The causes of cancer in France.

BACKGROUND: While external factors are responsible for many human cancers, precise estimates of the contribution of known carcinogens to the cancer burden in a given population have been scarce. METHODS: We estimated the proportion of cancer deaths which occurred in France in 2000 attributable to known risk factors, based on data on frequency of exposure around 1985. RESULTS: In 2000, tobacco smoking was responsible for 23.9% of cancer deaths (33.4% in men and 9.6% in women), alcohol drinking for 6.9% (9.4% in men and 3.0% in women) and chronic infections for 3.7%. Occupation is responsible for 3.7% of cancer deaths in men; lack of physical activity, overweight/obesity and use of exogenous hormones are responsible for 2%-3% of cancer deaths in women. Other risk factors, including pollutants, are responsible for <1% of cancer deaths. Thus, known risk factors explain 35.0% of cancer deaths, and 15.0% among never smokers. CONCLUSIONS: While cancer mortality is decreasing in France, known risk factors of cancer explain only a minority of cancers, with a predominant role of tobacco smoking.

The role of the biomedical physicist in the education of the healthcare professions: an EFOMP project.

The role of the biomedical physicist in the education of the healthcare professions has not yet been studied in a systematic manner. This article presents the first results of an EFOMP project aimed at researching and developing this important component of the role of the biomedical physicist. A background to the study expands on the reasons that led to the need for the project. This is followed by an extensive review of the published literature regarding the role. This focuses mainly on the teaching contributions within programmes for physicians, diagnostic radiographers, radiation therapists, and the postgraduate medical specializations of radiology, radiotherapy, interventional radiology and cardiology. Finally a summary list of the specific research objectives that need to be immediately addressed is presented. These are the carrying out of a Europe-wide position audit for the role, the construction of a strategic role development model and the design of a curriculum development model suitable for modern healthcare professional education.

Usefulness of fine needle aspiration cytology in the diagnosis of loco-regional recurrence of differentiated thyroid carcinoma.

AIM: The aim of our study was to define the usefulness of fine needle aspiration cytology (FNAC) in the assessment of loco-regional recurrence of differentiated thyroid carcinoma (DTC). METHODS: Among 1182 consecutive patients treated and followed for DTC from 1992 to 2001, we retrospectively analysed 65 FNAC results of patients presenting a suspicion of loco-regional recurrence. Recurrences were proved at histology in 35 cases and by cervical radioiodine uptake on post-therapeutic WBS (whole body scan) in nine cases. RESULTS: Among the 44 recurrences, FNAC results were malignant, benign and unsatisfactory in 33, two and nine cases, respectively. For the diagnosis of malignancy, FNAC sensitivity was 94%, specificity 100%, positive predictive value 100% and negative predictive value 87%. In the 35 cases where divergent results between diagnostic WBS (37-111MBq (131)I) and Tg level were observed, FNAC assessed the final status in 22 cases (malignant and benign in 17 and five cases, respectively). Of the 12 non-functioning and non-secreting lesions, FNAC diagnosed malignancy in four of the five malignant cases and ruled out malignancy in all seven benign lesions. CONCLUSION: These results outline the interest of FNAC in the assessment of loco-regional recurrences of DTC, especially when classical follow-up tools such as WBS and/or Tg level are unable to detect the recurrences.

Indications and limits of ultrasound-guided cytology in the management of nonpalpable thyroid nodules.

Although ultrasound (US)-guided fine needle aspiration biopsy (FNAB) is widely prescribed in nonpalpable thyroid nodules, the goal of this study was to define precisely the indications and limits of US-FNAB in a series of 450 nonpalpable nodules. Among 94 surgically controlled cases, 20 (8 infracentimetric and 12 centimetric or supracentimetric) carcinomas were diagnosed. The diagnosis of malignancy was successfully made by US-FNAB in 16 of 20 carcinomas, 3 were missed because of insufficient cytological material, and 1 was misdiagnosed. US-FNAB sensitivity and specificity were 94% and 63%, respectively. A logistic model indicated that nodule size (P < 0.6) was not associated with histological diagnosis, but that solid hypoechoic features were more likely to be malignant (P < 0.0003), with US sensitivity and specificity for malignancy of 80% and 70%, respectively. Logistic regression indicated that adequate cytological material significantly increased with nodule size (P < 0.0001). This result outlined the limits of US-FNAB in small nodules. Hence, indication of US-FNAB appears judicious in centimetric or supracentimetric nodules or in solid and hypoechoic ones. Such a management would allow the discovery of 15 of 20 carcinomas and would avoid 16% of unnecessary biopsies.

Survival and therapeutic modalities in patients with bone metastases of differentiated thyroid carcinomas.

Data for patients with bone metastases (BMs) of differentiated thyroid carcinoma (DTC) were retrospectively studied to identify factors associated with survival. We especially studied the impact of therapies. Among the 1977 patients followed for DTC in our department from 1958 to 1999, 109 (77 females and 32 males; age range, 20--87 yr) presented BMS: All patients except 1 underwent total thyroidectomy, followed by radioiodine therapy (> or =3.7 gigabecquerels) in 95 cases. Survival rates at 5 and 10 yr were 41% and 15%, respectively. Univariate analyses indicated that a young age at BM discovery (P < 0.005) and the discovery of BM as a revealing symptom of DTC (P < 0.05) were features significantly associated with improved survival as well as radioiodine therapy (P < 10(-4)) and BM complete surgery (P < 0.02). Using multivariate analysis, the detection of BMs as a revealing symptom of thyroid carcinoma (P < 0.0005), the absence of metastasis appearance in other organs than bones during the follow-up (P < 0.03), the cumulative dose of radioiodine therapy (P < 0.0001), and complete BM surgery in young patients (P < 0.04) appeared as independent prognostic features associated with an improved survival.

Would I-123 di-iodotyrosine provide a harmless deiodination test? Concise communication.

Defective iodotyrosine deiodinase activity may benefit from a specific treatment, thus requiring an unequivocal diagnosis. In reported cases this diagnosis has been obtained from an in vivo deiodination test making use of di-iodotyrosine (DIT) labeled either with I-131 or I-125. Dosimetric calculation indicates that such tests may result in unacceptable irradiation of the thyroid of a child wrongly suspected of having defective iodotyrosine deiodinase activity; therefore other methods are needed. The use of I-123 DIT is shown to be feasible, but even a 1:30 reduction in the thyroid dose still remains too high. Suppression of thyroid I- uptake by ClO4-, together with I-125 DIT, eliminates almost all thyroid irradiation and provides a sensitive, harmless, and rapid test.

Artificial neural network as a tool to compensate for scatter and attenuation in radionuclide imaging.

UNLABELLED: This study investigates the ability of artificial neural networks (ANN) to simultaneously correct for attenuation and Compton scattering in scintigraphic imaging. METHODS: Three sets of experiments are conducted using images of radioactive sources with various shapes and distributions in a homogeneous medium. Numerical Monte Carlo simulations and physical phantom acquisitions of radioactive geometric sources provide the basic material for correction. Our method is based on the following assumptions: information needed to correct for scattering can be extracted from the energy spectrum at each pixel without any assumption concerning the source distribution, and two diametrically opposed energy spectrum acquisitions yield enough information on the source location in the diffusing medium for simultaneous correction for attenuation and scattering. RESULTS: Qualitative and quantitative evaluations of scatter correction by ANN demonstrate its ability to perform scatter correction from the energy spectra observed in each pixel. By using the energy spectra of incident photons detected in two diametrically opposed images, multilayer neural networks are able to perform a proper restitution of projection images without any assumption on geometry or position of radioactive sources in simple geometric cases. ANN corrections compare favorably to those provided by five of the most popular methods. A satisfying correction of both scatter and attenuation is observed for a human pelvis scan obtained during routine clinical practice. CONCLUSION: An ANN is an efficient tool for attenuation and Compton scattering in simple model cases. The results obtained for routine scintigrams in a much more complex situation are strong incentives for performing further studies.

Factor analysis in successive hepatobiliary imaging of native and transplant livers.

UNLABELLED: A young male suffering from fulminant hepatic failure of unknown origin had an auxiliary partial orthotopic liver transplantation performed. The aim of the present study was to test the performance of factor analysis of medical image sequences (FAMIS) in the post-transplantation monitoring of the graft and native liver functions. METHODS: Four successive hepatobiliary studies within 63 days following transplantation using 99mTc-mebrofenin were performed (on days 13,20,34,63). The 60 one-minute dynamic series were subjected to two successive FAMIS procedures. RESULTS: For all studies, except the first, FAMIS was able to extract three factor couples (factor images and factors or curves) those of the native liver, the graft liver and the biliary region. The factors time evolution in uptake and excretion components showed the correlations between clinical status and scintigraphic results and helped interpretation of biochemical tests. CONCLUSION: The possible utility of systematic liver transplant monitoring by radionuclide hepatobiliary imaging in identification of complications requiring medical or surgical intervention in graft livers was demonstrated. Furthermore, our study showed the functional recovery potential of the native liver in patients suffering from fulminant hepatitis.

Absolute activity quantitation in simultaneous 123I/99mTc brain SPECT.

UNLABELLED: Dual-isotope imaging can allow simultaneous assessment of brain perfusion using a 99mTc-labeled tracer and neurotransmission using an 123I-labeled tracer. However, the images are affected by scatter, cross talk, attenuation, distance-dependent collimator response (DCR), and partial-volume effect. We determined the accuracy and precision of activity quantitation in simulated normal and pathologic studies of simultaneous 123I/99mTc brain SPECT when compensating for all degrading phenomena. METHODS: Monte Carlo simulations were performed using the Zubal brain phantom. Contamination caused by high-energy 123I decay photons was incorporated. Twenty-four 99mTc and 123I activity distributions were simulated on the basis of normal and pathologic patient activity distributions. Cross talk and scatter were corrected using a new method based on a multilayer perceptron artificial neural network (ANN), as well as by the asymmetric window (AW) approach; for comparison, unscattered (U) photons of 99mTc and 123I were recorded. Nonuniform attenuation and DCR were modeled in an iterative ordered-subset expectation maximization (OSEM) algorithm. Mean percentage biases and SDs over the 12 normal and 12 pathologic simulated studies were computed for each structure with respect to the known activity distributions. RESULTS: For 123I, AW + OSEM yielded a bias of 7% in the cerebellum, 21% in the frontal cortex, and 36% in the corpus callosum in the simulated normal population. The bias was increased significantly in the striata of simulated pathologic studies (P < 0.05). The bias associated with ANN was significantly lower (<9% in these brain structures, P < 0.05). For 99mTc with AW + OSEM, the bias was 60% in the corpus callosum, 36% in the striata, and 18%-22% in the cortical lobes in the simulated normal population. This bias was <11% in all brain structures with ANN. In the simulated pathologic population, the bias associated with AW increased significantly in the cortical lobes to 55% (P < 0.05), although it did not change significantly with ANN. CONCLUSION: The accuracy and variability over simulated normal and pathologic studies of both 99mTc and 123I activity estimates were very close with ANN to those obtained with U + OSEM. ANN + OSEM is a promising approach for absolute activity quantitation in simultaneous 99mTc/123I SPECT.

Advantages of SPECT in technetium-99m-sestamibi parathyroid scintigraphy.

UNLABELLED: We demonstrate several advantages of SPECT in parathyroid scintigraphy. METHODS: Forty-four parathyroid 99mTc-MIBI scintigrams were obtained before surgery in 43 patients suffering from hyperparathyroidism. For each patient, we obtained dynamic views and planar and SPECT images of the neck and thorax. For 15 patients, we also acquired a delayed static view of the neck 2 hr after tracer injection. Abnormal thyroid-area glands were detected with factor analysis of dynamic structure (FADS) of the initial dynamic acquisition. In the 15 patients with delayed views of the neck, we compared FADS and the double-phase study results to detect glands in the thyroid uptake area. Glands outside the thyroid area were demonstrated on planar views. The location of enlarged glands was more precisely defined on the tomographic slices. The anatomic and histologic findings and the evolution of hypercalcemia after surgery were taken as reference. RESULTS: Sixty-four abnormal glands were found during surgery, including 39 observed in patients who underwent reoperation for persistent or recurrent hyperparathyroidism. Twenty-two of these glands were in an abnormal location, including 10 in the mediastinum. SPECT allowed the detection of three glands not demonstrated on planar views or FADS. Fifty-eight glands were correctly localized scintigraphically, including 34 in patients who underwent reoperation. Therefore, SPECT raised the sensitivity from 86% to 90.5% and from 79.5% to 87% in the reoperated patients. Tracer uptake in the low mediastinal area was better analyzed on tomographic slices than on planar views. Only seven false-positive results were depicted by planar views or FADS; none were depicted on SPECT. CONCLUSION: A combination of FADS and SPECT permits detection of small glands, even in a posterior location, inside or outside the thyroid area. This scintigraphic method enables the surgeon to define more precisely details about the location of the enlarged gland and contributes to improved parathyroid surgery.

Identifying abnormal parathyroid glands in the thyroid uptake area using technetium-99m-sestamibi and factor analysis of dynamic structures.

UNLABELLED: A rapid (25 min) single tracer scintigraphic method to localize parathyroid gland abnormalities was evaluated in 24 patients with hyperparathyroidism. METHODS: Scintigraphy was performed with 99mTc-sestamibi prior to surgery. A 25-min dynamic series centered on the neck was acquired immediately after injection of 99mTc-MIBI. Two planar static views were obtained after 1 and 2 hr. To identify abnormal parathyroid tissue in the thyroid uptake area, a factor analysis of dynamic structure (FADS) was applied to the dynamic acquisition. The results were compared to the analysis of the two planar static views. RESULTS: FADS demonstrated abnormal uptake of the tracer in the thyroid area for 26 of the 31 parathyroid glands found to be abnormal at surgery (5/6 adenomas, 21/25 hyperplastic glands). In three cases, FADS demonstrated parathyroid uptake despite the absence of parathyroid tissue at surgery. FADS revealed as specific and more sensitive than the visual analysis of the two static views, since only 13/30 glands were still visible after 1 hr, and 5/26 after 2 hr. Furthermore, a study with two static views was found to be less sensitive for the detection of hyperplastic glands. CONCLUSION: FADS99mTc-MIBI is performed in less time than existing scintigraphic protocols. It is a promising method to detect abnormal parathyroid glands in the cervical area with a single tracer.

Differential transferrin receptor density in human colorectal cancer: A potential probe for diagnosis and therapy.

Transferrin receptor density was investigated in human colorectal surgical specimens. Crude membranes were prepared from 23 cancer tumors (adenocarcinoma or malignant villous tumor) and 3 non-cancer tumors (polyadenoma or villous tumor) and 26 adjacent control mucosa. Contrary to non-cancer tumors, Scatchard analysis of 125I-transferrin binding data evidenced higher maximal transferrin binding capacity and lower dissociation constant in cancer tissues (Bmax cancer 1.828+/-0.320 nmol/g, Kd 24.1+/-4.7 nM), as compared to paired control colonic mucosa (Bmax contol 0.851+/-0.182 nmol/g, Kd 30.7+/-7.3 nM), paired t-tests: Bmax p<0.001, Kd p<0.05). As the cancer/control Bmax ratio was 2.6+/-0.4,transferrin carrier constructs should be proposed for cancer imaging or therapy.

Secondary thyroidectomy in patients with prior thyroid surgery for benign disease: a study of 203 cases.

BACKGROUND: The goal of this study was to evaluate the complication rate of secondary thyroidectomy in patients with prior thyroid surgery for benign disease. METHODS: Over an 8-year period, 203 thyroid reoperations were performed on 202 patients. All information relating to operative procedures, pathology, and complications was recorded prospectively. RESULTS: There were 24 men and 178 women with a mean age of 52 years. Prior surgery was unilateral in 136 cases (67%) and bilateral in 67 cases (33%), and 14 patients (6.9%) had more than 1 previous thyroid operation. For euthyroid or pretoxic recurrent nodular goiter, 190 reoperations were performed and 13 reoperations were performed for recurrent thyrotoxicosis. Twenty-three cancers were found in a specimen (11.4%). Completion thyroidectomy was done in 143 patients. Postoperative complications occurred in 21 patients (10.4%): recurrent laryngeal nerve palsy (7 patients), hypocalcemia (8 patients), hematoma requiring surgical evacuation (5 patients), and wound infection (1 patient). Complications remained permanent in 4 patients (2%). CONCLUSIONS: The permanent complication rate is higher in thyroid reoperations than in primary thyroid operations. However, we believe that this 2% rate is low enough to allow reoperation whenever it is necessary, provided precise operative rules are respected.

Iodine kinetics and effectiveness of stable iodine prophylaxis after intake of radioactive iodine: a review.

Ingestion of potassium iodide (KI) offers effective protection against irradiation of the thyroid after accidental exposure to radioactive iodine. This prophylaxis aims at rapidly obtaining maximal thyroid protection without adverse effects. This article reviews studies on iodine kinetics in humans and on the efficacy of KI in protecting the thyroid. In adults with normal thyroid function, ingestion of 100 mg of iodide just before exposure to radioactive iodine blocks at least 95% of the thyroid dose. If exposure persists after iodide ingestion (100 mg), the percentage of averted dose may decrease significantly. Daily ingestion of a dose of 15 mg of KI would then maintain the thyroid blockade at a level above 90%. The efficacy of iodide and the occurrence of antithyroid effects also depend on external and individual factors such as dietary iodine intake, thyroid function, and age. The KI dosage regimen should be adjusted for age at exposure. For the fetus, the newborn, children, and adolescents, the risk of radiation-induced thyroid cancer in case of accidental exposure to radioactive iodine justifies KI prophylaxis, despite the risk of hypothyroidism, especially in newborns. For the elderly, the benefits of KI may be lower than the risk of iodine-induced hyperthyroidism.

Fetal biometric parameters, twin type and birth weight difference. A longitudinal study.

OBJECTIVE: To examine the relationship between twin type, divided by zygosity, chorionicity, and birth weight difference [more or less than 15% intertwin weight difference at delivery] on fetal biometric measurements, including biparietal diameter, transverse abdominal diameter, head and abdominal circumferences (AC) and head and abdominal areas, femur length (FL), transverse cerebellar diameter, cerebellar circumference and cerebellar area at 18, 23, 28 and 32 weeks of gestational age. STUDY DESIGN: A prospective and longitudinal study was done on 75 twin pairs that did not present the twin-twin transfusion syndrome (150 fetuses) divided into birth weight difference group I (<15%) and group II (>/=15%). The twin pairs were divided into three groups: dizygotic, monochorionic, and dichorionic-monozygotic. In each group the differences in various ultrasound indices were evaluated in reference to discordant growth or concordant growth. RESULTS: In our sample, there were no monozygotic twin pairs with dichorionic placentation with a birth weight difference of more than 15%. Significant associations of group and gestational age were found in dizygotic and monochorionic twins. Intrapair differences were significantly higher in group II (>/=15%) than in group I (<15%) for all fetal parameters studied except for AC, abdominal area and all cerebellar parameters. The value of these discrepancies increased according to gestational age except for FL. Significant interactions between group and zygosity type indicated that intrapair FL differences were more associated with group in monochorionic twins, whereas intrapair transverse cerebellar diameter differences were more associated with group in dizygotic twins. CONCLUSION: Our data show that most fetal biometric parameters are associated with birth weight discordancy. Abdominal area could be a relevant marker for twins with obstetric complications. Note that this is the first research that has studied a twin sample divided by both twin type and birth weight group.

Biparietal diameter in twins at gestational weeks 18-32. Differences and similarities. Le Groupe Romulus.

OBJECTIVE: To examine twin similarities on biparietal diameter (BPD) measurements by zygosity (monozygotic [MZ] and dizygotic [DZ]) and chorionicity (monochorionic [MC] and dichorionic [DC]) and their evolution during pregnancy. METHOD: A sample of 54 pairs of twins (43 DZ sets, 11 MZ sets [7 MC and 4 DC]) was constructed using retrospective data. Despite the small sample size, our data were complete, and, for the first time we measured different fetal parameters on digital ultrasound images outside routine examination. The intraexaminer and interexaminer reliability of BPD measurement was significant (r = .95, P < .001). RESULTS: In this study, developmental results indicate significant linear regression coefficient (R) through the whole period of gestation (r = .96, P < .001), though product moment correlations comparing the periods of gestation two by two are weaker. The distribution of BPD values was slightly wider at the 28th week and markedly wider at the 32nd week than that at the 18th and 23rd weeks. The intraclass correlations of DZ and MZ (MC and DC) twins were examined at the 18th, 23rd, 28th and 32nd weeks of amenorhea. The intraclass correlations of DZ twins were significant through the whole period of gestation (r = .45, P = .001; r = .27, P = .04; r = .36, P = .008; and r = .42, P = .002, respectively), whereas the intraclass correlations of MZ twins were significant only at the 18th, 23rd and 28th weeks (r = .73, P = .002; r = .69, P = .005; r = .49, P = .047, respectively). We found significant within-variance differences not only between DZ and DC-MZ but also between DC-MZ and MC-MZ in late gestation. CONCLUSION: Our analysis of twin BPD development demonstrated that zygosity and chorionicity type are both important determinants of twin fetal development.

Quantitative characterization of blood rheological behavior in transient flow with a model including a structure parameter.

Transient rheological behavior of blood which involves non newtonian viscosity, elasticity and thixotropy can be modelized with a Maxwell rheological state equation which depends on a structure parameter having dimension of a shear rate. Identification of the model parameters leads to use an exponential apparent shear rate step and to use recursive filters for taking into account the impulse response of the viscometer servo-control device. Typical results for a normal blood sample are given.

Computer-assisted individual estimation of radioiodine thyroid uptake in Grave's disease.

A computer-assisted Bayesian individual estimation of radioiodine thyroid uptake kinetics for patients suffering from Grave's disease is proposed. The program provides a fast computation of the activity to be administered to a given patient to achieve a target thyroid absorbed dose. This determination relies upon the patient biological covariates and upon a small number of measurements performed during a preliminar kinetic study of radioiodine thyroid uptake. Our results indicate that a two-sample Bayesian approach is reliable when external thyroid counts are performed at 2 h and 168 h after a test dose and has advantages over conventional kinetic experiments in terms of patient acceptability. This method is implemented on widespread computers and interfaced with a patient database. An interactive user interface with in-line data checking is provided. The program could be also a tool to better study the relationship between the absorbed dose and the clinical effect.

[Analytical aspects of the semiquantitative determination of urinary iodine using ferroin: value of rapid screening for iodine deficiency or excess]. / Aspects méthodologiques de la détermination semi-quantitative de l'iodurie par la ferroïne: intérêt dans le dépistage rapide de carence ou surcharge en iode.

Iodine is an essential element for thyroid hormone synthesis. Iodine disorders induced biological and/to clinical expression of thyroid dysfunction. Inappropriate iodine intake (by default or by excess) is worrying in terms of public health in France regarding the iodine deficiency and the frequency of iatrogen iodine overloads. Urinary iodine determination which generally implicates the use of a cerimetric method, is an useful tool to evaluate iodine intakes. In this study, we described the analytical aspects of a semiquantitative method of urinary iodine using a redox indicator, ferroin. This method allows the screening of iodine excess or deficiency in a short time (< 3 hours) with a good specificity and sensitivity. Since this assay does not require specific apparatus, it could be easily developed in clinical chemistry laboratories for the detection of inappropriate iodine intakes, and could be useful for prevention programs of iodine deficiency.