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991.
Purpose: To determine the variability of position of internal mammary vessels (IMV) and glandular breast tissue (GBT) in patients undergoing breast-conserving radiation therapy. To assess the frequency and magnitude of tangential field border shifts based on preradiation therapy (RT) computed tomography (CT) imaging in breast cancer patients.

Methods and Materials: Five hundred and ninety breast cancer patients irradiated between 9/94 and 3/98 underwent routine CT-based treatment planning. Two analyses were performed. First, the position of IMV and GBT, outlined on the central axis CT image, was determined relative to the midsternum in 111 patients irradiated during a 12-month period. In the second analysis, the difference between anticipated (pre-CT) and actual (CT-based) tangential field borders was assessed in 254 patients irradiated during a 2-year period.

Results: In the first analysis, the depth of the IMVs varied from 1 to 6 cm (median 2.4 cm). The lateral distance from the midsternum also varied widely (range 1.7 to 3.7 cm, median 2.5 cm). Similar variability was found in the position of the GBT. In the second analysis, CT information led to changes of anticipated field borders in 65% of patients. The lateral border was shifted in 56% of patients (anteriorly 18%, posteriorly 38%). When the patients were segregated based on internal mammary node (IMN) treatment, the medial border was shifted in 49% of patients when the IMNs were treated in the tangential fields and in 24% when the GBT only was treated. The frequency of lateral field border shifts was similar in both groups.

Conclusions: The position of IMVs and GBT varies widely in breast cancer patients. Tangential field borders based on surface anatomy may not be ideal. Among 254 breast cancer patients, the field borders were shifted in 65% of patients when CT information was available. Thus, in most breast cancer patients, field borders are shifted when CT-based treatment planning is used.  相似文献   

992.
PURPOSE: Compare dose distributions of traditional versus conformal beam orientations in paranasal sinus malignancies. MATERIALS AND METHODS: Maximum normal tissue doses, dose volume histograms (DVH), normal tissue complication probabilities (NTCP), and the percentage of each normal tissue receiving >80% of the average target dose (V80) were calculated. RESULTS/CONCLUSIONS: Conformal planning reduced the V80 to the optic nerves and chiasm as well as the normal tissue maximum doses to the ipsilateral and contralateral optic nerves and chiasm, and mean NTCPs.  相似文献   
993.
T Byers  J Mouchawar  J Marks  B Cady  N Lins  G M Swanson  D G Bal  H Eyre 《Cancer》1999,86(4):715-727
BACKGROUND: Cancer incidence and mortality rates both began to decline in the U. S. in the early 1990s. Recognizing the unprecedented potential benefits of accelerating this decline, the American Cancer Society (ACS) has set ambitious challenge goals for the American public for a 25% reduction in cancer incidence rates and a 50% reduction in cancer mortality rates by the year 2015. This analysis examined the feasibility of reaching those goals by estimating future changes in cancer rates that can result from past and future reductions in cancer risk factors. METHODS: Estimates for future declines in cancer risk factors in the U. S. under alternative scenarios were applied to conservative population-attributable risk estimates for cancer incidence and mortality rates in 1990 to estimate cancer rate trends in the year 2015. RESULTS: If the current trends toward a decline in the prevalence of cancer risk factors continue over the next decade, by the year 2015 one can expect a 13% decline in cancer incidence rates and a 21% decline in cancer mortality rates below their 1990 levels. With redoubled efforts to reduce the prevalence of known cancer risk factors further, by the year 2015 cancer incidence rates could be reduced by 19% and cancer mortality rates reduced by 29%. Such redoubled efforts would equate to approximately 100,000 cancer cases and 60,000 cancer deaths prevented each year by the year 2015. CONCLUSIONS: Past reductions in cancer risk factors in the U.S. population have led to recent declines in the rates of cancer incidence and mortality in the U.S. Redoubled efforts to act on current knowledge regarding how to prevent, detect, and treat cancer can result in attaining approximately 80% of the ACS challenge goal for cancer incidence rates and 60% of the ACS challenge goal for cancer mortality rates by the year 2015. New findings from cancer research are needed and will have to be applied quickly if the ACS challenge goals are to be met fully.  相似文献   
994.
Background. The role of chemotherapy in recurrent ependymoma is poorly defined. This study was performed to help clarify the benefits of chemotherapy in this setting. Patients and methods. We retrospectively reviewed the charts of patients with advanced ependymoma of the CNS who received chemotherapy in our institution between 1974 and 1993, inclusive. Sixteen consecutive patients were treated with regimens containing either nitrosourea, platinum, or other combinations exclusive of nitrosourea or platinum. No patient received nitrosourea and platinum concurrently. Two methods were used to define response. The first was a direct comparison of radiographic images before and after chemotherapy more than one month apart. A second broader definition of response that employed four other criteria in addition to imaging studies (symptoms, signs, performance status, and neurologic functional status) was also used. Results. Results were as follows (response rate by imaging studies followed by response rate by scoring in parenthesis): Platinum-based chemotherapy resulted in a 67% (83%) response rate with 33% (0%) remaining stable. Nitrosourea-based regimens resulted in a 25% (60%) response rate with 50% (10%) remaining stable. When combinations other than platinum or nitrosourea were used, 11% (22%) responded and 56% (44%) remained stable. Relative differences in response rates between chemotherapy regimens persisted when the data were analyzed by grade. Median time to progression was 6, 10, and 3 months, respectively. Conclusion. Platinum-based chemotherapy regimens appear to result in higher response rates with lower rates of progression than nitrosourea-based regimens. Other regimens that do not include cisplatinum or nitrosourea appear to be even less effective.  相似文献   
995.
A retrospective analysis of 175 patients having a histopathologic diagnosis of epidermoid carcinoma of the pyriform sinus presenting between January 1, 1964 and December 31, 1973 was undertaken to establish the effectiveness of conservation surgery in preserving voice. Patients were treated by three separate methods: 1. preoperative radiation therapy, partial laryngopharyngectomy and radical neck dissection (PLP and RND) (N = 85); 2. preoperative radiation therapy, total laryngopharyngectomy and radical neck dissection (TLP and RND), (N = 57); and 3. palliation, which consisted of palliative radiation therapy alone or combinations of radiation therapy and chemotherapy or palliative surgery (N = 33). Of the 85 patients treated with the expectation of cancer cure and voice preservation (PLP and RND), 44 or 52% actually had their voice preserved. Of course, in none of the patients treated by TLP and RND was voice preserved, but 2 of the 33 patients treated palliatively retained ability to speak. Overall, 46 of 175 patients (26%) with carcinoma of the pyriform sinus were afforded voice preservation. The ability to preserve voice is correlated with stage and an analysis of operative complications is presented.  相似文献   
996.
Alpha1-antitrypsin deficiency allele carriers among lung cancer patients.   总被引:3,自引:0,他引:3  
Lung cancer (LC) and chronic obstructive pulmonary lung diseases (COPDs; including emphysema and chronic bronchitis) share a common etiology. Despite the known associations of alpha1-antitrypsin deficiency (alpha1AD) with COPD and COPD with LC, few studies examined the association of alpha1AD alleles and LC. We hypothesize that heterozygous individuals who carry a deficient allele of the alpha1AD gene Pi (protease inhibitor locus) are at an increased risk of developing LC. The Pi locus is highly polymorphic with >70 variants reported. There are at least 10 alleles associated with deficiency in alpha1-antitrypsin. Using an exact binomial test, we compared the alpha1AD carrier rate in 260 newly diagnosed Mayo Clinic LC patients to the reported carrier rate in Caucasians in the United States (7%). alpha1AD carrier status, determined by isoelectric focusing assay, was examined with respect to the history of cigarette smoking, COPD, and histological types. Thirty-two of the 260 patients (12.3%; 95% confidence interval, 8.6-16.9%) carried an alpha1AD allele, which was significantly higher than expected (P = 0.002). Twenty-four of the 32 carriers had allele S, 6 had allele Z, and 2 had allele I. Patients who never smoked cigarettes were three times more likely to carry a deficient allele (20.6%; P = 0.008), although smokers had a higher carrier rate (11.1%; P = 0.025) when compared with the 7% rate. Patients with squamous cell or bronchoalveolar carcinoma had a significantly higher carrier rate than expected (15.9% and 23.8%, P < or = 0.01, respectively). Our preliminary findings suggest that individuals who carry an alpha1AD allele may have an increased risk for developing LC, specifically squamous cell or bronchoalveolar carcinoma.  相似文献   
997.
Cases are presented which show the clinical utility of recording an electrocochleographic response to bone-conducted stimuli. The procedure is fraught with problems of acoustic control and artifact generation, but has distinct although limited values in clarifying masking dilemmas in patients with bilateral hearing loss.  相似文献   
998.
The validity of the recommendation that routine screening for tuberculosis precede the administration of live viral vaccines was tested in a field study. One hundred and ten children already known to be tuberculin-positive, mostly on the basis of prior vaccination with BCG, were immunized with live viral vaccine and retested with tuberculin at the same time. Reversion to a negative tine test occurred in 3% of children given measles, mumps, or rubella vaccine, and 3.6% of controls who received no vaccine but had the tuberculin test repeated at the same interval. Very few Mantoux reactions (two of 68) reverted to negative in children given one of the three vaccines, singly or in combination; some became smaller, but there was no significant difference in the changes in the size of the Mantoux reaction between the vaccinated group and the control group, with the exception of an unexplained increase in the size of the reaction in many of those who received rubella vaccine. Screening for tuberculosis by tine or Mantoux test is not invalidated by simultaneous administration of vaccines against measles, mumps, or rubella, given singly or in combination, as part of preventive care programs.  相似文献   
999.
Visceral nociception readily sensitizes the central nervous system, causing referred somatic pain and hyperalgesia via somato-visceral convergence. Hyperalgesia in the perioperative period may increase vulnerability to subsequent development of chronic pain. The study aim is to investigate the role of angina pectoris, an ischemic visceral pain, in long-term pain after coronary artery bypass surgery (CABG). We sent questionnaires to 369 patients who underwent CABG surgery in 2003. Questions were asked about angina pectoris and other pain in the period before surgery, the first week postoperatively (= acute pain), and the period after 3 months after surgery (= chronic pain). We obtained results from 256 patients (response rate = 69%). The point prevalence of chronic pain after CABG was 27% after a mean follow-up of 16 months (SD +/- 3 months). Patients with chronic pain after CABG had more angina pectoris than those without chronic pain: Before surgery (P = .07), early on postoperatively (P = .004), and more than 3 months after surgery (P = .000004). We found cumulative prevalences of chronic pain after CABG at 3 months of 39%, and of 32% after 6 months. Other predictive factors for chronic pain after CABG were acute postoperative pain (P = .00002) and younger age (P = .002). Angina pectoris is associated with chronic pain after CABG surgery. Other predictive factors include acute postoperative pain and younger age. PERSPECTIVE: The influence of postoperative angina pectoris for chronic pain after CABG surgery has not been described in the literature to date. Visceral nociception may play an important role in the development of chronic pain after surgery and should be taken into account in future studies.  相似文献   
1000.
BACKGROUND: To our knowledge, this is the first assessment of trends in tuberculosis (TB)/human immunodeficiency virus (HIV) comorbidity in the United States based on national TB surveillance data. METHODS: We analyzed all incident TB cases reported to the Centers for Disease Control and Prevention national TB surveillance system from all 50 states and the District of Columbia from 1993 through 2004. Trends in TB/HIV cases were examined according to selected demographic and clinical characteristics. RESULTS: Cases of TB/HIV decreased from 3681 (15% of 25,108 TB cases) in 1993 to 1187 (8% of 14,515 TB cases) in 2004, accounting for 23% of the overall decrease in TB cases during this period. The TB/HIV case rate decreased from 1.4/100,000 in 1993 to 0.4/100,000 in 2004. The highest TB/HIV comorbidity rates persisted in persons aged 25 to 44 years (13.8%), males (9.7%), US-born persons (10.7%), non-Hispanic blacks (17.8%), and persons from the Northeast (11.0%) and the South (10.1%). Propensity stratification, used to account for the unequal probability of patients with TB being tested for HIV during the study period, did not show important differences in TB/HIV comorbidity trends. CONCLUSIONS: Comorbidity due to TB/HIV decreased substantially between 1993 and 2004, primarily in US-born persons in states that experienced a TB resurgence between 1985 and 1992. These decreases coincide with improvements in TB control and advances in HIV treatment and diagnosis. The overall decreases obscure the wide variation in comorbidity that exists among some demographic groups and the recent slowing in the decline over the past 3 years.  相似文献   
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