Twice-daily prophylactic cranial irradiation for patients with limited disease small-cell lung cancer with complete response to chemotherapy and consolidative radiotherapy: report of a single institutional phase II trial

Study protocol: watchful observation of patients with limited small cell lung cancer instead of the PCI-prospective, multi-center one-arm study

Background

Prophylactic cranial irradiation (PCI) is a current standard of care after confirmed response to radical chemoradiotherapy for limited disease small cell lung cancer (LD-SCLC). This standard is mostly based on results of old randomized studies when brain imaging with magnetic resonance (MRI) was not available. Survival benefit of PCI in extended disease SCLC was recently challenged by the results of randomized phase III study from Japan.

Methods

Eighty patients with LD-SCLC after response to chest chemoradiotherapy will be enrolled. Patients will be followed up by brain MRI every 3 to 6 months up to 3 years. Neurocognitive function tests will be performed at baseline and after 12 and 24 months. Patients who develop brain metastases will be irradiated with stereotactic (SRT) or whole brain RT (WBRT). The primary endpoint is overall survival. The secondary endpoints are: response rate to radiotherapy of early detected brain metastases, analysis of efficacy of SRT and WBRT; assessment and analysis of neurocognitive functions and QoL in the studied cohorts: QLQ-C30 questionnaire and the California Verbal Learning Test, Color connection test, Benton visual retention test, and verbal fluency test will be carried out.

Discussion

The results of this trial may contribute to changing of LD-SCLC clinical management by deescalating the treatment. There is a lack of prospective, recent studies in LD-SCLC patients with omission of PCI and modern radiation therapy technologies for developed brain metastases. The comprehensive neurocognitive function testing will help to assess the impact of modern radiotherapy (SRT) compared with WBRT and no-PCI in SCLC patients. A subgroup of long-term survivors, who will not develop brain metastases, will not be exposed to unnecessary brain irradiation with its deleterious consequences. The limitation of our study is a lack of parallel randomized control arm. This is a potential source of bias; however, randomized study will be difficult to complete for two major reasons: (1) limited population of LD-SCLC eligible for the study and (2) opinions of our patients, who after information and discussion about benefits and potential harms of PCI, often choose to omit PCI in our practice.

Trial registration

ClinicalTrials.gov Identifier: NCT04168281, 19 Nov. 2019.

Prophylactic Cranial Irradiation for Extensive-Stage Small-Cell Lung Cancer: A Retrospective Analysis

Purpose

Extensive-stage small-cell lung cancer (esSCLC) is an incurable disease and represents a therapeutic challenge because of its poor prognosis. Studies in prophylactic cranial irradiation (PCI) in esSCLC have shown a decreased incidence of symptomatic brain metastases in patients who respond to systemic chemotherapy. However, its effect on overall survival is debatable. We evaluated the benefit of PCI in patients with esSCLC in terms of overall survival, progression-free survival, incidence of brain metastases, recurrence rate, and exposure to postrecurrence therapies.

Materials and Methods

We retrospectively reviewed electronic charts from patients diagnosed with esSCLC from 2008 to 2014 at our institution. All patients had negative baseline brain imaging before chemotherapy and PCI and received at least 4 cycles of platinum-based chemotherapy in the first-line setting without progressive disease on follow-up. PCI was performed at the discretion of the treating physician. Analyses were based on descriptive statistics. Survival curves were calculated by Kaplan-Meier method.

Results

Among 46 eligible patients, 16 (35%) received PCI and 30 (65%) did not. Compared with no PCI, PCI led to improved progression-free survival (median, 10.32 v 7.66 months; hazard ratio, 0.4521; 95% CI, 0.2481 to 0.8237; P < .001) and overall survival (median, 20.94 v 11.05 months; hazard ratio, 0.2655; 95% CI, 0.1420 to 0.4964; P < .001) as well as lower incidence of brain metastases (19% v 53%; P = .0273) and higher exposure to second-line chemotherapy (87% v 57%; P = .0479).

Conclusion

Careful patient selection for PCI can improve not only brain metastases control and higher second-line chemotherapy exposure but also patient survival.

Prophylactic cranial irradiation for patients with lung cancer

The incidence of brain metastases in patients with lung cancer has increased as a result of improved local and systemic control and better diagnosis from advances in brain imaging. Because brain metastases are responsible for life-threatening symptoms and serious impairment of quality of life, resulting in shortened survival, prophylactic cranial irradiation has been proposed in both small-cell lung cancer (SCLC) and non-small-cell lung cancer (NSCLC) to try to improve incidence of brain metastasis, survival, and eventually quality of life. Findings from randomised controlled trials and a meta-analysis have shown that prophylactic cranial irradiation not only reduces the incidence of brain metastases in patients with SCLC and with non-metastatic NSCLC, but also improves overall survival in patients with SCLC who respond to first-line treatment. Although prophylactic cranial irradiation is potentially associated with neurocognitive decline, this risk needs to be balanced against the potential benefit in terms of brain metastases incidence and survival. Several strategies to reduce neurotoxicity are being investigated.

Prophylactic cranial irradiation: 5 years on

With advances in cancer management, patients are living with the long-term sequelae of both cancer and its treatment. This era of cancer survivorship poses unique challenges to the interdisciplinary cancer team in terms of management and prevention of treatment-related toxicities. This paper describes the case of a 55-year-old patient with neurocognitive disturbance as a result of prophylactic cranial irradiation (PCI). Five years after a diagnosis of small cell lung cancer, she is now an inpatient at a specialist palliative care unit. The current evidence for PCI and for potentially modifiable risk factors for neurocognitive disturbance as a consequence of PCI is explored.

[Present role of prophylactic cranial irradiation]

Prophylactic cranial irradiation (PCI) plays a role in the management of lung cancer patients, especially small cell lung cancer (SCLC) patients. As multimodality treatments are now able to ensure better local control and a lower rate of extracranial metastases, brain relapse has become a major concern in lung cancer. As survival is poor after development of brain metastases (BM) in spite of specific treatment, PCI has been introduced in the 1970's. PCI has been evaluated in randomized trials in both SCLC and non-small cell lung cancer (NSCLC) to reduce the incidence of BM and possibly increase survival. PCI reduces significantly the BM rate in both limited disease (LD) and extensive disease (ED) SCLC and in non-metastatic NSCLC. Considering SCLC, PCI significantly improves overall survival in LD (from 15 to 20% at 3 years) and ED (from 13 to 27% at 1 year) in patients who respond to first-line treatment; it should thus be part of the standard treatment in all responders in ED and in good responders in LD. No dose-effect relationship for PCI was demonstrated in LD SCLC patients so that the recommended dose is 25 Gy in 10 fractions. In NSCLC, even if the risk of brain dissemination is lower than in SCLC, it has become a challenging issue. Studies have identified subgroups at higher risk of brain failure. There are more local treatment possibilities for BM related to NSCLC, but most BM will eventually recur so that PCI should be reconsidered. Few randomized trials have been performed. Most of them could demonstrate a decreased incidence of BM in patients with PCI, but they were not able to show an effect on survival as they were underpowered. New trials are needed. Among long-term survivors, neuro-cognitive toxicity may be observed. Several approaches are being evaluated to reduce this possible toxicity. PCI has no place for other solid tumours at risk such as HER2+ breast cancer patients.

Primary analysis of a phase II randomized trial Radiation Therapy Oncology Group (RTOG) 0212: impact of different total doses and schedules of prophylactic cranial irradiation on chronic neurotoxicity and quality of life for patients with limited-disease small-cell lung cancer

PURPOSE

To determine the effect of dose and fractionation schedule of prophylactic cranial irradiation (PCI) on the incidence of chronic neurotoxicity (CNt) and changes in quality of life for selected patients with limited-disease small-cell lung cancer (LD SCLC).

METHODS AND MATERIALS

Patients with LD SCLC who achieved a complete response after chemotherapy and thoracic irradiation were eligible for randomization to undergo PCI to a total dose of 25 Gy in 10 daily fractions (Arm 1) vs. the experimental cohort of 36 Gy. Those receiving 36 Gy underwent a secondary randomization between daily 18 fractions (Arm 2) and twice-daily 24 fractions (Arm 3). Enrolled patients participated in baseline and follow-up neuropsychological test batteries along with quality-of-life assessments.

RESULTS

A total of 265 patients were accrued, with 131 in Arm 1, 67 in Arm 2, and 66 in Arm 3 being eligible. There are 112 patients (42.2%) alive with 25.3 months of median follow-up. There were no significant baseline differences among groups regarding quality-of-life measures and one of the neuropsychological tests, namely the Hopkins Verbal Learning Test. However, at 12 months after PCI there was a significant increase in the occurrence of CNt in the 36-Gy cohort (p=0.02). Logistic regression analysis revealed increasing age to be the most significant predictor of CNt (p=0.005).

CONCLUSIONS

Because of the increased risk of developing CNt in study patients with 36 Gy, a total PCI dose of 25 Gy remains the standard of care for patients with LD SCLC attaining a complete response to initial chemoradiation.

Standard-dose versus higher-dose prophylactic cranial irradiation (PCI) in patients with limited-stage small-cell lung cancer in complete remission after chemotherapy and thoracic radiotherapy (PCI 99-01, EORTC 22003-08004, RTOG 0212, and IFCT 99-01): a randomised clinical trial

BACKGROUND

The optimum dose of prophylactic cranial irradiation (PCI) for limited-stage small-cell lung cancer (SCLC) is unknown. A meta-analysis suggested that the incidence of brain metastases might be reduced with higher PCI doses. This randomised clinical trial compared the effect of standard versus higher PCI doses on the incidence of brain metastases.

METHODS

Between September, 1999, and December, 2005, 720 patients with limited-stage SCLC in complete remission after chemotherapy and thoracic radiotherapy from 157 centres in 22 countries were randomly assigned to a standard (n=360, 25 Gy in 10 daily fractions of 2.5 Gy) or higher PCI total dose (n=360, 36 Gy) delivered using either conventional (18 daily fractions of 2 Gy) or accelerated hyperfractionated (24 fractions in 16 days with two daily sessions of 1.5 Gy separated by a minimum interval of 6 h) radiotherapy. All of the treatment schedules excluded weekends. Randomisation was stratified according to medical centre, age (</=60 and >60 years), and interval between the start of induction treatment and the date of randomisation (</=90, 91-180, and >180 days). Eligible patients were randomised blindly by the data centre of the Institut Gustave Roussy (PCI99-01 and IFCT) using minimisation, and by the data centres of EORTC (EORTC ROG and LG) and RTOG (for CALGB, ECOG, RTOG, and SWOG), both using block stratification. The primary endpoint was the incidence of brain metastases at 2 years. Analysis was by intention-to-treat. This study is registered with ClinicalTrials.gov number NCT00005062.

FINDINGS

Five patients in the standard-dose group and four in the higher-dose group did not receive PCI; nonetheless, all randomised patients were included in the effectiveness anlysis. After a median follow-up of 39 months (range 0-89 months), 145 patients had brain metastases; 82 in the standard-dose group and 63 in the higher-dose group. There was no significant difference in the 2-year incidence of brain metastases between the standard PCI dose group and the higher-dose group, at 29% (95% CI 24-35) and 23% (18-29), respectively (hazard ratio [HR] 0.80 [95% CI 0.57-1.11], p=0.18). 226 patients in the standard-dose group and 252 in the higher-dose group died; 2-year overall survival was 42% (95% CI 37-48) in the standard-dose group and 37% (32-42) in the higher-dose group (HR 1.20 [1.00-1.44]; p=0.05). The lower overall survival in the higher-dose group is probably due to increased cancer-related mortality: 189 patients in the standard group versus 218 in the higher-dose group died of progressive disease. Five serious adverse events occurred in the standard-dose group versus zero in the higher-dose group. The most common acute toxic events were fatigue (106 [30%] patients in the standard-dose group vs 121 [34%] in the higher-dose group), headache (85 [24%] vs 99 [28%]), and nausea or vomiting (80 [23%] vs 101 [28%]).

INTERPRETATION

No significant reduction in the total incidence of brain metastases was observed after higher-dose PCI, but there was a significant increase in mortality. PCI at 25 Gy should remain the standard of care in limited-stage SCLC.

FUNDING

Institut Gustave-Roussy, Association pour la Recherche sur le Cancer (2001), Programme Hospitalier de Recherche Clinique (2007). The European Organisation for Research and Treatment of Cancer (EORTC) contribution to this trial was supported by grants 5U10 CA11488-30 through 5U10 CA011488-38 from the US National Cancer Institute.

Small cell carcinoma of the head and neck: a review

Small cell carcinoma (SCC) has become recognized as a distinct, though relatively infrequent, clinical pathology that occurs in multiple sites throughout the head and neck. Excluding cases that are considered to arise from skin, SCC in the head and neck has been found to develop in nearly all structures associated with the upper aerodigestive tract. Among the head and neck sites, the frequency of SCC is greatest in the larynx, with salivary glands and the sinonasal region comprising the other principle areas of origin. Controversy exist as to whether SCC can develop as a distinct entity in the thyroid, with most tumors that previously would have been considered as SCC now found to be lymphomas or variant forms of other types of thyroid malignancy. While there seems to be some differences among tumors arising from the various subsites, in general all SCC that originate in the head and neck have a tendency for aggressive local invasion and a strong propensity for both regional and distant metastasis. Treatment may include surgical resection, radiotherapy, chemotherapy, or some combination of these modalities. Due to the infrequency of these tumors, it is very unlikely that any large, controlled study will ever be done. For this reason, recommendations for treatment of SCC arising in the head and neck are based primarily on retrospective data from various small case series and on comparative data for treatment of SCC of bronchogenic and other extrapulmonary origin. Although patients with truly limited local disease may enjoy some prolonged survival, most patients with this tumor do poorly despite all current attempts at treatment.

Prophylactic cranial irradiation in small cell lung cancer

Prophylatic cranial irradiation (PCI) in patients with small cell lung cancer (SCLC) is a treatment under evaluation for about 30 years. Since the first randomized trials, it was clear that its use significantly decreased the brain metastasis rate. However, its effect on overall survival was not demonstrated. Retrospective reviews suggested that PCI could induce late neurologic damage. In recent years, two large randomized trials did not confirm this deleterious effect and even suggested a beneficial effect on survival. A recent meta-analysis including almost 1,000 randomized patients confirmed an improvement in overall survival. We discuss here the different aspects of this preventive treatment in a potentially curable disease.