Impact of Adjuvant Therapy on Survival in Surgically Resected Limited-Stage Small Cell Lung Cancer

Clinical and Pathologic Differences between Small-Cell Carcinoma and Large-Cell Neuroendocrine Carcinoma of the Lung

BACKGROUND

Both small-cell carcinoma (SCLC) and large-cell neuroendocrine carcinoma (LCNEC) of the lung are often clinically dealt with as being in the same category as neuroendocrine carcinoma, and their clinical differences have not been adequately assessed.

METHODS

The postoperative prognosis was retrospectively analyzed using the data of 196 patients who underwent resection for SCLC or LCNEC.

RESULTS

Of the patients included, 99 (50.5%) had SCLC and 97 (49.5%) had LCNEC. The median duration of follow-up was 39 months (interquartile range [IQR] 21-76) and 56 months (IQR 21-87) for SCLC and LCNEC, respectively. The estimated 5-year overall survival (OS) probabilities were 53.7% and 62.7% (p = 0.133) for patients with SCLC and LCNEC, respectively. In the SCLC group, a multivariate analysis showed that adjuvant chemotherapy (hazard ratio 0.54, 95% confidence interval 0.30-0.99, p = 0.04) was the only factor that was significantly associated with OS. In the LCNEC group, univariate analyses demonstrated that pathologic stage I (p = 0.01) was the only factor that was associated with better OS after surgery.

CONCLUSIONS

We found different clinical features in SCLC and LCNEC; in patients with SCLC, because OS could be expected to significantly improve with postoperative adjuvant chemotherapy, patients with resected SCLC of any pathologic stage should receive adjuvant chemotherapy. For patients with LCNEC, because pathologic stage I LCNEC is related to better prognosis than any other stages, a thorough clinical staging, including invasive staging, according to present guidelines should be performed to identify clinical stage I LCNEC with the highest certainty.

CD3, CD8, IFN-γ, tumor and stroma inflammatory cells as prognostic indicators for surgically resected SCLC: evidences from a 10-year retrospective study and immunohistochemical analysis

Current clinical guidelines limit surgical intervention to patients with cT1-2N0M0 small cell lung cancer (SCLC). Our objective was to reassess the role of surgery in SCLC management, and explore novel prognostic indicators for surgically resected SCLC. We reviewed all patients diagnosed with SCLC from January 2011 to April 2021 in our institution. Survival analysis was conducted using the Kaplan-Meier method, and independent prognostic factors were assessed through the Cox proportional hazard model. In addition, immunohistochemistry (IHC) staining was performed to evaluate the predictive value of selected indicators in the prognosis of surgically resected SCLC patients. In the study, 177 SCLC patients undergoing surgical resection were ultimately included. Both univariate and multivariate Cox analysis revealed that incomplete postoperative adjuvant therapy emerged as an independent risk factor for adverse prognosis (p < 0.001, HR 2.96). Survival analysis revealed significantly superior survival among pN0-1 patients compared to pN2 patients (p < 0.0001). No significant difference in postoperative survival was observed between pN1 and pN0 patients (p = 0.062). Patients with postoperative stable disease (SD) exhibited lower levels of tumor inflammatory cells (TIC) (p = 0.0047) and IFN-γ expression in both area and intensity (p < 0.0001 and 0.0091, respectively) compared to those with postoperative progressive disease (PD). Conversely, patients with postoperative SD showed elevated levels of stromal inflammatory cells (SIC) (p = 0.0453) and increased counts of CD3+ and CD8+ cells (p = 0.0262 and 0.0330, respectively). Survival analysis indicated that high levels of SIC, along with low levels of IFN-γ+ cell area within tumor tissue, may correlate positively with improved prognosis in surgically resected SCLC (p = 0.017 and 0.012, respectively). In conclusion, the present study revealed that the patients with pT1-2N1M0 staging were a potential subgroup of SCLC patients who may benefit from surgery. Complete postoperative adjuvant therapy remains an independent factor promoting a better prognosis for SCLC patients undergoing surgical resection. Moreover, CD3, CD8, IFN-γ, TIC, and SIC may serve as potential indicators for predicting the prognosis of surgically resected SCLC.

Role of Adjuvant Chemotherapy in Early-Stage Combined Small Cell Lung Cancer

BACKGROUND

The role of adjuvant therapy in completely resected primary tumors that have components of both non-small cell lung cancer and small cell lung cancer (combined SCLC) is poorly understood. We sought to determine the potential benefits of adjuvant chemotherapy in patients who undergo complete resection for early-stage combined SCLC.

METHODS

Overall survival of patients with pathologic T1-2 N0 M0 combined SCLC who underwent complete resection in the National Cancer Database from 2004 to 2017, stratified by adjuvant chemotherapy vs surgery alone, was evaluated by multivariable Cox proportional hazards modeling and propensity score-matched analysis. Patients treated with induction therapy and those who died within 90 days of surgery were excluded from analysis.

RESULTS

Of 630 patients who had pT1-2 N0 M0 combined SCLC during the study period, 297 patients (47%) underwent complete R0 resection. Adjuvant chemotherapy was administered to 63% of patients (n = 188), and 37% of patients underwent surgery alone (n = 109). In unadjusted analysis, the 5-year overall survival was 61.6% (95% CI, 50.8-70.7) for patients who underwent surgery alone and 66.4% (95% CI, 58.4-73.3) for patients who underwent adjuvant chemotherapy. In multivariable and propensity score-matched analysis, there were no significant differences in overall survival between adjuvant chemotherapy and surgery alone (adjusted hazard ratio, 1.16; 95% CI, 0.73-1.84). These findings were consistent when limited to patients who underwent lobectomies or to healthier patients who have at most 1 major comorbidity.

CONCLUSIONS

In this national analysis, patients with pT1-2 N0 M0 combined SCLC treated with surgical resection alone have similar outcomes to those who undergo adjuvant chemotherapy.

PI3K/AKT/mTOR pathway, hypoxia, and glucose metabolism: Potential targets to overcome radioresistance in small cell lung cancer

Small cell lung cancer (SCLC) is a highly aggressive tumor type for which limited therapeutic progress has been made. Platinum-based chemotherapy with or without thoracic radiotherapy remains the backbone of treatment, but most patients with SCLC acquire therapeutic resistance. Given the need for more effective therapies, better elucidation of the molecular pathogenesis of SCLC is imperative. The phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway is frequently activated in SCLC and strongly associated with resistance to ionizing radiation in many solid tumors. This pathway is an important regulator of cancer cell glucose metabolism, and its activation probably effects radioresistance by influencing bioenergetic processes in SCLC. Glucose metabolism has three main branches-aerobic glycolysis, oxidative phosphorylation, and the pentose phosphate pathway-involved in radioresistance. The interaction between the PI3K/AKT/mTOR pathway and glucose metabolism is largely mediated by hypoxia-inducible factor 1 (HIF-1) signaling. The PI3K/AKT/mTOR pathway also influences glucose metabolism through other mechanisms to participate in radioresistance, including inhibiting the ubiquitination of rate-limiting enzymes of the pentose phosphate pathway. This review summarizes our understanding of links among the PI3K/AKT/mTOR pathway, hypoxia, and glucose metabolism in SCLC radioresistance and highlights promising research directions to promote cancer cell death and improve the clinical outcome of patients with this devastating disease.