Prognostic factors and clinical outcomes after stereotactic radiotherapy for primary lung tumors

Deep inspiratory breath hold assisted by continuous positive airway pressure ventilation for lung stereotactic body radiotherapy

PURPOSE

Continuous positive airway pressure (CPAP) ventilation hyperinflates the lungs and reduces diaphragmatic motion. We hypothesized that CPAP could be safely combined with deep inspiratory breath hold (CPAP-DIBH) during lung stereotactic radiotherapy (SBRT).

MATERIAL AND METHODS

Patients with stage-1 lung cancer or lung metastasis treated with CPAP-DIBH SBRT between 3/2017-5/2021 were analyzed retrospectively. Patient characteristics, treatment parameters, duration of breath holds in all sessions and tolerance to CPAP-DIBH were recorded. Local control (LC) was assessed from CT or PET-CT imaging. The distances between the tumor and mediastinal organs at risk (OAR) in centrally located tumors using either free breathing (FB) or CPAP-DIBH were compared. Toxicity was graded retrospectively.

RESULTS

Forty-five patients with 71 lesions were treated with CPAP-DIBH SBRT. Indications for CPAP-DIBH were prior radiation (35/71, 65%), lower lobe location (34/71, 48%), multiple lesions (26/71, 36.6%) and proximity to mediastinal OAR (7/71, 10%). Patient characteristics were: F:M 43%: 57%; mean gross tumor volume 4.5cm³ (SD 7.9), mean planning target volume 20cm³ (SD 27), primary: metastatic lesions (7%:93%). Mean radiation dose was 52.5 Gray (SD3.5). Mean lung volume was 5292cm³ (SD 1106). Mean duration of CPAP-DIBH was 41.3s (IQR 31-46.8). LC at 2 years was 89.5% (95% CI 76-95.5). In patients with central lesions, the distance between the tumor and mediastinal OAR increased from 0.84cm (SD 0.65) with FB to 1.23cm (SD 0.8) with CPAP-DIBH (p=0.002). Most patients tolerated CPAP well and completed all treatments after starting therapy. Three patients did not receive treatment: 2 were unable to tolerate CPAP and 1 had syncope (pre-existing). Toxicity was grade 2 in 4/65 (6%) and grade 3 in 1/65 (1.5%). There was no grade 2 or higher esophageal or tracheal toxicities.

CONCLUSION

CPAP-DIBH assisted lung SBRT was tolerated well and was associated with minimal toxicity and favorable LC. This technique may be considered when treating multiple lung lesions, lesions located in the lower lobes or adjacent to mediastinal OAR.

Local Control With Single-Fraction Lung Stereotactic Body Radiotherapy is not influenced by Non-Small Cell Lung Cancer Histologic Subtype

INTRODUCTION/BACKGROUND

For early stage medically inoperable lung cancer treated with fractionated stereotactic body radiotherapy (SBRT), higher local failure is associated with squamous carcinoma (SqC) compared to adenocarcinoma (AC). This study explored whether histology influences single-fraction SBRT local control.

MATERIALS AND METHODS

We surveyed our prospective data registry from 12/2009 to 12/2019 for SF-SBRT cases with biopsy-proven AC or SqC only. Outcomes of interest included local (LF), nodal (NF), distant (DF) failure rates and overall survival (OS), as well as treatment-related toxicity.

RESULTS

For the 10-year interval surveyed, 113 patients met study criteria. There was no association between histology and dose received (34 Gy or 30 Gy). Median follow up was 22.9 months. Patient characteristics were balanced between histologic cohorts. Median tumor size was 1.9 cm. Comparing total AC vs. SqC cohorts, 2-year LF rates (%) were 7.3 vs. 9.6, respectively (P = .9805). In %, 2-year LF, NF, DF and OS rates for AC for 30 Gy and 34 Gy, respectively, were 10.8 vs. 6.4; 10.5 vs. 16.2; 15.8 vs. 13.0; 77.9 vs.71.2 (all P = non-significant). In %, 2-year LF, NF, DF, and OS rates for SqC for 30 Gy and 34 Gy, respectively, were 11.8 vs. 8.1; 5.9 vs. 18.0; 23.5 vs. 9.7; 70.6 vs. 77.1 (all P = non-significant). When considering toxicities, there were no grade 4/5 toxicities and no significant differences in any other toxicity rate by histology or dose.

CONCLUSION

SF-SBRT local control was not associated with histology, unlike fractionated schedules. This novel finding adds to the evolving understanding of this treatment schedule.

A guide for managing patients with stage I NSCLC: deciding between lobectomy, segmentectomy, wedge, SBRT and ablation-part 4: systematic review of evidence involving SBRT and ablation

Background

Clinical decision-making for patients with stage I lung cancer is complex. It involves multiple options [lobectomy, segmentectomy, wedge, stereotactic body radiotherapy (SBRT), thermal ablation], weighing multiple outcomes (e.g., short-, intermediate-, long-term) and multiple aspects of each (e.g., magnitude of a difference, the degree of confidence in the evidence, and the applicability to the patient and setting at hand). A structure is needed to summarize the relevant evidence for an individual patient and to identify which outcomes have the greatest impact on the decision-making.

Methods

A PubMed systematic review from 2000-2021 of outcomes after SBRT or thermal ablation vs. resection is the focus of this paper. Evidence was abstracted from randomized trials and non-randomized comparisons with at least some adjustment for confounders. The analysis involved careful assessment, including characteristics of patients, settings, residual confounding etc. to expose degrees of uncertainty and applicability to individual patients. Evidence is summarized that provides an at-a-glance overall impression as well as the ability to delve into layers of details of the patients, settings and treatments involved.

Results

Short-term outcomes are meaningfully better after SBRT than resection. SBRT doesn't affect quality-of-life (QOL), on average pulmonary function is not altered, but a minority of patients may experience gradual late toxicity. Adjusted non-randomized comparisons demonstrate a clinically relevant detriment in long-term outcomes after SBRT vs. surgery. The short-term benefits of SBRT over surgery are accentuated with increasing age and compromised patients, but the long-term detriment remains. Ablation is associated with a higher rate of complications than SBRT, but there is little intermediate-term impact on quality-of-life or pulmonary function tests. Adjusted comparisons show a meaningful detriment in long-term outcomes after ablation vs. surgery; there is less difference between ablation and SBRT.

Conclusions

A systematic, comprehensive summary of evidence regarding Stereotactic Body Radiotherapy or thermal ablation vs. resection with attention to aspects of applicability, uncertainty and effect modifiers provides a foundation for a framework for individualized decision-making.

12 × 6 Gy stereotactic radiotherapy for lung tumors. Is there a difference in response between lung metastases and primary bronchial carcinoma?

PURPOSE

The aim of this study was to evaluate the safety and long-term tumor control after stereotactic radiotherapy (SRT) with 12 × 6 Gy of patients with primary bronchial carcinoma (BC) or with pulmonary metastases (MET) of various solid tumors. Local progression-free survival (LPFS), progression-free survival (PFS), overall survival (OS), and prognostic factors were compared.

METHODS

Between May 2012 and January 2020, 168 patients with 206 pulmonary lesions (170 MET and 36 primary BC) were treated with 12 × 6 Gy (BED₁₀ 116 Gy). The irradiated pulmonary MET were from the following cancers: 47 (27.6%) head and neck, 37 (21.8%) rectum or colon, 30 (17.6%) bronchial, 13 (7.6%) malignant melanoma, 9 (5.3%) esophageal, 9 (5.3%) sarcoma, and 25 (14.8%) other.

RESULTS

The median follow-up was 16.26 months (range: 0.46-89.34) for BC and 19.18 months (0.89-91.11) for MET. Survival rates at 3 years were: OS 43% for BC and 35% for MET; LPFS BC 96% and MET 85%; PFS BC 35% and MET 29%. The most frequently observed grade 3 adverse events (AEs) were pneumonitis (5.9% BC, 4.8% MET), pulmonary fibrosis (2.9% BC, 4% MET), and pulmonary embolism (2.9% BC, 0.8% MET). The favorable prognostic effects on overall survival of patients with MET were female gender (log-rank: p < 0.001), no systemic progression (log-rank; p = 0.048, multivariate COX regression p = 0.039), and malignant melanoma histology (log-rank; p = 0.015, multivariate COX regression p = 0.020). For patients with BC, it was tumor location within the lower lobe (vs. upper lobe, log-rank p = 0.027). LPFS of patients with metastatic disease was beneficially influenced by female gender (log-rank: p = 0.049).

CONCLUSION

The treatment concept of 12 × 6 Gy is associated with 96% local progression-free survival for BC and 85% for pulmonary metastases after 3 years. There was no difference in response after SRT of primary lung carcinoma or pulmonary metastases.