditionally not recommended for stage I patients, and should be a shared decision for patients at higher risk of neurocognitive toxicities. In ES-SCLC, radiation oncologist consultation for consideration of PCI versus magnetic resonance surveillance is strongly recommended. Lastly, the use of thoracic RT is strongly recommended in select patients with ES-SCLC after chemotherapy treatment, including a conditional recommendation in those responding to chemotherapy and immunotherapy.

CONCLUSIONS

RT plays a vital role in both LS-SCLC and ES-SCLC. These guidelines inform best clinical practices for local therapy in SCLC.

Comparison of treatment strategies for patients with limited-stage small cell lung cancer who received chemotherapy

Background

The standard care for limited-stage small cell lung cancer (SCLC) is unclear. The purpose of this study is to compare the outcome for patients receiving chemotherapy alone, chemotherapy plus surgery (CS), chemotherapy plus radiation (CR), or chemotherapy plus surgery and radiation (CSR) for limited-stage SCLC.

Methods

Patients with T1-4N0-2M0 SCLC who received chemotherapy from 2004 to 2014 were retrieved from the Surveillance, Epidemiology, and End Results (SEER) database. The overall survival (OS) of these patients, stratified by different stage, was compared in accordance to the method of receiving different treatments using Kaplan-Meier method and Cox regression analysis.

Results

A total of 7,204 patients were included, where 1,347 (18.7%) patients received chemotherapy alone, 296 (4.1%) undergone CS, 5,296 (73.5%) patients were subjected to CR and 267 (3.7%) patients were managed by the three combination of CSR. Chemotherapy alone was associated with the worst survival in comparison to the other two method of combination i.e., chemotherapy with radiation or surgery. When compared with CR, CS had no survival benefit in patients with stage in excess of T1-2N0 disease, but was associated with improved 5-year OS in patients with T1-2N0 disease, which ranged from 29.1% to 54.3% (P<0.001). For patients with T1-2N2 disease who received CSR demonstrated superior OS over those who received CR (P=0.004) or CS (P=0.036). Cox regression analysis showed CS was associated with improved OS when compared with CR in patients with N0 disease (HR, 0.54; 95% CI, 0.43–0.68; P=0.000) and CSR was associated with better OS in comparison with CR in patients with N2 disease (HR, 0.71; 95% CI, 0.55–0.93; P=0.013).

Conclusions

Patients with limited-stage SCLC can benefit from local treatment such as surgery, radiation, and surgery plus radiation. For patients with N0 disease, CS was associated with improved survival in comparison to CR. If N2 was identified after surgery, radiation may be added to improve OS.

Defining the role of adjuvant therapy for early-stage large cell neuroendocrine carcinoma

INTRODUCTION

Large cell neuroendocrine carcinoma is a rare, high-grade neuroendocrine tumor. The mainstay of treatment for early, node-negative disease is surgical resection, and optimal adjuvant treatment strategies are not well defined.

METHODS

Patients with early, node-negative large cell neuroendocrine carcinoma were identified in the National Cancer Database from 2004 to 2014. Patient, tumor, treatment, and hospital characteristics were examined. Survival differences in patients receiving adjuvant chemotherapy (AC) were evaluated using Kaplan-Meier curves, and adjusted multivariate Cox models were constructed. A conditional landmark analysis was used to address immortal time bias. T-stage-specific propensity score matching was used to address covariate imbalances between groups.

RESULTS

One thousand seven hundred seventy patients were identified, of whom 463 (26.2%) received AC. Patients receiving AC were younger, less comorbid, and more likely to have T2 tumors. AC was associated with significantly longer survival, which persisted after adjustment in Cox models, for patients overall (5-year overall survival, 59.2% vs 45.3%; hazard ratio, 0.69; 95% confidence interval, 0.58-0.82; P < .0001), T2 tumors (overall survival, 59.8% vs 42.1%; hazard ratio, 0.63; 95% confidence interval, 0.50-0.81; P < .0001), and tumors 2 to 3 cm (overall survival, 60.0% vs 42.6%; hazard ratio, 0.64; 95% confidence interval, 0.46-0.8; P = .002), but not tumors smaller than 2 cm. Adjuvant chest radiotherapy was not associated with longer survival. Sublobar resection was associated with worse overall survival compared with lobectomy (hazard ratio, 1.40; 95% confidence interval, 1.20-1.64; P < .0001). Propensity score matching confirmed these findings, but the association with survival for tumors 2 to 3 cm in size was not significant.

CONCLUSIONS

In this national study of early-stage large cell neuroendocrine carcinoma, AC was associated with significantly longer survival for tumors larger than 3 cm, and possibly for tumors 2 to 3 cm. Adjuvant radiation was not associated with prolonged survival.

Strengths and limitations of large databases in lung cancer radiation oncology research

There has been a substantial rise in the utilization of large databases in radiation oncology research. The advantages of these datasets include a large sample size and inclusion of a diverse population of patients in a real-world setting. Such observational studies hold promise in enhancing our understanding of questions for which evidence is conflicting or absent in lung cancer radiotherapy. However, it is critical that investigators understand the strengths and limitations of large databases in order to avoid the common pitfalls that beset observational analyses. This review begins by outlining the data variables available in major registries that are used most often in observational analyses. This is followed by a discussion of the type of radiotherapy-related questions that can be addressed using such datasets, accompanied by examples from the lung cancer literature. Finally, we describe some limitations of observational research and techniques to mitigate bias and confounding. We hope that clinicians and researchers find this review helpful for designing new research studies and interpreting published analyses in the literature.

Choice of surgical procedure - lobectomy, segmentectomy, or wedge resection - for patients with stage T1-2N0M0 small cell lung cancer: A population-based study

Background

To date, few studies have evaluated the impact of lobectomy versus sublobar resection for early small cell lung cancer (SCLC). We investigated the survival rates of patients with pathological stage T1‐2N0M0 SCLC who underwent lobectomy or sublobar resection.

Methods

We identified 548 SCLC patients in the Surveillance, Epidemiology, and End Results database who underwent lobectomy or sublobar resection. Propensity score matching (PSM) and Cox regression analysis were used to adjust for baseline characteristics.

Results

The three‐year overall survival (OS) of patients treated with lobectomy (n = 376, 60%) was significantly higher than those treated with sublobar resection (n = 172, 38%). PSM and Cox multivariable analysis further confirmed this result (hazard ratio [HR] 0.543, 95% confidence interval [CI] 0.421–0.680; P < 0.001). The three‐year OS of patients treated with segmentectomy (n = 24, 54%) and wedge resection (n = 148, 36%) was not significantly different (HR 0.639, 95% CI 0.393–1.039; P = 0.071). Based on PSM analysis, segmentectomy conferred a superior survival advantage to patients relative to wedge resection (HR 0.466, 95% CI 0.221–0.979; P = 0.040).

Conclusion

Lobectomy correlated with superior survival. For patients in which lobectomy is unsuitable, prognosis following segmentectomy appears to be better than after wedge resection.

Evaluation of short-term and long-term efficacy of surgical and non-surgical treatment in patients with early-stage small cell lung cancer: A comparative study

OBJECTIVE

The aim of this study is to compare surgery with adjuvant chemoradiotherapy versus non-surgical treatments for patients with early-stage small cell lung cancer (SCLC) based on the short-term and long-term efficacy.

METHODS

SCLC patients who underwent a pulmonary lobectomy with post-surgical radiotherapy or chemotherapy were assigned to the surgical group. SCLC patients who received radiotherapy or chemotherapy alone were classified into the non-surgical group. The clinical efficacy was evaluated as complete remission (CR), partial remission (PR), stable disease (SD), or progressive disease (PD). The total effectiveness rate was calculated as CR + PR. The 1-, 3-, and 5-year survival rates of the two groups were compared.

RESULTS

Compared with the non-surgical group, the CR rate and the total effectiveness rate were higher in the surgical group, and the total effectiveness rate for male patients and patients without a smoking history were also higher in the surgical group. Distant metastasis and local recurrence concurrent with distant metastasis in the surgical group were both lower in the surgical group than in the non-surgical group. Compared with the non-surgical group, the local recurrence in male patients was lower in the surgical group, and patients in the surgical group had lower distant metastasis at TNM stage IIb. The 1-, 3-, and 5-year survival rates were higher in the surgical group than in the non-surgical group.

CONCLUSIONS

These findings indicate that for patients with early-stage SCLC, better scores in effectiveness rate, disease progression, and 1-, 3-, and 5-year survival rates were observed in patients who underwent surgery followed by adjuvant chemoradiotherapy when compared with patients without surgical treatment.

Selection of candidates for surgery as local therapy among early-stage small cell lung cancer patients: a population-based analysis

Background

Surgery and radiotherapy are considered local therapies for small cell lung cancer (SCLC). The present study aimed to select candidates for surgery as local therapy among patients with stage I or II SCLC, based on the eighth edition of the TNM classification for lung cancer.

Methods

Patients diagnosed with SCLC between 2004 and 2013 were selected from the Surveillance, Epidemiology, And End Results database. The TNM stage of SCLC in these patients was re-classified according to the eighth edition of the TNM classification for lung cancer. Patients with stage I or II SCLC were included in the present study. Overall survival (OS) and lung cancer-specific survival (LCSS) were separately compared in the different TNM stages between patients who received surgery and radiotherapy as local therapy. Multivariate analysis was applied to evaluate multiple factors associated with survival.

Results

Among the 2129 patients included in the present study, 387 (18.2%) received surgery, 1032 (48.5%) underwent radiotherapy as local therapy, 154 (7.2%) underwent surgery and radiotherapy, and 556 (26.1%) did not undergo either surgery or radiotherapy. Among patients with T1-2N0 (tumor size ≤ 50 mm without positive lymph nodes) disease, patients who underwent surgery had higher 5-year OS and LCSS rates than patients who received radiotherapy (T1N0: 46.0% vs. 23.8%, P < 0.001, and 58.4% vs. 36.4%, P < 0.001, respectively; T2N0: 42.6% vs. 24.7%, P = 0.004, and 48.8% vs. 31.3%, P = 0.011, respectively). Multivariate analysis results revealed that surgery was associated with low risk of death. However, among T3N0 or T1-2N1 (stage IIB) SCLC patients, patients who underwent surgery did not have higher 5-year OS and LCSS rates than patients who received radiotherapy (T3N0: 16.2% vs. 26.5%, P = 0.085, and 28.7% vs. 30.9%, P = 0.372, respectively; T1-2N1: 20.3% vs. 29.0%, P = 0.146, and 25.6% vs. 35.5%, P = 0.064, respectively).

Conclusions

Based on the assumption that the overwhelming majority of stage I or II SCLC patients who underwent surgery or radiotherapy also received certain types of systemic therapy, only patients with T1-2N0 SCLC may benefit from surgery as local therapy. Patients with T3N0 or T1-2N1 SCLC may consider radiotherapy as local therapy.

The role of radiation therapy in the management of small cell lung cancer

Small cell lung cancer (SCLC) is a very aggressive form of lung cancer. SCLC treatment requires multidisciplinary management and timely treatment. Radiation therapy is an important part of management of all stages of SCLC, in the curative as well as in the palliative setting. The role of radiation therapy in all stages of SCLC has changed in recent years; this article describes these changes and highlights the role of radiation therapy in the management of SCLC.

Surgical Treatment for Early Small Cell Lung Cancer: Variability in Practice and Impact on Survival

BACKGROUND

Surgical resection with lobectomy is recommended for T1/T2 N0 small cell lung cancer (SCLC) patients after negative mediastinal staging. We sought to characterize variation in surgical therapy for early SCLC and determine the effect of a hospital's practice patterns on patient survival.

METHODS

The National Cancer Database was examined from 2004 to 2013. Risk- and reliability-adjusted hierarchical logistic regression was used to estimate the adjusted odds of resection by hospital. Hospitals were then grouped into quartiles by observed-to-expected rates of surgical treatment. Patient, tumor, and hospital characteristics were compared across quartiles. Kaplan-Meier plots and Cox proportional hazard models were built to compare patient survival as a function of a hospital's tendency to use surgical intervention.

RESULTS

We identified 5,079 patients with T1/T2 N0 SCLC in 317 hospitals, and 1,260 underwent resection. Analysis after adjusting for demographic, comorbidity, and tumor factors showed patients treated at hospitals in the highest quartile of surgical use were 17 times more likely to undergo surgical resection than those in the lowest quartile (44.8% vs 7.6%; odds ratio, 16.7l; 95% confidence interval, 12.59 to 22.18). Hospitals in the highest quartile were more likely to be academic centers (48% vs 21%), more likely to perform lobectomy (28.3% vs 5.0%), and treated more mixed-histology tumors (11.1% vs 4.5%). Survival was significantly longer for patients treated at hospitals most likely to use surgical therapy (median, 25.3 vs. 18.8 months; p < 0.0001). Hazard ratio differences in mortality persisted in multivariate Cox models (hazard ratio, 0.80; 95% confidence interval, 0.72 to 0.89; p < 0.0001).

CONCLUSIONS

Large variation exists in the use of surgical therapy for early SCLC in the United States, which may represent a significant quality improvement opportunity for patients with early SCLC.

Treatment of limited disease small cell lung cancer: the multidisciplinary team

Small cell lung cancer (SCLC) presents multiple interdisciplinary challenges with several paradigm shifts in its treatment in recent years. SCLC treatment requires multidisciplinary management and timely treatment. The aim of this review is to focus on the team management aspects in the treatment of limited disease SCLC and how this can contribute towards improving outcomes.

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.

Indications for Adjuvant Mediastinal Radiotherapy in Surgically Resected Small Cell Lung Cancer

BACKGROUND

Adjuvant mediastinal radiotherapy (AMR) is used after surgical resection for patients with small cell lung cancer (SCLC), but data guiding its use are scant. We sought to examine whether AMR was associated with an improvement in survival for resected SCLC patients and to define subpopulations who should be selected for AMR.

METHODS

Patients undergoing lobectomy, pneumonectomy, and sublobar resection for SCLC were identified in the National Cancer Database (2004 to 2013). Kaplan-Meier survival curves and Cox proportional hazards were used to evaluate associations between AMR and survival. Hazard ratios were adjusted for patient comorbidity, demographics, tumor characteristics, such as stage, grade, histology, and margin status, and receipt of adjuvant chemotherapy.

RESULTS

We identified 3,101 patients. Those receiving AMR were younger, more likely to have greater pathologic T and N stage, to undergo sublobar resection, and to have a positive margin. Kaplan-Meier curves showed better median survival for patients with pN1 or pN2 disease who received AMR. After adjustment, Cox models showed AMR was associated with a lower risk of death for pN1 (hazard ratio, 0.79; 95% confidence interval, 0.63 to 1.00; p = 0.05) and pN2 (hazard ratio, 0.60; 95% confidence interval, 0.48 to 0.75; p < 0.0001). In the overall cohort, AMR was not associated with better survival in node-negative patients. AMR was, however, associated with improved survival for patients receiving sublobar resection (hazard ratio, 0.72; 95% confidence interval, 0.57 to 0.90; p = 0.004).

CONCLUSIONS

AMR is associated with longer survival for node-positive patients after resection for SCLC, especially those with pN2. AMR may also be associated with longer survival in patients undergoing sublobar resections.