Accelerated Hypofractionated Radiotherapy for Centrally Located Lung Tumours Not Suitable for Stereotactic Body Radiotherapy or Chemoradiotherapy.

AIMS: Accelerated hypofractionated radiotherapy is used at our institution for non-small cell lung cancer (NSCLC) patients not eligible for stereotactic body radiotherapy or chemoradiotherapy. The purpose of this study was to report clinical outcomes of delivering 60 Gy in 15 fractions for these patients. MATERIALS AND METHODS: All NSCLC patients who received 60 Gy in 15 fractions were reviewed. Outcomes of interest were local failure, regional failure, distant progression, overall survival and treatment-associated toxicities. RESULTS: In total, 111 patients were included. The median age was 78.8 years and most tumours were adenocarcinoma (n = 55, 49.6%). Sixty-five patients (58.6%) were N0. The cumulative incidence of local failure at 12 and 24 months in the N0 cohort was 5.2% and 14.2%, respectively, compared with 11.5% and 14.8% for N+ patients. Tumour size >35 mm predicted for local failure (hazard ratio 2.706, 95% confidence interval 1.002-7.307, P = 0.0494). Distant progression at 12 and 24 months in N0 patients was 13.7% and 24.3% compared with 24.6% and 33.5% in N+ patients. In N0 patients, larger tumour size was associated with increased risk of distant progression. The median overall survival was 38.1 months in N0 patients versus 31.7 months in N+ patients. The most common toxicity was radiation pneumonitis (n = 6, 6.4%). The incidence of any grade 3 toxicity was 10.3% at ≥1 year. There were no deaths or hospitalisations attributed to treatment. CONCLUSIONS: Accelerated hypofractionated radiotherapy is well tolerated and resulted in favourable clinical outcomes in various stages of NSCLC patients.

Initial management of small-cell lung cancer (limited- and extensive-stage) and the role of thoracic radiotherapy and first-line chemotherapy: a systematic review.

Background: Patients with limited-stage (ls) or extensive-stage (es) small-cell lung cancer (sclc) are commonly given platinum-based chemotherapy as first-line treatment. Standard chemotherapy for patients with ls sclc includes a platinum agent such as cisplatin combined with the non-platinum agent etoposide. The objective of the present systematic review was to investigate the efficacy of adding radiotherapy to chemotherapy in patients with es sclc and to determine the appropriate timing, dose, and schedule of chemotherapy or radiation for patients with sclc. Methods: The medline and embase databases were searched for randomized controlled trials (rcts) comparing treatment with radiotherapy plus chemotherapy against treatment with chemotherapy alone in patients with es sclc. Identified rcts were also included if they compared various timings, doses, and schedules of treatment for patients with es sclc or ls sclc. Results: Sixty-four rcts were included. In patients with ls sclc, overall survival was greatest with platinum-etoposide compared with other chemotherapy regimens. In patients with es sclc, overall survival was greatest with chemotherapy containing platinum-irinotecan than with chemotherapy containing platinum-etoposide (hazard ratio: 0.84; 95% confidence interval: 0.74 to 0.95; p = 0.006). The addition of radiation to chemotherapy for patients with es sclc showed mixed results. There was no conclusive evidence that the timing, dose, or schedule of thoracic radiation affected treatment outcomes in sclc. Conclusions: In patients with ls sclc, cisplatin-etoposide plus radiotherapy should remain the standard therapy. In patients with es sclc, the evidence is insufficient to recommend the addition of radiotherapy to chemotherapy as standard practice to improve overall survival. However, on a case-by-case basis, radiotherapy might be added to reduce local recurrence. The most commonly used chemotherapy is platinum-etoposide; however, platinum-irinotecan can be considered.

Surgery after chemoradiotherapy in patients with stage III (N2 or N3, excluding T4) non-small-cell lung cancer: a systematic review.

Background: Chemoradiation with curative intent is considered the standard of care in patients with locally advanced, stage iii non-small-cell lung cancer (nsclc). However, some patients with stage iii (N2 or N3, excluding T4) nsclc might be eligible for surgery. The objective of the present systematic review was to investigate the efficacy of surgery after chemoradiotherapy compared with chemoradiotherapy alone in patients with potentially resectable locally advanced nsclc. Methods: A search of the medline, embase, and PubMed databases sought randomized controlled trials (rcts) comparing surgery after chemoradiotherapy with chemoradiotherapy alone in patients with stage iii (N2 or N3, excluding T4) nsclc. Results: Three included rcts consistently found no statistically significant difference in overall survival between patients with locally advanced nsclc who received surgery and chemoradiotherapy or chemoradiotherapy alone. Only one rct found that progression-free survival was significantly longer in patients treated with chemoradiation and surgery (hazard ratio: 0.77; 95% confidence interval: 0.62 to 0.96). In a post hoc analysis of the same trial, the overall survival rate was higher in the surgical group than in matched patients in a chemoradiation-only group if a lobectomy was performed (p = 0.002), but not if a pneumonectomy was performed. Furthermore, fewer treatment-related deaths occurred in patients who underwent lobectomy than in those who underwent pneumonectomy. Conclusions: For patients with locally advanced nsclc, the benefits of surgery after chemoradiation are uncertain. Surgery after chemoradiation for patients who do not require a pneumonectomy might be an option.

Guideline for the Initial Management of Small Cell Lung Cancer (Limited and Extensive Stage) and the Role of Thoracic Radiotherapy and First-line Chemotherapy.

AIMS: We investigated the efficacy of adding radiotherapy to chemotherapy in patients with extensive stage small cell lung cancer (ES-SCLC) and the appropriate timing, dose and schedule of treatment for patients with ES-SCLC or limited stage SCLC (LS-SCLC). MATERIALS AND METHODS: The guideline was developed by Cancer Care Ontario's Program in Evidence-Based Care and by the Lung Cancer Disease Site Group through a systematic review of randomised controlled trials. KEY RECOMMENDATIONS: In patients with LS-SCLC (stage I, II and III), the addition of thoracic radiotherapy to standard chemotherapy is recommended. However, there is no clear evidence to inform definitive recommendations for optimal timing, sequential versus concurrent therapies and optimal dose or regimen. In patients with LS-SCLC, etoposide-cisplatin is the preferred regimen for adults who are being treated with combined modality therapy with curative intent. In patients with ES-SCLC (stage IV), there is insufficient evidence to recommend the addition of thoracic radiotherapy to standard chemotherapy as a standard practice for survival benefit; however, it could be considered on a case-by-case basis to reduce local recurrence. In patients with ES-SCLC, a platinum agent plus etoposide is the preferred regimen for adult patients who are being treated with combined modality therapy. Cisplatin and irinotecan represents an alternative treatment option to this, but is associated with increased rates of adverse events such as diarrhoea.

Guideline for radiotherapy with curative intent in patients with early-stage medically inoperable non-small-cell lung cancer.

OBJECTIVES: For this guideline, we investigated the effectiveness of radiotherapy with curative intent in medically inoperable patients with early-stage non-small-cell lung cancer (nsclc). METHODS: The guideline was developed by Cancer Care Ontario's Program in Evidence-Based Care and by the Lung Cancer Disease Site Group through a systematic review of mainly retrospective studies, expert consensus, and formal internal and external reviews. RECOMMENDATIONS: ■ Stereotactic body radiation therapy (sbrt) with curative intent is an option that should be considered for patients with early-stage, node-negative, medically inoperable nsclc. Qualifying Statements■ Because of the high dose per fraction, the planning process and treatment delivery for sbrt require the use of advanced technology to maintain an appropriate level of safety. Consistent patient positioning and 4-dimensional analysis of tumour and critical structure motion during simulation and treatment delivery are essential.■ Preliminary results for proton-beam therapy have been promising, but the technique requires further clinical study.■ Recommended fractionation schemes for sbrt should result in a biologically effective dose of 100 or greater by the linear quadric model, choosing an α/ß value of 10 [bed10(LQ) ≥ 100]. Qualifying Statements■ Because of the increased risk of treatment-related adverse events associated with centrally located tumours, consideration of tumour size and proximity to critical central structures is required when determining the dose and fractionation.■ Examples of dose-fractionation schemes used in the included studies have been provided.■ Based on the current evidence and the opinion of the authors, radiation doses at bed10(LQ) greater than 146 might significantly increase toxicity and should be avoided.■ Determination of the radiation bed by the linear quadratic model has limitations for the extreme hypofractionated schemes used in sbrt.

Use of the epidermal growth factor receptor inhibitors gefitinib, erlotinib, afatinib, dacomitinib, and icotinib in the treatment of non-small-cell lung cancer: a systematic review.

INTRODUCTION: This systematic review addresses the use of epidermal growth factor receptor (egfr) inhibitors in three populations of advanced non-small-cell lung cancer (nsclc) patients-unselected, selected, and molecularly selected-in three treatment settings: first line, second line, and maintenance. METHODS: Ninety-six randomized controlled trials found using the medline and embase databases form the basis of this review. RESULTS: In the first-line setting, data about the efficacy of egfr tyrosine kinase inhibitors (tkis) compared with platinum-based chemotherapy are inconsistent. Results from studies that selected patients based on clinical characteristics are also mixed. There is high-quality evidence that an egfrtki is preferred over a platinum doublet as initial therapy for patients with an activating mutation of the EGFR gene. The egfrtkis are associated with a higher likelihood of response, longer progression-free survival, and improved quality of life. Multiple trials of second-line therapy have compared an egfrtki with chemotherapy. Meta-analysis of those data demonstrates similar progression-free and overall survival. There is consequently no preferred sequence for second-line egfrtki or second-line chemotherapy. The egfrtkis have also been evaluated as switch-maintenance therapy. No molecular marker could identify patients in whom a survival benefit was not observed; however, the magnitude of the benefit was modest. CONCLUSIONS: Determination of EGFR mutation status is essential to making appropriate treatment decisions in patients with nsclc. Patients who are EGFR mutation-positive should be treated with an egfrtki as first-line therapy. An egfrtki is still appropriate therapy in patients who are EGFR wild-type, but the selected agent should be administered as second- or third-line therapy.

Neoadjuvant chemoradiotherapy and multivisceral resection for primary locally advanced adherent colon cancer: a single institution experience.

BACKGROUND: Although there is an extensive body of literature on the role of neoadjuvant chemoradiotherapy (CRT) in the management of rectal cancer, its role in primary locally advanced adherent colon cancer (LAACC) is unclear. OBJECTIVE: To analyzed the outcomes of neoadjuvant CRT and multivisceral resection in the management of LAACC patietns. METHODS: We retrospectively reviewed our institutional Colorectal Carcinoma Database for 33 patients with potentially resectable, non-metastatic primary LAACC who received neoadjuvant CRT followed by multivisceral resection. CRT consisted of external beam radiation (45-50 Gy in 25 daily fractions) and concurrent 5-FU infusion (225 mg/m(2)/day). RESULTS: There were 21 males and 12 females. Median age was 64 (31-83) and median follow-up was 36 months. All patients had microscopically clear resection margins (R0). Complete pathologic response was documented in 1 patient (3%) and 66% had ypT4b disease. Post-operative complications were observed in 36% of patients with no 30-day mortality. The 3-year overall survival and 3-year disease-free survival were 85.9% and 73.7% respectively. Two patients developed a local recurrence. CONCLUSIONS: Neoadjuvant CRT and en-bloc multivisceral resection may result in high rates of R0 resection and excellent local control with acceptable morbidity and mortality in selected patients with LAACC.

Developing a methodology for three-dimensional correlation of PET-CT images and whole-mount histopathology in non-small-cell lung cancer.

BACKGROUND: Understanding the three-dimensional (3D) volumetric relationship between imaging and functional or histopathologic heterogeneity of tumours is a key concept in the development of image-guided radiotherapy. Our aim was to develop a methodologic framework to enable the reconstruction of resected lung specimens containing non-small-cell lung cancer (NSCLC), to register the result in 3D with diagnostic imaging, and to import the reconstruction into a radiation treatment planning system. METHODS AND RESULTS: We recruited 12 patients for an investigation of radiology-pathology correlation (RPC) in nsclc. Before resection, imaging by positron emission tomography (PET) or computed tomography (CT) was obtained. Resected specimens were formalin-fixed for 1-24 hours before sectioning at 3-mm to 10-mm intervals. To try to retain the original shape, we embedded the specimens in agar before sectioning. Consecutive sections were laid out for photography and manually adjusted to maintain shape. Following embedding, the tissue blocks underwent whole-mount sectioning (4-mum sections) and staining with hematoxylin and eosin. Large histopathology slides were used to whole-mount entire sections for digitization. The correct sequence was maintained to assist in subsequent reconstruction. Using Photoshop (Adobe Systems Incorporated, San Jose, CA, U.S.A.), contours were placed on the photographic images to represent the external borders of the section and the extent of macroscopic disease. Sections were stacked in sequence and manually oriented in Photoshop. The macroscopic tumour contours were then transferred to MATLAB (The Mathworks, Natick, MA, U.S.A.) and stacked, producing 3D surface renderings of the resected specimen and embedded gross tumour. To evaluate the microscopic extent of disease, customized "tile-based" and commercial confocal panoramic laser scanning (TISSUEscope: Biomedical Photometrics, Waterloo, ON) systems were used to generate digital images of whole-mount histopathology sections. Using the digital whole-mount images and imaging software, we contoured the gross and microscopic extent of disease. Two methods of registering pathology and imaging were used. First, selected pet and ct images were transferred into Photoshop, where they were contoured, stacked, and reconstructed. After importing the pathology and the imaging contours to MATLAB, the contours were reconstructed, manually rotated, and rigidly registered. In the second method, MATLAB tumour renderings were exported to a software platform for manual registration with the original pet and ct images in multiple planes. Data from this software platform were then exported to the Pinnacle radiation treatment planning system in DICOM (Digital Imaging and Communications in Medicine) format. CONCLUSIONS: There is no one definitive method for 3D volumetric RPC in nsclc. An innovative approach to the 3D reconstruction of resected nsclc specimens incorporates agar embedding of the specimen and whole-mount digital histopathology. The reconstructions can be rigidly and manually registered to imaging modalities such as ct and pet and exported to a radiation treatment planning system.

Improving observer variability in target delineation for gastro-oesophageal cancer--the role of (18F)fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography.

AIM: To evaluate the effect of the addition of fused positron emission tomography-computed tomography (PET-CT) imaging vs computed tomography alone in the identification of the gross tumour volume (GTV) in patients with gastro-oesophageal carcinoma. MATERIALS AND METHODS: Ten patients with gastro-oesophageal cancer referred for radiation therapy underwent both (18F)fluoro-2-deoxy-d-glucose-PET (FDG-PET) and computed tomography in the treatment position. Image sets were anonymised and co-registered. Six radiation oncologists independently defined the GTV, first using the computed tomography data alone supplemented by standardised clinical and diagnostic imaging information, and second, using co-registered computed tomography and FDG-PET data (PET-CT). The standard deviation for both GTV length and volume (excluding involved lymph nodes) was taken as a measurement of inter-observer and intra-observer variability. Computer software that calculates volume overlap between contours was also used to generate an observer agreement index to compare intra- and inter-observer variability. RESULTS: The addition of FDG-PET imaging decreased the median standard deviation for tumour length from 10 mm (range 8.1-33.3, mean 12.4 mm) for computed tomography alone to 8mm (range 4.4-18.1, mean 8.1 mm) for PET-CT (P = 0.02). Eight of the 10 patients showed an increase in volume of overlap between observers with the addition of FDG-PET imaging to the contouring process (P = 0.05). The average observer agreement index in PET-CT was 72.7% compared with 69.1% when using computed tomography alone. There was significantly less intra-observer variability in all measures when PET-CT was used. The median standard deviation in length improved from 5.3 to 1.8 mm, the median standard deviation in volume improved from 4.5 to 3 cm3 and the median observer agreement index improved from 76.2 to 78.7% when computed tomography alone was compared with PET-CT. The corresponding P values were 0.001, 0.033 and 0.022, respectively. CONCLUSIONS: The addition of FDG-PET to computed tomography-based planning for the identification of primary tumour GTV in patients with gastro-oesophageal carcinoma decreases both inter-observer and intra-observer variability.

A phase I/II study to evaluate the toxicity and efficacy of accelerated fractionation radiotherapy for the palliation of dysphagia from carcinoma of the oesophagus.

AIMS: We hypothesised that accelerated fractionated radiotherapy may provide a good palliative approach for dysphagia relief in patients with incurable oesophageal cancer, significantly reducing the overall duration of treatment, while providing symptom response with an acceptable toxicity profile. A phase I/II accelerated fractionation study was conducted to evaluate the efficacy and toxicity of this approach. MATERIALS AND METHODS: Patients with incurable oesophageal cancer, symptomatic with dysphagia, Eastern Cooperative Oncology Group performance statusor=6 h apart), 5 days a week, over 2 weeks. RESULTS: Of the 39 evaluable patients, the dysphagia response rate was 69% (27/39) with a median response duration of 5.5 months. The median time to response was 4 weeks. Twenty-eight per cent (11/39) of patients had transient worsening in their dysphagia scores. Acute toxicity (weeks 1-8) occurred in 41% (16/39) of patients. An improvement in global quality of life by week 8 was seen in 42% of patients. There were no late neurological sequelae. The median overall survival was 8 (range 1.7-58+) months. CONCLUSION: The ideal palliative regimen should be relatively short, with minimal toxicity, while offering a favourable response profile. Accelerated fractionation fulfils these criteria and is a suitable treatment alternative for the palliation of dysphagia, especially if the goal is to deliver a higher total biological dose within a shorter (2 week) period of time.

Integrating regional and community lung cancer services to improve patient care.

Lung cancer is the leading cause of cancer death in Canada. The organization of health care services is central to the delivery of accessible, high-quality medical care and may be one factor that influences patient outcome. An exciting opportunity arose for clinicians to initiate the redesign of lung cancer services provided by three institutions in the Greater Toronto Area. This qualitative report describes the integrated lung cancer network that they developed, the innovation it has facilitated, and the systematic approach being taken to evaluate its impact. Available clinical resources were deployed to restructure services along patient-centred lines and to provide greater access to the specialist lung cancer team. A non-hierarchical clinical network was established that consolidates the lung cancer team. A multi-institutional and multidisciplinary tumour board and comprehensive thoracic oncology clinics are at its core. This innovative organizational paradigm considers all of the available services at each facility and aims to fully integrate specialists across the three institutions, thereby maximizing resource utilization. We believe that this paradigm may have wider applicability. The network is currently working to complete a current program of further service improvements and to objectively assess its impact on patient outcome.

Observer variation in contouring gross tumor volume in patients with poorly defined non-small-cell lung tumors on CT: the impact of 18FDG-hybrid PET fusion.

PURPOSE: To quantify interobserver variation in gross tumor volume (GTV) localization using CT images for patients with non-small-cell lung carcinoma and poorly defined tumors on CT and to determine whether variability would be reduced if coregistered 2-[18F]fluoro-2-deoxy-d-glucose (FDG)-hybrid positron emission tomography (PET) with CT images were used. METHODS AND MATERIALS: Prospectively, 30 patients with non-small-cell lung carcinoma had CT and FDG-hybrid PET examinations in radiation treatment position on the same day. Images were coregistered using eight fiducial markers. Guidelines were established for contouring GTVs. Three radiation oncologists performed localization independently. The coefficient of variation was used to assess interobserver variability. RESULTS: The size of the GTV defined showed great variation among observers. The mean ratios of largest to smallest GTV were 2.31 and 1.56 for CT only and for CT/FDG coregistered data, respectively. The addition of PET reduced this ratio in 23 of 30 cases and increased it in 7. The mean coefficient of variation for GTV based on the combined modalities was significantly smaller (p < 0.01) than that for CT data only. CONCLUSIONS: High observer variability in CT-based definition of the GTV can occur. A more consistent definition of the GTV can often be obtained if coregistered FDG-hybrid PET images are used.

Phase II study assessing the effectiveness of Biafine cream as a prophylactic agent for radiation-induced acute skin toxicity to the breast in women undergoing radiotherapy with concomitant CMF chemotherapy.

PURPOSE: To assess the efficacy of Biafine cream in preventing Grade 2 acute radiation dermatitis, according to the National Cancer Institute of Canada skin radiation toxicity criteria in patients undergoing concomitant adjuvant chemotherapy and radiotherapy to the breast. METHODS AND MATERIALS: Sixty patients participated in this study. Patients were treated with a lumpectomy followed by concomitant chemotherapy and radiotherapy to the breast. Biafine cream was applied daily, starting on the first day and ending 2 weeks post-radiotherapy. Patients underwent weekly skin assessments throughout radiotherapy and at 2 and 4 weeks after treatment. Outcome measures were assessed using a Skin Assessment Questionnaire that was scored according to the National Cancer Institute of Canada skin radiation toxicity criteria and a self-administered questionnaire that evaluated skin symptoms. RESULTS: The maximum skin toxicity observed during the course of treatment was as follows: less than Grade 2 toxicity, 15% (9 patients); Grade 2, 83% (50 patients); Grade 3, 2% (1 patient); Grade 4, 0% (0 patients). The majority of the radiation dermatitis was observed after 3 weeks of radiotherapy. CONCLUSION: The majority of patients who underwent concomitant chemo- and radiotherapy for breast cancer developed Grade 2 radiation dermatitis with the use of Biafine cream. However, no treatment delays or interruptions were observed because of skin toxicity.

Bcl-2 expression in F-MuLV-induced erythroleukemias: a role for the anti-apoptotic action of Bcl-2 during tumor progression.

Erythroleukemias induced by various strains of Friend virus are multistage malignancies that result from the accumulation of genetic mutations, including the activation of proto-oncogenes and the inactivation of tumor suppressor genes. In this study, we demonstrate that Bcl-2 expression is activated in the majority of F-MuLV-induced erythroleukemia cell lines. In contrast, Bcl-2 was not expressed in any of the FV-P-induced erythroleukemia cell lines and protein levels were low or negligible in FV-A-induced erythroleukemia cell lines examined. In vivo, Bcl-2 expression levels gradually increased in F-MuLV-induced erythroleukemic cells prior to adaptation to culture. High expression of Bcl-2 in F-MuLV-induced erythroleukemic cells was shown to proceed the emergence of p53 mutation suggesting that Bcl-2 expression may delay p53 mutation in the leukemic cells. This is further supported by the demonstration that the majority of F-MuLV-induced erythroleukemia cell lines established from primary tumors induced in p53 mutant mice express low to negligible levels of Bcl-2. We have shown that the high levels of Bcl-2 expression in FV-P-induced erythroleukemic cells inhibited apoptosis induced by etoposide, low serum and p53 expression. Similarly, ectopic Bcl-2 expression within these cells also provided protection from apoptosis induced by etoposide and growth in low serum. These results suggest that the anti-apoptotic action of Bcl-2 may confer a selective in vivo and in vitro growth advantage to F-MuLV-induced erythroleukemic cells, which is not shared by FV-P/FV-A-induced erythroleukemic cells. The observed induction of Bcl-2 expression in vivo constitutes a novel but late oncogenic event associated with the progression of F-MuLV-induced erythroleukemias.

Deep inspiration breath hold to reduce irradiated heart volume in breast cancer patients.

PURPOSE: To evaluate the use of deep inspiration breath hold (DIBH) during tangential breast radiation therapy as a means of reducing irradiated cardiac volume. METHODS AND MATERIALS: The Active Breathing Control (ABC) device designed at William Beaumont Hospital, Michigan was used to quantify the potential benefit of radiation delivery during DIBH for five left-sided breast cancer patients. This device initiates a breath hold at a predefined, reproducible lung volume. For each patient, two CT scans were acquired with and without breath hold, and virtual simulation was performed for regular tangent and wide-tangent techniques. The resulting dose-volume histograms were calculated, and the volume of heart irradiated to 25 Gy or more was assessed. RESULTS: The influence of ABC on irradiated heart volumes varied considerably among the five patients. Three patients with substantial cardiac volume in the treatment field during normal respiration showed a significant dose-volume histogram reduction when deep inspiration was applied, with decreases in the heart volume receiving 25 Gy of more than 40 cc observed. For one patient, deep inspiration reduced irradiated cardiac volumes only with the wide-tangent technique, while one patient showed no substantial irradiated volume decrease. CONCLUSION: A DIBH technique during tangential breast irradiation has the potential to significantly decrease irradiated cardiac volume for suitably selected patients. The magnitude of the impact of the breath hold application depends on patient anatomy, lung capacity, and pulmonary function.

The influence of patient geometry on the selection of chest wall irradiation techniques in post-mastectomy breast cancer patients.

BACKGROUND AND PURPOSE: To evaluate three chest wall (CW) irradiation techniques: wide tangential photon beams, direct appositional electron field and electron arc therapy with regards to target coverage and normal tissue tolerance. MATERIALS AND METHODS: Thirty-two post-mastectomy breast cancer patients were planned using three CW irradiation techniques. Computed tomography (CT) simulation was done on all patients and clinical target, heart and lung volumes were contoured. For each technique, dose distributions and dose-volume histograms (DVH) were calculated. Pass/fail criteria were applied based on volumetric target and critical structure dose coverage. Passing criteria for target was 95% of target receiving 95% of dose using a standard dose of 50 Gy/25 fractions, for heart

Decreased levels of the cell-cycle inhibitor p27Kip1 protein: prognostic implications in primary breast cancer.

Breast cancer is the second leading cause of cancer death in North American women. There is considerable need for reliable prognostic markers to assist clinicians in making management decisions. Although a variety of factors have been tested, only tumor stage, grade, size, hormone receptor status, and S-phase fraction are used on a routine basis. The cell cycle is governed by a family of cyclin-dependent kinases (cdks), which are regulated by associated cyclins and by phosphorylation. p27Kip1, a cyclin-dependent kinase inhibitor, regulates progression from G1 into S phase by binding and inhibiting cyclin/cdks. p27Kip1 protein levels and/or activity are upregulated by growth inhibitory cytokines including transforming growth factor-beta (TGF-beta) and, thus, provide an important link between extracellular regulators and the cell cycle. Loss of p27Kip1, a negative cell-cycle regulator, may contribute to oncogenesis and tumor progression. However, p27Kip1 mutations in human tumors are extremely rare. We have demonstrated by immunohistochemistry that p27Kip1 protein levels are reduced in primary breast cancers and that this is associated with tumor progression in both in situ and invasive lesions. This was confirmed by western analysis, reflected in increased G1/S-phase cyclin-dependent kinase activities and shown to be regulated posttranscriptionally by in situ hybridization. Furthermore, on multivariate analysis, low p27Kip1 is a predictor of reduced disease-free survival. This simple and reliable immunohistochemical assay may become a routine part of breast cancer evaluation and may influence patient management.

p53-independent tumor growth and in vitro cell survival for F-MuLV-induced erythroleukemias.

Retroviral insertional activation of the Fli-1 proto-oncogene is the first genetic event associated with the induction of erythroleukemias by the Friend murine leukemia virus (F-MuLV). Mutations within p53, which are only detected in cell lines established from transplanted tumors, have been previously shown to be associated with the immortalization of erythroleukemic cells in culture. In this study, we have demonstrated that primary erythroleukemic cells grown in liquid culture undergo rapid apoptosis independent of the stabilization of wild-type p53 protein. Further confirmation that the programmed cell death observed for liquid-cultured F-MuLV-induced primary erythroleukemic cells is largely p53 independent was provided by experimentation with a transgenic mouse line containing multiple copies of the dominant negative mutant p53Pro-193 allele. Erythroleukemic cells taken from tumor-bearing transgenic mice expressing high levels of the mutant p53Pro-193 undergo programmed cell death in culture in a manner that is largely identical to that observed for tumor cells derived from nontransgenic littermates. Furthermore, the rate of development of F-MuLV-induced erythroleukemias for both p53Pro-193-transgenic and nontransgenic littermates are similar. Moreover, cytogenetic analysis indicates that primary erythroleukemia cells are diploid, whereas chromosomal aberrations were observed in all established cell lines. These results are consistent with the notion that mutations within the p53 tumor suppressor gene affect genomic stability, subsequently leading to changes in gene expression that are associated with the immortalization of erythroid progenitor cells.

DNA double-strand break induction and rejoining as determinants of human tumour cell radiosensitivity. A pulsed-field gel electrophoresis study.

Measurement of the surviving fraction after 2 Gy (SF2) may predict for local control of the tumour and patients cure, but clonogenic assays are unsuitable for wider clinical application. Promising results have been obtained using DNA damage assays such as pulsed-field gel electrophoresis, PFGE. In the current study, nine human tumour cell lines (SF2, range 0.08-0.62) were studied for DNA double-strand break (dsb) induction and six of these for dsb rejoining using PFGE. Differences in dsb induction, as the slope (+/- SEM) of DNA release per Gy, varied from 1.30 (0.05) to 2.42 (0.17). The dsb induction frequency varied from 3.55 (0.33) to 9.69 (2.18) dsb x 10(-9)/bp/Gy (21-56 dsb/Gy/cell). Variations in the half-time for fast phase (18-60 min) and slow phase (38-445 min) dsb rejoining were observed. Statistically significant correlations were found between SF2 and the slope of the DNA release curve (p = 0.003), DNA release after 10 Gy (p = 0.029) and 20 Gy (p = 0.011) and slow phase dsb rejoining (p = 0.012). While the underlying mechanisms of cell killing remain unclear, PFGF measurement of dsb induction and rejoining shows great potential as a predictive assay for intrinsic cellular radiosensitivity.