Adrenal and Renal Physiology, and Medical Renal Disease

ADRENAL AND RENAL PHYSIOLOGY, AND MEDICAL RENAL DISEASE the relationship between continuity of care and receipt of colorectal and prostate cancer screening. Methods: Subjects were enrolled in a Washington State health plan that operates an integrated delivery system that emphasizes access to primary care. Among patients age 50 –78 years old with 2 or more primary care visits in 2002–2003 (N ⫽ 67,633), we determined whether higher continuity (⬎/⫽50% of visits with the most visited primary care provider) was associated with colorectal, breast, and prostate cancer screening. Random-effects logistic regression estimated adjusted percentages of patients who received fecal occult blood testing, lower endoscopy (sigmoidoscopy or colonoscopy), screening mammography, and prostate specific antigen (PSA) testing. Results: Patients with higher continuity were more likely to receive fecal occult blood testing than patients with lower continuity (28.9% vs. 26.8%; P ⬍ 0.001) but less likely to receive lower endoscopy (12.9% vs. 14.3%; P ⬍ 0.001). Although higher continuity was not significantly associated with screening mammography (P ⫽ 0.38), men with higher continuity were more likely to receive PSA testing than men with lower continuity (39.4% vs. 37.4%; P ⫽ 0.008). Conclusions: In an insured population with a high degree of primary care access, continuity with a specific primary care physician was associated with the selection of less invasive colorectal cancer screening tests by patients and physicians and greater likelihood of PSA testing. Editorial Comment: This article is remarkable for 2 reasons. First, it demonstrates that increased continuity of primary care is associated with higher rates of prostate cancer screening. In other words, if a patient receives primary care from the same provider for a prolonged period, that patient is more likely to undergo colorectal, breast (for women) or prostate cancer screening (for men). Therefore, if we want to improve cancer screening rates, we should find ways to improve the continuity of primary care. However, in prostate cancer the effect is minimal (37% vs 39% for patients who see the same primary care provider fewer than 2 times vs 2 times or more). What is really shocking here is the astonishingly low prostate cancer screening rates among eligible men. This finding may be reflective of the study cohort. These patients were all members of Group Health Cooperative (GHC), a health maintenance organization based in Seattle, Washington, that actively opposed and refused to cover routine prostate cancer screening in the early 1990s. They have since changed their coverage policies and it is my understanding that now GHC neither encourages nor discourages prostate cancer screening. Interestingly, their stance in the 1990s appears to have had a lingering effect. Recent legislation in Washington State has mandated prostate cancer screening, which hopefully will bring the GHC patterns of care more in line with the rest of the state. However, urologists and policy makers in Washington State should monitor this situation and force action if changes do not occur. While there still is no level I evidence supporting screening, patients should not be denied access to screening, either explicitly or implicitly, purely on the basis of their insurance status. David F. Penson, M.D., M.P.H.

ADRENAL AND RENAL PHYSIOLOGY, AND MEDICAL RENAL DISEASE Assessment of Age-Related Changes in Abdominal Organ Structure and Function With Computed Tomography and Positron Emission Tomography J. M. Meier, A. Alavi, S. Iruvuri, S. Alzeair, R. Parker, M. Houseni, M. Hernandez-Pampaloni, A. Mong and D. A. Torigian, Department of Radiology, Division of Nuclear Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania Semin Nucl Med 2007; 37: 154 –172. With the size of the aged population in the United States expected to grow considerably during the next several decades, the number of imaging studies performed on such aged individuals will similarly increase. Thus, it is important to understand normal age-related changes in the structural and functional imaging appearance of the abdominal organs. We therefore present preliminary data and a review of the literature relevant to structural and functional changes in the abdominal organs of children and older adults. In a retrospective study of both adult and pediatric populations, we used computed tomography (CT), positron emission tomography (PET), and PET/CT imaging to investigate age-associated changes in size, attenuation, and metabolic function of the abdominal organs. Organs of interest include the liver, spleen, pancreas,

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BLADDER, PENIS AND URETHRAL CANCER, AND BASIC PRINCIPLES OF ONCOLOGY kidneys, adrenal glands, stomach, small bowel, colon, and rectum. Although volumes of adult liver, spleen, pancreas, and kidneys do not change significantly with age, adult left and right adrenal gland volumes do significantly increase with age (r ⫽ 0.2823, P ⫽ 0.0334, and r ⫽ 0.3676, P ⫽ 0.0049, respectively). Also, the attenuation of adult liver (r ⫽ ⫺0.2122, P ⫽ 0.0412), spleen (r ⫽ ⫺0.4508, P ⬍ 0.0001), pancreas (r ⫽ ⫺0.5124, P ⫽ 0.0007), and left and right adrenal gland (r ⫽ ⫺0.5835, P ⬍ 0.0001 and r ⫽ ⫺0.6135, P ⬍ 0.0001, respectively) decrease significantly with increasing age. Every organ studied in the pediatric population demonstrates a positive association between organ volume and age. Significant age-related changes in organ function are noted in the adult liver and small bowel, with the liver demonstrating a positive association between metabolic activity and age (r ⫽ 0.4434, P ⫽ 0.0029) and the small bowel showing an inverse association between mean small bowel standardize uptake value and age (r ⫽ ⫺0.2435, P ⫽ 0.0174). Also, the maximum overall small bowel and colon metabolic activity in children increases with age (r ⫽ 0.6478, P ⫽ 0.0008). None of the other organs studied (ie, spleen, pancreas, adrenal glands, stomach, colon, rectum) demonstrate significant changes in metabolism with advancing age. The metabolic volumetric product (calculated as the product of organ volume and mean organ SUV) of the liver and spleen does not change significantly with age. In conclusion, various abdominal organs demonstrate differential changes in volume, attenuation, and/or metabolism with increasing age in pediatric and adult populations. Editorial Comment: It is interesting that the size of adult kidneys does not change significantly with age, nor is there decreased attenuation with age. However, adrenal gland volumes increase with age in the adult and the attenuation coefficient decreases with age. Obviously organ size is correlated with age in children, and kidneys and adrenals increase in size from childhood to adulthood. W. Scott McDougal, M.D.

UROLOGICAL ONCOLOGY: BLADDER, PENIS AND URETHRAL CANCER, AND BASIC PRINCIPLES OF ONCOLOGY Hospital Volume and Late Survival After Cancer Surgery J. D. Birkmeyer, Y. Sun, S. L. Wong and T. A. Stukel, Department of Surgery, Michigan Surgical Collaborative for Outcomes Research and Evaluation, University of Michigan, Ann Arbor, Michigan Ann Surg 2007; 245: 777–783. Context: Although hospital procedure volume is clearly related to operative mortality with many cancer procedures, its effect on late survival is not well characterized. Objective: To examine relationships between hospital volume and late survival after different types of cancer resections. Design: Using the national Surveillance Epidemiology and End Results (SEER)-Medicare linked database (1992–2002), we identified all patients undergoing major resections for lung, esophageal, gastric, pancreatic, colon, and bladder cancer (n ⫽ 64,047). Relationships between hospital volume and survival were assessed using Cox proportional hazards models, adjusting for patient characteristics and use of adjuvant radiation and chemotherapy. Study Participants: U.S. Medicare patients residing in SEER regions. Main Outcome Measures: 5-year survival. Results: Although there were statistically significant relationships between hospital volume and 5-year survival with all 6 cancer types, the relative importance of volume varied markedly. Absolute differences in 5-year survival probabilities rates between low-volume hospitals (LVHs) and high-volume hospitals (HVHs) ranged from 17% for esophageal cancer resection (17% vs. 34%, respectively) to only 3% for colon cancer resection (45% vs. 48%). Absolute differences in 5-year survival between LVHs and HVHs fell between these ranges for lung (6%), gastric (6%), pancreatic (5%), and bladder cancer (4%). Volumerelated differences in late survival could not be attributed to differences in rates of adjuvant therapy. Conclusions: Along with lower operative mortality, HVHs have better late survival rates with selected cancer resections than their lower-volume counterparts. Mechanisms underlying their better outcomes and thus opportunities for improvement remain to be identified. Editorial Comment: Most hospital volume/outcome relationships have looked at short-term mortality, complications or length of stay. This SEER-Medicare study of patients undergoing resection for 1 of 6 cancers (lung, esophageal, gastric, pancreatic, colon or bladder) shows a lower 5-year survival rate in low volume hospitals compared to high volume hospitals. The largest absolute difference was seen in esophageal cancer at 17% but a diminished survival rate was also noted for bladder cancer (4% difference). James E. Montie, M.D.