Treatment outcomes of patients with small cell lung cancer without prophylactic cranial irradiation

Construction and Validation of a Novel Nomogram to Predict the Overall Survival of Patients With Combined Small Cell Lung Cancer: A Surveillance, Epidemiology, and End Results Population-Based Study

INTRODUCTION

Combined small cell lung cancer (C-SCLC) represents a rare subtype of all small cell lung cancer cases, with limited studies investigated its prognostic factors. The aim of this study was to construct a novel nomogram to predict the overall survival (OS) of patients with C-SCLC.

METHODS

In this retrospective study, a total of 588 C-SCLC patients were selected from the Surveillance, Epidemiology, and End Results database. The univariate and multivariate Cox analyses were performed to identify optimal prognostic variables and construct the nomogram, with concordance index (C-index), receiver operating characteristic curves, and calibration curves being used to evaluate its discrimination and calibration abilities. Furthermore, decision curve analysis (DCA), integrated discrimination improvement (IDI), and net reclassification index (NRI) were also adopted to assess its clinical utility and predictive ability compared with the classic TNM staging system.

RESULTS

Seven independent predictive factors were identified to construct the nomogram, including T stage, N stage, M stage, brain metastasis, liver metastasis, surgery, and chemotherapy. We observed a higher C-index in both the training (.751) and validation cohorts (.736). The nomogram has higher area under the curve in predicting 6-, 12-, 18-, 24-, and 36-month survival probability of patients with C-SCLC. Meanwhile, the calibration curves also revealed high consistencies between the actual and predicted OS. DCA revealed that the nomogram could provide greater clinical net benefits to these patients. We found that the NRI for 6- and 12-month OS were .196 and .225, and the IDI for 6- and 12-month OS were .217 and .156 in the training group, suggesting that the nomogram can predict a more accurate survival probability. Similar results were also observed in the validation cohort.

CONCLUSION

We developed and verified a novel nomogram that can help clinicians recognize high-risk patients with C-SCLC and predict their OS.

Intracranial failure after hippocampal-avoidance prophylactic cranial irradiation in limited-stage small-cell lung cancer patients

We evaluated intracranial failure after hippocampus-avoidance-prophylactic cranial irradiation (HA-PCI) for limited-stage small-cell lung cancer (SCLC). Data of 106 patients who received PCI with 25 Gy were retrospectively reviewed. The patients were divided into two groups based on whether they underwent HA-PCI: the HA-PCI group (n = 48) and the conventional PCI (C-PCI) group (n = 58). Twenty-one patients experienced intracranial failure: 11 and 10 patients in the C-PCI and HA-PCI groups, respectively. Using the log-rank test, the intracranial failure rate was not significantly different between the groups (p = 0.215). No clinical factor was significantly associated with intracranial failure in multivariate Cox regression analysis, but HA-PCI tended to be associated with increased incidence of intracranial failure (HR 2.87, 95% CI 0.86–9.58, p = 0.087). Among patients who received HA-PCI, two developed peri-hippocampal recurrence. A higher thoracic radiotherapy dose (≥ 60 Gy) was significantly associated with DFS (HR 0.52, p = 0.048) and OS (HR 0.35, p = 0.003). However, HA-PCI was associated with neither DFS nor OS. Although HA-PCI may be associated with an increased risk of intracranial failure, HA-PCI did not impair disease control or survival. Future prospective randomized trials are needed to reach a definite conclusion.

Sequential Versus Concurrent Thoracic Radiotherapy in Combination With Cisplatin and Etoposide for N3 Limited-Stage Small-Cell Lung Cancer

At present, concurrent chemoradiotherapy (CRT) is considered the standard treatment of limited-stage small cell lung cancer (LS-SCLC). However, LS-SCLC is highly heterogeneous in the T stage, N stage, and prognosis. Increasing evidence has shown that individual treatment should be considered when treating LS-SCLC patients. The aim of the present study was to explore the optimal combination model of thoracic radiotherapy (TRT) and chemotherapy in N3 LS-SCLC. We retrospectively analyzed 93 N3 LS-SCLC patients treated in the Department of Oncology of Binzhou Medical University Hospital (Shandong, China) between March 2010 and October 2015. A total of 52 (52/93; 55.9%) patients received sequential CRT, and 41 (41/93; 44.1%) patients received concurrent CRT. All patients received 4-6 cycles of chemotherapy and TRT (50-60 Gy). The median follow-up time was 25.4 months (range was 6-65 months).The overall response rate was 88.5% in the sequential CRT group (9.6% complete response rate and 78.8% partial response rate) and 90.2% in the concurrent CRT group (14.6% complete response rate and 75.6% partial response rate). The PFS and OS were 15.4 months and 19.1 months in sequential CRT group, and 16.9 months and 20.5 months in concurrent CRT group. There was no significant difference in treatment response rate, PFS, and OS between sequential and concurrent CRT patients. The most common treatment-related toxicities were nausea/vomiting, neutropenia, and esophagitis. In conclusion, when concurrent CRT is performed in N3 LS-SCLC patients, tolerance to treatment should be fully considered. In our study, sequential CRT and concurrent CRT showed the same efficacy, and sequential CRT demonstrated better tolerance. However, these results require confirmation in future follow-up studies.

The value of prophylactic cranial irradiation in limited-stage small cell lung cancer: should it always be recommended?

Purpose

Prophylactic cranial irradiation (PCI) is a standard treatment for limited-stage small cell lung cancer (LS-SCLC) showing a response to initial treatment, but many patients do not receive PCI due to comorbidities or refusal. This study aims to define the patient group for whom PCI can be omitted with minimal risk.

Materials and Methods

Patients with LS-SCLC who underwent radiotherapy with curative aim at our institution between January 2004 and December 2015 were retrospectively reviewed. Patients who did not receive PCI were evaluated for brain metastasis-free survival (BMFS), progression-free survival (PFS), overall survival (OS), and prognostic factors for survival, and treatment outcomes were compared with a patient cohort who received PCI.

Results

A total of 350 patients achieved a response following thoracic radiotherapy, and 190 of these patients did not receive PCI. Stage I–II and a complete response (CR) to initial therapy were good prognostic factors for BMFS and OS on univariate analysis. Patients with both stage I–II and a CR who declined PCI showed comparable 2-year BMFS to those who received PCI (92% vs. 89%). In patients who achieved CR, PCI did not significantly improve OS or PFS.

Conclusion

There should be less concern about omitting PCI in patients with comorbidities if they have stage I–II or a CR, with brain metastasis control being comparable to those patients who receive PCI.

Efficacy of prophylactic cranial irradiation in patients with limited-disease small-cell lung cancer who were confirmed to have no brain metastasis via magnetic resonance imaging after initial chemoradiotherapy

Background

Prophylactic cranial irradiation (PCI) is recommended for patients with limited-disease small-cell lung cancer (LD-SCLC) who achieved good response to definitive chemoradiotherapy. However, most clinical studies lacked brain imaging scans before PCI. Our study aimed to investigate whether PCI has a survival benefit in patients who have no brain metastases (BM) confirmed via magnetic resonance imaging (MRI) before PCI.

Results

Eighty patients were included in this study. Sixty patients received PCI (PCI group) and 20 patients did not (non-PCI group). OS was not significantly different between the two groups. The median OS time was 4.3 years (95% CI: 2.6 years–8.6 years) in the PCI group and was not reached (NR) (95% CI: 1.9 years–NR) in the non-PCI group (p = 0.542). Moreover, no differences were observed in the 3-year rates of PFS (46.2% and 44.4%, p = 0.720) and cumulative incidence of BM (24.0% vs. 27%, p = 0.404).

Conclusions

Our result suggests that PCI may not have a survival benefit in patients with LD-SCLC confirmed to have no BM after initial therapy, even if patients achieve a good response to definitive chemoradiotherapy.

Patients and Methods

We retrospectively evaluated patients with LD-SCLC who were confirmed to have no BM via MRI after initial chemoradiotherapy at the Shizuoka Cancer Center between September 2002 and August 2015. The overall survival (OS), progression-free survival (PFS), and cumulative incidence of BM were estimated using the Kaplan–Meier method between patients who received PCI and those who did not. Propensity score matching was used to balance baseline characteristics.

The Road Less Traveled: Should We Omit Prophylactic Cranial Irradiation for Patients With Small Cell Lung Cancer?

New randomized data from Japan have raised questions regarding the use of prophylactic cranial irradiation for patients with extensive-stage small-cell lung cancer but without detectable brain metastases on magnetic resonance imaging. In the present focused review, we examine the general role of prophylactic cranial irradiation in the management of small-cell lung cancer and present relevant controversies from both sides of the discussion. Future directions for clinical investigation and research are also highlighted. Strategies for neurocognitive protection, including memantine use and hippocampal sparing using modulated radiotherapy techniques, are also presented.