Jai Smith

A Pattern of Early Radiation-Induced Inflammatory Cytokine Expression Is Associated with Lung Toxicity in Patients with Non-Small Cell Lung Cancer

Purpose Lung inflammation leading to pulmonary toxicity after radiotherapy (RT) can occur in patients with non-small cell lung cancer (NSCLC). We investigated the kinetics of RT induced plasma inflammatory cytokines in these patients in order to identify clinical predictors of toxicity. Experimental Design In 12 NSCLC patients, RT to 60 Gy (30 fractions over 6 weeks) was delivered; 6 received concurrent chemoradiation (chemoRT) and 6 received RT alone. Blood samples were taken before therapy, at 1 and 24 hours after delivery of the 1st fraction, 4 weeks into RT, and 12 weeks after completion of treatment, for analysis of a panel of 22 plasma cytokines. The severity of respiratory toxicities were recorded using common terminology criteria for adverse events (CTCAE) v4.0. Results Twelve cytokines were detected in response to RT, of which ten demonstrated significant temporal changes in plasma concentration. For Eotaxin, IL-33, IL-6, MDC, MIP-1α and VEGF, plasma concentrations were dependent upon treatment group (chemoRT vs RT alone, all p-values <0.05), whilst concentrations of MCP-1, IP-10, MCP-3, MIP-1β, TIMP-1 and TNF-α were not. Mean lung radiation dose correlated with a reduction at 1 hour in plasma levels of IP-10 (r2 = 0.858, p<0.01), MCP-1 (r2 = 0.653, p<0.01), MCP-3 (r2 = 0.721, p<0.01), and IL-6 (r2 = 0.531, p = 0.02). Patients who sustained pulmonary toxicity demonstrated significantly different levels of IP-10 and MCP-1 at 1 hour, and Eotaxin, IL-6 and TIMP-1 concentration at 24 hours (all p-values <0.05) when compared to patients without respiratory toxicity. Conclusions Inflammatory cytokines were induced in NSCLC patients during and after RT. Early changes in levels of IP-10, MCP-1, Eotaxin, IL-6 and TIMP-1 were associated with higher grade toxicity. Measurement of cytokine concentrations during RT could help predict lung toxicity and lead to new therapeutic strategies.

Failure of T stage to predict survival in patients with non-small-cell lung cancer treated by radiotherapy with or without concomitant chemotherapy

PURPOSE Because T stage does not consistently reflect tumor size in non-small-cell lung cancer (NSCLC), we hypothesized that T stage may be of limited prognostic value in patients with locoregional NSCLC treated by nonsurgical means. METHODS AND MATERIALS The study population consisted of 243 patients with histologically or cytologically proven NSCLC treated in three consecutive prospective trials between 1989 and 1998. The eligibility criteria for this analysis included planned for and began treatment at 60 Gy; Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1; weight loss < or = 10%; no prior treatment; and no supraclavicular nodes, pleural effusion, or distant metastases. In the first study, 204 patients were randomized to receive conventional or accelerated radiotherapy (RT) with or without concomitant carboplatin. In the second, 15 patients were treated with concomitant cisplatin, etoposide, and RT in a single-arm study. In the third, 24 patients were treated with concomitant carboplatin, 5-fluorouracil, and RT in a dose-escalation study. RESULTS A total of 231 patients for whom the T and N stage were known met the eligibility criteria. The patient characteristics were 77% male, 64% squamous histologic features, 33% ECOG status of 0, and 69% no weight loss. The nodal status was 36% N0, 7% N1, 52% N2, and 5% N3. The estimated median survival for all patients was 1.4 years (95% confidence interval 1.2-1.6), with an estimated 10% surviving 5 years (95% confidence interval 7-15). No significant difference was found in survival among the three trials (p = 0.16). The estimated median survival time and 5-year survival rate according to T stage were as follows: T1 (n = 29), 1.6 years and 16%; T2 (n = 88), 1.3 years and 9%; T3 (n = 59), 1.4 years and 9%; and T4 (n = 55), 1.4 years and 9%. No significant trend was found in overall survival according to T stage (p = 0.85, log-rank). To test whether a significant effect of T stage on overall survival existed after adjusting for N stage, trial, ECOG status, and weight loss, a multifactor analysis using Cox proportional hazards regression analysis was carried out. There was still no significant effect of T stage on survival (p = 0.66) when all factors were taken into account. CONCLUSION Although there is some evidence that T stage is an independent prognostic factor in patients with NSCLC treated surgically, it did not appear to be of value in this series of patients treated with RT with and without concomitant chemotherapy.

Radiotherapy for Non-Small Cell Lung Cancer Induces DNA Damage Response in Both Irradiated and Out-of-field Normal Tissues.

Purpose: To study the response of irradiated and out-of-field normal tissues during localized curative intent radiotherapy. Experimental Design: Sixteen patients with non–small cell lung carcinoma (NSCLC) received 60 Gy in 30 fractions of definitive thoracic radiotherapy with or without concurrent chemotherapy. Peripheral blood lymphocytes (PBL) and eyebrow hairs were sampled prior, during, and after radiotherapy. Clinical variables of radiotherapy dose/volume, patient age, and use of chemoradiotherapy were tested for association with γ-H2AX foci, a biomarker of DNA damage that underlies cellular response to irradiation. Results: Radiotherapy induced an elevation of γ-H2AX foci in PBL, representing normal tissues in the irradiated volume, 1 hour after fraction one. The changes correlated directly with mean lung dose and inversely with age. γ-H2AX foci numbers returned to near baseline values in 24 hours and were not significantly different from controls at 4 weeks during radiotherapy or 12 weeks after treatment completion. In contrast, unirradiated hair follicles, a surrogate model for out-of-field normal tissues, exhibited delayed “abscopal” DNA damage response. γ-H2AX foci significantly increased at 24 hours post-fraction one and remained elevated during treatment, in a dose-independent manner. This observed abscopal effect was associated with changes in plasma levels of MDC/CCL22 and MIP-1α/CCL3 cytokines. No concordant changes in size and concentration of circulating plasma exosomes were observed. Conclusions: Both localized thoracic radiotherapy and chemoradiotherapy induce pronounced systemic DNA damage in normal tissues. Individual assessment of biologic response to dose delivered during radiotherapy may allow for therapeutic personalization for patients with NSCLC. Clin Cancer Res; 22(19); 4817–26. ©2016 AACR. See related commentary by Verma and Lin, p. 4763

Tumour targeting of Auger emitters using DNA ligands conjugated to octreotate

Abstract Purpose: The objective of the study was to conjugate the DNA binding ligand para-[125I]-iodoHoechst to octreotate, and to explore the tumour targeting potential of this conjugate in the octreotate-somatostatin receptor system. Methods: We synthesized a Hoechst analogue containing a tri-butylstannyl group in the para position of phenyl ring, conjugated it to the N-terminal amino group of octreotate and prepared 125I-labelled conjugate by iododestannylation. We used the somatostatin receptor (SSTR2) over-expressing cell line A427-7 derived from its parent A427 human non-small cell lung carcinoma cell line to investigate SSTR2 affinity and receptor-mediated internalisation of the conjugate, and the mouse A427-7 tumour xenograft model for in vivo biodistribution studies of the radiolabelled conjugate. Results: A method was developed for convenient preparation of high specific activity radioiodinated conjugate which retains affinity for somatostatin receptors and is internalised into A427-7 SSTR2 over-expressing cells via a receptor-mediated mechanism. The conjugate accumulates in mouse A427-7 tumour xenografts following intravenous administration. Conclusions: A dual targeting strategy for Auger endoradiotherapy, in which a DNA ligand is used to target the Auger decay to DNA, in conjunction with receptor-mediated targeting to specific receptors, using a labelled DNA ligand/peptide conjugate, has been demonstrated for the octreotate-somatostatin receptor system.

Abstract 4826: Mobilization of tumor cells into the circulation during radiation therapy for lung cancer

Thousands of patients die annually with distant metastasis after curative-intent or “radical” radiation therapy (RT). Because non-small cell lung cancer (NSCLC), the most common cause of cancer-related mortality, exhibits an especially high rate of distant metastasis after radical RT or chemo-RT for locoregionally-advanced disease, it represents a suitable model to investigate the relationship between RT and metastasis. We hypothesized that disruption of tumour architecture during RT could result in the release of viable tumor cells into the peripheral circulation. We enumerated circulating tumor cells (CTCs) by fluorescence microscopy of blood samples immunostained with conventional CTC markers. We measured their DNA damage levels using γ-H2AX, a biomarker for radiation-induced DNA double-strand breaks, either by fluorescence-activated sorting (FACS) or by immunofluorescence microscopy. Twenty seven RT-treated NSCLC patients had blood samples analyzed by one or more methods. We identified increased CTC numbers after commencement of RT in 7 of 9 patients treated with palliative RT, and in 4 of 8 patients treated with curative-intent RT. CTCs were also identified, singly and in clumps in large numbers during RT by cytopathologic examination (in all 5 cases studied). Elevated γ-H2AX signal in post-RT blood samples signified the presence of CTCs derived from irradiated tumors. Blood taken after the commencement of RT contained tumor cells that proliferated extensively in vitro (in all 6 cases studied), and first experiments revealed that these cells survive in bloodstream of NOD/SCID mice for several months. CTCs formed γ-H2AX foci in response to ex vivo irradiation providing further evidence of their viability. Although of concern, these findings could represent an opportunity to monitor and target CTCs during RT. They provide a rationale for the development of strategies to reduce the concentration of viable CTCs by modulating RT fractionation or by co-administering systemic therapies. Citation Format: Michael MacManus, Robin Anderson, Prudence Russell, Ashley Cox, Agnieszka Swierczak, Judy P. Doherty, Daphne Jacobs, Jai Smith, Shankar Siva, Patricia E. Daly, David L. Ball, Roger F. Martin, Olga A. Martin. Mobilization of tumor cells into the circulation during radiation therapy for lung cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4826. doi:10.1158/1538-7445.AM2014-4826