The impact of pre-radiotherapy surgery on radiation-induced lung injury.

AIMS: The use of postoperative radiation therapy (PORT) is predicated by an assessment of the potential benefits and risks, including radiation-induced lung injury. In this study, the risk of radiation-induced lung injury is assessed in patients who received PORT, and compared with a group of patients who received radiation without prior surgery, to determine if surgery increases the risk of radiation pneumonitis. MATERIALS AND METHODS: From 1991 to 2003, 251 patients with lung cancer were enrolled into a prospective study to assess radiation-induced lung injury. All patients received three-dimensional-planned, external-beam radiotherapy. One hundred and seventy-seven patients with over 6-months follow-up were eligible. For the current analysis, 49 patients (28%) had surgical intervention before radiotherapy. The rates of Grade 2 symptomatic pneumonitis in subgroups, based on the type of pre-radiation surgery, were computed and compared using Fisher's Exact Test. To consider the confounding factor of irradiated lung volume, patient subgroups were further defined on the basis of the mean lung dose. RESULTS: Surgical procedures included pneumonectomy (n=9), lobectomy (n=16), wedge resection (n=8) and exploration without resection (n=16). Radiation-induced lung injury occurred in 33 out of 177 (19%) patients, including 18% of the surgical group and 19% of the non-surgical group. Additionally, no statistically significant difference was found in the rate of radiation-induced lung injury based on the extent of resection. CONCLUSIONS: The incidence of pneumonitis is similar in the surgical and non-surgical groups. Thus, PORT may be safely given to selected patients after surgical exploration or resection.

Radiation-induced pulmonary toxicity: a dose-volume histogram analysis in 201 patients with lung cancer.

PURPOSE: To relate lung dose-volume histogram-based factors to symptomatic radiation pneumonitis (RP) in patients with lung cancer undergoing 3-dimensional (3D) radiotherapy planning. METHODS AND MATERIALS: Between 1991 and 1999, 318 patients with lung cancer received external beam radiotherapy (RT) with 3D planning tools at Duke University Medical Center. One hundred seventeen patients were not evaluated for RP because of <6 months of follow-up, development of progressive intrathoracic disease making scoring of pulmonary symptoms difficult, or unretrievable 3D dosimetry data. Thus, 201 patients were analyzed for RP. Univariate and multivariate analyses were performed to test the association between RP and dosimetric factors (i.e., mean lung dose, volume of lung receiving >or=30 Gy, and normal tissue complication probability derived from the Lyman and Kutcher models) and clinical factors, including tobacco use, age, sex, chemotherapy exposure, tumor site, pre-RT forced expiratory volume in 1 s, weight loss, and performance status. RESULTS: Thirty-nine patients (19%) developed RP. In the univariate analysis, all dosimetric factors (i.e., mean lung dose, volume of lung receiving >or=30 Gy, and normal tissue complication probability) were associated with RP (p range 0.006-0.003). Of the clinical factors, ongoing tobacco use at the time of referral for RT was associated with fewer cases of RP (p = 0.05). These factors were also independently associated with RP according to the multivariate analysis (p = 0.001). Models predictive for RP based on dosimetric factors only, or on a combination with the influence of tobacco use, had a concordance of 64% and 68%, respectively. CONCLUSIONS: Dosimetric factors were the best predictors of symptomatic RP after external beam RT for lung cancer. Multivariate models that also include clinical variables were slightly more predictive.

Clear cell pleomorphic xanthoastrocytoma: case report.

Pleomorphic xanthoastrocytoma (PXA) is a well-described astrocytic neoplasm with distinctive clinical and pathological features. Although most patients with PXAs are cured by surgical excision, other patients experience malignant progression and tumor recurrence. We describe a 47-year-old woman with a left temporal lobe PXA that had classic histopathological characteristics as well as extensive clear cell and focal papillary changes, and some anaplastic findings. The patient has now suffered two recurrences after complete resection. The case illustrates a rare, previously undescribed histological variant of PXA, with a prominent clear cell and focal papillary morphology. The study of histologically similar cases is needed to determine whether this variant is always associated with a greater likelihood of recurrence.

Using plasma transforming growth factor beta-1 during radiotherapy to select patients for dose escalation.

PURPOSE: The ability to prescribe treatment based on relative risks for normal tissue injury has important implications for oncologists. In non-small-cell lung cancer, increasing the dose of radiation may improve local control and survival. Changes in plasma transforming growth factor beta (TGFbeta) levels during radiotherapy (RT) may identify patients at low risk for complications in whom higher doses of radiation could be safely delivered. PATIENT AND METHODS: Patients with locally advanced or medically inoperable non-small-cell lung cancer received three-dimensional conformal RT to the primary tumor and radiographically involved nodes to a dose of 73.6 Gy (1.6 Gy twice daily). If the plasma TGFbeta level was normal after 73.6 Gy, additional twice daily RT was delivered to successively higher total doses. The maximum-tolerated dose was defined as the highest radiation dose at which < or = one grade 4 (life-threatening) late toxicity and < or = two grade 3 to 4 (severe life-threatening) late toxicities occurred. RESULTS: Thirty-eight patients were enrolled. Median follow-up was 16 months. Twenty-four patients were not eligible for radiation dose escalation beyond 73.6 Gy because of persistently abnormal TGFbeta levels. Fourteen patients whose TGFbeta levels were normal after 73.6 Gy were escalated to 80 Gy (n = 8) and 86.4 Gy (n = 6). In the 86.4-Gy group, dose-limiting toxicity was reached because there were two (33%) grade 3 late toxicities. CONCLUSION: It is feasible to use plasma TGFbeta levels to select patients for RT dose escalation for non-small-cell lung cancer. The maximum-tolerated dose using this approach is 86.4 Gy.

Relating radiation-induced regional lung injury to changes in pulmonary function tests.

PURPOSE: To determine whether the sum of radiotherapy (RT)-induced reductions in regional lung perfusion is quantitatively related to changes in global lung function as assessed by reductions in pulmonary function tests (PFTs). METHODS AND MATERIALS: Two hundred seven patients (70% with lung cancer) who received incidental partial lung irradiation underwent PFTs (forced expiratory volume in 1 s and diffusion capacity for carbon monoxide) before and repeatedly after RT as part of a prospective clinical study. Regional lung function was serially assessed before and after RT by single photon emission computed tomography perfusion scans. Of these, 53 patients had 105 post-RT evaluations of changes in both regional perfusion and PFTs, were without evidence of intrathoracic disease recurrence that might influence regional perfusion and PFT findings, and were not taking steroids. The summation of the regional functional perfusion changes were compared with changes in PFTs using linear regression analysis. RESULTS: Follow-up ranged from 3 to 86 months (median 19). Overall, a significant correlation was found between the sum of changes in regional perfusion and the changes in the PFTs (p = 0.002-0.24, depending on the particular PFT index). However, the correlation coefficients were small (r = 0.16-0.41). CONCLUSIONS: A statistically significant correlation was found between RT-induced changes in regional function (i.e., perfusion) and global function (i.e., PFTs). However, the correlation coefficients are low, making it difficult to relate changes in perfusion to changes in the PFT results. Thus, with our current techniques, the prediction of changes in perfusion alone does not appear to be sufficient to predict the changes in PFTs accurately. Additional studies to clarify the relationship between regional and global lung injury are needed.

Carboplatin/paclitaxel or carboplatin/vinorelbine followed by accelerated hyperfractionated conformal radiation therapy: a preliminary report of a phase I dose escalation trial from the Carolina Conformal Therapy Consortium.

The maximum tolerated dose of conformal radiation therapy delivered at 1.6 Gy bid is being assessed in patients with unresectable stage IIB-IIIB non-small cell lung cancer who have been treated with induction regimens consisting of carboplatin plus paclitaxel or carboplatin plus vinorelbine. Data from the early stages of this parallel phase I study show that the two induction regimens are similar in toxicity and that both induce partial responses in 45% of patients. Both regimens can be followed by conformal radiotherapy using an accelerated hyperfractionated schedule to a dose of at least 80 Gy without experiencing unacceptable toxicity. Key morbidity observed thus far has involved the esophagus. Further cohorts of patients will receive higher doses of conformal radiotherapy (in 6.4 Gy increments) until the maximum tolerated dose is reached.

Phase I trial results of iodine-131-labeled antitenascin monoclonal antibody 81C6 treatment of patients with newly diagnosed malignant gliomas.

PURPOSE: To determine the maximum-tolerated dose (MTD) of iodine-131 ((131)I)-labeled 81C6 antitenascin monoclonal antibody (mAb) administered clinically into surgically created resection cavities (SCRCs) in malignant glioma patients and to identify any objective responses with this treatment. PATIENTS AND METHODS: In this phase I trial, newly diagnosed patients with malignant gliomas with no prior external-beam therapy or chemotherapy were treated with a single injection of (131)I-labeled 81C6 through a Rickham reservoir into the resection cavity. The initial dose was 20 mCi and escalation was in 20-mCi increments. Patients were observed for toxicity and response until death or for a minimum of 1 year after treatment. RESULTS: We treated 42 patients with (131)I-labeled 81C6 mAb in administered doses up to 180 mCi. Dose-limiting toxicity was observed at doses greater than 120 mCi and consisted of delayed neurotoxicity. None of the patients developed major hematologic toxicity. Median survival for patients with glioblastoma multiforme and for all patients was 69 and 79 weeks, respectively. CONCLUSION: The MTD for administration of (131)I-labeled 81C6 into the SCRC of newly diagnosed patients with no prior radiation therapy or chemotherapy was 120 mCi. Dose-limiting toxicity was delayed neurologic toxicity. We are encouraged by the survival and toxicity and by the low 2.5% prevalence of debulking surgery for symptomatic radiation necrosis.

Systemic metastasis in glioblastoma may represent the emergence of neoplastic subclones.

Glioblastomas only rarely metastasize to sites outside the central nervous system, for reasons that are poorly understood. We report the clinicopathological and molecular genetic findings in 6 patients with metastatic glioblastoma. Four patients were under the age of 32 and all but 1 patient died within 2 yr of diagnosis. The number of metastases ranged from 1 to 3. At the time of death, 3 patients had apparent tumor control at their primary site. We evaluated DNA from both primary and metastatic glioblastomas for genetic alterations commonly found in glioblastomas: TP53 mutations, CDKN2A/p16 deletions, EGFR amplification, and allelic loss of chromosomes 1p, 10q and 19q. Four of 6 cases had TP53 mutations and only single cases had EGFR amplification, CDKN2A/p16 deletions, or allelic loss of 1p, 10q and 19q; 2 cases had no detectable genetic alterations. In 2 cases, the primary and metastatic tumors had identical genotypes. Remarkably, however, 2 cases had different TP53 alterations in the primary and metastatic lesions, or among the metastatic tumors, which suggests that some metastatic deposits may represent emergence of subclones that were not necessarily dominant in the primary tumor. The present observations and a review of the recent literature demonstrate that metastatic glioblastomas tend to occur in younger adults who do not follow long clinical courses, and may be characterized by TP53 mutations and differential clonal selection.

Prevalence of germline truncating mutations in ATM in women with a second breast cancer after radiation therapy for a contralateral tumor.

Patients treated with conservative surgery and radiation therapy for early-stage breast cancer develop a contralateral breast cancer at a rate of approximately 0.75% per year. Ataxia-telangiectasia (AT) is an autosomal recessive disease that is characterized by increased sensitivity to ionizing radiation (IR) and cancer susceptibility. Epidemiologic studies have suggested that AT carriers, who comprise 1% of the population, may be at an increased risk for developing breast cancer, particularly after exposure to IR. To test this hypothesis, we analyzed blood samples from 57 patients who developed a contralateral breast cancer at least 6 months after completion of radiation therapy for an initial breast tumor. A cDNA-based truncation assay in yeast was used to test for heterozygous mutations in the ATM gene, which is responsible for AT. No mutations were detected. Our findings fail to support the hypothesis that AT carriers account for a significant fraction of breast cancer cases arising in women after exposure to radiation. Genes Chromosomes Cancer 27:124-129, 2000.

Heterozygous germline ATM mutations do not contribute to radiation-associated malignancies after Hodgkin's disease.

PURPOSE: The successful treatment of Hodgkin's disease has been associated with an increased incidence of secondary malignancies. To investigate whether genetic factors contribute to the development of secondary tumors, we collected family cancer histories and performed mutational analysis of the ataxia-telangiectasia (AT) gene, ATM, in a cohort of Hodgkin's disease survivors with secondary malignancies. ATM was chosen for evaluation because of the increased radiosensitivity of cells derived from AT patients and obligate heterozygotes and the epidemiologic observation that AT carriers are at increased risk for radiation-induced breast cancer. PATIENTS AND METHODS: Fifty-two patients who developed one or more neoplasms after treatment for Hodgkin's disease participated in this study. Personal and family histories of cancer were obtained through patient interviews and review of medical records. ATM mutational analysis was performed using a yeast-based protein truncation assay. RESULTS: Seventy-six secondary neoplasms were observed in this cohort of 52 Hodgkin's disease survivors, with 18 patients (35%) developing more than one secondary neoplasm. Positive family histories of cancer were present in 11 (21%) of 52 patients, compared with three (4%) of 68 Hodgkin's disease patients in a comparison cohort who did not develop secondary neoplasms (P =.008; Fisher's exact test). No germline ATM mutations were identified, resulting in an estimated AT carrier frequency in this population of 0% (90% confidence interval, 0% to 4%). CONCLUSION: Analysis of the number of tumors per individual and the family history of cancer in our cohort suggests that genetic factors may contribute to development of secondary neoplasms in a subset of Hodgkin's disease survivors. Mutational analysis, however, does not support a significant role for heterozygous truncating ATM mutations. Future studies evaluating other genes involved in DNA damage response pathways are warranted.

Novel radiation technologies for malignant gliomas.

Despite the advent of new technologies available for the imaging of brain tumors and the evolution of methods to deliver more focused radiation therapy, most malignant gliomas recur locally. Therapies aimed at increasing local control of gliomas will set the stage for improved survival in a disease with a dismal overall prognosis. This review focuses on several radiotherapeutic approaches to dose escalation that may help improve local control.

Interaction between ATM protein and c-Abl in response to DNA damage.

The gene mutated in the autosomal recessive disorder ataxia telangiectasia (AT), designated ATM (for 'AT mutated'), is a member of a family of phosphatidylinositol-3-kinase-like enzymes that are involved in cell-cycle control, meiotic recombination, telomere length monitoring and DNA-damage response. Previous results have demonstrated that AT cells are hypersensitive to ionizing radiation and are defective at the G1/S checkpoint after radiation damage. Because cells lacking the protein tyrosine kinase c-Abl are also defective in radiation-induced G1 arrest, we investigated the possibility that ATM might interact with c-Abl in response to radiation damage. Here we show that ATM binds c-Abl constitutively in control cells but not in AT cells. Our results demonstrate that the SH3 domain of c-Abl interacts with a DPAPNPPHFP motif (residues 1,373-1,382) of ATM. The results also reveal that radiation-induction of c-Abl tyrosine kinase activity is diminished in AT cells. These findings indicate that ATM is involved in the activation of c-Abl by DNA damage and this interaction may in part mediate radiation-induced G1 arrest.

Activation of the c-Abl tyrosine kinase in the stress response to DNA-damaging agents.

The product of the c-abl gene is a non-receptor tyrosine kinase that is localized to the nucleus and cytoplasm. The precise function of c-Abl is unknown. Here we show that ionizing radiation activates c-Abl. Similar results were obtained with the alkylating agents cis-platinum and mitomycin C. We also demonstrate that cells deficient in c-Abl fail to activate Jun kinase (JNK/SAP kinase) after ionizing radiation or alkylating agent exposure and that reconstitution of c-Abl in these cells restores that response. In contrast, the stress response to tumour-necrosis factor is stimulated by a c-Abl-independent mechanism. These findings indicate that c-abl is involved in the stress response to DNA-damaging agents.

Defective induction of stress-activated protein kinase activity in ataxia-telangiectasia cells exposed to ionizing radiation.

The activity of stress-activated protein (SAP) kinase is stimulated by diverse agents such as tumor necrosis factor, UV light, and protein synthesis inhibitors. The present study demonstrates that ionizing radiation (IR) exposure is also associated with the induction of SAP kinase activity. Cells derived from patients with ataxia-telangiectasia (A-T) are characterized by hypersensitivity to IR. In this study, we demonstrate that IR-induced activation of SAP kinase is defective in A-T cells. In contrast, exposure of A-T cells to UV light or anisomycin results in the induction of SAP kinase activity. These findings indicate that IR-induced signals involved in SAP kinase activation are defective in A-T cells.

Ionizing radiation stimulates a Grb2-mediated association of the stress-activated protein kinase with phosphatidylinositol 3-kinase.

The stress-activated protein (SAP) kinases are induced by tumor necrosis factor, oncoproteins, and UV light. The present studies demonstrate that ionizing radiation (IR) activates p54 SAP kinase. IR-induced activation of SAP kinase is associated with binding to the SH2/SH3-containing adaptor protein Grb2. This interaction is mediated by the SH3 domains of Grb2 and the proline-rich sequence PPPKIP in the carboxy-terminal region of SAP kinase. We also demonstrated that SAP kinase and the p85 alpha-subunit of phosphatidylinositol (PI) 3-kinase form a complex in irradiated cells. The results indicate that this complex involves binding of the p85 alpha subunit of PI 3-kinase to the SH2 domain of Grb2. The functional role of linking SAP kinase to PI 3-kinase is further supported by the finding that wortmannin, an inhibitor of PI 3-kinase, stimulates SAP kinase activity. These results suggest that the cellular response to IR may include regulation of SAP kinase by a PI 3-kinase-dependent signaling pathway.

Activation of the pp90rsk and mitogen-activated serine/threonine protein kinases by ionizing radiation.

The cellular response to ionizing radiation (IR) includes induction of the c-jun and EGR1 early response genes. The present work has examined potential cytoplasmic signaling cascades that transduce IR-induced signals to the nucleus. The results demonstrate activation of the 40S ribosomal protein S6 kinase, pp90rsk, in human U-937 myeloid leukemia cells. Partial purification of pp90rsk by affinity chromatography demonstrated an increase in S6 peptide phosphorylation when comparing irradiated with control cells. IR-induced activation of pp90rsk was further confirmed in immune-complex kinase assays. In contrast to these findings, there was no detectable induction of pp70S6K. Previous work has demonstrated that mitogen-activated protein kinase activates pp90rsk. The present results further show that IR treatment is associated with induction of mitogen-activated protein kinase activity and that this event is temporally related to activation of pp90rsk and early response gene expression. These findings suggest that activation of the mitogen-activated protein kinase/pp90rsk cascade is involved in the response of cells to IR exposure.

Coinduction of c-jun gene expression and internucleosomal DNA fragmentation by ionizing radiation.

Previous work has demonstrated that the cellular response to ionizing radiation includes transcriptional activation of the c-jun early response gene. The present studies demonstrate that this induction of c-jun expression is temporally related to the appearance of internucleosomal DNA fragmentation. These events were maximal at 6 h and transient after exposure to lethal doses (20 Gy) of ionizing radiation. We also demonstrate that N-acetyl-L-cysteine (NAC), an antioxidant, inhibits X-ray-induced c-jun expression and endonucleolytic DNA cleavage. These findings suggested that both events are mediated at least in part through the formation of reactive oxygen intermediates (ROIs). Since ROIs damage DNA and X-ray-induced DNA damage is associated with activation of poly(ADP-ribose) polymerase (ADPRP), we studied the effects of the ADPRP inhibitors 3-aminobenzamide (3-AB), nicotinamide, and theophylline. 3-AB blocked both X-ray-induced c-jun expression and internucleosomal DNA fragmentation. Similar findings were obtained with nicotinamide and theophylline. In contrast, 3-AB had little if any effect on induction of c-jun transcripts or DNA fragmentation induced by the alkylating agent mitomycin C. While c-jun expression is restricted to cells in G1 and G1/S phases, we have found that X-ray-induced c-jun transcripts are detectable throughout all phases of the cell cycle. The induction of internucleosomal DNA fragmentation by X-rays was also detectable throughout the cell cycle. Taken together, these results support the coinduction of c-jun transcription and internucleosomal DNA fragmentation by ionizing radiation. Similar studies were performed with H2O2 since this agent also results in the production of ROIs.(ABSTRACT TRUNCATED AT 250 WORDS)

Tiazofurin induction of mouse erythroleukemia cell hemoglobin production in the absence of commitment or changes in protooncogene expression.

Tiazofurin (2-beta-D-ribofuranosylthiazole-4-carboxamide, NSC 286193), is a synthetic nucleoside inhibitor of inosine monophosphate dehydrogenase and blocks guanine nucleotide biosynthesis. In the present study, we examined the effects of tiazofurin on mouse erythroleukemia (MEL) cell differentiation and protooncogene expression. Tiazofurin induced hemoglobin production in MEL cells in a concentration-dependent manner, as measured by an increase in benzidine staining. Northern blot analysis of MEL cells treated with 7 mumol/L tiazofurin demonstrated accumulation of both alpha- and beta-globin RNA transcripts. This induction of differentiation was blocked by the presence of exogenous guanosine (100 mumol/L). In contrast to the down-regulation of c-myc and c-myb RNA in MEL cells induced by dimethyl sulfoxide (DMSO) or hexamethylene bisacetamide (HMBA), there was no detectable change in levels of these transcripts after tiazofurin treatment. Furthermore, MEL cells induced by tiazofurin did not commit to terminal differentiation. These results suggest a role for guanine nucleotides, at least in part, in the regulation of MEL cell differentiation.

Modulation of cyclic AMP levels and differentiation by adenosine analogs in mouse erythroleukemia cells.

Friend virus-transformed mouse erythroleukemia (MEL) cells can be induced to undergo erythroid differentiation by a variety of compounds, including dimethyl sulfoxide (DMSO) and the adenosine analog xylosyladenine. The present studies have monitored the effects of the stable adenosine receptor ligand N6-phenylisopropyladenosine (PIA) on induction of MEL cell differentiation. PIA has been previously shown to stimulate adenylate cyclase activity in rat hepatic and mouse Leydig 1-10 cells as well as inhibit adenylate cyclase in adipocytes. In the present study, PIA was ineffective as an inducer of the differentiated MEL cell phenotype. However, the results demonstrate that PIA inhibits the induction of MEL cell differentiation by DMSO and xylosyladenine. The extent of this inhibition as determined by benzidine staining, induction of globin RNA, and loss of self-renewal capacity was dependent on PIA concentration. The results also demonstrate that PIA induces a rapid and sustained increase in cyclic AMP (cAMP) levels. Furthermore, there was a highly significant correlation between cAMP levels and inhibition of xylosyladenine-induced differentiation (r = 0.962, P less than 0.0005). This relationship is further supported by the demonstration that prostaglandins E1 and E2 increase MEL cell cAMP levels and inhibit induction of the differentiated MEL cell phenotype. Moreover, PIA inhibited induction of MEL cell differentiation by butyric acid, diazepam, hypoxanthine, and the aminonucleoside analog of puromycin. These results suggest that cAMP may act as a negative regulatory signal in the induction of MEL cell differentiation.