| 61. |
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| 62. |
- Jestin, Pia, 1955-
(författare)
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Colorectal Cancer : Audit and Health Economy in Colorectal Cancer Surgery in a Defined Swedish Population
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Colorectal cancer is one of the most common malignancies in Sweden, with more than 5000 new cases annually. Median age at time of diagnosis is approximately 75 years. Owing to the ageing population, the incidence of colorectal cancer is increasing. The improvement in surgical technique and the introduction of adjuvant radio- and chemotherapy increased the 5-year survival rate from approximately 30-40% in the early 1960s to almost 60% in the late 1990s. The cost of public health care has risen considerably, and case-costing systems are increasingly demanded. Linked to clinical guidelines and quality registers, such control systems form a proper basis for quality assurance projects and improvement. The aim of this thesis is to describe the efficiency and cost effectiveness of colorectal cancer treatment in a defined Swedish population. Emergency surgery for colon cancer, constituting 25% of the cases, increased both mortality and cost. Among emergency cases there was not only an increase in postoperative mortality but also a stage specific decrease in long-term survival rate. Correct staging is decisive for further treatment of patients after colon cancer surgery and influences long-term survival. The number of lymph nodes examined varied between different pathology departments and could be used as a quality measurement. The proportion of tumour stage III increased the more nodes examined. A prognostic estimation of stage III cases that is less sensitive to the number of nodes examined is proposed. A case-control study aimed at identifying risk factors for anastomotic leakage after rectal cancer surgery confirmed previously known risk factors but failed to identify further steps during the perioperative course that were amenable to improvement. This research has confirmed that population-based quality and case-costing registers, linked to clinical guidelines, constitute a proper source for projects of quality improvement and decisions about distribution of resources in health care.
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| 63. |
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| 64. |
- Jestin, Pia, et al.
(författare)
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Emergency surgery for colonic cancer in a defined population
- 2005
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Ingår i: British Journal of Surgery. - : Oxford University Press (OUP). - 0007-1323 .- 1365-2168. ; 92:1, s. 94-100
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The aim of this study was to identify risk factors in emergency surgery for colonic cancer in a large population and to investigate the economic impact of such surgery. METHODS: Data from the colonic cancer registry (1997-2001) of the Uppsala/Orebro Regional Oncological Centre were analysed and classified by hospital category. Some 3259 patients were included; 806 had an emergency and 2453 an elective procedure. Data for calculating effects on health economy were derived from a national case-costing register. RESULTS: Patients who had emergency surgery had more advanced tumours and a lower survival rate than those who had an elective procedure (5-year survival rate 29.8 versus 52.4 per cent; P < 0.001). There was a stage-specific difference in survival, with poorer survival both for patients with stage I and II tumours and for those with stage III tumours after emergency compared with elective surgery (P < 0.001). Emergency surgery was associated with a longer hospital stay (mean 18.0 versus 10.0 days; P < 0.001) and higher costs (relative cost 1.5 (95 per cent confidence interval 1.4 to 1.6)) compared with elective surgery. The duration of hospital stay was the strongest determinant of cost (r(2) = 0.52, P < 0.001). CONCLUSION: Emergency surgery for colonic cancer is associated with a stage-specific increase in mortality rate.
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| 65. |
- Johansson, Birgitta, et al.
(författare)
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Health-related quality of life and distress in cancer patients : results from a large randomised study
- 2008
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Ingår i: British Journal of Cancer. - : Springer Science and Business Media LLC. - 0007-0920 .- 1532-1827. ; 99:12, s. 1975-1983
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Tidskriftsartikel (refereegranskat)abstract
- To compare the effectiveness of individual support, group rehabilitation and a combination of the two in improving health-related quality of life (HRQOL) and psychological well-being in cancer patients during 24 months after diagnosis, as compared with standard care (SC). Furthermore, to compare the study sample and a random sample of the Swedish population with regard to HRQOL. A total of 481 consecutive patients, newly diagnosed with cancer, were randomly assigned to one of the four alternatives. Data on HRQOL and psychological well-being were collected at baseline and after 3, 6, 12 and 24 months. The interventions did not improve HRQOL or psychological well-being, as compared with SC. At 3 months, the study sample reported an HRQOL comparable with the normal population. Many cancer patients are able to manage their cancer-related concerns with the support available from SC. However, it is reasonable to assume that the findings suffer from a lack of data from especially vulnerable patients and a possible Hawthorne effect. It cannot be concluded that cancer patients have no need for additional psychosocial interventions. Future projects should include screening and target interventions for those at risk for significant and prolonged psychological distress.
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| 66. |
- Johansson, Jonas, 1970-
(författare)
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Comparative Treatment Planning in Radiotherapy and Clinical Impact of Proton Relative Biological Effectiveness
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The development of new irradiation techniques is presently a very active field of research with increased availability of more sophisticated modalities such as intensity modulated photons (IMRT), protons and light ions. The primary aim of this work is to evaluate if the dose-distributions using IMRT and protons contribute to clinical advantages. A secondary aim is to investigate the potential clinical implication of the increased relative biological effect (RBE) for protons at the end of the Bragg peak. The potential benefits are evaluated using physical dose measures and dose-response models for normal tissue complication probability (NTCP) and tumour control probability (TCP). Comparative treatment planning was performed using three locally advanced tumour types, left-sided node positive breast cancer, hypopharyngeal cancer, and rectal cancer. All studies showed that both IMRT and protons could improve the dose distributions compared to 3D-CRT, and significantly improve treatment results with lower NTCPs and, concerning hypopharyngeal cancer, higher TCP. Protons always resulted in smaller volumes receiving intermediate and low radiation doses.Using protons or IMRT for left-sided node-positive breast cancer, the advantage is a significantly decreased risk for cardiac mortality (from 6.7% to 1%) and radiation induced pneumonitis (from 28.2% to less than 3%) compared to 3D-CRT. For hypopharyngeal cancer, protons and IMRT provide more selective treatment plans, higher TCP since a simultaneous boost technique is feasible, and better parotid gland sparing for several patients. For locally advanced rectal cancer, the NTCP for small bowel is potentially reduced by approximately 50% using IMRT or protons; protons have an even greater potential if the structure of the small bowel is parallel.A variable RBE correction is developed and applied to a clinical proton treatment plan. A significant difference is obtained compared to the commonly accepted RBE correction of 1.1. This indicates that a variable RBE may be of importance in future proton treatment planning.This thesis provides support for increased use both IMRT and proton radiotherapy, although stronger for protons. Therefore, investments in proton facilities with capacity for large clinical trials can be supported.
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| 67. |
- Kettis, Åsa, et al.
(författare)
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Patients'and doctors' views of using the schedule for individual quality of life in clinical practice.
- 2007
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Ingår i: JOURNAL OF SUPPORTIVE ONCOLOGY. - 1544-6794. ; 5:6, s. 281-287
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Tidskriftsartikel (refereegranskat)abstract
- This study explored patients’ and oncologists’ perceptions ofusing a computer-administered, individualized quality-of-life (QOL) in-strument to support an oncologic consultation. Twenty patients with gas-trointestinal cancer (50% female; mean age 60 years) at two hospitals inSweden completed the Schedule for the Evaluation of Individual Quality ofLife-Direct Weight (SEIQoL–DW) and the Disease-Related (DR) SEIQoL-DWand brought the results to the consultation. Afterwards, interviews wereconducted with all patients and six of eight doctors. All interviews wereaudiotaped, transcribed, and analyzed using an interpretivist approach.Most patients and doctors believed that the instrument would facilitatedetection of patients’ areas of concern and would support monitoringof patients’ QOL. This tool may empower the patient, give the doctor abroader picture of the patient, and influence clinical decision-making. TheSEIQoL-DW may be a systematic method of stimulating patient-centeredcare. It apparently encourages patients to reflect upon their own situationand allows them to be seen as whole persons. However, further quantita-tive evaluation of the intervention’s outcomes is required.
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| 68. |
- Kimstrand, Peter, et al.
(författare)
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A beam source model for scanned proton beams
- 2007
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Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 0031-9155 .- 1361-6560. ; 52:11, s. 3151-3168
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Tidskriftsartikel (refereegranskat)abstract
- A beam source model, i.e. a model for the initial phase space of the beam, for scanned proton beams has been developed. The beam source model is based on parameterized particle sources with characteristics found by fitting towards measured data per individual beam line. A specific aim for this beam source model is to make it applicable to the majority of the various proton beam systems currently available or under development, with the overall purpose to drive dose calculations in proton beam treatment planning. The proton beam phase space is characterized by an energy spectrum, radial and angular distributions and deflections for the non-modulated elementary pencil beam. The beam propagation through the scanning magnets is modelled by applying experimentally determined focal points for each scanning dimension. The radial and angular distribution parameters are deduced from measured two-dimensional fluence distributions of the elementary beam in air. The energy spectrum is extracted from a depth dose distribution for a fixed broad beam scan pattern measured in water. The impact of a multi-slab range shifter for energy modulation is calculated with an own Monte Carlo code taking multiple scattering, energy loss and straggling, non-elastic and elastic nuclear interactions in the slab assembly into account. Measurements for characterization and verification have been performed with the scanning proton beam system at The Svedberg Laboratory in Uppsala. Both in-air fluence patterns and dose points located in a water phantom were used. For verification, dose-in-water was calculated with the Monte Carlo code GEANT 3.21 instead of using a clinical dose engine with approximations of its own. For a set of four individual pencil beams, both with the full energy and range shifted, 96.5% (99.8%) of the tested dose points satisfied the 1%/1 mm (2%/2 mm) gamma criterion.
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| 69. |
- Kimstrand, Peter, 1975-
(författare)
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Beam Modelling for Treatment Planning of Scanned Proton Beams
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Scanned proton beams offer the possibility to take full advantage of the dose deposition properties of proton beams, i.e. the limited range and sharp peak at the end of the range, the Bragg peak. By actively scanning the proton beam, laterally by scanning magnets and longitudinally by shifting the energy, the position of the Bragg peak can be controlled in all three dimensions, thereby enabling high dose delivery to the target volume only. A typical scanned proton beam line consists of a pair of scanning magnets to perform the lateral beam scanning and possibly a range shifter and a multi-leaf collimator (MLC). Part of this thesis deals with the development of control, supervision and verification methods for the scanned proton beam line at the The Svedberg laboratory in Uppsala, Sweden.Radiotherapy is preceded by treatment planning, where one of the main objectives is predicting the dose to the patient. The dose is calculated by a dose calculation engine and the accuracy of the results is of course dependent on the accuracy and sophistication of the transport and interaction models of the dose engine itself. But, for the dose distribution calculation to have any bearing on the reality, it needs to be started with relevant input in accordance with the beam that is emitted from the treatment machine. This input is provided by the beam model. As such, the beam model is the link between the reality (the treatment machine) and the treatment planning system. The beam model contains methods to characterise the treatment machine and provides the dose calculation with the reconstructed beam phase space, in some convenient representation. In order for a beam model to be applicable in a treatment planning system, its methods have to be general.In this thesis, a beam model for a scanned proton beam is developed. The beam model contains models and descriptions of the beam modifying elements of a scanned proton beam line. Based on a well-defined set of generally applicable characterisation measurements, ten beam model parameters are extracted, describing the basic properties of the beam, i.e. the energy spectrum, the radial and the angular distributions and the nominal direction. Optional beam modifying elements such as a range shifter and an MLC are modelled by dedicated Monte Carlo calculation algorithms. The algorithm that describes the MLC contains a parameterisation of collimator scatter, in which the rather complex phase space of collimator scattered protons has been parameterised by a set of analytical functions.Dose calculations based on the phase space reconstructed by the beam model are in good agreement with experimental data. This holds both for the dose distribution of the elementary pencil beam, reflecting the modelling of the basic properties of the scanned beam, as well as for complete calculations of collimated scanned fields.
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| 70. |
- Lambert, Paul C., et al.
(författare)
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Temporal trends in the proportion cured for cancer of the colon and rectum : a population-based study using data from the Finnish Cancer Registry
- 2007
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 121:9, s. 2052-2059
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Tidskriftsartikel (refereegranskat)abstract
- Colorectal cancer is the third most common cancer worldwide and the second most common cancer in Europe. Cumulative relative survival curves for both cancer of the colon and cancer of the rectum generally plateau after approximately 6-8 years. When this occurs, "population" or "statistical" cure is reached. We analyzed data from the Finnish Cancer Registry over a 50-year period using methods that simultaneously estimate the proportion of patients cured of disease (the cure fraction) and the survival time distribution of the "uncured" group. Our primary aim was to investigate temporal trends in the cure fraction and median survival of the uncured by age group for both cancer of the colon and rectum. For both cancers, the cure fraction has increased dramatically over time for all age groups. However, the difference in the cure fraction between age groups has reduced over time, particularly for cancer of the colon. Median survival in the uncured has also increased over time in all age groups but there still remains an inverse relationship between age and median survival, with shorter median survival with increasing age. The reasons for these impressive increases in patient survival are complex, but are highly likely to be strongly related to many improvements in cancer care over this same time period.
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