Application of a radiation pneumonitis prediction model in patients with locally advanced lung squamous cell cancer

BACKGROUND

The aim of the present study was to establish a new prediction model for radiation pneumonitis (RP) in locally advanced non-small cell lung cancer (LA-NSCLC) patients before and after radiotherapy.

METHODS

The study involved 153 patients. Age, arterial partial oxygen pressure (PO2), forced vital capacity, pulmonary emphysema (PE), subclinical interstitial lung disease (sILD), and dosimetric parameters, such as mean lung dose and percentage of lung volume, and a dose >5/20 Gy (V5/V20), were considered candidate RP predictors.

RESULTS

Of the 153 eligible patients, 33 (21.6%) developed RP, 68 had PE (43.8%), and 24 (15.7%) had sILD. Grades 2, 3, and 5 RP were scored in 17 (11.1%), 15 (9.8%), and 1 (0.7%) patient/s, Grade 4 RP was not observed. Grades 1, 2, and 3 PE were scored in 45 (29.4%), 22 (14.4%), and 1 (0.7%) patient/s. Grades 0 and 1 sILD were observed in 129 (84.3%) and 24 (15.7%) patients. Univariate analysis found age, PE, and sILD to be significantly correlated with grade ≥2 RP. Multivariate analysis revealed age >68 years, PE grade >1, and sILD grade ≥1 as independent risk factor for grade ≥2 RP in LA-NSCLC with squamous cell carcinoma (SCC). Finally, a new predictive risk score (PRS) comprised of these factors was developed. The PRS score was 0, 3-5, and 6-11 when the cumulative incidence of grade ≥2 RP was 8.8% (5 patients), 13% (3 patients), and 84.6% (13 patients) (P=<0.001).

CONCLUSIONS

Age, PE, and sILD could independently and significantly predict RP in LA-NSCLC with SCC.

Stereotactic body radiotherapy for early stage non-small cell lung cancer in patients with subclinical interstitial lung disease

Background

For lung cancer patients with subclinical (untreated and asymptomatic) interstitial lung disease (ILD), there is a lack of relatively safe and effective treatment. Stereotactic body radiation therapy (SBRT) can achieve a high level of tumor control with low toxicity in early-stage non-small cell lung cancer (NSCLC). This study aimed to evaluate the efficacy and toxicity of early stage NSCLC patients with subclinical ILD receiving SBRT.

Methods

A total of 109 early stage NSCLC patients receiving SBRT treatment between December 2011 and August 2016 were reviewed in our institutions; patients with clinical ILD were excluded. The median dose of SBRT was 50 Gy in 5 fractions. The median biologically effective dose (BED; α/β=10) was 100 Gy (range, 72–119 Gy). An experienced radiation oncologist and an experienced radiologist reviewed the presence of subclinical ILD in the CT findings before SBRT. The relationships among the efficacy, radiation-induced lung injury (RILI) and subclinical ILD were explored.

Results

In all, 38 (34.9%) of 109 patients were recognized with subclinical ILD before SBRT, 48 (44.0%) of 109 patients were recognized with grade 2–5 RILI after SBRT, and 18 (47.4%) of 38 patients with subclinical ILD were observed with grade 2–5 RILI. Subclinical ILD was not a significant factor of grade 2–5 RILI (P=0.608); however, 3 patients had extensive RILI, and they all suffered from subclinical ILD. Dosimetric factor of the lungs, such as mean lung dose (MLD) was significantly related with Grade 2–5 RILI in patients with subclinical ILD (P=0.042). The progression-free survival (PFS) rates at 3 years in the subclinical ILD patients and those without ILD were 61.6% and 66.8%, respectively (P=0.266).

Conclusions

Subclinical ILD was not a significant factor for RILI or PFS in early stage NSCLC patients receiving SBRT; however, patients with subclinical ILD receiving SBRT may experience uncommon extensive RILI.

Reference values for high attenuation areas on chest CT in a healthy, never-smoker, multi-ethnic sample: The MESA study

BACKGROUND AND OBJECTIVE

Normative values for HAA-a quantitative, CT-based measure of subclinical ILD-in healthy adults are needed to improve interpretability in clinical and research settings.

METHODS

HAA was measured on full-lung CT in 3110 participants in the MESA study. Clinical prediction models were developed using a healthy never-smoker subset with normal spirometry (n = 696). RMSE on cross-validation was used as the primary criterion for model selection. Parametric and non-parametric methods were considered. z-Scores were calculated for the entire study sample. Associations between z-scores and several ILD features were estimated.

RESULTS

In the healthy never-smoker subset, the mean age was 69 years with a range of 54-93 years. The median HAA was 4.3% with a range of 2.7-17.8%. Linear regression had better predictive performance than other methods. The final model included race, height, weight, age and sex. The standard error of the estimate was 1.62 with a cross-validated RMSE of 1.64 and an adjusted R² of 0.139. z-Scores were associated with several ILD outcomes in adjusted models, including ILA (OR: 1.40 per z-unit; 95% CI: 1.30, 1.52), exertional dyspnoea (OR: 1.08 per z-unit; 95% CI: 1.02, 1.15) and FVC (expected increase per z-unit: -2.49; 95% CI: -2.95, - 2.03).

CONCLUSION

We present a reference equation and z-scores to define expected values of HAA on full-lung CT to aid HAA interpretation in middle-aged and older adults.

High-Attenuation Areas on Chest Computed Tomography and Clinical Respiratory Outcomes in Community-Dwelling Adults

RATIONALE

Areas of increased lung attenuation visualized by computed tomography are associated with all-cause mortality in the general population. It is uncertain whether this association is attributable to interstitial lung disease (ILD).

OBJECTIVES

To determine whether high-attenuation areas are associated with the risk of ILD hospitalization and mortality in the general population.

METHODS

We performed a cohort study of 6,808 adults aged 45-84 years sampled from six communities in the United States. High-attenuation areas were defined as the percentage of imaged lung volume with attenuation values between -600 and -250 Hounsfield units. An adjudication panel determined ILD hospitalization and death.

MEASUREMENTS AND MAIN RESULTS

After adjudication, 52 participants had a diagnosis of ILD during 75,232 person-years (median, 12.2 yr) of follow-up. There were 48 hospitalizations attributable to ILD (crude rate, 6.4 per 10,000 person-years). Twenty participants died as a result of ILD (crude rate, 2.7 per 10,000 person-years). High-attenuation areas were associated with an increased rate of ILD hospitalization (adjusted hazard ratio, 2.6 per 1-SD increment in high-attenuation areas; 95% confidence interval, 1.9-3.5; P < 0.001), a finding that was stronger among men, African Americans, and Hispanics. High-attenuation areas were also associated with an increased rate of ILD-specific death (adjusted hazard ratio, 2.3; 95% confidence interval, 1.7-3.0; P < 0.001). Our findings were consistent among both smokers and nonsmokers.

CONCLUSIONS

Areas of increased lung attenuation are a novel risk factor for ILD hospitalization and mortality. Measurement of high-attenuation areas by screening and diagnostic computed tomography may be warranted in at-risk adults.