Radiation-Induced Brachial Plexopathy (RIBP) after Stereotactic Body Radiotherapy (SBRT): Pooled Analyses of Risks

PURPOSE/OBJECTIVE(S)

RIBP, with symptomatic upper extremity motor or sensory deficits, is a risk after SBRT. We herein model dosimetric factors associated with risks of RIBP of the inferior aspect of the brachial plexus following SBRT for apical lung tumors.

MATERIALS/METHODS

Literature searches (PubMed & Embase databases) were performed to identify reports published from 2000-2021, using search criteria of ["brachial plex*" and stereotactic]. From a PRISMA systematic review, studies were identified that included individual patient data on: (1) RIBP endpoints after SBRT for apical lung tumors; and (2) brachial plexus Dmax, or maximum point doses (i.e., D0.035cc or D0.03cc). These data were amenable to normal tissue complication probability (NTCP) modelling. Doses were converted using the linear-quadratic model with an alpha-beta ratio of 3 Gy. For the probit models, the parameter values were determined using the maximum likelihood method and the 95% confidence intervals (CI) were determined using the profile likelihood method. The ability of the NTCP models to distinguish patients with and without RIBP was evaluated using the area under the curve (AUC).

RESULTS

Two probit NTCP models were derived: one from 3 studies (185 patients with 192 targets and 11 events) and another from 4 studies (221 patients with 229 targets and 18 events). NTCP models (summarized in table) suggest ≈10% risks associated with brachial plexus maximum dose (Dmax) of ∼32-34 Gy in 3 fractions and ∼40-43 Gy in 5 fractions, with a clear dose response. These dose-responses with SBRT (with steep dose gradients beyond the target volume and thus only partial-irradiation of the brachial plexus) are far less steep than those reported following conventionally-fractionated or moderately-hypofractionated radiotherapy used for breast, lung and head and neck cancers (that tend to use radiotherapy fields that circumferentially irradiate the brachial plexus).

CONCLUSION

A dose-response for risk of RIBP after SBRT is observed relative to brachial plexus Dmax. The less-steep dose-response compared to that seen from conventionally-fractionated or moderately-hypofractionated radiotherapy (with large irradiated plexus volumes) suggest a possible volume dependence of RIBP risks. Future work should focus on understanding possible volume effects.

Interpretable Deep Learning Identified the Significance of 1 Gy Volume on Lymphopenia after Radiotherapy in Breast Cancer

PURPOSE/OBJECTIVE(S)

Lymphopenia is common after radiotherapy (RT) and is known for its significance on poor survival outcomes in patients with breast cancer. Previous work has demonstrated the significance of point dosimetric factors like the volume receiving 5 Gy. Considering the full dosimetric data together, this study aimed to develop and validate predictive models for lymphopenia after RT in breast cancer.

MATERIALS/METHODS

Patients with breast cancer treated with radiation therapy in adjuvant setting and with complete dosimetric data were eligible. Combining dose-volume histogram (DVH) dosimetric and clinical factors, dense neural network (DNN) models were developed to predict both the reduction in lymphocyte counts and the graded lymphopenia in breast cancer patients after adjuvant RT. A Shapley additive explanation was applied to explain each feature's directional contributions. The generalization of DNN models was validated in both internal and independent external validation cohorts. P<0.05 was considered to be significant.

RESULTS

A total of 928 consecutive patients with invasive breast cancer were eligible for this study. Treatment volumes of nearly all irradiation dose levels of DVH were significant predictors for lymphopenia after RT, including volumes at very low-dose 1 Gy (V1) of all structures considered including the lung, heart and body. DNN models using full DVH dosimetric and clinical factors were built and a simplified model was further established and validated in both internal and external validation cohorts. This simplified DNN AI model, combining full DVH dosimetric parameters of all OARs and five key clinical factors including baseline lymphocyte counts, tumor stage, RT technique, RT fields and RT fractionation, showed a predictive accuracy of 77% and above.

CONCLUSION

This study demonstrated and externally validated the significance of an AI model of combining clinical and full dosimetric data, especially the volume of low dose at as low as 1 Gy of all critical structures on lymphopenia after RT in patients with breast cancer. The significance of V1 deserves special attention, as modern arc RT technology often has relatively high value of this parameter. Further study warranted for breast cancer RT plan optimization.

Exploration of AI-Assisted On-Board Perfusion Imaging Technique on Patients Undergoing Thoraxradiotherapy

PURPOSE/OBJECTIVE(S)

Pulmonary function of lung cancer patients can significantly change along the radiation therapy (RT) course. Scholars have synthesized lung function maps from computed tomography (CT) images. Still, there is lack of study exploring the feasibility of generating lung perfusion information from cone-beam CT (CBCT). Our study aims to fill up this gap in the body of literatures.

MATERIALS/METHODS

One-hundred-and-six pairs of planning CT and CBCT images of thoracic cancer patients from XX hospital were collected retrospectively. All CT images were registered to CBCT with a deformable algorithm, and referred as deformed planning CT (dCT). A 2D convolutional neural network (CNN) model built with cycle generative adversarial network (cycle-GAN) was trained to correct CBCT image artifacts and HU value discrepancies. The corrected CBCT was named enhanced CBCT (eCBCT) in this study. All CBCT, eCBCT and dCT images were then input to a pre-trained CT-to-perfusion deep learning (DL) model to synthesize perfusion images (PI), namely PICBCT, PIeCBCT and PIdCT respectively. For model training, 80 image pairs were assigned to the training set while others to the testing set. dCT and PIdCT were respectively regarded as the ground truth in two consecutive models. One extra validation case acquired with SPECT perfusion scan was collected for model performance test. Quantitative evaluation was done between the ground truth and the synthesized images. Peak signal-to-noise ratio (PSNR) and mean absolute error (MAE) were computed to assess efficacy of CBCT enhancement. Correlation (R) and Dice similarity coefficient (DSC) were used to evaluate voxel-wise and function-wise concurrence in CBCT-derived perfusion mapping.

RESULTS

In CBCT enhancement, [eCBCT-dCT] pairs demonstrated higher agreement than [CBCT-dCT] pairs. Quantitatively, PSNR and MAE were improved from 21.10±1.60 to 24.08±1.76, and 68.99±13.51 to 47.06±11.31 (p<0.01), respectively. For perfusion translation, higher correlation was demonstrated in both voxel-wise and function-wise evaluation within [PIeCBCT-PIdCT] than [PICBCT-PIdCT]. R correlation increased from 0.84±0.09 to 0.89±0.06 (p<0.01), whereas DSC in high-functional regions increased from 0.77±0.06 to 0.82±0.05 (p<0.01). In the validation case, strong correlation was observed between SPECT perfusion scan and PIeCBCT, with R increasing from 0.57 to 0.65 when compared to PICBCT.

CONCLUSION

We proposed a novel DL framework that synthesized perfusion images from fractionally acquired CBCT. Our framework met the clinical needs in providing real-time lung perfusion maps. It can be used to track the continuously changing pulmonary function status throughout the RT course using routinely scanned CBCT, without additional imaging modalities. The framework can facilitate functionally guided adaptive radiation therapy by providing immediate pulmonary function information.

Single-Cell and Spatial Transcriptomics Revealing the Role of IDO1 in HPV+ Cervical Cancer Tumor Immune Microenvironment and Its Implications in Radiotherapy and Immunotherapy

PURPOSE/OBJECTIVE(S)

Persistent infection of human papillomavirus (HPV) is one major etiology of cervical cancer (CC). By now, anti-PD-1 immunotherapy is approved for advanced CC patients, but the response rate was just about 10-20%, tumor immune microenvironment (TIME) might be one factor that affect the efficacy. The indoleamine 2,3-dioxygenase (IDO), a metabolic immune checkpoint, is recently shown to have a correlation-ship with HPV carcinogenesis in CC, with unknown mechanism. This study, using the single cell transcriptomic single-cell sequencing and spatial transcription sequencing analysis/immunologic technology, aimed to exam the role of IDO1 expression in HPV+ CC TIME and explore the changes after radiotherapy.

MATERIALS/METHODS

Newly diagnosed advanced HPV- CC and HPV+ CC patients were tested for the tumor and tumor immune microenvironment (TIME) heterogeneity and their changes after fractionated radiation therapy. Tumor tissues were collected, single cell suspension was made for Single-cell RNA sequencing (SCRNAseq) using the 10 × Genomics, while frozen tissue was embedded for spatial transcriptome sequencing (STRNAseq). Seurat 4.0 was used to cluster and annotate cell clusters and map SCRNAseq data to the STRNAseq data. The specific characters of cell clusters were computed by Gene Set Enrichment Analysis (GSEA). SPOTLight and CellChat were used to analyze cell location and interaction respectively.

RESULTS

A total of 28631 cells were clustered into 31 cell subsets in HPV- CC and HPV+ CC tissues, including baseline (Pre HPV- CC and Pre HPV+ CC) and 3-week after radiotherapy (Post 3w HPV- CC and Post 3w HPV+CC). There were 10431 epithelial cells (Epi) in all these 4 tumor tissues, with heterogenous IDO1 expression, including IDO1-high Epi, IDO1-low Epi, and IDO1-neg Epi. Interestingly, more than 99% of Epi in Pre HPV- CC tissues were IDO1-neg cells, while more than 99% in Pre HPV+ CC tissue were IDO1-high. Furthermore, the proportion of IDO1-high Epi in Pre HPV+ CC patient dropped to 16.7% after radiotherapy, while the proportion of IDO1-low Epi rase to 63.3%. Using GSEA, the characters of IDO1-high Epi group was shown to have positive regulation of leukocyte chemotaxis and negative regulation of cell adhesion and differentiation. IDO1-high Epi cells also had the hallmark of interferon gamma response. These cells could mainly receive regulative information of interferon gamma pathway from exhausted CD8 T cells, which could affect the apoptosis of tumor cells.

CONCLUSION

This study comprehensively analyzed the immune suppressive role of IDO1-high Epi cells in HPV+ CC TIME at the single-cell transcriptional scale and explored their functional characters in CC radiotherapy. This would be able to provide more evidence to combine with radiotherapy and immunotherapy to improve patients' prognosis.

Combination atezolizumab, bevacizumab, pemetrexed and carboplatin for metastatic EGFR mutated NSCLC after TKI failure

INTRODUCTION

Acquired resistance to TKI is an important unmet need in the management of EGFR mutated lung cancer. Recent clinical trial IMPower150 suggested that combination approach with VEGF inhibitor, check point inhibitor immunotherapy and platinum-based chemotherapy was effective in oncogene driven lung cancer. The current trial examined the efficacy of a modified regimen in an EGFR mutated cohort.

METHODS

An open-labelled, single arm, phase II study was conducted in patients with EGFR mutated NSCLC who had progressed on at least one EGFR TKI. For those with T790M mutation, radiological progression on osimertinib was required for enrolment. Patients were treated with combination atezolizumab (1200 mg), bevacizumab (7.5 mg/kg), pemetrexed (500 mg/m2) and carboplatin (AUC 5) given once every 3 weeks until progression.

RESULTS

Forty patients were enrolled. Median age was 62 (range 45-76) years. More than one half (23/40, 57.5%) had progressed on osimertinib. PD-L1 expression was < 1% in 52.5%. Median follow-up time was 17.8 months. ORR was 62.5%. Median PFS was 9.4 months (95% CI: 7.6 - 12.1). One year OS was 72.5% (95% CI: 0.56-0.83). Treatment related grade 3 or above adverse events (AE) occurred in 37.5% (15/40). Immune-related AE occurred in 32.5% (13/40) patients. Quality of life measures of function and symptoms did not change significantly throughout the course of treatments. Post-trial rechallenge with EGFR TKI containing regimen resulted in PFS of 5.8 months (95% CI 3.9-10.0 months).

CONCLUSION

Combination approach of atezolizumab, bevacizumab, pemetrexed and carboplatin achieved promising efficacy in metastatic EGFR mutated NSCLC after TKI failure. The results were comparable with taxane based regimen of IMPower150 while toxicity profile was improved.

Enhanced therapeutic efficacy and cytotoxicity of doxorubicin-loaded vitamin E – Pluronic micelles against liver cancer

In this study, a new polymeric micelle delivery system was developed to increase the therapeutic efficacy of doxorubicin (DOX) and to reduce its associated side effects.

Predicting the risk of symptomatic radiation-induced lung injury using both the physical and biologic parameters V(30) and transforming growth factor beta

PURPOSE

To correlate the volume of lung irradiated with changes in plasma levels of the fibrogenic cytokine transforming growth factor beta (TGFbeta) during radiotherapy (RT), such that this information might be used to predict the development of symptomatic radiation-induced lung injury (SRILI).

METHODS AND MATERIALS

The records of all patients with lung cancer treated with RT with curative intent from 1991 to 1997 on a series of prospective normal tissue injury studies were reviewed. A total of 103 patients were identified who met the following inclusion criteria: (1) newly diagnosed lung cancer of any histology treated with RT +/- chemotherapy with curative intent; (2) no evidence of distant metastases or malignant pleural effusion; (3) no thoracic surgery after lung RT; (4) no endobronchial brachytherapy; (5) follow-up time more than 6 months; (6) plasma TGFbeta1 measurements obtained before and at the end of RT. The concentration of plasma TGFbeta1 was measured by an enzyme-linked immunosorbent assay. Seventy-eight of the 103 patients were treated with computed tomography based 3-dimensional planning and had dose-volume histogram data available. The endpoint of the study was the development of SRILI (modified NCI [National Cancer Institute] common toxicity criteria).

RESULTS

The 1-year and 2-year actuarial incidence of SRILI for all 103 patients was 17% and 21%, respectively. In those patients whose TGFbeta level at the end of RT was higher than the pre-RT baseline, SRILI occurred more frequently (2-year incidence = 39%) than in patients whose TGFbeta1 level at the end of RT was less than the baseline value (2-year incidence = 11%, p = 0.007). On multivariate analysis, a persistent elevation of plasma TGFbeta1 above the baseline concentration at the end of RT was an independent risk factor for the occurrence of SRILI (p = 0.004). The subgroup of 78 patients treated with 3-dimensional conformal radiotherapy, who consequently had dose-volume histogram data, were divided into groups according to their TGFbeta1 kinetics and whether their V(30) level was above or below the median of 30%. Group I (n = 29), with both a TGFbeta1 level at the end of RT that was below the pre-RT baseline and V(30) < 30%; Group II (n = 35), with a TGFbeta1 level at the end of irradiation that was below the baseline but a V(30) > or = 30% or with a TGFbeta1 level at the end of RT that was above the pre-RT baseline but V(30) < 30%; Group III (n = 14), with both a TGFbeta1 level at the end of RT that was above the baseline and V(30) > or = 30%. A significant difference was found in the incidence of SRILI among these three groups (6.9%, 22.8%, 42.9%, respectively, p = 0.02).

CONCLUSIONS

(1) An elevated plasma TGFbeta1 level at the end of RT is an independent risk factor for SRILI; (2) The combination of plasma TGFbeta1 level and V(30) appears to facilitate stratification of patients into low, intermediate, and high risk groups. Thus, combining both physical and biologic risk factors may allow for better identification of patients at risk for the development of symptomatic radiation-induced lung injury.

Loss of heterozygosity at the mannose 6-phosphate insulin-like growth factor 2 receptor (M6P/IGF2R) locus predisposes patients to radiation-induced lung injury

PURPOSE

To investigate the relationship between loss of heterozygosity (LOH) at the mannose 6-phosphate/insulin-like growth factor 2 receptor (M6P/IGF2R) gene locus and the development of radiation-induced lung injury.

MATERIAL AND METHODS

Thirty-five lung cancer patients with both stored plasma for Transforming Growth Factor beta1 (TGFbeta1) analysis and sufficient quantities of archival pathology tissue to screen for LOH were studied. All patients had been treated with thoracic radiotherapy for their malignancy and had radiographically detectable tumor present before beginning radiotherapy. Tumor and normal cells were microdissected from archival lung cancer pathology specimens. Two polymorphisms in the 3' untranslated region of the M6P/IGF2R were used to screen for LOH. Plasma TGFbeta1 levels were measured using acid-ethanol extraction and an ELISA. TGFbeta1 and M6P/IGF2R protein expression was estimated by immunofluorescence and immunohistochemical staining. Symptomatic radiation pneumonitis was scored according to National Cancer Institute Common Toxicity Criteria without knowledge of the results of TGFbeta or LOH analyses.

RESULTS

Of the 35 patients, 10 were homozygous for this polymorphism (noninformative) and were excluded. Of the 25 informative patients, 13 had LOH. Twelve of 13 patients with LOH had increased pretreatment plasma TGFbeta1 levels, vs. 3/12 patients without LOH (p < 0.01). A decrease or loss of M6P/IGF2R protein in the malignant cell accompanied by increased latent TGFbeta1 protein in extracellular matrix and tumor stroma was found in tumors with LOH, suggesting that this mutation resulted in loss of function of the receptor. Seven of 13 (54%) LOH patients developed symptomatic radiation-induced lung injury vs. 1/12 (8%) of patients without LOH (p = 0.05).

CONCLUSION

Loss of the M6P/IGF2R gene strongly correlates with the development of radiation pneumonitis after thoracic radiotherapy (RT). Furthermore, patients with LOH (in the setting of measurable tumor) are much more likely to have elevated plasma TGFbeta, suggesting an inability to normally process this cytokine. Thus, loss of the M6P/IGF2R gene may predispose patients to the development of radiation-induced lung injury.

M6P/IGF2R is mutated in squamous cell carcinoma of the lung

In addition to the intracellular sorting of lysosomal enzymes, the mannose 6-phosphate/insulin-like growth factor II receptor (M6P/IGF2R) plays a critical role in regulating the bioavailability of extracellular proteolytic enzymes and growth factors. It has also been shown to be mutated in a number of human cancers, and to suppress cancer cell growth. The purpose of this study was to determine if the M6P/IGF2R is mutated in lung cancer, a leading cause of cancer death worldwide. Archival pathology specimens were obtained on 22 patients with newly diagnosed, untreated squamous cell carcinoma of the lung. Two polymorphisms in the 3'-untranslated region of the M6P/IGF2R were used to screen lung tumors for loss of heterozygosity (LOH) by PCR amplification of DNA. Nineteen of 22 (86%) patients were informative (heterozygous), and 11/19 (58%) squamous cell carcinomas of the lung had LOH at the M6P/IGF2R locus. The remaining allele in 6/11 (55%) LOH patients contained mutations in either the mannose 6-phosphate or the IGF2 binding domain of the M6P/IGF2R. Thus, the M6P/IGF2R is mutated frequently in squamous cell carcinoma of the lung, providing further support for its function as a tumor suppressor.

Circulating thrombomodulin during radiation therapy of lung cancer

The endothelial cell glycoprotein, thrombomodulin (TM), is an important physiological anticoagulant. TM is downregulated and released from the cell membrane into the circulation by ionizing radiation and during inflammation. The present study measured plasma TM in 17 patients before, during, and after radiation therapy of lung cancer: nine patients developed radiation pneumonitis, whereas eight matched patients did not. Plasma TM did not change significantly in patients who developed radiation pneumonitis. In contrast, patients who did not develop pneumonitis exhibited a moderate, but statistically significant, decrease in plasma TM antigen during the initial 1-2 weeks, with complete normalization towards the end of treatment. Our study suggests that decreased release of TM during the early phase of radiation therapy may be associated with reduced pulmonary toxicity. The use of plasma TM as a marker of pulmonary toxicity needs further study.

Bacterial cell wall polymers promote intestinal fibrosis by direct stimulation of myofibroblasts

Normal luminal bacteria and bacterial cell wall polymers are implicated in the pathogenesis of chronic intestinal inflammation. To determine the direct involvement of bacteria and their products on intestinal fibrogenesis, the effects of purified bacterial cell wall polymers on collagen and cytokine synthesis were evaluated in intestinal myofibroblast cultures established from normal fetal and chronically inflamed cecal tissues. In this study, the intestines of Lewis rats were intramurally injected with peptidoglycan-polysaccharide polymers. Collagen and transforming growth factor (TGF)-beta1 mRNA levels were measured and correlated with mesenchymal cell accumulation by immunohistochemistry. The direct effects of cell wall polymers on fibrogenic cytokine and collagen alpha1 (type I) expression were evaluated in intestinal myofibroblast cultures. We found that intramural injections of bacterial cell wall polymers induced chronic granulomatous enterocolitis with markedly increased collagen synthesis and concomitant increased TGF-beta1 and interleukin (IL)-6 expression. Intestinal myofibroblast cultures were established, which both phenotypically and functionally resemble the mesenchymal cells that are involved in fibrosis in vivo. Bacterial cell wall polymers directly stimulated collagen alpha1 (I), TGF-beta1, IL-1beta, and IL-6 mRNA expression in the intestinal myofibroblasts derived from both normal and inflamed cecum. Neutralization of endogenous TGF-beta1 inhibited in vitro collagen gene expression. From our results, we conclude that increased exposure to luminal bacterial products can directly activate intestinal mesenchymal cells, which accumulate in areas of chronic intestinal inflammation, thus stimulating intestinal fibrosis in genetically susceptible hosts.

Plasma transforming growth factor beta1 as a predictor of radiation pneumonitis

PURPOSE

To investigate prospectively the utility of plasma transforming growth factor beta1 (TGFbeta1) as a marker for the development of symptomatic radiation pneumonitis.

MATERIALS AND METHODS

Seventy-three patients with lung cancer treated with curative intent are reported herein. Plasma TGFbeta1 samples were obtained before, weekly during, and at each follow-up after radiation therapy (RT). TGFbeta1 was extracted using an acid/ethanol method. An enzyme-linked immunosorbent assay was used to quantify plasma TGFbeta1 concentrations. The TGFbeta1 level at the end of RT was considered "normal" if it was both < or = 7.5 ng/ml and less than the pretreatment value. All patients were followed for at least 6 months, unless symptomatic pneumonitis developed sooner. Pneumonitis was defined by National Cancer Institute (NCI) common toxicity criteria.

RESULTS

Fifteen of the 73 patients (21%) developed symptomatic pneumonitis and the remaining 58 (79%) did not. A normal plasma TGFbeta1 by the end of RT, as defined above, was more common in patients who did not develop pneumonitis. A return of the plasma TGFbeta1 to normal accurately identified patients who would not develop pneumonitis with both a sensitivity and positive predictive value of 90%.

CONCLUSION

Plasma TGFbeta1 levels appear to be a useful means to identify patients at low risk for the development of pneumonitis from thoracic RT. Thus, monitoring of plasma TGFbeta1 levels may identify candidates for dose escalation studies in the treatment of lung cancer.

The relevance of transforming growth factor beta 1 in pulmonary injury after radiation therapy

The maximum dose of radiation which can be delivered to a tumor is limited by the tolerance of the surrounding normal tissues. The ability to identify patients at high or low risk of injury from radiation therapy might enable the clinician to tailor radiation doses in order to maximize efficacy and minimize risk. The cytokine transforming growth factor beta 1 (TGF beta 1) has been implicated in the development of normal tissue injury after irradiation in several organs, including the lung. Herein, the evidence supporting the role of TGF beta 1 in radiation-induced lung injury is reviewed. Using the treatment of non-small cell lung cancer as a model, we also discuss how it may be possible to identify patients at risk for this complication using measurements of plasma TGF beta 1, and how this information may be used in the future to adjust doses of radiation in the treatment of lung cancer.

Endogenous expression of transforming growth factor beta1 inhibits growth and tumorigenicity and enhances Fas-mediated apoptosis in a murine high-grade glioma model

It has been hypothesized that transforming growth factor beta (TGF-beta) may prevent immune-mediated glioma cell elimination; however, previous work has also indicated that increased TGF-beta may lead to reduced proliferation, induction of apoptosis, and enhancement of Fas-induced apoptosis. We have investigated the role of TGF-beta in the progression of malignant glioma using an immunocompetent murine model. SMA 560 malignant glioma cells were stably transfected with constructs that resulted in over- or underproduction of active TGF-beta1. Using these cell lines, we have shown that (a) TGF-beta1 inhibits induction of antitumor cytotoxicity when the tumor cells are given s.c. but not when they are given intracranially; (b) Fas/APO-1 is expressed on SMA 560 cells in vitro and in vivo, SMA 560 cells are susceptible to TGF-beta1- and Fas-induced apoptosis in vitro, and TGF-beta1 and Fas act synergistically to induce glioma cell death; (c) increased levels of endogenous TGF-beta1 production by SMA 560 cells lead to increased sensitivity to Fas-mediated apoptosis; (d) overproduction of endogenous TGF-beta1 reduces the rate of s.c. SMA 560 tumor growth and also reduces the tumorigenicity of tumors located in the central nervous system, with opposite effects observed with underproduction of TGF-beta1 using antisense cell lines; and (e) the observed changes in growth parameters in vivo were associated with increased rates of apoptosis in TGF-beta1-overproducing cells. Taken together, these results indicate that, despite decreased induction of CTL responses, the dominant net effect of TGF-beta1 on the growth of the SMA 560 murine high-grade glioma in vivo is growth inhibition. This contrasts with results seen with non-central nervous system malignant tumors in immunocompetent animals, in which TGF-beta1 production provides a major growth advantage.

Effect of 13-cis-retinoic acid and alpha-interferon on transforming growth factor beta1 in patients with rising prostate-specific antigen

The objective of this study was to test the hypothesis that 13-cis-retinoic acid (CRA) and alpha-interferon (IFN-alpha) have antitumor activity in patients with early recurrence of prostate cancer measured by rising prostate-specific antigen (PSA) after local therapy, and that this activity is associated with the increase of plasma transforming growth factor beta1 (TGF-beta1). Thirty patients with a PSA > 7 ng/ml that increased >0.4 ng/ml/month after initial radiation therapy or a PSA > 2.0 ng/ml after prostatectomy were treated with 1 mg/kg/day of CRA and 3 million units of IFN-alpha administered three times per week. Patients were followed clinically with serum measurements of PSA and assessment of toxicity. Biological activity of CRA and IFN-alpha was assessed by the measurement of plasma TGF-beta1. Twenty-six percent of patients had a partial (50% decrease maintained for 1 month) or minimal (<50% decrease maintained for 1 month) biochemical response of PSA, with a median decrease of 23% (11-55%) at 3 months. Plasma TGF-beta1 levels increased with CRA and IFN-alpha therapy and correlated with a decrease in PSA; patients with a decrease in PSA had a 151% increase in TGF-beta1 compared to 27% in patients without a decrease in PSA (P = 0.04). CRA and IFN-alpha can produce transient reduction or stabilization of PSA. The measurement of plasma TGF-beta1 at 1 month of therapy correlates with changes in PSA and may represent a useful marker for the biological effect of these agents; further analysis in larger numbers of patients and methods to optimize these effects should be explored.

Hyperfractionated accelerated radiation therapy for non-small cell lung cancer: clinical phase I/II trial

PURPOSE

In an attempt to improve local control and survival of nonsmall cell lung cancer (NSCLC), hyperfractionated accelerated radiation therapy (HART) was carried out as a clinical phase I/II trial.

METHODS AND MATERIALS

HART was delivered by 1.1 Gy/fraction, three fractions per day with intervals of 4 h and five treatment days per week. The clinical tumors were irradiated to 74.3 Gy (72.6-75.9)/66-69 fx, 33 days (29-40) (not corrected for lung density), and the subclinical lesions, to 50.0 Gy (48.4-50.6)/44-46 fx, 33 days (29-40). Sixty-nine patients with NSCLC were enrolled in this study. Nine patients were withdrawn from the study during HART due to different reasons. Sixty patients formed the study for outcome analyses. They were 57 males and 3 females with median age of 61 years (21-77). There were 41 cases of squamous cell carcinoma, 15 cases of adenocarcinoma, and 4 cases of large cell carcinoma. Overall, favorable patients (KPS > or = 70, weight loss < 5% and Stages I, II, IIIa) accounted for 73% (44 of 60) of all patients. Forty-four patients (73%) received adjuvant chemotherapy (DDP + VP16) with median cycles of 1.8 before and/or after HART. In order to compare the outcome of HART with conventional irradiation, 50 NSCLC patients treated by conventional fractionated irradiation (CFI) during the same period were chosen as the basis to evaluate relative effects of HART. They derived from the control group of another clinical trial of hyperfractionated irradiation for NSCLC in the same department. They received median tumor dose of 63.9 Gy (62.8-65.0)/34 fx (32-36), 48 days (45-53).

RESULTS

1. Acute and late complications: (a) In HART, 87% of patients (52 cases) developed acute radiation esophagitis: Grade 1-2, 46 cases (77%) and Grade 3, 6 cases (10%), at 2.5 weeks (2-3.5 weeks) after HART began. Five patients with Grade 3 esophagitis had their HART interrupted for <7 days. In CFI, esophagitis was much less (44%,p < 0.05) with 38% of Grade 1-2 and 6% of Grade 3. (b) In HART, acute pulmonary symptoms (RTOG Grade 1-2) occurred in 17% (10 cases), and acute radiation pneumonitis (Grade 3), in 8% (5 cases), while in CFI, they were 24% and 2% (p > 0.05), respectively. Late lung fibrosis (RTOG Grade 1-2) appeared in 20% (12 cases), whereas 18% in CFI (p > 0.05). (c), No other severe acute or late complications have been observed so far in HART. 2. Immediate response. In HART, 20% of patients (12 cases) achieved CR, 60% (36 cases), PR and 20% (12 cases), NR or PD. In CFI, the above three percentages were 10, 28, and 62%, respectively (p < 0.001). 3. Follow-up. The 1-, 2-, and 3-year actuarial survivals were 72, 47, and 28% for HART, and 60, 18, and 6% for CFI, respectively (p < 0.001). Better local control was seen in HART than in CFI with 1-, 2-, and 3-year local control rates being 71, 44, 29%, and 60, 20, and 5%, respectively (p = 0.001). Distant metastases developed less in HART than in CFI. The 1-, 2-, and 3-year distant metastasis rates were 23, 36, and 50% in HART, but 30, 48, and 80% in CFI (p = 0.021).

CONCLUSION

1. HART could be tolerated by most of the favorable NSCLC patients. The predominant complication was acute esophagitis. No other severe acute or late complications have been observed so far. 2. HART resulted in better survivals and local controls, and less distant metastases than CFI.

Physical and biological predictors of changes in whole-lung function following thoracic irradiation

PURPOSE

To develop methods of predicting the pulmonary consequences of thoracic irradiation (RT) by prospectively studying changes in pulmonary function following RT.

METHODS AND MATERIALS

100 patients receiving incidental partial-lung irradiation during treatment of tumors in or adjacent to the thorax had whole-lung function assessed via symptoms and pulmonary function tests (PFTs: FEV1-forced expiratory volume 1 s; DLCO-diffusion capacity) before and repeatedly 6-48 months following RT. All had computed tomography-based three-dimensional (3D) dose calculations with lung density heterogeneity corrections for dose-volume histogram (DVH) and normal tissue complication probability (NTCP) calculations. Functional DVHs (DVfH) based on SPECT (single photon emission computed tomography) lung perfusion scans, and serial transforming growth factor-beta (TGF-beta1) levels were available in 50 and 48 patients, respectively. The incidence and severity of changes in whole-lung function were correlated with clinical, physical, and biological factors. Exploratory statistical analyses were performed using chi-square, Pearson correlations, logistic regression, and multiple linear regression.

RESULTS

RT-induced symptoms developed in 21 patients. In the overall group, the single best predictor for the development of symptoms was the NTCP (p < 0.05). Pre-RT PFTs alone were less predictive (p = 0.1 for FEV1, p = 0.08 for DLCO). A multivariate model based on pre-RT DLCO and CT-based NTCP was strongly predictive for the development of symptoms (p < 0.001). NTCPs based on SPECT-derived DVf Hs and TGF-beta1 levels did not appear to provide additional predictive value. The presence or absence of pulmonary symptoms was correlated with the decline in PFT 6 months following RT (p < 0.05). In the overall group, the degree of decline in PFTs was not well correlated with any of the dose-volume variables considered. In patients with "good" pre-RT PFTs, there was a relationship between the percent reduction in PFT and dose-volume parameters such as the percent of lung volume receiving > 30 Gy (p < 0.05).

CONCLUSION

The extent of alteration in whole-lung function (symptoms or PFT changes) appears to be related to both dose-volume and pre-RT PFT parameters. The data suggest that no one variable is likely to be an adequate predictor and that multivariate predictive models will be needed. Additional studies are underway to develop better predictive models that consider physical factors such as the DVH and regional perfusion, as well as biological/clinical factors such as pre-RT PFTs and TGF-beta1.

Changes in plasma transforming growth factor beta during radiotherapy and the risk of symptomatic radiation-induced pneumonitis

PURPOSE

To determine whether changes in the plasma Transforming Growth Factor beta1 (TGF beta1) concentration during radiotherapy could identify patients at risk for developing symptomatic radiation pneumonitis.

METHODS AND MATERIALS

Thirty-six patients who received radiation therapy with curative intent for lung cancer (n = 31), Hodgkin's disease (n = 4), or thymoma (n = 1) were evaluated prospectively. All patients had serial plasma TGF beta1 measurements obtained before, during, and after treatment. Plasma TGF beta1 was quantified using an enzyme-linked immunosorbent assay. Pneumonitis was defined clinically. Plasma TGF beta1 levels were considered to have normalized if the following occurred: the last on-treatment TGF beta1 level was both <7.5 ng/ml and lower than the pretreatment level.

RESULTS

Thirteen of these 36 patients developed pneumonitis. Significant changes in plasma TGF beta1 levels during treatment were seen only in the subset of patients whose TGF beta1 levels were >7.5 ng/ml at baseline (n = 22). Failure of plasma TGF beta1 to normalize by the end of treatment, as defined above, much more accurately identified patients at risk for symptomatic pneumonitis if their baseline TGF beta1 was >7.5 ng/ml than if it was <7.5 ng/ml.

CONCLUSIONS

Changes in plasma TGF beta1 levels during radiotherapy appears to be a useful means by which to identify patients at risk for the development of symptomatic radiation pneumonitis, particularly in the subset of patients whose pretreatment TGF beta1 levels are >7.5 ng/ml.

Plasma transforming growth factor-beta 1 reflects disease status in patients with lung cancer after radiotherapy: a possible tumor marker

PURPOSE

To determine the frequency with which elevated plasma transforming growth factor-beta 1 (TGF beta 1) concentrations occur in lung cancer patients, to determine the kinetics of TGF beta 1 expression during and after radiotherapy and to correlate plasma TGF beta 1 levels with disease status after treatment.

MATERIALS AND METHODS

Plasma samples were obtained before, during and after radiotherapy in 54 patients with lung cancer and 20 normal controls. Plasma TGF beta 1 levels were measured using an enzyme-linked immunosorbent assay.

RESULTS

Baseline TGF beta 1 levels in lung cancer patients and normal controls were 13.0 +/- 2.5 and 4.4 +/- 0.3 ng/ml, respectively. Elevated TGF beta 1 were found in 50% (27/54) of lung cancer patients. During radiation therapy plasma TGF beta 1 levels declined, however, by the completion of treatment the mean TGF beta 1 level had not normalized in patients with lung cancer. The TGF beta 1 level at last follow-up correlated with disease status in those patients with an increased pretreatment plasma level. Three of four patients with no evidence of cancer had normal follow-up TGF beta 1 levels, compared to 2/16 patients with residual or recurrent tumor (P = 0.02).

CONCLUSIONS

Elevated plasma TGF beta 1 levels occur frequently in patients with lung cancer. In those patients with an elevated plasma TGF beta 1 level at diagnosis, monitoring this level may be useful in detecting both disease persistence and recurrence after therapy.

Bone morphogenetic protein-9 binds to liver cells and stimulates proliferation

A new member of the transforming growth factor (TGF)-beta superfamily, BMP-9, has recently been identified and shown to be expressed in the developing mouse liver. This report demonstrates that human HepG2 liver tumor cells bind recombinant human BMP-9 (rhBMP-9) with high affinity. Cross-linking analysis indicates that HepG2 cells express two BMP-9 receptors of approximately 54 and 80 kilodaltons, similar in size to the Type I and Type II receptors reported by others for TGF-beta and BMP-4. However, cross-competition experiments demonstrate that the BMP-9 receptors on HepG2 cells do not bind other BMPs or TGF-beta s, indicating that these are novel receptors with binding specificity for BMP-9. In functional studies, rhBMP-9 stimulates HepG2 cell proliferation as indicated by [3H]thymidine incorporation and cell counting assays. A proliferative effect of rh-BMP-9 was also observed on primary rat hepatocytes. In contrast, TGF-beta had no effect on HepG2 cell proliferation and inhibited proliferation in primary hepatocytes. These results suggest that BMP-9, acting through a novel set of receptors, may play a regulatory role in hepatic growth and function.

Transforming growth factor-beta receptors and mannose 6-phosphate/insulin-like growth factor-II receptor expression in human hepatocellular carcinoma

OBJECTIVE

The authors examined the expression of transforming growth factor-beta receptor (TGF-beta r) types I and II and the mannose 6-phosphate/insulin-like growth factor-II receptor (M6-P/IGF-IIr) in human hepatocellular carcinoma (HCC).

SUMMARY BACKGROUND DATA

Transforming growth factor-beta (TGF-beta) is part of a superfamily of peptide-signaling molecules that play an important role in modulating cell growth. It is secreted as a latent complex and therefore, must be activated to elicit a biological response. Bioactivation of the TGF-beta complex is facilitated by binding to the M6-P/IGF-IIr. Once activated, TGF-beta exerts its effects by binding to specific cell membrane TGF-beta receptors. The loss of responsiveness of hepatocytes to TGF-beta has been implicated in hepatocarcinogenesis and could result from a loss in the expression of either the TGF-beta receptors or the M6-P/IGF-IIr.

METHODS

Human hepatocellular carcinomas and surrounding normal tissue were collected from operating room samples and snap-frozen in liquid nitrogen (n = 13). Tissues from two tumors were fixed in Omni-fix for sectioning and immunohistochemistry staining for the M6-P/IGF-IIr and TGF-beta 1. RNA was extracted from both normal and malignant liver tissue and analyzed using an RNase protection assay. SDS-PAGE of purified membrane hybridized with 125I-TGF-beta 1 and 125I-IGF-II was used to determine the TGF-beta type I (TGF-betarI) and type II (TGF-beta rII) receptors and M6-P/IGF-IIr protein levels, respectively. Gels were quantitated by phosphorimager, and a paired t test was used for statistical analysis.

RESULTS

In HCC, a 60% (p < 0.01) and 49% (p < 0.02) reduction in the mRNA levels for T beta rI and T beta rII, respectively, relative to the receptor levels in surrounding normal liver, was shown. A similar decrease in the receptor protein levels also was observed. The M6-P/IGF-IIr mRNA and protein levels were reduced in 7 of 11 hepatocellular carcinomas. Immunohistochemical staining demonstrated an absence of intracellular TGF-beta 1 and reduced M6-P/IGF-IIr in the hepatocellular carcinoma cells.

CONCLUSIONS

These results demonstrate that human HCCs have a significantly reduced expression of both the TGF-beta rI- and TGF-beta rII-signaling receptors for TGF-beta. This may provide a selective growth advantage to the HCC by allowing them to escape the mito-inhibitory effects of activated TGF-beta. Furthermore, in the subset of HCC in which the expression of the M6-P/IGF-IIr is downregulated, the bioactivation of TGF-beta also may be impaired.

Elevated plasma transforming growth factor-beta 1 levels in breast cancer patients decrease after surgical removal of the tumor

OBJECTIVE

The authors determined whether untreated breast cancer patients have elevated plasma levels of transforming growth factor-beta 1 (TGF-beta 1).

SUMMARY BACKGROUND DATA

Increased plasma TGF-beta 1 levels recently were found after chemotherapy in patients with advanced breast cancer. However, it currently is unknown whether this elevation in plasma TGF-beta 1 is caused by chemotherapy-induced normal tissue damage or whether it results from the presence of the tumor.

METHODS

An enzyme-linked immunosorbent assay was used to measure plasma TGF-beta 1 levels in 26 newly diagnosed breast cancer patients before and after definitive surgery. Patients were grouped by postoperative tumor status: 1) negative lymph nodes (group 1); 2) positive lymph nodes (group 2); and 3) overt residual disease (group 3). The site of TGF-beta 1 production in the tumors was localized by immunohistochemistry and in situ hybridization.

RESULTS

Plasma TGF-beta 1 levels were elevated preoperatively in 81% of the patients; TGF-beta 2 and TGF-beta 3 were undetectable. The preoperative TGF-beta 1 levels in the three patient groups were similar; however, the postoperative plasma TGF-beta 1 levels differed by disease status. The mean plasma TGF-beta 1 level in group 1 (n = 12) normalized after surgery (19.3 +/- 3.2 vs. 5.5 +/- 1.0 ng/mL, p < 0.001). In contrast, the mean plasma TGF-beta 1 levels remained above normal in both group 2 (n = 9) and group 3 (n = 5) after surgery. Transforming growth factor-beta 1 expression was found to be preferentially increased in the tumor stroma.

CONCLUSIONS

Breast tumors result in increased plasma TGF-beta 1 levels in 81% of patients. After surgical removal of the primary tumor, the plasma TGF-beta 1 level normalizes in the majority of patients; persistently elevated levels correlate with the presence of lymph node metastases or overt residual tumor. These findings suggest that the usefulness of TGF-beta 1 as a potential plasma marker for breast tumors deserves further study.

Short communication: normal tissue injury after cancer therapy is a local response exacerbated by an endocrine effect of TGF beta

The sensitivity of normal tissues rather than of the tumour usually limits the effectiveness of cancer treatment. The normal tissue side effects from chemotherapy and/or radiotherapy result from both direct cellular loss and the extensive fibrosis that develops at the site of injury. Recent evidence suggests that the cytokine, transforming growth factor beta (TGF beta), mediates this fibrogenic process. Herein, we provide evidence in support of the hypothesis that the fibrosis formation following therapy results not only from TGF beta produced locally in the injured normal tissue, but also from circulating TGF beta released by the tumour. Thus, therapy-induced normal tissue damage appears in part to be a local manifestation of a systemic condition.