Assessing dose rate distributions in VMAT plans.

Dose rate is an essential factor in radiobiology. As modern radiotherapy delivery techniques such as volumetric modulated arc therapy (VMAT) introduce dynamic modulation of the dose rate, it is important to assess the changes in dose rate. Both the rate of monitor units per minute (MU rate) and collimation are varied over the course of a fraction, leading to different dose rates in every voxel of the calculation volume at any point in time during dose delivery. Given the radiotherapy plan and machine specific limitations, a VMAT treatment plan can be split into arc sectors between Digital Imaging and Communications in Medicine control points (CPs) of constant and known MU rate. By calculating dose distributions in each of these arc sectors independently and multiplying them with the MU rate, the dose rate in every single voxel at every time point during the fraction can be calculated. Independently calculated and then summed dose distributions per arc sector were compared to the whole arc dose calculation for validation. Dose measurements and video analysis were performed to validate the calculated datasets. A clinical head and neck, cranial and liver case were analyzed using the tool developed. Measurement validation of synthetic test cases showed linac agreement to precalculated arc sector times within ±0.4 s and doses ±0.1 MU (one standard deviation). Two methods for the visualization of dose rate datasets were developed: the first method plots a two-dimensional (2D) histogram of the number of voxels receiving a given dose rate over the course of the arc treatment delivery. In similarity to treatment planning system display of dose, the second method displays the dose rate as color wash on top of the corresponding computed tomography image, allowing the user to scroll through the variation over time. Examining clinical cases showed dose rates spread over a continuous spectrum, with mean dose rates hardly exceeding 100 cGy min(-1) for conventional fractionation. A tool to analyze dose rate distributions in VMAT plans with sub-second accuracy was successfully developed and validated. Dose rates encountered in clinical VMAT test cases show a continuous spectrum with a mean less than or near 100 cGy min(-1) for conventional fractionation.

Depletion of the novel p53-target gene carnitine palmitoyltransferase 1C delays tumor growth in the neurofibromatosis type I tumor model.

Despite the prominent pro-apoptotic role of p53, this protein has also been shown to promote cell survival in response to metabolic stress. However, the specific mechanism by which p53 protects cells from metabolic stress-induced death is unknown. Earlier we reported that carnitine palmitoyltransferase 1C (CPT1C), a brain-specific member of a family of mitochondria-associated enzymes that have a central role in fatty acid metabolism promotes cell survival and tumor growth. Unlike other members of the CPT family, the subcellular localization of CPT1C and its cellular function remains elusive. Here, we report that CPT1C is a novel p53-target gene with a bona fide p53-responsive element within the first intron. CPT1C is upregulated in vitro and in vivo in a p53-dependent manner. Interestingly, expression of CPT1C is induced by metabolic stress factors such as hypoxia and glucose deprivation in a p53 and AMP activated kinase-dependent manner. Furthermore, in a murine tumor model, depletion of Cpt1c leads to delayed tumor development and a striking increase in survival. Taken together, our results indicate that p53 protects cells from metabolic stress via induction of CPT1C and that CPT1C may have a crucial role in carcinogenesis. CPT1C may therefore represent an exciting new therapeutic target for the treatment of hypoxic and otherwise treatment-resistant tumors.

High symptom improvement and local tumor control using stereotactic radiotherapy when given early after diagnosis of meningioma. A multicentre study.

PURPOSE: The goal of the present study was to analyze long-term results of fractionated stereotactic radiotherapy (SRT) in patients with a meningioma. METHODS AND MATERIALS: A total of 72 patients treated between 1996 and 2008 in MAASTRO clinic (n = 45) and University Hospital Zurich (n = 27) were included. SRT was given as primary treatment (n = 46), postoperatively (n = 19) or at recurrence (n = 7); 49 tumours (68%) were located in the skull base. Median total dose was 54 Gy. RESULTS: Median follow-up was 4.13 years (range 0.66-11 years). The 3- and 5-year overall survival were 92 and 79% for grade 0 and I meningioma. Progression-free survival for grade 0 and I was 95% at 3 and 5 years, and 40% for grade II and III at 3 years. In 98.4% of patients, clinical symptoms were stable or improved. The majority of symptoms improved within 24 months after SRT. Local control is significantly better if patients are irradiated immediately after diagnosis compared to a watchful waiting policy (p = 0.017). Grade IV toxicity was low (4.2%, n = 3) CONCLUSION: SRT is an effective treatment with high local and clinical control. Early SRT resulted in better outcome than late treatment at progression.

Palliative care education in Swiss undergraduate medical curricula: a case of too little, too early.

Palliative medicine education is an important strategy in ensuring that the needs of terminally ill patients are met. A review was conducted in 2007 of the undergraduate curricula of all five of Switzerland's medical schools to identify their palliative care-related content and characteristics. The average number of mandatory hours of palliative care education is 10.2 h (median 8 h; range 0-27 h), significantly short of the 40 h recommended by the European Palliative Care Association's Education Expert Group. The median time allocated to designated palliative care blocks is 3 h (range 0-8 h). Most of the education occurs before the clinical years, and there are no mandatory clinical rotations. Three schools offer optional clinical rotations but these are poorly attended (<10% of students). Although a number of domains are covered, ethics-related content predominates; 21 of a total of 51 obligatory hours (41%). Communication related to palliative care is largely limited to 'breaking bad news'. In two of the schools, the teaching is done primarily by palliative care physicians and nurses (70% or more of the teaching). In the others, it is done mostly by educators in other clinical specialties and ethics (approximately 90% of the teaching). These findings show significant deficiencies.

Key targets for the execution of radiation-induced tumor cell apoptosis: the role of p53 and caspases.

In many human hematologic and solid malignancies, intrinsic or acquired treatment resistance remains a major obstacle for successful cancer therapy. The molecular understanding of how tumor cells respond to chemotherapy and ionizing radiation is rapidly evolving. Induction of programmed cell death, apoptosis, is one important strategy for successful cancer therapy. This has been shown convincingly for oncogene-transformed normal cells as well as tumor cells of lymphoid origin. However, the relevance of apoptosis in solid human malignancies is less clear. Loss of apoptosis might be linked to specific mutations in the often tissue-specific apoptotic pathways due to aberrations in the stress-related signal transduction cascades. Restoration of a dysfunctional apoptotic program in cancer tissue where apoptosis has been identified as an important mechanism for tissue homeostasis is one rational approach for innovative cancer therapy. In this review, we focus on the relevance of the tumor suppressor p53 for apoptosis-induction and successful cancer therapy outlining the importance of an intact caspase machinery for apoptosis execution. Strategies are discussed to overcome treatment resistance and a high apoptotic threshold in human malignancies where apoptosis is the dominant mode of cell death and the status of p53 is an important determinant for apoptosis induction.

Differential p53-dependent mechanism of radiosensitization in vitro and in vivo by the protein kinase C-specific inhibitor PKC412.

The cellular response to ionizing radiation is governed by the DNA-damage recognition process but is also modulated by cytoplasmic signal transduction cascades that are part of the cellular stress response. Growth-promoting protein kinase C activity antagonizes irradiation-induced cell death, and, therefore, protein kinase C inhibitors might be potent radiosensitizers. The antiproliferative and radiosensitizing effect of the novel N-benzoylated staurosporine analogue PKC412 was tested in vitro against genetically defined p53-wild type (+/+) and p53-deficient (-/-) murine fibrosarcoma cells and in vivo against radioresistant p53-/- murine fibrosarcoma and human colon adenocarcinoma tumor xenograft (SW480, p53-mutated). PKC412 sensitized both p53+/+ and p53-/- tumor cells in vitro and in vivo for treatment with ionizing radiation but with a different mechanism of radiosensitization depending on the p53 status. In p53+/+, cells combined treatment with PKC412 and ionizing radiation drastically induced apoptotic cell death, whereas no apoptosis induction could be observed in p53-deficient cells in vitro and in histological tumor sections. Combined treatment resulted in an increased G2 cell cycle distribution in p53-/- cells at PKC412 concentrations that did not alter cell cycle distribution when applied alone. In vivo, a minimal treatment regimen during 4 consecutive days of PKC412 (4 x 100 mg/kg) in combination with ionizing radiation (4 x 3 Gy) exerted a substantial tumor growth delay for both p53-disfunctional tumor xenografts and showed that the clinically relevant protein kinase C inhibitor PKC412 is a promising new radiosensitizer with a potentially broad therapeutic window.

Is there a role for molecular prognostic factors in the clinical management of ductal carcinoma in situ (DCIS) of the breast?

INTRODUCTION: The incidence of ductal carcinoma of the breast (DCIS) increased in Europe and the US up to 10-fold over the last 20 years ¿8. This could be linked to more vigorous screening mammography, as well as changes of histopathologic and diagnostic criteria for breast lesions during the last decades ¿31,26. Optimal screening for DCIS, the diagnostic procedures and best treatment is still controversial. For many DCIS patients lumpectomy and adjuvant radiotherapy are a valid treatment option. There is need for better prognostic factors in DCIS, which indicate the need for therapy and tailor the intensity of treatment. Recently prognostic factors based on clinical and pathological findings for DCIS were established and are currently validated. Molecular mechanisms involved in DCIS formation, DCIS progression to invasive breast cancer, and predicting DCIS treatment response are rapidly emerging ¿46. RESULTS AND CONCLUSION: Here we discuss some of the known molecular mechanisms of DCIS and how they could be further exploited as prognostic factors for screening and tailoring DCIS therapy. This review will summarize relevant molecular mechanism of DCIS carcinogenesis including dysregulation of the cell cycle clock and changes of the apoptotic threshold. In particular, recently published molecular and cellular abnormalities in DCIS, potentially relevant for treatment decision, will be discussed.

Frequency and severity of sexual harassment in pharmacy practice in Ohio.

OBJECTIVE: To determine the frequency and severity of sexual harassment in the pharmacy workplace for both male and female pharmacists, and to identify: (1) instigators, (2) places of occurrence, and (3) pharmacists' responses. DESIGN: Mailed survey using elements of the Sexual Experience Questionnaire (SEQ). One repeat mailing to nonrespondents. SETTING: Community pharmacies, hospital pharmacies, other pharmacies in the state of Ohio. PATIENTS AND OTHER PARTICIPANTS: 789 randomly selected pharmacists registered in Ohio. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Amount of gender harassment, unwanted sexual attention, and sexual coercion; differences in occurrences of sexual harassment between men and women; identification of instigators as colleagues, patients, or supervisors; identification of place of occurrence as community pharmacy, hospital pharmacy, or elsewhere; pharmacists' responses and reactions. RESULTS: After two mailings, 265 usable surveys were returned for a response rate of 34%. Women differed significantly from men in total occurrences of sexual harassment, with men reporting 183 instances of sexual harassment and women reporting 281 such experiences. Instigators were colleagues (43%), patients (30%), and superiors (27%). Men reported 143 experiences of unwanted sexual attention, whereas women reported 272 such occurrences. Colleagues were responsible for 47% of instances of unwanted sexual attention, patients were responsible for 37%, and superiors 16%. No significant differences were found between men and women in total number of occurrences of sexual coercion. CONCLUSION: Sexual harassment in the workplace has been experienced by both male and female pharmacists. Women experienced more hostile work environment harassment than did men. However, quid pro quo harassment did not differ significantly between the sexes.