Relationship between radiation pneumonitis and prognosis in patients with primary lung cancer treated by radiotherapy

Safety of Combined Immunotherapy and Thoracic Radiation Therapy: Analysis of 3 Single-Institutional Phase I/II Trials

PURPOSE

The safety of combined immunotherapy and thoracic radiation therapy (iRT) has been understudied. We evaluated toxicities in patients receiving iRT from 3 single-institutional phase 1/2 trials.

METHODS AND MATERIALS

Clinical/treatment characteristics and toxicities (per the Common Toxicity Criteria for Adverse Events, version 4.0) were extracted. For purposes of this analysis, groupings were made into (1) patients receiving immunotherapy plus stereotactic body radiation therapy (50 Gy/4 fractions or 60 Gy/10 fractions), (2) immunotherapy plus 45 Gy/15 fractions, and (3) twice-daily chemoimmunoradiotherapy (45 Gy in twice-daily fractions).

RESULTS

None of the 60 patients undergoing immunotherapy plus stereotactic body radiation therapy (50 Gy, n = 49; 60 Gy, n = 11) experienced grade ≥4 events. There were 34 instances of any grade 3 event (in 15 total patients), with 9 pulmonary specific grade 3 events (in 4 patients). In the patients receiving 45 Gy/15 fractions (small cell lung cancers, n = 26; non-small cell lung cancers, n = 27), there were 2 grade 4 events (in the same patient), along with 17 grade 3 toxicities experienced by 10 total patients (2 pulmonary specific). Lastly, in the twice-daily cohort (n = 22), there were 5 grade 4 events (3 of which occurred in 1 patient) and 16 grade 3 toxicities occurring in 8 total patients (half of which were hematologic).

CONCLUSIONS

Administration of combined iRT is safe in the short term. Toxicities did not appreciably associate with demographics or dosimetry.

The Fate of Residual Tumor Masses That Persist After Stereotactic Body Radiotherapy for Solitary Lung Nodules: Will They Recur?

BACKGROUND

After stereotactic body radiotherapy (SBRT) to the lung, radiation pneumonitis and fibrotic changes often develop, and the tumor shadow usually becomes indistinguishable from the fibrotic shadow. Occasionally, however, a residual mass in patients with no or mild radiation pneumonitis will be observed on serial computed tomography (CT) scans. The purpose of the present study was to evaluate the fate of such residual masses and, if possible, to determine the types of tumor at increased risk of local recurrence.

PATIENTS AND METHODS

A total of 50 patients (underlying disease: primary lung cancer in 45, local recurrence in 2, and metastasis in 3) were selected because they had been followed up for > 2 years or until death and had observable CT changes and measurable tumor size for > 1 year, regardless of the influence of radiation pneumonitis. The patients' outcomes were compared according to various patient and tumor characteristics, including the presence and absence of emphysema, tumor size, and tumor shrinkage rate. The median follow-up period was 52 months.

RESULTS

Of the 50 patients, only 8 developed local recurrence. The local control rate was 81% at 3 years and 73% at 5 years. The local control rates were similar between patients with a high tumor shrinkage rate and those with a low rate. The patients with emphysema exhibited a lower local control rate.

CONCLUSION

The persistence of lung masses for > 1 year after SBRT is not necessarily indicative of an increased risk of local recurrence. A low tumor shrinkage rate also was not predictive of recurrence.

Prediction of radiation pneumonitis in lung cancer patients: a systematic review

PURPOSE

Factors prediction in the development of radiation pneumonitis (RP) remains unclear. A meta-analysis about this was performed.

MATERIALS

Articles were searched in February 2012 from PubMed, EMBASE, Cochrane Library and CNKI (Chinese Journal Full-text Database) using the keywords "lung cancer," "radiation pneumonitis" or "radiation lung injury." The outcome was the RP incidence. We pooled the data using RevMan 5.1 software and tested the statistical heterogeneity.

RESULTS

We included the following factors: age, gender, weight loss, smoking history, complications, performance status, pre-radiation therapy (RT) pulmonary function, TNM, histological type, tumor location, pre-RT surgery, RT combined with chemotherapy (RCT), RT/RCT combined with amifostine, plasma end/pre-RT TGF-β1 ratio and irradiation volume. The significant risk factors for RP ≥ grade 2 were patients with chronic lung disease, tumor located in the middle or lower lobe, without pre-RT surgery, RCT, plasma end/pre-RT TGF-β1 ratio ≥1 and gross tumor volume (GTV). Following factors were identified significant for RP, including tumor located not in the upper lobe, smokers, combined with chronic lung diseases or diabetes mellitus, low pre-RT pulmonary function, RCT, RT/RCT without amifostine and plasma end/pre-RT TGF-β1 ratio ≥1. Dose-volume parameters included the average of mean lung dose (MLD) of disease lung, GTV and V (5), V (10) (≥34 %), V (20) (≥25 %), V (30) (≥18 %) of bilateral lung.

CONCLUSIONS

More attention should be paid to the levels of patients' pulmonary function, plasma TGF-β1 and dose-volume histogram (DVH). Rigorous studies are needed to identify the relationship between the above-mentioned factors and RP ≥grade 1 or 3.

Chemotherapy significantly increases the risk of radiation pneumonitis in radiation therapy of advanced lung cancer

INTRODUCTION

The reported rate of developing radiation pneumonitis (RP) in patients receiving definitive radiation therapy (RT) for lung cancer is 5% to 36%. However, this incidence is probably underreported because of the nonspecific symptoms of RP that may be erroneously attributed to another cardiovascular or respiratory disorder. The objective of this study was to evaluate the incidence of RP in lung cancer patients receiving RT or chemoradiation therapy.

METHODS

Of the 110 patients that were reviewed, 86 were chosen for a retrospective analysis. A diagnosis of RP was made based on clinical assessment in the first 6 to 12 months after RT. Radiation pneumonitis was graded as per Radiation Therapy Oncology Group grading criteria.

RESULTS

The incidence of developing grade 2 or higher RP was significantly associated with addition of chemotherapy. The incidence of RP in patients receiving chemotherapy was 62.7% (42/67) versus 15.8% (3/19) in patients receiving no chemotherapy (P < 0.001). However, there was no significant effect of the type or sequence of chemotherapy on the incidence of RP. The risk of developing RP is 5 times greater in patients receiving chemotherapy when compared with those not receiving this treatment (hazard ratio: 5.0; 95% confidence interval 1.5, 16.1). In addition, patients in age group 61 to 70 years had a significantly increased risk of developing RP compared with patients of age 60 or younger (hazard ratio: 3.0; 95% confidence interval: 1.4, 6.5). Histology and radiation dose were not significant factors in development of RP.

CONCLUSION

The incidence of RP in patients receiving external-beam RT is significantly increased with addition of chemotherapy and 61 to 70 year age group.

Polymorphisms of homologous recombination genes and clinical outcomes of non-small cell lung cancer patients treated with definitive radiotherapy

The repair of DNA double-strand breaks (DSBs) is the major mechanism to maintain genomic stability in response to irradiation. We hypothesized that genetic polymorphisms in DSB repair genes may affect clinical outcomes among non-small cell lung cancer (NSCLC) patients treated with definitive radio(chemo)therapy. We genotyped six potentially functional single nucleotide polymorphisms (SNPs) (i.e., RAD51 −135G>C/rs1801320 and −172G>T/rs1801321, XRCC2 4234G>C/rs3218384 and R188H/rs3218536 G>A, XRCC3 T241M/rs861539 and NBN E185Q/rs1805794) and estimated their associations with overall survival (OS) and radiation pneumonitis (RP) in 228 NSCLC patients. We found a predictive role of RAD51 −135G>C SNP in RP development (adjusted hazard ratio [HR] = 0.52, 95% confidence interval [CI], 0.31–0.86, P = 0.010 for CG/CC vs. GG). We also found that RAD51 −135G>C and XRCC2 R188H SNPs were independent prognostic factors for overall survival (adjusted HR = 1.70, 95% CI, 1.14–2.62, P = 0.009 for CG/CC vs. GG; and adjusted HR = 1.70; 95% CI, 1.02–2.85, P = 0.043 for AG vs. GG, respectively) and that the SNP-survival association was most pronounced in the presence of RP. Our study suggests that HR genetic polymorphisms, particularly RAD51 −135G>C, may influence overall survival and radiation pneumonitis in NSCLC patients treated with definitive radio(chemo)therapy. Large studies are needed to confirm our findings.