Developments in early-stage NSCLC: advances in radiotherapy

Prospective Cohort Study to Compare Long-Term Lung Cancer-Specific and All-Cause Survival of Clinical Early Stage (T1a-b; ≤20 mm) NSCLC Treated by Stereotactic Body Radiation Therapy and Surgery

INTRODUCTION

We aimed to compare outcomes of patients with first primary clinical T1a-bN0M0 NSCLC treated with surgery or stereotactic body radiation therapy (SBRT).

METHODS

We identified patients with first primary clinical T1a-bN0M0 NSCLCs on last pretreatment computed tomography treated by surgery or SBRT in the following two prospective cohorts: International Early Lung Cancer Action Program (I-ELCAP) and Initiative for Early Lung Cancer Research on Treatment (IELCART). Lung cancer-specific survival and all-cause survival after diagnosis were compared using Kaplan-Meier analysis. Propensity score matching was used to balance baseline demographics and comorbidities and analyzed using Cox proportional hazards regression.

RESULTS

Of 1115 patients with NSCLC, 1003 had surgery and 112 had SBRT; 525 in I-ELCAP in 1992 to 2021 and 590 in IELCART in 2016 to 2021. Median follow-up was 57.6 months. Ten-year lung cancer-specific survival was not significantly different: 90% (95% confidence interval: 87%-92%) for surgery versus 88% (95% confidence interval: 77%-99%) for SBRT, p = 0.55. Cox regression revealed no significant difference in lung cancer-specific survival for the combined cohorts (p = 0.48) or separately for I-ELCAP (p = 1.00) and IELCART (p = 1.00). Although 10-year all-cause survival was significantly different (75% versus 45%, p < 0.0001), after propensity score matching, all-cause survival using Cox regression was no longer different for the combined cohorts (p = 0.74) or separately for I-ELCAP (p = 1.00) and IELCART (p = 0.62).

CONCLUSIONS

This first prospectively collected cohort analysis of long-term survival of small, early NSCLCs revealed that lung cancer-specific survival was high for both treatments and not significantly different (p = 0.48) and that all-cause survival after propensity matching was not significantly different (p = 0.74). This supports SBRT as an alternative treatment option for small, early NSCLCs which is especially important with their increasing frequency owing to low-dose computed tomography screening. Furthermore, treatment decisions are influenced by many different factors and should be personalized on the basis of the unique circumstances of each patient.

Improved survival with stereotactic ablative radiotherapy (SABR) over lobectomy for early stage non-small cell lung cancer (NSCLC): addressing the fallout of disruptive randomized data

The gold-standard therapy for early stage non-small cell lung cancer (esNSCLC) has historically been lobectomy with mediastinal lymph node dissection. However, up to one-third of patients with esNSCLC are considered medically-inoperable due to factors such as advanced age and comorbid illnesses. The past decade has witnessed a dramatic increase in the use of high-dose conformal radiotherapy delivered over 1-5 fractions, synonymously termed stereotactic ablative radiotherapy (SABR) or stereotactic body radiation therapy (SBRT). High rates of tumor control and favorable toxicity profiles have led to the adoption of SABR as the treatment of choice for medically-inoperable patients. Limited but growing data exist using SABR for medically-operable patients who are also candidates for lobectomy. A recent pooled analysis of two multicenter prospective randomized trials, the STARS (NCT00840749) and ROSEL (NCT00687986) protocols, published by Chang and colleagues (PMID 25981812) reported improved overall survival (OS) and reduced toxicity with SABR over lobectomy for medically-operable patients with esNSCLC. In this article we review the outcomes of this analysis in the context of existing radiotherapy and surgical data for NSCLC. Further, we discuss the potential causes and implications of these provocative results, including the shifting balance between oncologic control and treatment-related mortality in comparisons of SABR and surgical resection, termed the Head Start Effect.

Stereotactic ablative radiotherapy versus lobectomy for operable stage I non-small-cell lung cancer: a pooled analysis of two randomised trials

BACKGROUND

The standard of care for operable, stage I, non-small-cell lung cancer (NSCLC) is lobectomy with mediastinal lymph node dissection or sampling. Stereotactic ablative radiotherapy (SABR) for inoperable stage I NSCLC has shown promising results, but two independent, randomised, phase 3 trials of SABR in patients with operable stage I NSCLC (STARS and ROSEL) closed early due to slow accrual. We aimed to assess overall survival for SABR versus surgery by pooling data from these trials.

METHODS

Eligible patients in the STARS and ROSEL studies were those with clinical T1-2a (<4 cm), N0M0, operable NSCLC. Patients were randomly assigned in a 1:1 ratio to SABR or lobectomy with mediastinal lymph node dissection or sampling. We did a pooled analysis in the intention-to-treat population using overall survival as the primary endpoint. Both trials are registered with ClinicalTrials.gov (STARS: NCT00840749; ROSEL: NCT00687986).

FINDINGS

58 patients were enrolled and randomly assigned (31 to SABR and 27 to surgery). Median follow-up was 40·2 months (IQR 23·0-47·3) for the SABR group and 35·4 months (18·9-40·7) for the surgery group. Six patients in the surgery group died compared with one patient in the SABR group. Estimated overall survival at 3 years was 95% (95% CI 85-100) in the SABR group compared with 79% (64-97) in the surgery group (hazard ratio [HR] 0·14 [95% CI 0·017-1·190], log-rank p=0·037). Recurrence-free survival at 3 years was 86% (95% CI 74-100) in the SABR group and 80% (65-97) in the surgery group (HR 0·69 [95% CI 0·21-2·29], log-rank p=0·54). In the surgery group, one patient had regional nodal recurrence and two had distant metastases; in the SABR group, one patient had local recurrence, four had regional nodal recurrence, and one had distant metastases. Three (10%) patients in the SABR group had grade 3 treatment-related adverse events (three [10%] chest wall pain, two [6%] dyspnoea or cough, and one [3%] fatigue and rib fracture). No patients given SABR had grade 4 events or treatment-related death. In the surgery group, one (4%) patient died of surgical complications and 12 (44%) patients had grade 3-4 treatment-related adverse events. Grade 3 events occurring in more than one patient in the surgery group were dyspnoea (four [15%] patients), chest pain (four [15%] patients), and lung infections (two [7%]).

INTERPRETATION

SABR could be an option for treating operable stage I NSCLC. Because of the small patient sample size and short follow-up, additional randomised studies comparing SABR with surgery in operable patients are warranted.

FUNDING

Accuray Inc, Netherlands Organisation for Health Research and Development, NCI Cancer Center Support, NCI Clinical and Translational Science Award.

Effects of late administration of pentoxifylline and tocotrienols in an image-guided rat model of localized heart irradiation

Radiation-induced heart disease (RIHD) is a long-term side effect of radiotherapy of intrathoracic, chest wall and breast tumors when radiation fields encompass all or part of the heart. Previous studies have shown that pentoxifylline (PTX) in combination with α-tocopherol reduced manifestations of RIHD in rat models of local heart irradiation. The relative contribution of PTX and α-tocopherol to these beneficial effects are not known. This study examined the effects of PTX alone or in combination with tocotrienols, forms of vitamin E with potential potent radiation mitigation properties. Rats received localized X-irradiation of the heart with an image-guided irradiation technique. At 3 months after irradiation rats received oral treatment with vehicle, PTX, or PTX in combination with a tocotrienol-enriched formulation. At 6 months after irradiation, PTX-treated rats showed arrhythmia in 5 out of 14 animals. PTX alone or in combination with tocotrienols did not alter cardiac radiation fibrosis, left ventricular protein expression of the endothelial markers von Willebrand factor and neuregulin-1, or phosphorylation of the signal mediators Akt, Erk1/2, or PKCα. On the other hand, tocotrienols reduced cardiac numbers of mast cells and macrophages, but enhanced the expression of tissue factor. While this new rat model of localized heart irradiation does not support the use of PTX alone, the effects of tocotrienols on chronic manifestations of RIHD deserve further investigation.