Radiotherapy in Small-Cell Lung Cancer: Lessons Learned and Future Directions

Impact of Hippocampal Avoidance - Prophylactic Cranial Irradiation in Small Cell Lung Cancer Patients

BACKGROUND/AIM

Prophylactic cranial irradiation (PCI) is a well-established treatment of small cell lung cancer (SCLC) patients following response to initial chemoradiotherapy. The benefit of PCI does, however, come at the cost of cognitive decline. This has been attributed to radiation-induced toxicity at the hippocampus, a crucial anatomic area for cognition. Modern radiotherapy techniques allow dose reduction at the hippocampal region. In this review, the safety profile, effect on cognition, and changes on brain imaging modalities of hippocampal avoidance-PCI (HA-PCI) will be presented, aiming to identify a potential clinical rationale for SCLC patients.

MATERIALS AND METHODS

A systematic review of the literature was performed in Pubmed, Cochrane library databases and ClinicalTrials.gov with no past date limitations until 07/01/2022. Principles as outlined in the preferred reporting items for systematic reviews and meta-analysis (PRISMA) statement were followed.

RESULTS

Eight studies published from 2015 to 2021 were included.

CONCLUSION

HA-PCI is safe, yet its effect on neurocognition and imaging remains unclear, as studies have shown contradictory results.

Influencing Factors and Prognostic Value of 18F-FDG PET/CT Metabolic and Volumetric Parameters in Non-Small Cell Lung Cancer

Objective

This study aims to explore factors influencing metabolic and volumetric parameters of [¹⁸F]fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) imaging in non-small cell lung cancer (NSCLC) and the predictive value for prognosis of NSCLC.

Methods

Retrospective analysis was performed on 133 NSCLC patients who received ¹⁸F-FDG PET/CT imaging. After ¹⁸F-FDG injection at 3.7 MBq/kg, 1 h early imaging and 2 h delayed imaging were performed. The metabolic and volumetric parameters such as SUVmax, SUVpeak, SULmax, SULpeak, MTV and TLG were measured. The tumor markers including CFYRA21-1, NSE, SCC-ag and the immunohistochemical biomarkers including Ki-67, P53 and CK-7 were examined. All patients were followed up for 24 months, and the 1-year and 2-year overall survival rate (OS) were recorded.

Results

There were significant differences in metabolic and volumetric parameters (SUVmax, SUVpeak, SULmax, SULpeak and TLG) between adenocarcinoma and squamous cell carcinoma of NSCLC. SUVmax, SUVpeak, SULmax, SULpeak, MTV and TLG were correlated with tumor marker NSE and TNM stage. MTV and TLG were related to CYFRA21-1, and only MTV was associated with SCC-ag. SUVpeak and SULmax were related to P53. In addition, early SULpeak and delayed MTV were significant prognostic factors of 1-year OS, while early SUVpeak, delayed TLG and delayed MTV were predictive factors of 2-year OS in NSCLC.

Conclusion

The metabolic and volumetric parameters of ¹⁸F-FDG PET/CT were related to a variety of factors such as NSE, CFYRA21-1, SCC-ag, P53 and TNM stage, and have a predictive value in prognosis of NSCLC.

Pathological diagnosis and treatment outcome of gastric metastases from small cell lung cancer: A case report

Small cell lung cancer (SCLC) is a type of lung cancer characterized by a rapid disease progression and poor prognosis. Its diagnosis is often accompanied by distant metastasis. A literature review revealed that metastases to the stomach from breast, lung and esophageal cancer are frequently reported. While SCLC is a common pathological subtype of lung cancer, literature on SCLC with gastric metastases is sporadic. The present study reviewed the literature using databases, including PubMed, WanFang Data and China National Knowledge Infrastructure, to analyze the clinicopathological features and outcome of patients with gastric metastases from SCLC. A total of 11 case reports and 6 retrospective studies comprising of 19 cases were compared and analyzed. In addition to the aforementioned studies, a case study describing a patient who survived for 10 months following a diagnosis of SCLC with gastric metastases is presented. The aim of the present study was to increase the understanding regarding the diagnosis and treatment of SCLC gastric metastasis.

Survival Outcomes With Thoracic Radiotherapy in Extensive-Stage Small-Cell Lung Cancer: A Propensity Score-Matched Analysis of the National Cancer Database

BACKGROUND

The prognosis of patients with extensive-stage small-cell lung carcinoma (ES-SCLC) is poor. The benefit of consolidative thoracic radiation therapy (TRT) in ES-SCLC has been inconclusive, and its use inconsistent. The objective of this study was to evaluate overall survival (OS) of ES-SCLC patients treated with chemotherapy (CT) with or without TRT using an administrative database approach.

PATIENTS AND METHODS

The National Cancer Database was queried to identify patients with ES-SCLC diagnosed between 2010 and 2014. Those with brain metastases, those who received radiotherapy before CT, or radiotherapy outside the thorax, were excluded. Propensity score-matching (PSM) was used to compare OS of patients treated with CT and TRT with those who received CT alone. Patients who received >10 radiotherapy fractions were also compared with those who received 10 or fewer.

RESULTS

We included 14,367 patients in the primary analysis; 12,019 received CT alone, and 2348 received CT with TRT. In multivariate analysis, CT was associated with an increased risk of death relative to CT with TRT (hazard ratio [HR], 1.74 [95% confidence interval (CI), 1.64-1.84]; log-rank P < .001), which remained significant with PSM. Median OS was 12.1 versus 8.2 months (CT with TRT vs. CT); 12-month OS was 50.5% versus 28.5%, and 5-year OS 7.6% versus 2.0% (HR, 1.80 [95% CI, 1.67-1.95], HR P < .001). Of 3099 patients who received TRT, >10 radiotherapy fractions was associated with superior OS (HR, 1.70 [95% CI, 1.49-1.95], log-rank P < .001); this finding remained significant with PSM.

CONCLUSION

Use of TRT after CT in ES-SCLC patients was associated with long-term survival; its use should be considered in addition to standard of care CT.

Recent developments in radiotherapy for small-cell lung cancer: a review by the Oncologic Group for the Study of Lung Cancer (Spanish Radiation Oncology Society)

Small-cell lung cancer (SCLC) accounts for 13% of all lung tumours. The standard treatment in patients with limited-stage disease is radiotherapy combined with chemotherapy. In extensive SCLC, the importance of consolidation thoracic radiotherapy in patients with a good treatment response has become increasingly recognized. In both limited and extensive disease, prophylactic cranial irradiation is recommended in patients who respond to treatment. New therapeutic approaches such as immunotherapy are being increasingly incorporated into the treatment of SCLC, although more slowly than in non-small cell lung cancer (NSCLC). Diverse radiation dose and fractionation schemes, administered in varying combinations with these new drugs, are being investigated. In the present study we review and update the role of radiotherapy in the treatment of SCLC. We also discuss the main clinical trials currently underway in order to identify future trends.

N-tert-Prenylation of the indole ring improves the cytotoxicity of a short antagonist G analogue against small cell lung cancer

Natural prenylated indoles have been proposed as potential anticancer agents. To exploit this discovery for developing new peptide therapeutics, we report the first studies whereby incorporation of prenylated indoles into primary sequences has been achieved. We developed a route to synthesise Nα-Fmoc-protected tryptophan derivatives in which the prenyl group is linked to the N-indole core, using Pd(ii)-mediated C-H functionalisation of 2-methyl-2-butene. Based on the Substance P antagonist G (SPG), a well-known Small Cell Lung Cancer (SCLC) anticancer agent, we designed a new penta-peptide sequence to include a prenyl moiety on one of the tryptophan residues. The N-tert-prenylated tryptophan analogue was assembled into the pentameric peptide using standard solid phase peptide synthesis or liquid phase synthesis by fragment coupling. In vitro screening showed that the N-tert-prenylation of the indole ring on the tryptophan residue located near the C-terminal of the penta-peptide enhanced the cytotoxicity against H69 (IC50 = 2.84 ± 0.14 μM) and DMS79 (IC50 = 4.37 ± 0.44 μM) SCLC cell lines when compared with the unmodified penta-peptide (H69, IC50 = 30.74 ± 0.30 μM and DMS79, IC50 = 23.00 ± 2.07 μM) or the parent SPG sequence (IC50 > 30 μM, both cell lines). SCLC almost invariably relapses with therapy-resistant disease. The DMS79 cell line was established from a patient following treatment with a number of chemotherapeutics (cytoxan, vincristine and methotrexate) and radiation therapy. Treating DMS79 tumour-bearing nude mice provided a human xenograft model of drug resistance to test the efficacy of the prenylated peptide. A low dose (1.5 mg kg-1) of the prenylated peptide was found to reduce tumour growth by ∼30% (P < 0.05) at day 7, relative to the control group receiving vehicle only. We conclude that the availability of the Fmoc-Trp(N-tert-prenyl)-OH amino acid facilitates the synthesis of prenylated-tryptophan-containing peptides to explore their therapeutic potential.

Analysis of risk factors for pulmonary complications in patients with limited-stage small cell lung cancer : A single-centre retrospective study

INTRODUCTION

The most effective therapy in patients with limited-stage small cell lung cancer (LS SCLC) seems to be chemotherapy (using platinum-based regimens) and thoracic radiotherapy (TRT), which is followed by prophylactic cranial irradiation.

MATERIALS AND METHODS

The analysed group comprised 217 patients who received combined treatment for LS SCLC, i.e. chemotherapy (according to cisplatin and etoposide schedule) and TRT (concurrent in 101 and sequential in 116 patients). The influence of chemoradiotherapy (ChT-RT) schedule on treatment results (frequency of complete response, survival rates, and incidence of treatment failure and complications) was evaluated, and the frequency and severity of pulmonary complications were analysed to identify risk factors.

RESULTS

The 5‑year survival rates in concurrent vs. sequential ChT-RT schedules were 27.3 vs. 11.7% (overall) and 28 vs. 14.3% (disease-free). The frequencies of adverse events in relation to concurrent vs. sequential therapy were 85.1 vs. 9.5% (haematological complications) and 58.4 vs. 38.8% (pulmonary fibrosis), respectively. It was found that concurrent ChT-RT (hazard ratio, HR 2.75), a total dose equal to or more than 54 Gy (HR 2.55), the presence of haematological complications (HR 1.89) and a lung volume receiving a dose equal to or greater than 20 Gy exceeding 31% (HR 1.06) were the risk factors for pulmonary complications.

CONCLUSION

Pulmonary complications after ChT-RT developed in 82% of patients treated for LS SCLC. In comparison to the sequential approach, concurrent ChT-RT had a positive effect on treatment outcome. However, this is a factor that can impair treatment tolerance, which manifests in the appearance of side effects.

[Radiotherapy for small cell lung carcinoma]

Radiotherapy for small cell lung carcinoma has known significant improvements over the past 10 years especially through routine use of PET-CT in the initial work-up and contouring before treatment. Prophylactic cranial irradiation remains a standard of care for locally advanced disease and is a subject of controversy for metastatic disease. A new indication for thoracic radiotherapy may soon arise for metastatic disease, still confirmation studies are ongoing.

Intrathoracic extensive-stage small cell lung cancer: assessment of the benefit of thoracic and brain radiotherapy using the SEER database

BACKGROUND

Extensive-stage small cell lung cancer (ESCLC) includes metastatic disease and locally advanced disease confined to the thorax that cannot be encompassed in a typical radiation portal. We assessed and then compared the benefits of thoracic radiotherapy (TRT) and/or brain radiotherapy (BRT) on overall survival (OS) between the intrathoracic (T-ESCLC) and metastatic (M-ESCLC) groups using the Surveillance Epidemiology and End Results database.

METHODS

TRT and BRT data were available for 10150 patients treated from 1988-1997. The T-ESCLC group included 1774 patients. The Kaplan-Meier method was used to estimate OS and the proportional hazards model was used to estimate OS hazard ratios for prognostic factors including age, gender, race, tumor size, T/N stage, TRT, and BRT.

RESULTS

The 2-year OS for T-ESCLC was 7.8 % compared to 3 % in the M-ESCLC group (p < 0.001). In the T-ESCLC group, TRT and BRT were delivered to 750 and 102 patients, respectively. The 2-year OS was 13 % in the TRT group compared to 4.1 % in the no-TRT group (p ≤ 0.001) and 22.5 % in the BRT group compared to 7 % in the no-BRT group (p < 0.001). In the M-ESCLC group, TRT and BRT were delivered to 3093 and 1887 patients, respectively. The 2-year OS was 4.4 % in the TRT group compared to 2.8 % in the no-TRT group (p < 0.001) and 4.3 % in the BRT compared to 2.6 % in the no-BRT group (p < 0.001). Age, gender, TRT and BRT were significant OS prognostic factors in both groups.

CONCLUSIONS

Our study suggests that T-ESCLC is a disease entity distinct from M-ESCLC. Prospective studies to determine whether TRT should be recommended for the thoracic-only subgroup are warranted.

Pro-gastrin-releasing peptide and neuron-specific enolase: useful predictors of response to chemotherapy and survival in patients with small cell lung cancer

PURPOSE

The aim of this study was (1) to evaluate and predict the value of ProGRP and NSE in therapy and survival; (2) as well as to investigate the correlation between the ProGRP mRNA expression in peripheral blood and serum ProGRP protein.

METHODS

The study included 122 patients with SCLC without prior therapy. The serum levels of ProGRP and NSE were detected by enzyme-linked immunosorbent assay and eletro-chemiluminescence immunoassay, respectively. The expression of ProGRP mRNA was detected by real-time reverse transcriptase-polymerase chain reaction.

RESULTS

Distribution of serum levels of ProGRP, NSE and ProGRP mRNA differed significantly according to tumor size, disease stage and distant metastasis (all P < 0.05), and no association was found between them and gender or age (both P > 0.05). After two courses of chemotherapy, patients of remission and stable groups showed a marked decrease in ProGRP and NSE concentrations (P < 0.05). The ProGRP concentration of patients in progression group was significantly higher than pretreatment level (P < 0.05), while NSE concentration was not. A linear nonparametric (Spearman) correlation test revealed that there was a significant correlation between ProGRP mRNA expression in peripheral blood and serum ProGRP protein level (P < 0.05). Univariate analysis found a statistically significant association of survival with disease stage, distant metastasis, ProGRP and NSE (P < 0.05). Gender, age and tumor size were not prognostic factors (P > 0.05). Multiple Cox regression model analysis found that only disease stage and NSE were significant predictors (P < 0.05).

CONCLUSIONS

This study has found that there is a potential role for ProGRP and NSE in both therapy monitoring and predicting survival in SCLC patients.

Use of thoracic radiotherapy for extensive stage small-cell lung cancer: a phase 3 randomised controlled trial

BACKGROUND

Most patients with extensive stage small-cell lung cancer (ES-SCLC) who undergo chemotherapy, and prophylactic cranial irradiation, have persistent intrathoracic disease. We assessed thoracic radiotherapy for treatment of this patient group.

METHODS

We did this phase 3 randomised controlled trial at 42 hospitals: 16 in Netherlands, 22 in the UK, three in Norway, and one in Belgium. We enrolled patients with WHO performance score 0-2 and confirmed ES-SCLC who responded to chemotherapy. They were randomly assigned (1:1) to receive either thoracic radiotherapy (30 Gy in ten fractions) or no thoracic radiotherapy. All underwent prophylactic cranial irradiation. The primary endpoint was overall survival at 1 year in the intention-to-treat population. Secondary endpoints included progression-free survival. This study is registered with the Nederlands Trial Register, number NTR1527.

FINDINGS

We randomly assigned 498 patients between Feb 18, 2009, and Dec 21, 2012. Three withdrew informed consent, leaving 247 patients in the thoracic radiotherapy group and 248 in the control group. Mean interval between diagnosis and randomisation was 17 weeks. Median follow-up was 24 months. Overall survival at 1 year was not significantly different between groups: 33% (95% CI 27-39) for the thoracic radiotherapy group versus 28% (95% CI 22-34) for the control group (hazard ratio [HR] 0.84, 95% CI 0.69-1.01; p=0.066). However, in a secondary analysis, 2-year overall survival was 13% (95% CI 9-19) versus 3% (95% CI 2-8; p=0.004). Progression was less likely in the thoracic radiotherapy group than in the control group (HR 0.73, 95% CI 0.61-0.87; p=0.001). At 6 months, progression-free survival was 24% (95% CI 19-30) versus 7% (95% CI 4-11; p=0.001). We recorded no severe toxic effects. The most common grade 3 or higher toxic effects were fatigue (11 vs 9) and dyspnoea (three vs four).

INTERPRETATION

Thoracic radiotherapy in addition to prophylactic cranial irradiation should be considered for all patients with ES-SCLC who respond to chemotherapy.

FUNDING

Dutch Cancer Society (CKTO), Dutch Lung Cancer Research Group, Cancer Research UK, Manchester Academic Health Science Centre Trials Coordination Unit, and the UK National Cancer Research Network.

Quantitative analysis of tumor shrinkage due to chemotherapy and its implication for radiation treatment planning in limited-stage small-cell lung cancer

Background

The optimal timing of chemoradiotherapy in limited-stage small-cell lung cancer (LS-SCLC) hasn’t been established, although evidence from studies supported that patients can benefit from early radiation therapy. The purpose of this study was to quantify tumor shrinkage in response to induction chemotherapy (IC), evaluate the impact of tumor shrinkage on radiation dosimetric parameters and determine its implication for the timing of radiation therapy for patients with LS-SCLC.

Methods

Twenty patients with LS-SCLC who were treated with IC followed by concomitant radiation therapy were investigated retrospectively. Ten patients received 1 cycle of IC, and 10 patients received 2 cycles of IC. Pre-IC CT imaging was coregistered with a simulation CT, and virtual radiation plans were created for pre- and post-IC thoracic disease in each case. The changes in the gross target volume (GTV), planning target volume (PTV) and dosimetric factors associated with the lungs, esophagus and heart were analyzed.

Results

The mean GTV and PTV for all of the patients decreased by 60.9% and 40.2%, respectively, which resulted in a significant reduction in the radiation exposure to the lungs, esophagus and heart. Changes in the PTV and radiation exposure of normal tissue were not significantly affected by the number of chemotherapy cycles delivered, although patients who received 2 cycles of IC had a greater decrease in GTV than those who received only 1 cycle of IC (69.6% vs. 52.1%, p = 0.273).

Conclusions

Our data showed that targeting the tumor post-IC may reduce the radiation dose to normal tissue in patients with LS-SCLC. However, the benefit to the normal tissue was not increased by an additional cycle of IC. These findings suggest that the first cycle of chemotherapy is very important for tumor shrinkage and that initiating thoracic radiation therapy at the second cycle of chemotherapy may be a reasonable strategy for timing of radiation therapy in LS-SCLC treatment.

Small cell lung cancer

Neuroendocrine tumors account for approximately 20% of lung cancers; most (≈15%) are small cell lung cancer (SCLC). These NCCN Clinical Practice Guidelines in Oncology for SCLC focus on extensive-stage SCLC because it occurs more frequently than limited-stage disease. SCLC is highly sensitive to initial therapy; however, most patients eventually die of recurrent disease. In patients with extensive-stage disease, chemotherapy alone can palliate symptoms and prolong survival in most patients; however, long-term survival is rare. Most cases of SCLC are attributable to cigarette smoking; therefore, smoking cessation should be strongly promoted.

Percutaneous endoscopic gastrostomy site metastasis from head and neck squamous cell carcinoma: case series and literature review

Objectives

To present our experience with head and neck squamous cell carcinoma (HNSCC) seeding of percutaneous endoscopic gastrostomy (PEG) sites and to review all reported cases to identify risk factors and develop strategies for complication avoidance.

Materials and methods

The records of 4 patients with PEG site metastasis from HNSCC were identified from the authors’ institution. Thirty-eight further cases were reviewed following a PubMed search and evaluation of references in pertinent articles.

Results

Review of 42 cases revealed the average time from PEG to diagnosis of metastatic disease to be 8 months. Average time to death from detection of PEG disease was 5.9 months. One-year survival following PEG metastasis was 35.5% with an overall mortality of 87.1%.

Conclusion

PEG site metastatic disease portends a poor prognosis. Early detection and aggressive therapy may provide a chance of cure. Changes in PEG technique or in timing of adjunctive therapies are possible avenues in further research to prevent this complication.

Prophylactic cranial irradiation for small-cell lung cancer: how, when and for whom?

Prophylactic cranial irradiation (PCI) reduces the incidence of brain metastases and improves overall survival in both limited disease (LD) and extensive disease (ED) small-cell lung cancer (SCLC), in complete and good responders to initial chemo(radio)therapy. In LD-SCLC, a standard dose of 25 Gy given in ten fractions is recommended, whereas in ED-SCLC a shorter schedule of 20 Gy in five fractions could be used. The issues of acute neurotoxicity (NT) and the potential impact of PCI on quality of life are of particular concern in ED-SCLC patients, as their expected survival is short. In LD-SCLC late neurologic sequelae may worsen quality-adjusted life expectancy for long-term survivors, as the pronounced effect of NT becomes apparent after several years. Some novel potential approaches to reduce the PCI-related late NT have recently been investigated. Despite the growing incidence of lung cancer in elderly people, there are no established standards of treatment for this subset of the population.

Therapeutic approaches for HER2-positive brain metastases: circumventing the blood-brain barrier

We aim to summarize data from studies of trastuzumab in patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC) and brain metastasis and to describe novel methods being developed to circumvent the blood-brain barrier (BBB). A literature search was conducted to obtain data on the clinical efficacy of trastuzumab and lapatinib in patients with HER2-positive MBC and brain metastasis, as well as the transport of therapeutic molecules across the BBB. Trastuzumab-based therapy is the standard of care for patients with HER2-positive MBC. Post hoc and retrospective analyses show that trastuzumab significantly prolongs overall survival when given after the diagnosis of central nervous system (CNS) metastasis; this is probably attributable to its control of extracranial disease, although trastuzumab may have a direct effect on CNS disease in patients with local or general perturbation of the BBB. In patients without a compromised BBB, trastuzumab is thought to have limited access to the brain, because of its relatively large molecular size. Several approaches are being developed to enhance the delivery of therapeutic agents to the brain. These include physical or pharmacologic disruption of the BBB, direct intracerebral drug delivery, drug manipulation, and coupling drugs to transport vectors. Available data suggest that trastuzumab extends survival in patients with HER2-positive MBC and brain metastasis. Novel methods for delivery of therapeutic agents into the brain could be used in the future to enhance access to the CNS by trastuzumab, thereby improving its efficacy in this setting.