Cystic pancreatic neoplasms: observe or operate

OBJECTIVE: The objectives of this analysis were to define the incidence, natural history, and predictors of neoplasia in pancreatic cysts to determine which patients can safely be observed and which should undergo an operation. SUMMARY BACKGROUND DATA: With advancements in imaging technology, cystic lesions of the pancreas are being detected with increased frequency. Many of these lesions are small and asymptomatic, but they may be associated with pancreatitis or have malignant potential. Therefore, the management of these patients is complex, and knowledge of pancreatic cyst natural history and predictors of neoplasia are important. METHODS: From January 1995 through December 2002, all radiologic, surgical, and pathology records were reviewed for the presence of pancreatic cysts. In determining natural history, only patients with 2 scans more than 1 month apart at our institution were included. Patients with a clinical history and laboratory evidence of pancreatitis and/or pathologic confirmation of a pseudocyst were excluded. Factors analyzed as potential predictors of neoplasia included age, gender, cyst size, and symptoms. Serous cystadenomas, solid and cystic papillary (Hamoudi) tumors, lymphoepithelial cysts and simple cysts were all benign, whereas mucinous cystic neoplasms, intraductal papillary mucinous neoplasm, cystic neuroendocrine tumors, and cystadenocarcinomas were considered to be premalignant or malignant. RESULTS: Among 24,039 CT or MR scans, 290 patients (1.2%) had pancreatic cysts, and 168 of these patients (0.7%) had no documentation of pancreatitis. Seventy-nine of these patients with 103 cysts had more than 1 scan with an average interval of 16 months. These cysts increased in size in 19%, did not change in 59% and decreased in 22% of patients. Forty-nine patients underwent surgery for 14 benign (serous cystadenomas = 10, Hamoudi = 2, lymphoepithelial = 1, simple = 1) 25 premalignant (mucinous cystic neoplasm =16, intraductal papillary mucinous neoplasm = 5, neuroendocrine tumors = 4), or 10 malignant (intraductal papillary mucinous neoplasm = 7, cystadenocarcinomas = 3) lesions. Gender and cyst size did not predict neoplasia. However, presence of symptoms predicted premalignant or malignant pathology (60% vs. 23%, P < 0.05), and age over 70 years was associated with malignancy (60% vs. 21%, P < 0.02). CONCLUSIONS: These data suggest that cystic pancreatic neoplasms 1) occur in 0.7% of patients, 2) increase in 19% over 16 months, and 3) are likely (60%) to be malignant in patients older than 70 years. Therefore, we recommend surgical excision for pancreatic cysts that are increasing under observation, symptomatic, or detected radiologically in fit older patients.     

Combining information in different color-coding mechanisms to facilitate visual search

An earlier experiment using a yes-no procedure with a search accuracy task [A.L. Nagy, G. Thomas, Distractor heterogeneity, attention, and color in visual search tasks, Vision Research, 43 (2003) 1541-1552] showed that observers could combine information in different cardinal color mechanisms to facilitate search performance. In the experiments reported here we attempted to replicate these results with a forced-choice procedure and tested three different models of the manner in which information in different feature coding mechanisms is combined. One model was a linear summing model in which signals in different mechanisms are linearly summed in a mechanism under the control of attention. The summed signals are used to guide attention to likely targets. The second model was a nonlinear selection model in which signals in one mechanism are used to select stimuli for attention. A decision is then based on signals generated by the selected stimuli in a mechanism other than the one that is used for selection. The third model was the linear separability model, which suggests that the chromaticity of the target stimulus must be separated from the chromaticities of the distractor stimuli by a straight line in a chromaticity diagram for efficient search. Results favored the nonlinear selection model over the linear summing model and the linear separability model.     

Color mechanisms used in selecting stimuli for attention and making discriminations

Previous work (Nagy & Thomas, 2003) showed that signals in different Cardinal color mechanisms could be combined to facilitate search for a color target. Further investigation (Nagy et al., 2003) suggested that signals in one Cardinal color mechanism were used to select a subset of stimuli to be attended, while signals in second Cardinal mechanism were used to discriminate the stimuli within the selected subset. In the studies described below, we asked if observers could use color mechanisms tuned to directions other than the Cardinal directions to select and discriminate stimuli. Observers searched for a single target stimulus that differed in chromaticity from nine distractor stimuli. A two-alternative forced-choice procedure was used to estimate thresholds. Results were consistent with the hypothesis that color mechanisms tuned to many different directions in color space mediate discrimination, but suggest that only signals in Cardinal mechanisms can be used to select stimuli for attention. Results imply that the selection of stimuli for attention on the basis of color may be mediated at the level of the lateral geniculate nucleus (LGN).     

Management of osteoporosis in adults with cystic fibrosis

Cystic fibrosis (CF) is the most common genetic disease that causes respiratory failure within the Caucasian population. The life span of patients with CF has gradually increased from a median of 2 years of age to >30 years. Concurrent with this increased lifespan, a variety of other nutritional, endocrine and bone issues have been recognised. Decreased absorption of fat-soluble vitamins (D and K in particular) because of pancreatic insufficiency, altered sex hormone production, chronic inflammation, a lack of physical activity, glucocorticoid treatment and an intrinsic hyper-resorptive bone physiology are some of the factors that contribute to the prominence of bone disease within the CF population. In some series, three-quarters of adult patients with CF have osteopenia or osteoporosis. Lung transplantation is one viable treatment for patients with end-stage CF, which requires a lifetime of antirejection medication. Immunosuppressant therapies have a detrimental effect on bone mineral density (BMD). To combat the multifactorial nature of CF-related bone disease, advances in nutritional and vitamin supplementation, and anti-resorptive and anabolic therapies have evolved. Chronic vitamin D depletion contributes to bone disease in the CF population. The isoform of vitamin D that is the best and safest supplement, with the lowest cost, has yet to be identified. However, it is clear that many patients with CF who receive the standard of care (i.e. two daily combination vitamin A, D, E and K tablets [ADEKs]) may still be vitamin D-deficient. More aggressive supplementation needs to be individualised, with close monitoring of serum 25-hydroxyvitamin D levels. Similarly, routine calcium supplementation may be important, and evidence is accumulating that vitamin K also plays an important role in maximising and maintaining BMD. Early recognition and treatment of delayed puberty in adolescents and hypogonadism in adults with hormone replacement therapy is recommended to maintain BMD in patients with CF. Bisphosphonates, including pamidronic acid, etidronic acid and alendronic acid, reduce bone resorption by inhibiting the recruitment and function of osteoclasts. Pamidronic acid is beneficial in improving BMD in CF patients before and after transplantation. Bisphosphonate therapy and minimisation of glucocorticoid dosage have been shown to be efficacious in glucocorticoid-induced osteoporosis. Teriparatide is the first US FDA-approved anabolic growth agent for bone, and has been shown to increase BMD and decrease fracture incidence in postmenopausal women. Teriparatide may offer a new avenue for treating bone disease in CF since many patients may have poor bone formation as well as accelerated bone breakdown. Numerous clinical trials are underway to optimise treatment of CF osteoporosis.     

Cancer survival in a southern African urban population

This paper provides the first comprehensive population based cancer survival estimates from the African continent. Five-year absolute and relative survival estimates are presented for black and white Zimbabwean patients diagnosed with cancer in Harare, Zimbabwe between the years 1993 and 1997. The survival of black Zimbabwean cancer patients are among the lowest ever reported from population based cancer registries. For most cancer sites, white Zimbabwean patients have much higher survival than black Zimbabweans, except for lung and colorectal cancer, for which the estimates are similarly poor. Race specific comparisons to cancer patients in the United States show that Zimbabwean patients have much lower survival than American cancer patients and that the gap between black Zimbabwean patients and black American patients is broader than between white Zimbabwean and white American patients. Access to and the ability to pay for medical care may be a very important barrier to better survival for the majority of black Zimbabwean patients and the most important cause for the very low cancer survival in this population.     

A review of thyroid cancer with intermediate differentiation

BACKGROUND AND OBJECTIVES: Tall cell (TCV), columnar cell (CCV), insular (IC), diffuse sclerosing (DSPTC) and solid/trabecular are uncommon subtypes of thyroid cancer, which have generally been described in case reports or small series in the world literature. Due to the rarity of these thyroid cancers, their clinical behavior remains incompletely understood. The aim of this review was to pool the currently available clinical information regarding these uncommon thyroid cancers so as to gain a better understanding of their clinical aspects and natural history. METHODS: A computer-aided search of MEDLINE (1966-2001, PUBMED website) and CINAHL (1982-2001) databases was performed, as well as a review of the reference section of each primary study was done. All cases of TCV, CCV, DSPTC, solid/trabecular, and IC described in the English medical literature were identified. For the subtypes DSPTC, TCV, and IC, clinical data from the published case series were combined in a weighted analysis. Weighting was based on the number of cases per series. For the CCV and the solid/trabecular variant, due to the small number of cases, raw figures for the clinical features were obtained. RESULTS: DSPTC (n = 65) appeared to have a tendency for intra-thyroidal extension (40%) and a high propensity for nodal metastates (68%). The mean overall tumor related mortality was similar to well differentiated thyroid cancer (WDTC) at only 2% at 8 years follow-up. The solid/trabecular variant was seen in 37% of the radiation induced thyroid tumors of the Chernobyl accident. It had a high propensity for extrathyroidal extension, and cervical lymph node metastases were found in up to 83% of patients. Unlike WDTC, TCV (n = 209) was a more aggressive tumor, associated with distant metastases in 22% of cases and had a mean tumor related mortality of 16%. The histological diagnosis of TCV was a poor prognostic factor regardless of patient age or tumor size. The CCV (n = 41) had a high overall mortality rate of 32%. When encapsulated, however, CCV had an excellent prognosis similar to that found in WDTC. In contrast, CCV tumors that were not encapsulated had extrathyroidal spread in 67% and had distant metastases in 87% of patients. The variant of IC (n = 213) appeared to be an aggressive subtype of thyroid cancer. The mean loco-regional recurrence and/or distant metastases rate was 64% and tumor related mortality was high at 32%. CONCLUSIONS: DSPTC, TCV, CCV, and IC are thyroid cancer subtypes, which have a biological aggressiveness, which appear to be intermediate between that of WDTC and poorly differentiated anaplastic thyroid cancer. J. Surg. Oncol. 2004;86:44-54.