Biomedical subjects
Lynn D Wilson
Publications and source records attributed to Lynn D Wilson.
Resident teaching: a tale of two places in time.
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Nutritional support of patients undergoing radiation therapy for head and neck cancer.
Malnutrition plays a key role in the morbidity of head and neck cancer patients receiving surgery, chemotherapy, radiotherapy, or combined-modality therapy. In addition to weight lost prior to the diagnosis of head and neck cancer, the patient may lose an additional 10% of pretherapy body weight during radiotherapy or combined-modality treatment. A reduction of greater than 20% of total body weight results in an increase in toxicity and mortality. Severe toxicity can result in prolonged treatment time, which has been implicated in poor clinical outcome. Early intervention with nutritional supplementation can reduce the chance of inferior outcome in patients at high risk of weight loss. The preferred route of nutritional support for these patients is enteral nutrition. Two commonly used methods for enteral feedings are nasoenteric and percutaneous endoscopic gastrostomy. It is important to take into account the ethical considerations involved in providing long-term nutritional support, particularly for patients with terminal conditions. Nutritional directives are best evaluated through multidisciplinary efforts, including input from the patient as well as members of the nursing, nutritionist, and medical staff.
National Residency Matching Program (NRMP) results for radiation oncology, 2004 update.
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Matching the dosimetry characteristics of a dual-field Stanford technique to a customized single-field Stanford technique for total skin electron therapy.
PURPOSE: To compare the dosimetry characteristics of a customized single-field and a matching dual-field electron beam for total skin electron therapy (TSET) within the framework of the Stanford technique. To examine and quantify its impact on patient dosimetry. METHODS AND MATERIALS: Two characteristically different electron beams were used for TSET employing the Stanford technique: a single-field beam created from a pencil beam of electrons passing through 7 meters of air and a dual-field beam created from two heavily scattered electron beams directed at oblique angles to patients. The dosimetry characteristics of the two beams were measured by using ionization chambers, radiographic films, and thermal luminescent detectors. The impact of beam characteristic on patient dosimetry was quantified on both anthromorphic phantoms and on patients. Treatment protocols aimed at matching the patient dose between the two systems were established on the basis of these and other measurements. RESULTS: The dual-field beam was matched to the single-field beam, resulting in approximately the same mean energy (approximately 4.0 MeV) and most probable energy (approximately 4.5 MeV) at their respective treatment source-to-patient-surface distance (SSD). The depth dose curves on the beam axis were nearly identical for both beams. X-ray contamination on the beam axis was 0.43% for the dual-field beam, slightly higher than that (0.4%) of the single-field beam. The beam uniformity, however, was quite different: the dual-field beam was more uniform in the vertical direction but was worse in the lateral direction compared to the single-field beam. For a TSET treatment using the Stanford technique, the composite depth dose curves were nearly identically at the level of beam axis: with an effective depth of maximum buildup (d(max)) at approximately 1 mm below the skin surface and the depth to 80% depth dose at around 6 mm. The overall X-ray contamination was approximately 1.0% and 1.2% for the single-field and dual-field system, respectively. Away from the beam axis level, treatment using either beam was able to deliver over 90% of prescription dose to the main body surfaces. For body surfaces tangential to the beam axis (e.g., top of head and shoulders), the dose was low especially when using the dual-field beam. By adding boost radiation to the tangential surfaces and by adjusting the planned shielding for critical structures, the total dose to the patient over a complete course of TSET treatment could be matched closely for the two systems. CONCLUSIONS: Although the depth doses can be matched at the level of the beam axis, there exist some characteristic differences in the angular distribution of the electrons between the large SSD single-field beam and the short SSD dual-field beam. These differences resulted in lower dose delivered to "tangential" body surfaces and to body structures that extended farther laterally when using the dual-field beam. However, by adjusting the treatment protocol regarding the boost irradiation and planned shielding, the total dose to patients from a complete course of TSET treatment using the dual-field beam can be matched to that given by the single-field beam. Special attention should be paid to the dosimetry at the "tangential" body surfaces when commissioning a dual-field TSET system.
The pathogenesis of mycosis fungoides.
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Prognostic significance of cyclooxygenase-2 in oropharyngeal squamous cell carcinoma.
PURPOSE: To determine the relative prognostic significance of cyclooxygenase (COX)-2 expression in patients with oropharyngeal squamous cell carcinoma (SCC). EXPERIMENTAL DESIGN: This retrospective cohort study included 82 patients with SCC referred to the Department of Therapeutic Radiology at Yale-New Haven Hospital (Connecticut) between 1980 and 1999 who were treated with primary external beam radiotherapy or gross total surgical resection and postoperative radiotherapy. A microarray of archival tumor tissue was constructed and stained with monoclonal antibodies directed against COX-2 and scored for intensity by a pathologist blinded to the clinical outcomes of the patients. COX-2 immunoreactivity and clinicopathological data were analyzed with respect to survival endpoints using bivariate and multivariate techniques. RESULTS: Frequency of COX-2 overexpression was 45%. In multivariate analysis, COX-2 positivity predicted poor 3-year survival (P = 0.02; odds ratio = 0.41; 95% confidence interval, 0.20-0.84). Increasing age was significantly associated with increased 3-year survival (P = 0.03; odds ratio = 1.04; 95% confidence interval, 1.004-1.09). Positive COX-2 status trended toward predicting decreased 3-year disease-free survival. CONCLUSIONS: COX-2 was the most important predictor of poor survival in this patient cohort. In patients with oropharyngeal SCC treated with external-beam radiation therapy, overexpression of COX-2 may affect clinical outcome, and COX-2 may therefore prove valuable both as a prognostic factor and as a therapeutic target.
Primary cutaneous B-cell lymphoma treated with radiotherapy: a comparison of the European Organization for Research and Treatment of Cancer and the WHO classification systems.
PURPOSE: To determine the relationship between the WHO and European Organization for Research and Treatment of Cancer (EORTC) pathologic classifications for primary cutaneous B-cell lymphoma (CBCL) and the implication of this relationship on initial treatment. PATIENTS AND METHODS: Patients with primary CBCL treated with radiotherapy were identified retrospectively. Initial biopsy specimens were reviewed by two dermatopathologists and classified according to the EORTC and WHO systems. Primary outcomes were recurrence-free and overall survival. RESULTS: Thirty-four patients were identified; initial biopsy specimens were adequate for classification in 32 patients. Four different composite histopathologic subtypes of lymphoma were identified: 53% (17 of 32) follicle center cell by EORTC and diffuse large B-cell by WHO (FCC/DLB), 25% (eight of 32) follicle center cell by EORTC and follicular by WHO (FCC/Fol), 13% (four of 32) marginal zone by EORTC and WHO (MZ/MZ), and 9% (three of 32) large B-cell of the leg by EORTC and diffuse large B-cell by WHO (Leg/DLB). Five-year relapse-free survival ranged from 62% to 73% for FCC/DLB, FCC/Fol, and MZ/MZ but was 33% for Leg/DLB (P =.6). Five-year overall survival was 100% for FCC/DLB, FCC/Fol, and MZ/MZ but was 67% for Leg/DLB (P =.07). At 5 years, 21% of all patients had developed extracutaneous disease. CONCLUSION: Two-thirds of primary cutaneous FCC lymphomas by EORTC criteria satisfy WHO criteria for DLB lymphoma. Unlike DLB lymphoma presenting in nodal or noncutaneous sites, these lesions are associated with an indolent course and may be treated with local radiotherapy alone.
Merkel cell carcinoma and the controversial role of adjuvant radiation therapy: clinical choices in the absence of statistical evidence.
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Total skin electron beam therapy and cutaneous T-cell lymphoma: a clinical guide for patients and staff.
Total skin electron beam therapy (TSEBT) is a technically complicated treatment used in the management of mycosis fungoides (MF). A variety of technical and clinically oriented issues relating to TSEBT and its effects for patients with MF are reviewed.
Faculty mentorship and first year students at the Yale School of Medicine: reflections and perspective.
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Evaluation of the National Resident Matching Program (NRMP) radiation oncology data (1993-2003).
PURPOSE: Radiation oncology continues to evolve as a specialty. In the early 1990s, issues of manpower oversupply, resource allocation, development of academic radiation oncology, and residency training curricula were fervently considered and evaluated. Much of this effort continues. This communication endeavors to examine the National Residency Matching Program (NRMP) results as they pertain to radiation oncology to identify and document applicant trends over the last decade. METHODS AND MATERIALS: The NRMP database tables for inclusive dates 1993-2003 were evaluated. The database figures were supplied directly from the executive staff at the AAMC/NRMP. Data were reviewed for radiation oncology, and the following variables were evaluated for the study period (1993-2003): Training program participation, positions offered, applicant totals, proportion of US senior applicants, US seniors as a percentage of those who successfully matched, ratio of applicants to positions, and percentage of training program positions filled. Trends over the study period were analyzed. Data were also analyzed for all specialties collectively as a comparison group. RESULTS: The number of training programs has remained relatively stable between 1993 and 2003. In 2003, each radiation oncology program in the NRMP on average accepted two new candidates. The number of positions offered has fluctuated over time. There appeared to be a downward trend until 2003, during which 107 positions were offered. The number of applicants continues to rise with totals of 209 and 214 in 2003 and 2001, respectively. Percentage of US senior applicants compared with the total pool has remained relatively stable, but raw numbers are rising. The number of US seniors as a percentage of those who successfully matched escalated during 2001 compared with previous years. This value has been consistent over the past 3 years, at a level of approximately 94%. The ratio of applicants to positions, which is a broad indicator of level of competition for entrance, began to rise significantly in 2000 to a level of 1.9. It peaked at 2.6 in 2001, and the ratio for 2003 was approximately 2.0. For the first time, all positions offered were filled (100%) through the NRMP match process in 2003. Such positive trends have not been realized to the same degree for all specialties analyzed as a cohort. CONCLUSION: Acceptance into radiation oncology training programs through the NRMP has become very competitive. The explanation for this trend is likely complex with many variables. These data may be helpful in training program development and will certainly be of service to advisors of medical students seeking entrance into the field in the near future.
Skin cancers after organ transplantation.
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Delivery and sequelae of total skin electron beam therapy.
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Total skin electron beam radiotherapy for patients who have mycosis fungoides.
It has taken four decades of basic and clinical research to bring about a consensus process and published report that recognize a TSEB radiotherapy technique that is optimized from several perspectives (see references [2-4, 13]). Short and long-term clinical results with consensus TSEB radiotherapy technique are good. The therapeutic ratio of TSEB radiotherapy is well-defined and is clinically acceptable. Meanwhile, adjuvant PUVA and ECP may significantly improve results, but further data are needed to confirm these preliminary findings (see references [23, 34, 39, 40, 42]).
Disseminated herpes simplex after total skin electron beam radiotherapy for mycosis fungoides.
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Management of mycosis fungoides. Part 1. Diagnosis, staging, and prognosis.
Mycosis fungoides is a low-grade lymphoproliferative disorder caused by CD4+ lymphocytes. It is the most common type of cutaneous T-cell lymphoma. Typically, neoplastic T cells localize to the skin and produce patches, plaques, tumors, or erythroderma. Diagnosis of early mycosis fungoides can be difficult due to the nonspecific nature of cutaneous and histologic findings. However, recent advances in the application of histologic criteria, coupled with molecular biology tools such as immunophenotyping and polymerase chain reaction, have improved diagnostic accuracy. Independent prognostic factors include the extent and nature of skin involvement, the presence of extracutaneous disease, blood involvement, age > or = 60 years, and lactate dehydrogenase elevation. Accordingly, patients with limited patches and/or plaques (stage IA or IIA) experience long-term survival comparable to that of matched controls. The median survival is 11 years for patients with extensive patch/plaque (stage IB or IIA), 3.2 years for those with cutaneous tumors (stage IIB), 4.6 years for those with erythroderma (stage III), 1.2 years for those with pathologic nodal involvement (stage IVA), and 0.9 years for those with visceral disease (stage IVB). Over time, mycosis fungoides may progress to Sézary syndrome or transform to large-cell histology.