Radiotherapy as Elective Treatment of the Node-negative Neck in Oral Squamous Cell Cancer.

BACKGROUND/AIM: Previous studies of node-negative oral squamous cell carcinoma have shown a benefit of elective neck dissection compared to observation. Evidence for radiotherapy as single-modality elective treatment of the node-negative neck is so far lacking. PATIENTS AND METHODS: In a retrospective material of 420 early-stage oral cancers from 2000 to 2016, overall survival, disease-free survival, and regional relapse-free survival were calculated with the Kaplan-Meier method. RESULTS: At five years, overall survival was 59.7%, disease-specific survival was 77.2%, and regional relapse-free survival was 83.5%. Among those with adjuvant treatment of the neck after surgery of T1-T2 tumours during 2009-2016, regional relapse-free survival at five years was 85.7% for elective radiotherapy of the neck and 87.4% for elective neck dissection. CONCLUSION: Elective radiotherapy to the neck with a modern technique and adequate dose might be an alternative to neck dissection for patients with early-stage oral squamous cell cancer.

Validation of a Clinical Cancer Register at the Head and Neck Oncology Center in Örebro.

BACKGROUND: This was a validation study of a regional register of oral cancer in Örebro, Sweden. The purpose was to assess the rate of errors in baseline, and treatment, and the completeness and accuracy of data on recurrences. MATERIALS AND METHODS: A total of 653 cases with squamous cell cancer in the oral cavity were identified from the register. A randomized sample of 73 (11%) was selected, and a set of relevant data was compared to medical records. RESULTS: Data on patient and tumour characteristics showed high accuracy, with 98% correct data and more than 99% of treatment data were correct. Follow-up data had a higher rate of errors, with 23% of recurrences not recorded, 13.6% misclassified, and 9.1% of cases showing errors in timing of the recurrence. CONCLUSION: data concerning patients, tumour status, and treatment in the Regional Head and Neck Register in Örebro are highly accurate. However, the follow-up data contain a higher rate of errors, that must be taken into consideration when evaluating outcome after treatment.

Magnetic Resonance Compatibility of a Transponder Aimed for Radiotherapy Positioning - A Phantom Study.

BACKGROUND/AIM: Electromagnetic Positioning Systems (EMP) is a new position-ing technique in four-dimensional radiotherapy. Patients with implanted transponders may be referred for magnetic resonance imaging (MRI) making it important to establish the MR safety. MATERIALS AND METHODS: Oranges were prepared with transponders and imaged on a 3T MR scanner with different sequences. Computed tomography (CT) was performed as comparison. MR artifacts were assessed. An estimation of the maximum transponder de-flection force and heating was made. RESULTS: The mean measured displacement of transponders was 0.1 mm (range=0.03-0.3 mm). Artifacts were observed adjacent to transponders using all sequences. The deflection force on the transponder in the gantry was less than 38 mN. No heating was observed. CONCLUSION: The absence of any substantial movement, the weak measured deflection force and absence of observed heating speaks for the safe use of MR imaging with transponder 3T. Local artefacts makes evaluation impossible adjacent to transponders.

Differential locomotion of long- and short-term IL-2-activated murine natural killer cells in a model matrix environment.

Tumour infiltration by activated natural killer (A-NK) cells is a pre-requisite for tumour eradication by adoptive NK cell transfer. Extravasated A-NK cells do not always succeed in reaching the crucial target cell conjugation. Therefore, we wished to study A-NK cell locomotion and interactions with melanoma cells in a matrix environment (Matrigel) by electron, confocal and fluorescence microscopy. Two distinct patterns of A-NK cell-mediated matrix disintegration were revealed during incubation of tumour cells and A-NK cells in Matrigel: (1) A-NK cells pre-cultured for 5 days altered the homogeneous texture of the Matrigel, an initial microporous appearance became a loose filamentous meshwork by 24 h. Matrix degrading protease inhibitors could not fully prevent this, but could delay the process; and (2) A-NK cells pre-cultured for 6 days or more, instead formed large excavations in the Matrigel leaving the remaining matrix less affected compared to the effects by the younger A-NK cells. By histochemical staining with Cupromeronic Blue, the excavations were shown to contain proteoglycan material. Protease inhibitors had no discernable effect on the development of the excavations. The conspicuous capacity of A-NK cells to disintegrate extracellular matrix and the formation of large excavations seems only partially to depend on matrix-degrading proteases. Formation of extracellular proteoglycan material is suggested to facilitate A-NK cell locomotion within a matrix environment.

High dose-rate brachytherapy of prostate cancer utilising Iridium-192 after-loading technique: technical and methodological aspects.

The aim of this study was to focus on certain characteristic problems associated with Iridium-192 high dose-rate brachytherapy (Ir-192 HDR-BT) in combination with external beam radiation therapy (EBRT) in the treatment of patients with localised prostate cancer. Over a period of 16 years, >2,000 patients with prostate cancer have been treated in Sweden with a combination of two fractions of 10 Gy Ir-192 HDR-BT and 50 Gy of fractionated EBRT. Although this treatment is usually well tolerated, there are biological and technical factors to be considered before and during the treatment of the patient to avoid side effects or under-treatment of the target volume. Some of the problems facing the doctors are transducer stability, needle deviation, target definition, target motion, pubic arch interference, concomitant diseases and tolerance doses for different organs at risk. These problems are discussed and possible solutions are presented in this study.

Pharmacokinetics and tolerability of different doses of fentanyl following sublingual administration of a rapidly dissolving tablet to cancer patients: a new approach to treatment of incident pain.

AIMS: It is estimated that two-thirds of cancer patients will at some point during their illness experience breakthrough pain. In this study, the pharmacokinetics of a novel sublingual dosage form of fentanyl developed for breakthrough pain was evaluated. METHODS: Eleven Caucasian patients (seven male and 4 female, aged 34-75 years, median 60 years) with metastatic malignant disease were recruited initially, but three patients withdrew. Prior to the study all patients were on continuous nonfentanyl opiate medication. The study was a double-blind, cross-over trial, consisting of three 1-day treatment periods. A new rapidly dissolving preparation of fentanyl, was administered sublingually in single doses of 100, 200 and 400 microg, respectively, on three separate occasions. Plasma fentanyl concentrations were determined using liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). Pharmacokinetic parameters were calculated by noncompartment analysis. Tolerability and the occurrence of adverse events were monitored throughout the study by patient questionnaire. RESULTS: The data from nine subjects who completed at least two periods were used in the analysis of variance. There were no significant differences between doses (100, 200 and 400 microg) for dose adjusted AUC (F = 0.42, P = 0.6660), dose adjusted C(max) (F = 0.08, P = 0.9206) and Tmax (F = 0.94, P = 0.4107). Thus, these parameters showed dose proportionality. The differences (400-100microg) in dose adjusted AUC from the three-period crossover analysis was -0.016 min.ng/ml (t = 0.71, P = 0.8718). Interindividual variability in systemic exposure to fentanyl was fairly small (25-40%), which may be related to a good in vivo biopharmaceutical performance of the sublingual tablet, and a relatively small fraction of the dose being swallowed. The first detectable plasma concentration of fentanyl was observed between 8 and 11 min after administration. t(max) increased from 39.7 +/- 17.4 to 48.7 +/- 26.3 and 56.7 +/- 24.6 min for the 100, 200 and 400 microg doses, respectively. Adverse events were few and did not increase with increasing dose. CONCLUSION: With this rapidly dissolving fentanyl formulation, the first detectable plasma concentration of fentanyl was observed at 8-11 min after administration. The pharmacokinetics of the drug showed dose proportionately. This formulation of fentanyl seemed to be well tolerated by the patients.

Anorectal function after modern conformal radiation therapy for prostate cancer: a pilot study.

We evaluated whether, and if so to what extent, radiotherapy applied on a series of patients with prostate cancer influenced the patient's bowel habits and anorectal function. Ten consecutive patients participated in the study. The median age of the patients was 74 years (range, 61-71) and the average follow-up period was 22 (range, 15-28) months. Four patients were irradiated using external beam radiotherapy (2 Gy/day for a total of 70 Gy); 6 patients were irradiated with a combination of external beam radiotherapy (50 Gy, 2 Gy/day) and high dose rate brachytherapy (two 10-Gy fractions). Upon interview, patients disclosed characteristic functional disturbances such as urgency with occasional accidents, faecal soiling and spotting of underwear. Involuntary release of gas was another embarrassing problem. One or more of these problems were present in half of the patients. Endoscopy disclosed signs of mild proctitis. Sphincter pressure, rectal capacity and the volume threshold for appreciation of defecation urge were all significantly lower in patients than in 10 age-matched controls. In conclusion, disturbances of anorectal function with imperfection of incontinence still occur so some extent despite improved precision, and reduced margins offered by the modern conformal radiation therapy of prostate cancer. Anal sphincter function, the reservoir capacity of the rectum and its sensory function are adversely affected and radiation proctitis with rectal fibrosis and damage of the extrinsic innervations of the anal sphincters appear to be the principal causative factors. Although conformal radiotherapy together with better positioning may be two substantial improvements of modern radiotherapy, further improvements are needed.

Postoperative radiotherapy after prostatectomy can be associated with severe side effects.

This retrospective study was initiated to evaluate the efficacy and side effects of post-prostatectomy external beam radiation therapy (XRT) with a short time interval between surgery and irradiation in patients with prostate adenocarcinoma. Sixteen patients were investigated. The overall results in this study were 3 deaths due to recurring disease and two relapses after an average follow-up of 60 months. Severe side effects were observed. Two patients required surgical intervention due to severe post-radiotherapy side effects. The reason for this could be the high dose delivered to peripheral organs and/or a too short time interval between surgery and postoperative XRT. The results of this study confirmed that postoperative XRT can improve local control frequency in prostate carcinomas. It is recommended that the time interval between surgery and postoperative radiotherapy should to be 3-6 month.

Angiogenic factors: vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (b-FGF) are not necessarily elevated in patients with advanced renal cell carcinoma.

Serum analysis of Vascular Endothelial Growth Factor (VEGF) and basic Fibroblast Growth Factor (b-FGF) levels were studied in 53 patients with renal cell carcinoma (RCC). Approximately 2/3 of the patients had disseminated disease at diagnosis, the remainder had no evidence of metastases. The results confirmed that VEGF has a major role in the angiogenesis of RCC. No correlation was observed between VEGF and/or b-FGF and the presence or absence of metastases, nor was any correlation observed between VEGF and/or b-FGF and patient survival. Thus, to utilise VEGF and/or b-FGF as a tumour marker at the time of diagnosis to predict patients with a high risk of progression, where an adjuvant therapeutic approach would be of great value, seems to be limited. Not all patients with RCC exhibited elevated serum levels of VEGF and/or b-FGF. No correlation was observed between tumour stage and serum levels of these angiogenic peptides.

Silicon diodes as detectors for backscatter radiation in photon fields.

We investigated the use of unencapsulated silicon semiconductor detectors for backscatter radiation detection. The results were compared with Monte Carlo (MC) calculations modelling the experimental set-up. A special diode was manufactured, which was designed so that it allowed the positioning of different materials in close contact with the detector surface. Polymethylmethacrylate (PMMA), Pb, Ti and Fe (stainless steel) were used as backscatter materials. The diode signal was measured by integrating the current when irradiating the diode with an equal photon fluence obtained from a medical Co-60 source. When compared to the signal with PMMA as backscatter material the increase in signal was 21%, 27% and 73% for Ti, Fe and Pb, respectively. This is in reasonable agreement with the MC calculations, when taking the effective measurement depth in the Si diode detector into account.

Evaluation of the UBC test in the urine of healthy individuals, patients with benign disorders and urinary bladder cancer.

Using the UBC test, the specificity, sensitivity and prognostic information were evaluated in patients with recently diagnosed transitional cell carcinoma (TCC) and in a control group consisting of apparently healthy individuals and individuals with benign disorders. Frozen urine samples from the 485 individuals in the control group and 100 newly diagnosed TCC patients were analyzed with the UBC test, specific for epitopes on cytokeratin fragments released from the urothelial cells. All the samples were analyzed and corrected for creatinine. No significant concentration difference was found between males and females (p=0.65) and there was no age dependent relation. The median concentration for the entire control group was estimated at 3.7 microg/g and the 95th percentile was calculated at 53.0 microg/g. The apparently healthy individuals in the control group had a median value of 3.4 microg/g with a 95th percentile of 24.3 microg/g. An increased frequency of elevated UBC concentrations was found in some benign disorders e.g., anemia, thyroid disorders, diabetes mellitus, hyperlipemia, urosepsis and cystitis. Patients with superficial tumors exhibited a 66% sensitivity (at 95% specificity), and the UBC concentrations did not differ statistically (p=0.16) from those patients with muscle invasive lesions with a 52% sensitivity. When the UBC concentrations were related to histopathological grade, a significant concentration difference (p<0.004) was found between low grade tumors (sensitivity 41%) and high grade tumors (sensitivity 72%). Survival analysis showed that patient with muscle invasive tumors, high-grade tumors and high UBC concentrations have a significantly reduced survival (five-year survival was estimated to 30%, 35% and 30% respectively) compared to patients with superficial tumors, low-grade tumors or low UBC concentrations (five-year survival, 60%, 85% and 75% respectively). The UBC test showed good accuracy and repeatability. Clinically the test could assist in tumor grading and the detection of recurrent disease, which in turn could assist in treatment selection for the individual patient and possibly improve prognosis.

Human milk fat globule antigen 1 (HMFG1) expression in prostatic carcinoma and immunotargeting with a radiolabelled monoclonal anti-HMFG1 antibody.

BACKGROUND: Prostatic cancer is the leading cause of death in Swedish men. Approximately 50% have disseminated disease at diagnosis. Radiolabelled antibodies could possibly be a treatment modality for disseminated prostatic cancer, so that in this study the expression of the human milk fat globulin 1 (HMFG1) antigen in prostate cancer was examined. MATERIALS AND METHODS: An immunohistochemistry technique with a murine monoclonal antibody was used, as well as the human prostate cancer cell line DU-145, which expresses this cell surface antigen. TUR specimens from patients with prostate cancer were also examined. RESULTS: Eighteen out of 22 (82%) patients exhibited an HMFG1-positive tumour. An inhomogenity in the immunostaining could occasionally be seen, with smaller apparently negative areas. The immunolocalisation properties of the antibody were investigated using a radiolabelled antibody injection into nude mice bearing heterotransplants of the DU-145 cell line. The highest accumulation of the antibody was seen in the tumour tissue and the liver. CONCLUSION: The results obtained form a basis for further investigations with the goal of using the antibodies for staging and therapy for prostate cancer.

Estramustine a radio sensitising agent.

The present study revealed that estramustine acts as a radio sensitising agent on the human renal cell cancer cell lines, A498 and CAKI-2. In vitro experiments used the Bürker chamber technique. Both cell lines were markedly resistant to external beam irradiation. While pretreatment of the cell cultures with estramustine prior to external beam irradiation revealed an arrest of cell growth in both cell lines. The results of this study suggest that estramustine could be utilised as a radiosensitizing agent. This in turn could open a new method for the management of patients with advanced renal cell carcinoma (RCC).

Elevated activity of semicarbazide-sensitive amine oxidase in blood from patients with skeletal metastases of prostate cancer.

The semicarbazide-sensitive amine oxidases constitute a group of copper-containing enzymes whose physiological function is unclear. The enzymes are present in various tissues, including blood plasma. At present, the source of the plasma enzyme in humans is not known. Results of a recent study suggested that semicarbazide-sensitive amine oxidase is expressed in the skeleton, e.g. in the spine. Using an indirect autoradiographic method in mice, we provide evidence that semicarbazide-sensitive amine oxidase is present in high abundance in bone tissue. Specific activities of semicarbazide-sensitive amine oxidase were estimated in blood samples from subjects with femoral bone fractures. Moreover, enzyme activities were also measured in patients suffering from prostate cancer with skeletal metastases. The level of specific semicarbazide-sensitive amine oxidase activity in serum was significantly elevated in patients with skeletal metastases compared with both healthy controls and patients having prostate cancer without signs of skeletal metastases. Based on the results of the present study, we propose that semicarbazide-sensitive amine oxidase in blood plasma may originate, at least in part, from the skeleton.

Calculated effects of displacement errors in external beam radiotherapy of prostatic adenocarcinoma.

In order to evaluate the impact on the biological effective dose (BED) of irradiation delivered to a tumour with large displacement errors (LDE) and to estimate the effect on local control, simulated treatment of prostatic adenocarcinoma was performed. The calculation of BED in combination with the critical-voxel model and the LQ model was used to evaluate the effect of different combinations of LDEs. The model is called the Dose Volume Inhomogeneity Corrected BED (DVIC-BED) model. The dose-response curve was assumed to follow Poisson statistics. Different combinations of radiobiological parameters were used to test the model. A simulated clinical treatment with a dose of 66-80 Gy in 2 Gy fractions was carried out to evaluate displacement errors and non-optimal dose distributions. Five random LDEs excluding 33% of the target volume corresponded to an overall dose reduction of 3-5 Gy compared with a 10 Gy reduction if 100% of the target is missed five times. A 5 Gy decrease in dose corresponds to a reduction in clinical or chemical control up to 10-25% in the interval 65-85 Gy. LDEs in different directions are less deleterious than errors occurring in the same direction. Different alpha/beta-ratios (3-15) had little effect on the DIC-BED, but the effect of different alpha values (0.05, 0.2 and 0.5) was large. However, the results depend on radiobiological parameters for prostatic adenocarcinoma, which not are well known, and further studies in the field should be encouraged.

Serum concentrations of VEGF and b-FGF in renal cell, prostate and urinary bladder carcinomas.

Sixty nine patients with urogenital cancers (renal, bladder and prostate cancer) were studied to determine whether the serum concentrations of Vascular Endothelial Growth Factor (VEGF) and basic Fibroblast Growth Factor (b-FGF) reflected the status of the patients and/or the prognosis of the disease. Of the patients included in this study, renal cell carcinoma patients expressed the highest levels of VEGF indicating that these tumours are more VEGF dependent. The values of b-FGF could be considered normal in all three malignancies. No correlation was observed between the expression of VEGF and b-FGF, nor between VEGF and b-FGF and patients survival.

Patient positioning using artificial intelligence neural networks, trained magnetic field sensors and magnetic implants.

The purpose of this study was to evaluate the precision of a sensor and to ascertain the maximum distance between the sensor and the magnet, in a magnetic positioning system for external beam radiotherapy using a trained artificial intelligence neural network for position determination. Magnetic positioning for radiotherapy, previously described by Lennernäs and Nilsson, is a functional technique, but it is time consuming. The sensors are large and the distance between the sensor and the magnetic implant is limited to short distances. This paper presents a new technique for positioning, using an artificial intelligence neural network, which was trained to position the magnetic implant with at least 0.5 mm resolution in X and Y dimensions. The possibility of using the system for determination in the Z dimension, that is the distance between the magnet and the sensor, was also investigated. After training, this system positioned the magnet with a mean error of maximum 0.15 mm in all dimensions and up to 13 mm from the sensor. Of 400 test positions, 8 determinations had an error larger than 0.5 mm, maximum 0.55 mm. A position was determined in approximately 0.01 s.

Comparative treatment planning between proton and x-ray therapy in esophageal cancer.

PURPOSE: Conformal treatment planning with megavoltage x-rays and protons for five patients with esophageal cancer has been studied in an attempt to determine if there are advantages of using protons instead of x-rays. METHODS AND MATERIALS: For each of the five patients, two different proton plans, one x-ray plan, and one mixed plan with x-rays and protons were made. A three-dimensional treatment planning system, TMS, was used. The evaluation of the different plans was made by applying the tumor control probability (TCP) model proposed by Nahum and Webb and the normal tissue complication (NTCP) model proposed by Lyman on the dose distributions in terms of dose-volume histograms (DVHs). RESULTS: The comparison shows advantages of using protons instead of x-rays for all five patients. The dose-limiting organs at risk are the spinal cord, the lungs, and the heart, but the proton plans also spare the kidneys better than the x-ray plan does. At 5% NTCP in any risk organ, the calculated mean TCP value for the five patients is increased by an average of 20%-units (from 2 to 23%-units) with the best proton plan compared with x-rays only. However, if we assume maximally a 1% risk in the spinal cord and a total NTCP for the two lungs of 100%, the mean TCP value for the five patients is increased from 6 to 49% with the best proton plan compared with x-rays only. The corresponding figure for the mixed plan is 27%. These gains are relatively insensitive to variations within reasonable limits in the biological parameters. CONCLUSIONS: Protons appear to have clear therapeutic advantages over conventional external radiotherapy when treating esophageal carcinoma.

Patient positioning using magnetic implants and magnetic field sensors.

A phantom study was conducted in order to evaluate the precision and reproducibility of a magnetic field positioning system using magnetic implants and magnetic field sensors. Three implants and three magnetic field sensors were used to position a phantom on a Simulix Y simulator; x-ray films were used as reference. The reproducibility of the position determination of the three magnetic field sensors was checked three times in five different positions in both the X and Y dimensions of the sensors. The phantom was then positioned by the system five times and the displacement errors of four markers in the periphery of the phantom were noted. A reference x-ray film was exposed before the positioning procedure. An error of one millimetre was permitted in each dimension in one sensor. Only the maximum displacement errors of one of the four markers were noted. In the first reproducibility test the system was found to miss 1 mm in one reading out of 90 position readings. In the second part, the mean for the maximum displacement error was 0.46 and 0.6 mm for the maximum frontal and lateral displacements respectively, with a maximal error of 1.3 mm.