Integration analysis of tumor metagenome and peripheral immunity data of diffuse large-B cell lymphoma.

Background/purpose: It has been demonstrated that gut microbes are closely associated with the pathogenesis of lymphoma, but the gut microbe landscape and its association with immune cells in diffuse large B-cell lymphoma (DLBCL) remain largely unknown. In this study, we explored the associations between gut microbiota, clinical features and peripheral blood immune cell subtypes in DLBCL. Method: A total of 87 newly diagnosed DLBCL adults were enrolled in this study. The peripheral blood samples were collected from all patients and then submitted to immune cell subtyping using full-spectral flow cytometry. Metagenomic sequencing was applied to assess the microbiota landscape of 69 of 87 newly diagnosed DLBCL patients. The microbiotas and peripheral blood immune cell subsets with significant differences between different National Comprehensive Center Network-International Prognostic Indexes (NCCN-IPIs) (low-risk, low-intermediate-risk, intermediate-high-risk, high-risk) groups were screened. Results: A total of 10 bacterial phyla, 31 orders and 455 bacteria species were identified in 69 patients with newly diagnosed DLBCL. The abundances of 6 bacteria, including Blautia sp.CAG 257, Actinomyces sp.S6 Spd3, Streptococcus parasanguinis, Bacteroides salyersiae, Enterococcus faecalls and Streptococcus salivarius were significantly different between the low-risk, low-intermediate-risk, intermediate-high-risk and high-risk groups, among which Streptococcus parasanguinis and Streptococcus salivarius were markedly accumulated in the high-risk group. The different bacteria species were mostly enriched in the Pyridoxal 5'-phosphate biosynthesis I pathway. In addition, we found that 2 of the 6 bacteria showed close associations with the different immune cell subtypes which were also identified from different NCCN-IPIs. In detail, the abundance of Bacteroides salyersiae was negatively correlated with Treg cells, CD38+ nonrescue exhausted T cells, nature killer 3 cells and CD38+CD8+ effector memory T cells, while the abundance of Streptococcus parasanguinis was negatively correlated with HLA-DR+ NK cells, CD4+ Treg cells, HLA-DR+ NKT cells and HLA-DR+CD94+CD159c+ NKT cells. Conclusion: This study first reveals the gut microbiota landscape of patients with newly diagnosed DLBCL and highlights the association between the gut microbiota and immunity, which may provide a new idea for the prognosis assessment and treatment of DLBCL.

Peripheral immune cell profiling of double-hit lymphoma by mass cytometry.

BACKGROUND: Double-hit or Triple-hit lymphoma (DHL/THL) is a subset of high-grade B cell lymphoma harboring rearrangements of MYC and BCL2 and/or BCL6, and usually associate with aggressive profile, while current therapies tend to provide poor clinical outcomes and eventually relapsed. Further explorations of DHL at cellular and molecular levels are in demand to offer guidance for clinical activity. METHODS: We collected the peripheral blood of DHL patients and diffused large B cell lymphoma (DLBCL) patients from single institute and converted them into PBMC samples. Mass cytometry was then performed to characterize these samples by 42 antibody markers with samples of healthy people as control. We divided the immune cell subtypes based on the expression profile of surface antigens, and the proportion of each cell subtype was also analyzed. By comparing the data of the DLBCL group and the healthy group, we figured out the distinguished immune cell subtypes of DHL patients according to their abundance and marker expression level. We further analyzed the heterogeneity of DHL samples by pairwise comparison based on clinical characteristics. RESULTS: We found double-positive T cells (DPT) cells were in a significantly high percentage in DHL patients, whereas the ratio of double-negative T cells (DNT) was largely reduced in patients. Besides, CD38 was uniquely expressed at a high level on some naïve B cells of DHL patients, which could be a marker for the diagnosis of DHL (distinguishing from DLBCL), or even be a drug target for the treatment of DHL. In addition, we illustrated the heterogeneity of DHL patients in terms of immune cell landscape, and highlighted TP53 as a major factor that contributes to the heterogeneity of the T cells profile. CONCLUSION: Our study demonstrated the distinct peripheral immune cell profile of DHL patients by contrast to DLBCL patients and healthy people, as well as the heterogeneity within the DHL group, which could provide valuable guidance for the diagnosis and treatment of DHL.

The Prognostic Utility of 18F-Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography-Based Analyses of Metabolic Response Rates in Newly Diagnosed Diffuse Large B Cell Lymphoma Patients.

Background: Roughly one third of diffuse large B cell lymphoma (DLBCL) patients experience relapsed or refractory disease, and their prognosis is unsatisfactory. It is thus important to identify patients who respond poorly to first-line treatment. Some studies have evaluated the prognostic value of interim PET-CT (iPET-CT) or end-of-treatment PET-CT (ePET-CT) in lymphoma patients, but there have been few studies exploring the prognostic value of metabolic response rates in the evaluation of DLBCL patients. Methods: Consecutive newly diagnosed DLBCL patients were screened from March 2013 to June 2020. Patients received at least four cycles of chemotherapy, and underwent baseline, iPET-CT and ePET-CT scanning. Kaplan-Meier survival curves with log-rank tests were employed to assess survival outcomes including overall survival (OS) and progression-free survival (PFS). Independent predictors of survival were identified through univariable and multivariable Cox regression analyses. Results: 307 patients were evaluated. At the time of iPET-CT scanning, 250, 45, and 12 patients exhibited complete response (CR), partial response (PR), and stable disease (SD)/progressive disease (PD), respectively. The percentage of negative iPET-CT was 81.4% (250/307). Among 295 patients with ePET-CT, 262 (88.8%) achieved negativity and 33 (11.2%) exhibited positivity including 26 PR and 7 PD. The 2-year PFS and 2-year OS for patients with iPET-CT positivity were 50.7% and 76.5%, respectively, and were significantly shorter than those for patients with iPET-CT negativity (2-year PFS 82.7%, p<0.001; 2-year OS 94.2%, p<0.001). Patients with ePET-CT positivity had significant poorer 2-year PFS (48.1%) and 2-year OS (78.5%) compared with those ePET-CT negativity (2-year PFS 83.8%, p<0.001; 2-year OS 94.9%, p<0.001). The positivity rates on iPET-CT and ePET-CT evaluation were significantly higher in patients in the high/high-intermediate risk group compared with patients in the low/low-intermediate group. In a multivariable analysis, high/high-intermediate international prognostic index (IPI) and ePET-CT positivity were independently associated with poor PFS and OS. Conclusions: Our results suggest that the speed of metabolic response to treatment is of limited prognostic value in newly diagnosed DLBCL patients. Patients exhibiting PR at iPET-CT evaluation should carefully consider whether to change chemotherapy regimen.

High efficacy of PD-1 inhibitor after initial failure of PD-L1 inhibitor in Relapsed/Refractory classical Hodgkin Lymphoma.

PURPOSE: We sought to understand the clinical course and molecular phenotype of patients who showed disease progression after programmed cell death ligand 1 (PD-L1) inhibitor treatment but subsequently responded to PD-1 inhibitor treatment. We also explored the response to PD-1-axis targeted therapy of classical Hodgkin lymphoma (cHL) according to genetically driven PD-L1 and programmed cell death ligand 2 (PD-L2) expression. METHODS: Five patients in a phase II clinical trial of CS1001 (PD-L1 inhibitor) for relapsed or refractory (R/R) cHL were retrospectively reviewed. Formalin-fixed, paraffin-embedded whole tissues from the five patients were evaluated for 9p24.1 genetic alterations based on FISH and the expression of PD-L1, PD-L2, PD-1, major histocompatibility complex (MHC) class I-II, and the tumor microenvironment factorsCD163 and FOXP3 in the microenvironmental niche, as revealed by multiplex immunofluorescence. RESULTS: All five patients showed primary refractory disease during first-line treatment. Four patients received PD-1 inhibitor after dropping out of the clinical trial, and all demonstrated at least a partial response. The progression-free survival ranged from 7 to 28 months (median = 18 months), and 9p24.1 amplification was observed in all five patients at the PD-L1/PD-L2 locus. PD-L1 and PD-L2 were colocalized on Hodgkin Reed-Sternberg (HRS) cells in four of the five (80%) patients. There was differential expression of PD-L1 and PD-L2 in cells in the tumor microenvironment in cHL, especially in HRS cells, background cells and tumor-associated macrophages. CONCLUSIONS: PD-L1 monotherapy may not be sufficient to block the PD-1 pathway; PD-L2 was expressed in HRS and background cells in cHL. The immunologic function of the PD-L2 pathway in anti-tumor activity may be underestimated in R/R cHL. Further study is needed to elucidate the anti-tumor mechanism of PD-1 inhibitor and PD-L1 inhibitor treatment.

Distinct Molecular Subtypes of Diffuse Large B Cell Lymphoma Patients Treated with Rituximab-CHOP Are Associated with Different Clinical Outcomes and Molecular Mechanisms.

OBJECTIVE: Our purpose was to characterize distinct molecular subtypes of diffuse large B cell lymphoma (DLBCL) patients treated with rituximab-CHOP (R-CHOP). METHODS: Two gene expression datasets of R-CHOP-treated DLBCL patients were downloaded from GSE10846 (n = 233, training set) and GSE31312 (n = 470, validation set) datasets. Cluster analysis was presented via the ConsensusClusterPlus package in R. Using the limma package, differential expression analysis was utilized to identify feature genes. Kaplan-Meier survival analysis was presented to compare the differences in the prognosis between distinct molecular subtypes. Correlation between molecular subtypes and clinical features was analyzed. Based on the sets of highly expressed genes, biological functions were explored by gene set enrichment analysis (GSEA). Several feature genes were validated in the molecular subtypes via qRT-PCR and western blot. RESULTS: DLBCL samples were clustered into two molecular subtypes. Samples in subtype I displayed poorer overall survival time in the training set (p < 0.0001). Consistently, patients in subtype I had shorter overall survival (p = 0.0041) and progression-free survival time (p < 0.0001) than those in subtype II. Older age, higher stage, and higher international prognostic index (IPI) were found in subtype I. In subtype I, T cell activation, lymphocyte activation, and immune response were distinctly enriched, while cell adhesion, migration, and motility were significantly enriched in subtype II. T cell exhaustion-related genes including TIM3 (p < 0.001), PD-L1 (p < 0.0001), LAG3 (p < 0.0001), CD160 (p < 0.001), and CD244 (p < 0.001) were significantly highly expressed in subtype I than subtype II. CONCLUSION: Two molecular subtypes were constructed in DLBCL, which were characterized by different clinical outcomes and molecular mechanisms. Our findings may offer a novel insight into risk stratification and prognosis prediction for DLBCL patients.

Bruton's tyrosine kinase inhibitors in primary central nervous system lymphoma-evaluation of anti-tumor efficacy and brain distribution.

BACKGROUND: Primary central nervous system lymphoma (PCNSL) is an aggressive lymphoma confined to central nervous system. Current treatments including surgery, chemotherapy and whole-brain radiotherapy often fail to achieve satisfactory effect, especially in elderly. As a regimen in targeted therapy, Bruton's tyrosine kinase (BTK) inhibitor ibrutinib has been tested in several clinical trials against PCNSL, offering hope for patients unfit for chemotherapy. We aim to evaluate and compare the anti-PCNSL ability of three different BTK inhibitors, ibrutinib, zanubrutinib and tirabrutinib, providing direct evidence for the targeted therapy of PCNSL. METHODS: Retrospective study was done on patients who received ibrutinib-based therapy in our hospital. Cerebrospinal fluid (CSF) from one patient was collected to measure the concentration of ibrutinib. Inhibition assay and apoptosis assay were done on lymphoma cells to determine the anti-tumoral effects of three inhibitors. Pharmacokinetic study was conducted to evaluate their ability in penetrating blood brain barrier and distributing in brain. RESULTS: In retrospective study, we found three patients with PCNSL who had good clinical response to ibrutinib-based therapy (2 complete remission, 1 partial remission), which further support the use of BTK inhibitors in PCNSL. In vitro studies show that ibrutinib has the best anti-tumoral ability among three inhibitors. In vivo study on pharmacokinetic profiles indicate that both ibrutinib and tirabrutinib are good in distributing in brain parenchyma. CONCLUSIONS: In conclusion, our study results suggest that BTK inhibitors can be promising candidates for PCNSL treatment, preferring the use of ibrutinib and tirabrutinib as anti-PCNSL agents among the three inhibitors.

Radiosensitizing effect of c-Met kinase inhibitor BPI-9016M in esophageal squamous cell carcinoma cells in vitro and in vivo.

BACKGROUND: c-Met is the receptor of hepatocyte growth factor (HGF) which plays a key role in inhibiting apoptosis. BPI-9016M is a small-molecule c-Met inhibitor that can promote apoptosis and enhance the cytotoxicity of various DNA-damaging agents. Here, we evaluated the radiosensitizing potential of BPI-9016M in Eca109 human esophageal squamous cell carcinoma (ESCC) cells in vitro and in vivo. METHODS: Cell Counting Kit-8 (CCK-8) assay was used to measure cell viability. Clonogenic survival assay and a murine tumor xenograft in male nude mice were used to evaluate the radiosensitizing effect of BPI-9016M. Apoptosis was determined by the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining and flow cytometry experiment. Apoptosis-related proteins were detected by western blot. By evaluating the activation of the ATR-Chk1/ATM-Chk2 pathway to detect radiation-induced DNA double-strand break and homologous recombination repair. BPI-9016M induced a radiosensitizing effect in Eca109 cells and reduced the survival rate of clone formation in vitro. RESULTS: The combination of BPI-9016M with irradiation (IR) significantly delayed the growth of ESCC tumor xenografts than treatment alone (P<0.05). The radiosensitizing effects of BPI-9016M were due to increased apoptosis, such as the up-regulation of cleaved-caspase 3 and 9, down-regulation of mutant P53 and Bcl-2, the decreased of phosphorylation of ATR and ATM, and the inhibition of γ-H2AX accumulation in vitro and in vivo. CONCLUSIONS: These findings indicated that BPI-9016M exerts a radiosensitizing effect and enhances apoptosis by inhibiting homologous recombination DNA repair in irradiated ESCC cells.

Pretreatment systemic inflammation response index (SIRI) is an independent predictor of survival in unresectable stage III non-small cell lung cancer treated with chemoradiotherapy: a two-center retrospective study.

BACKGROUND: Circulating immune cells influence the efficacy of cancer therapy. This study aimed to investigate the prognostic values of different peripheral blood leukocyte (PBL) biomarkers in non-small lung cancer (NSCLC) patients treated with chemoradiotherapy. METHODS: An independent cohort of 176 stage III NSCLC patients who were diagnosed at Shanghai Pulmonary Hospital and Zhejiang Cancer Hospital between April, 2010, and September, 2018, and had available pretreatment peripheral blood tests was enrolled. The patients were all treated with concurrent or sequential chemoradiotherapy according to international clinical guidelines, with conventional fractionated radical radiotherapy. The receiver operating characteristic curve and the Youden index were used to determine the optional cutoff values of PBL biomarkers for distinguishing prognosis. Univariate and multivariate Cox proportional hazards regression analyses were performed to identify the factors significantly correlated with overall survival. RESULTS: The cohort had a median follow-up time of 21.7 (3.1-121) months. The 3- and 5-year OS rates of all patients were 34.7% and 27.5%, respectively. Univariate analysis showed that gender (P=0.011), smoking (P=0.011), tumor-node-metastasis (TNM) stage (P=0.002), pretreatment peripheral blood neutrophil-to-leukocyte ratio (P=0.013), and systemic inflammation response index (SIRI, P<0.001) were all correlated with OS in NSCLC patients. Moreover, multivariate analysis revealed that TNM stage (HR =1.541, 95% CI: 1.166-2.036, P=0.010) and SIRI (HR =1.868, 95% CI: 1.016-3.436, P=0.018) were significantly and independently associated with OS. However, the median OS of stage IIIB NSCLC patients with low SIRI (≤2.0) was longer than that of stage IIIA NSCLC patients with high SIRI (>2.0) (33.9±4.1 vs. 19.6±2.5 months). CONCLUSIONS: Pretreatment peripheral blood SIRI was found to be a simple independent predictor of OS in stage III NSCLC patients who underwent chemoradiotherapy. As a novel prognostic marker, the prognostic value of the SIRI is superior to that of the NLR. Low SIRI could be a better prognostic stratification factor for NSCLC patients with different TNM stages.

Prophylactic antibiotic treatment with TMP-SMX decreased the incidence of interstitial pneumonia in patients with B-cell lymphoma on chemotherapy.

BACKGROUND: Several studies have reported the incidence of interstitial pneumonia (IP) among patients with non-Hodgkin lymphoma (NHL) that are undergoing combination chemotherapy plus rituximab; however, the effective prophylactic treatment for IP remains unclear. This study aims to explore the prophylactic effect of trimethoprim-sulfamethoxazole (TMP-SMX) on IP and identify IP-associated risk factors in NHL patients. METHODS: Between March 2013 and April 2018, 498 patients (264 males, 53%) with B-cell NHL undergoing first-line RCHOP-like chemotherapy treatment with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone were enrolled in this study. RESULTS: These patients had a median age of 56 years, and 311 of the 498 patients (62.4%) were administered once daily with the prophylactic treatment of TMP-SMX. IP occurred in 65 patients (13.1%), indicating a significant reduction in the IP incidence rate (21.4% vs. 8.0%; p < 0.001). Among patients treated with TMP-SMX, 2 (1.2%) exhibited rashes, 38 (12.2%) suffered from nausea and vomiting, 52 (16.7%) showed signs of neutropenia, and 18 (5.8%) suffered from kidney dysfunction. Both univariate and multivariate analysis showed that gender (male), history of diabetes, and absence of prophylactic TMP-SMX treatment were significant risk factors associated with IP. Disease progression was observed in 55/311 (17.7%) patients that underwent prophylactic TMP-SMX treatment and in 63/187 (33.7%) patients that did not (p < 0.001). CONCLUSIONS: This study revealed that the occurrence of IP was common in B-cell NHL patients undergoing combined chemotherapy plus rituximab treatment. IP could be reduced with prophylactic treatment of once-daily oral TMP-SMX.

Long non-coding RNA NEAT1 serves as a novel biomarker for treatment response and survival profiles via microRNA-125a in multiple myeloma.

BACKGROUND: The present study aimed to explore the association of long non-coding RNA nuclear paraspeckle assembly transcript 1 (lncRNA NEAT1) with multiple myeloma (MM) risk and further investigate its correlation with clinical features, treatment response, survival profiles, and its interaction with microRNA-125a (miR-125a) in MM patients. METHODS: Totally, 114 de novo symptomatic MM patients and 30 healthy donors (as controls) were recruited. Their bone marrow samples were collected before treatment (MM patients) and at enrollment (healthy donors), respectively. Subsequently, plasma cells were isolated from bone marrow for detection of lncRNA NEAT1 and miR-125a expression via reverse transcription quantitative polymerase chain reaction. RESULTS: lncRNA NEAT1 was upregulated in MM patients compared with healthy donors and presented with excellent value in distinguishing MM patients from healthy donors. In MM patients, lncRNA NEAT1 positively associated with International Staging System (ISS) stage, beta-2 microglobulin (ß2-MG), and lactate dehydrogenase (LDH), but not correlated with core cytogenetics and other clinical features. Furthermore, lncRNA NEAT1 negatively associated with complete remission (CR), overall remission rate (ORR), progression-free survival (PFS), and overall survival (OS). Moreover, lncRNA NEAT1 negatively associated with miR-125a in MM patients. MiR-125a was downregulated in MM patients compared with healthy donors, and it negatively associated with ISS stage, ß2-MG, and LDH, but positively correlated with CR, ORR, PFS, and OS in MM patients. CONCLUSION: lncRNA NEAT1 might interact with miR-125a, and serves as a novel biomarker for treatment response and survival profiles in MM, indicating its clinical value for MM management.

A retrospective study of shrinking field radiation therapy during chemoradiotherapy in stage III non-small cell lung cancer.

BACKGROUND: and purpose: This retrospective study aimed to investigate the feasibility of shrinking field radiotherapy during chemoradiotherapy in non-small cell lung cancer (NSCLC). PATIENTS AND METHODS: Ninety-seven patients with stage III NSCLC who achieved a good response to chemoradiation were analyzed. Computed tomography was performed after 40-50 Gy dose radiation to evaluate curative effect. Patients in the shrinking field group underwent resimulation CT scans and shrinking field radiotherapy. Acute symptomatic irradiation-induced pneumonia (ASIP), progression patterns and survival were assessed. RESULTS: Of the 97 patients who achieved response after a median total dose of 60 Gy, fifty patients received shrinking field radiotherapy. The incidence of acute symptomatic irradiation-induced pneumonia tended to be lower for the shrinking field group (18.0% vs. 23.4%, P = 0.51). The rate of disease progression was significantly higher in the non-shrinking than shrinking field group (95.7% vs. 66.0%, P < 0.001). Compared to the non-shrinking field group, the shrinking field group had similar overall survival (30.0 vs. 30.0 months, P = 0.58) but significantly better median progression-free survival (14.0 vs. 11.0 months, P = 0.006). CONCLUSIONS: Shrinking field radiotherapy during chemoradiotherapy in stage III non-small cell lung cancer seems safe with acceptable toxicities and relapse, and potentially spares normal tissues and enables dose escalation. Prospective trials are warranted.

A Retrospective Comparison of Taxane and Fluorouracil-based Chemoradiotherapy in Patients with Inoperable Esophageal Squamous Cell Carcinoma.

PURPOSE: To retrospectively compare taxane-based with fluorouracil-based chemoradiotherapy in terms of toxicity profiles, efficacy and survival in patients with inoperable esophageal cancer. METHODS AND MATERIALS: We analyzed retrospectively 179 consecutive patients who were unresectable or medically unfit for surgery between March 2009 and November 2014. Eight-three patients were included in the taxane group and 96 cases were in the fluorouracil group. RESULTS: The overall response rate (ORR) in the taxane group was higher than fluorouracil group, but was not significantly different (71.6% vs. 63.5%, respectively, P=0.255). In total, 53.0% (44/83) of the patients in the taxane group had progressive disease versus 54.2% (52/96) in the fluorouracil group (not significantly different (P=0.758)). There was no significant difference in overall response rate, progression free survival and overall survival, as well as treatment-related death. In terms of non-hematological toxicity, patients in the taxane group experienced a lower incidence of ≥ grade 3 esophageal perforation or fistula (4.8% vs. 13.5%, P=0.047) and pneumonia (4.8% vs. 9.7%, P=0.242). Regarding hematological toxicity, thrombocytopenia in the taxane group was significantly lower (4.8% vs. 13.5%, P=0.047), but there was a trend towards a higher rate of ≥ grade 3 leukopenia (34.9% vs.26.0%, P=0.196). CONCLUSIONS: Chemoradiation with taxane-based regimens is well tolerated, with potentially promising efficacy, and could become a good alternative treatment in a first line setting for patients with inoperable esophageal squamous cell carcinoma.

Analysis of Clinical and Dosimetric Factors Influencing Radiation-Induced Lung Injury in Patients with Lung Cancer.

PURPOSE: Dose escalation of thoracic radiation can improve the local tumor control and surivival, and is in the meantime limited by the occurrence of radiation-induced lung injury (RILI). This study investigated the clinical and dosimetric factors influencing RILI in lung-cancer patients receiving chemoradiotherapy for better radiation planning. METHODS AND MATERIALS: A retrospective analysis was carried out on 161 patients with non-small-cell or small-cell lung cancer (NSCLC and SCLC, respectively), who underwent chemoradiotherapy between April 2010 and May 2011 with a median follow-up time of 545 days (range: 39-1453). Chemotherapy regimens were based on the histological type (squamous cell carcinoma, adenocarcinoma, or SCLC), and radiotherapy was delivered in 1.8-3.0 Gy (median, 2.0 Gy) fractions, once daily, to a total of 39-66 Gy (median, 60 Gy). Univariate analysis was performed to analyze clinical and dosimetric factors associated with RILI. Multivariate analysis using logistic regression identified independent risk factors correlated to RILI. RESULTS: The incidence of symptomatic RILI (≥grade 2) was 31.7%. Univariate analysis showed that V5, V20, and mean lung dose (MLD) were significantly associated with RILI incidence (P=0.029, 0.048, and 0.041, respectively). The association was not statistically significant for histological type (NSCLC vs. SCLC, P = 0.092) or radiation technology (IMRT vs. 3D-CRT, P = 0.095). Multivariate analysis identified MLD as an independent risk factor for symptomatic RILI (OR=1.249, 95%CI=1.055-1.48, P= 0.01). The incidence of bilateral RILI in cases where the tumor was located unilaterally was 22.7% (32/141) and all dosimetric-parameter values were not significantly different (P>0.05) for bilateral versus ipsilateral injury, except grade-1 (low) RILI (P < 0.05). The RILI grade was higher in cases of ipsilateral lung injury than in bilateral cases (Mann-Whitney U test, z=8.216, P< 0.001). CONCLUSION: The dosimetric parameter, MLD, was found to be an independent predictive factor for RILI. Additional contralateral injury does not seem to be correlated with increased RILI grade under the condition of conventional radiotherapy treatment planning.