Genetic testing for hereditary cancer predisposition: BRCA1/2, Lynch syndrome, and beyond.

Obstetrician/gynecologists and gynecologic oncologists serve an integral role in the care of women at increased hereditary risk of cancer. Their contribution includes initial identification of high risk patients, screening procedures like bimanual exam, trans-vaginal ultrasound and endometrial biopsy, prophylaxis via TAH and/or BSO, and chemoprevention. Further, gynecologists also serve a central role in the management of the secondary repercussions of efforts to mitigate increased cancer risks, including vasomotor symptoms, sexual function, bone health, cardiovascular disease, and mental health. The past several years has seen multiple new high and moderate penetrance genes introduced into the clinical care of women at increased risk of gynecologic malignancy. Awareness of these new genes and the availability of new multi-gene panel tests is critical for providers on the front-line of women's health.

Genetic counselors' (GC) knowledge, awareness, understanding of clinical next-generation sequencing (NGS) genomic testing.

Genomic tests are increasingly complex, less expensive, and more widely available with the advent of next-generation sequencing (NGS). We assessed knowledge and perceptions among genetic counselors pertaining to NGS genomic testing via an online survey. Associations between selected characteristics and perceptions were examined. Recent education on NGS testing was common, but practical experience limited. Perceived understanding of clinical NGS was modest, specifically concerning tumor testing. Greater perceived understanding of clinical NGS testing correlated with more time spent in cancer-related counseling, exposure to NGS testing, and NGS-focused education. Substantial disagreement about the role of counseling for tumor-based testing was seen. Finally, a majority of counselors agreed with the need for more education about clinical NGS testing, supporting this approach to optimizing implementation.

Oral contraceptive and reproductive risk factors for ovarian cancer within sisters in the breast cancer family registry.

BACKGROUND: Oral contraceptive use has been consistently associated with a reduced risk of ovarian cancer in unrelated, average risk women; however little data exist on whether this benefit extends to higher risk women from cancer families. To examine this, we conducted family-based analyses using the Breast Cancer Family Registry. METHODS: We used generalised estimating equations to obtain the population average effect across all families (n=389 cases, n=5643 controls) and conditional logistic regression to examine within-family differences in a subset with at least two sisters discordant on ovarian cancer status (n=109 cases, n=149 unaffected sister controls). RESULTS: In the multivariable generalised estimating equation model there was a reduced risk of ovarian cancer for ever use of oral contraceptives compared with never use (OR=0.58, 95% CI: 0.37, 0.91), and in the conditional logistic model there was a similar inverse association; however, it was not statistically significant (OR=0.52, 95% CI: 0.23, 1.17). We examined this association by BRCA1/2 status and observed a statistically significant reduced risk in the non-carriers only. CONCLUSION: We observed a decreased risk of ovarian cancer with oral contraceptive use supporting that this association observed in unrelated women extends to related women at higher risk.

Genetic counselor opinions of, and experiences with telephone communication of BRCA1/2 test results.

BRCA1/2 test disclosure has, historically, been conducted in-person by genetics professionals. Given increasing demand for, and access to, genetic testing, interest in telephone and Internet genetic services, including disclosure of test results, has increased. Semi-structured interviews with genetic counselors were conducted to determine interest in, and experiences with telephone disclosure of BRCA1/2 test results. Descriptive data are summarized with response proportions. One hundred and ninety-four genetic counselors completed self-administered surveys via the web. Although 98% had provided BRCA1/2 results by telephone, 77% had never provided pre-test counseling by telephone. Genetic counselors reported perceived advantages and disadvantages to telephone disclosure. Thirty-two percent of participants described experiences that made them question this practice. Genetic counselors more frequently reported discomfort with telephone disclosure of a positive result or variant of uncertain significance (p < 0.01) than other results. Overall, 73% of participants reported interest in telephone disclosure. Many genetic counselors have provided telephone disclosure, however, most, infrequently. Genetic counselors identify potential advantages and disadvantages to telephone disclosure, and recognize the potential for testing and patient factors to impact patient outcomes. Further research evaluating the impact of testing and patient factors on cognitive, affective, social and behavioral outcomes of alternative models of communicating genetic information is warranted.

Measuring, and identifying predictors of women's perceptions of three types of breast cancer risk: population risk, absolute risk and comparative risk.

Although a key function of cancer genetics services is to provide risk information, to date there has been little consistency in the way in which breast cancer risk perception has been measured. The aims of the study were to measure estimates of (i) population risk, (ii) absolute risk and (iii) comparative risk of developing breast cancer for Ashkenazi Jewish women, and to determine predictors of breast cancer risk perception. Of 152 women, 107 (70%) completed all questions. The mean (s.d.) estimates for population risk, absolute risk and comparative risk were 22.7% (15.9), 31.8% (20.6) and 1.9-fold (1.9), respectively. Most women overestimated population risk. Women at population risk generally overestimated the population risk and their own absolute risk, yet understood they are at the same risk as the population. Those with a family history understood that they are at increased risk, but underestimated the extent to which their familial risk is increased. Anxiety, high estimation of population risk and lesser family history predicted overestimation of absolute risk, whereas high estimation of population risk and a strong family history predicted underestimation of comparative risk.

Breast cancer prognosis in a mixed Caucasian-Hispanic population.

Prognostic factors were compared between 1,249 Caucasian and 360 Hispanic women with breast cancer. A significantly greater proportion of Hispanic women were less than 50 years of age at diagnosis compared to Caucasian women (P less than .0001). Significantly more Hispanic women presented with tumors larger than 3 cm in diameter and with positive axillary lymph nodes than did Caucasian women (P = .004 and P = .0001, respectively). Significantly more Hispanic women were estrogen receptor (ER) negative (P = .005). However, when examined by age groups, the relationships between ethnicity and extent of disease and ER status were observed only among women over 50 years of age. Multivariate analyses demonstrated that there was no difference in survival between Caucasian and Hispanic women once adjustments were made for the number of positive lymph nodes and ER status. Although complete data were not available, it appeared that the incidence of breast cancer is lower in this population of Hispanic women than in Caucasian women.

Microscopic benign and invasive malignant neoplasms and a cancer-prone phenotype in prophylactic oophorectomies.

BACKGROUND: The occurrence of approximately 5% of common epithelial malignant tumors of the ovary can be traced to inheritance of risk. One prophylactic strategy to decrease the probability of development of disease in individuals within families where this mendelian-dominant pattern of occurrence is apparent is to remove the ovaries of individuals at risk for ovarian cancer. The procedure, when done for this purpose, is recommended soon after completion of childbearing. PURPOSE: Our goal was to compare the histologic features of the ovaries of women at increased risk for ovarian cancer to those at no known increased risk for the disease. METHODS: Ovaries removed for prophylaxis from 20 women considered to be at increased risk for developing ovarian cancer were examined histologically. During the course of this work, it seemed apparent that these ovaries contained numerous atypical features compared with the expected appearance of normal ovaries. Hence, we expanded the study to include a control group whose ovaries were removed for reasons unrelated to cancer. The study, therefore, was not blinded. The increased risk in the cancer-prone individuals was determined by family history, specifically the presence of at least one first-degree relative and one second-degree relative with ovarian and/or breast cancer and positive linkage or mutational analysis of BRCA1 in some. The difference in mean ages of patients in the control and high-risk groups was not statistically significant. The difference among both groups with respect to the number of atypical features as well as the intensity of those features was ascertained by computing probabilities using Fisher's exact test (two-sided) for rows x columns contingency tables. RESULTS: Two unanticipated microscopic or near-microscopic malignant neoplasms and other benign and borderline tumors were discovered in the ovaries of the high-risk individuals. Of substantial interest was the finding that among the ovaries of high-risk women, 85% presented two or more and 75% presented three or more of the following histologic features: surface epithelial pseudostratification; surface papillomatosis; deep cortical invaginations of the surface epithelium, frequently with multiple papillary projections within small cystic spaces (microscopic papillary cystadenomas); epithelial inclusion cysts, frequently with epithelial hyperplasia and papillary formations; cortical stromal hyperplasia and hyperthecosis; increased follicular activity; corpus luteum hyperplasia; or hilar cell hyperplasia. Two or more or three or more such changes were observed in a lesser percentage (30% or 10%, respectively) of ovaries obtained from the control individuals, with a statistically significant difference (P = .001 or P = .00007, respectively), particularly considering that a detailed determination of a family history of cancer in the control group was not possible. CONCLUSIONS: The frequency of these changes in the high-risk ovaries compared with control ovaries suggests a characteristic histologic preneoplastic phenotype defined by an increased frequency and intensity of the above-described histologic features in the high-risk ovaries. Limited access to numerous small (stage I) ovarian cancers or cancer-prone ovaries by any one pathologist may explain the failure to identify the phenotype in the past. IMPLICATIONS: We suggest that the ovaries removed from ovarian cancer-prone individuals as a preventative measure should be thoroughly examined histologically to identify or rule out microscopic or near-microscopic invasive neoplasms.

Breast cancer risk after bilateral prophylactic oophorectomy in BRCA1 mutation carriers.

BACKGROUND: The availability of genetic testing for inherited mutations in the BRCA1 gene provides potentially valuable information to women at high risk of breast or ovarian cancer; however, carriers of BRCA1 mutations have few clinical management options to reduce their cancer risk. Decreases in ovarian hormone exposure following bilateral prophylactic oophorectomy (i.e., surgical removal of the ovaries) may alter cancer risk in BRCA1 mutation carriers. This study was undertaken to evaluate whether bilateral prophylactic oophorectomy is associated with a reduction in breast cancer risk in BRCA1 mutation carriers. METHODS: We studied a cohort of women with disease-associated germline BRCA1 mutations who were assembled from five North American centers. Surgery subjects (n = 43) included women with BRCA1 mutations who underwent bilateral prophylactic oophorectomy but had no history of breast or ovarian cancer and had not had a prophylactic mastectomy. Control subjects included women with BRCA1 mutations who had no history of oophorectomy and no history of breast or ovarian cancer (n = 79). Control subjects were matched to the surgery subjects according to center and year of birth. RESULTS: We found a statistically significant reduction in breast cancer risk after bilateral prophylactic oophorectomy, with an adjusted hazard ratio (HR) of 0.53 (95% confidence interval [CI] = 0.33-0.84). This risk reduction was even greater in women who were followed 5-10 (HR = 0. 28; 95% CI = 0.08-0.94) or at least 10 (HR = 0.33; 95% CI = 0.12-0.91) years after surgery. Use of hormone replacement therapy did not negate the reduction in breast cancer risk after surgery. CONCLUSIONS: Bilateral prophylactic oophorectomy is associated with a reduced breast cancer risk in women who carry a BRCA1 mutation. The likely mechanism is reduction of ovarian hormone exposure. These findings have implications for the management of breast cancer risk in women who carry BRCA1 mutations.

Modification of BRCA1- and BRCA2-associated breast cancer risk by AIB1 genotype and reproductive history.

Women who have inherited a germ-line mutation in the BRCA1 or BRCA2 (BRCA1/2) genes have a greatly increased risk of developing breast cancer compared with the general population. However, there is also substantial interindividual variability in the occurrence of breast cancer among BRCA1/2 mutation carriers. We hypothesize that genes involved in endocrine signaling may modify the BRCA1/2-associated age-specific breast cancer penetrance. We studied the effect of alleles at the AIB1 gene using a matched case-control sample of 448 women with germ-line BRCA1/2 mutations. We found that these women were at significantly higher breast cancer risk if they carried alleles with at least 28 or 29 polyglutamine repeats at AIB1, compared with women who carried alleles with fewer polyglutamine repeats [odds ratio (OR), 1.59; 95% confidence interval (CI), 1.03-2.47 and OR, 2.85; 95% CI, 1.64-4.96, respectively]. Late age at first live birth and nulliparity have been associated with increased breast cancer risk. We observed increases in BRCA1/2-associated breast cancer risk in women who were either nulliparous or had their first live birth after age 30 (OR, 3.06; 95% CI, 1.52-6.16). Women were at significantly increased risk if they were nulliparous or had a late age at first live birth and had AIB1 alleles no shorter than 28 or 29 or more AIB1 polyglutamine repeats (OR, 4.62; 95% CI, 2.02-10.56 and OR, 6.97; 95% CI, 1.71-28.43, respectively) than women with none of these risk factors. Our results support the hypothesis that pathways involving endocrine signaling, as measured through AIB1 genotype and reproductive history, may have a substantial effect on BRCA1/2-associated breast cancer risk.

Phase II trial of high-dose melphalan and autologous bone marrow transplantation for metastatic colon carcinoma.

Colon carcinoma, the second leading cause of cancer-related deaths in the United States, is resistant to chemotherapy in a large majority of cases. Single-agent and combination chemotherapy have failed to prolong survival. New approaches are clearly needed. In experimental models, a steep dose-response curve for colorectal cancer has been demonstrated using various agents. The hematopoietic toxicity of high-dose therapy with these drugs can be circumvented by autologous bone marrow transplantation. We investigated the use of high-dose melphalan with autologous bone marrow rescue in 20 patients with metastatic colon carcinoma. Each patient received melphalan, 180 mg/m2 intravenously (IV), followed eight hours later by bone marrow infusion. Median duration of granulocytopenia (less than 500 neutrophils/microL) was twelve days (range, 5 to 35 days), while transfusion-dependent thrombocytopenia (less than 20,000 platelets/microL) had a median duration of eight days (range, 3 to 23 days). Time to bone marrow engraftment was not affected by prior 5-fluorouracil therapy. Nausea and vomiting occurred in 14 patients but was generally short lived. Mild stomatitis, esophagitis, and diarrhea were common. Severe gastrointestinal (GI) side effects did not occur. One treatment-related death occurred secondary to intramural tumor necrosis, which resulted in massive lower GI bleeding. Complete responses were observed in three patients (15%) and partial responses in six patients (30%), for an overall response rate of 45%. Median survival was 198 days in this group of patients with extensive disease. High-dose melphalan therapy for metastatic colon carcinoma, when used with autologous bone marrow transplantation, appears to achieve a high response rate with tolerable toxicity. Further investigation is needed to define the role of this therapy in the care of advanced colon carcinoma.

Prolongation of survival for high-grade malignant gliomas with adjuvant high-dose BCNU and autologous bone marrow transplantation.

Employment of postoperative brain irradiation in the initial management of high-grade malignant glial tumors has now become standard. The addition of conventional chemotherapy to irradiation has not significantly improved median survival beyond 1 year. We treated 25 consecutive patients (13 pilot patients and 12 protocol patients) with histologically confirmed unresectable grade 3 or 4 malignant gliomas with high-dose BCNU (carmustine) followed by autologous bone marrow transplantation and whole brain irradiation. Within 3 weeks of initial surgery, each patient had autologous bone marrow stored (median 2 X 10(8) nucleated cells/kg), and then received BCNU 1,050 mg/m2 intravenously (IV). Peripheral granulocytes recovered (greater than 500/microL) at a median of 19 days (range, 10 to 37 days), and platelets recovered (greater than 20,000/microL) at a median of 18 days (range, 13 to 40 days), following bone marrow infusion. Patients received 60 Gy whole brain irradiation when granulocytes were greater than 1,500/microL. Toxicity was well tolerated. Nausea occurred in 19 patients (76%); however, only eight patients (32%) experienced vomiting (mild in three, moderate in five). Eleven patients (44%) did not require empiric antibiotics, six of whom never developed an absolute granulocyte count less than 500/microL. Three patients with a poor performance status died early (one seizure with vomiting and asphyxiation; one, klebsiella urinary tract infection (UTI) with bacteremia; one, candidal pneumonia), and one additional patient who was performing well died of pulmonary hemorrhage. The 13 pilot patients have now been followed for a median of 23 months, with a significant survival advantage compared with the 52 consecutive historical control patients who received similar surgery and radiotherapy without high-dose BCNU (P = .037). The overall study group of 25 patients also has a significant survival advantage when compared with the same historical control group, with a projected median survival of 26 months (P = .007). This new approach using early postoperative intensive therapy consisting of high-dose BCNU, autologous bone marrow transplantation, and whole brain irradiation appears to significantly improve survival.

The impact of tamoxifen on breast recurrence, cosmesis, complications, and survival in estrogen receptor-positive early-stage breast cancer.

PURPOSE: To evaluate the impact of tamoxifen on breast recurrence, cosmesis, complications, overall and cause-specific survival in women with Stage I-II breast cancer and estrogen receptor positive tumors undergoing conservative surgery and radiation. METHODS AND MATERIALS: From 1982 to 1991, 491 women with estrogen receptor positive Stage I-II breast cancer underwent excisional biopsy, axillary dissection, and radiation. The median age of patient population was 60 years with 21% < 50 years of age. The median follow-up was 5.3 years (range 0.1 to 12.8). Sixty-nine percent had T1 tumors and 83% had histologically negative axillary nodes. Re-excision was performed in 49% and the final margin of resection was negative in 64%. One hundred fifty-four patients received tamoxifen and 337 patients received no adjuvant therapy. None of the patients received adjuvant chemotherapy. RESULTS: There were no significant differences between the two groups for age, race, clinical tumor size, histology, the use of re-excision, or median total dose to the primary. Patients who received tamoxifen were more often axillary node positive (44% tamoxifen vs. 5% no tamoxifen), and, therefore, a greater percentage received treatment to the breast and regional nodes. The tamoxifen patients less often had unknown margins of resection (9% tamoxifen vs. 22% no tamoxifen). The 5-year actuarial breast recurrence rate was 4% for the tamoxifen patients compared to 7% for patients not receiving tamoxifen (p = 0.21). Tamoxifen resulted in a modest decrease in the 5-year actuarial risk of a breast recurrence in axillary node-negative patients, in those with unknown or close margins of resection, and in those who underwent a single excision. Axillary node-positive patients had a clinically significant decrease in the 5-year actuarial breast recurrence rate (21 vs. 4%; p = 0.08). The 5-year actuarial rate of distant metastasis was not significantly decreased by the addition of adjuvant tamoxifen in all patients or pathologic node-negative patients. Pathologically node-positive patients had a significant decrease in distant metastasis (35 vs. 11%; p = 0.02). There were no significant differences in cause-specific survival for patients receiving tamoxifen when compared to observation (95% no tamoxifen vs. 89% tamoxifen; p = 0.24). Similar findings were noted for pathologically node-negative patients. However, axillary node-positive patients receiving tamoxifen had an improvement in 5-year actuarial cause-specific survival (90% tamoxifen vs. 70% no tamoxifen; p = 0.10). Cosmesis (physician assessment) was good to excellent in 85% of the tamoxifen patients compared to 88% of the patients who did not receive tamoxifen. CONCLUSION: The addition of tamoxifen to conservative surgery and radiation in women with Stage I-II breast cancer and estrogen receptor positive tumors resulted in a modest but not statistically significant decrease in the 5-year actuarial risk of a breast recurrence. Tamoxifen significantly decreased the 5-year actuarial risk of distant metastasis in axillary node-positive patients and there was a trend towards improvement in cause-specific survival that was not statistically significant. Tamoxifen did not decrease the 5-year actuarial rate of distant metastasis in axillary node negative, patients and in this group, there was no improvement in cause-specific survival. Tamoxifen did not have an adverse effect on cosmesis or complications.

The central action of the 5-HT2 receptor agonist 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) on cardiac inotropy and vascular resistance in the anaesthetized cat.

Experiments were carried out to determine the effects of the application of the selective 5-HT2 receptor agonist DOI intravenously (in the presence of the peripherally acting 5-HT2 receptor antagonist, BW501C67, 1 mg kg(-1), i.v.) or to the 'glycine sensitive area' of the ventral surface (30 microg each side) on the left ventricular inotropic (left ventricular dP/dt max) and vascularly isolated hindlimb responses in anaesthetized cats. For the ventral surface experiments, NMDA (10 microg each side) was applied to act as a positive control. In all experiments heart rate and mean arterial blood pressure were held constant to exclude any secondary effects caused by changes in these variables. DOI (n=6) i.v or on the ventral surface had no effect on left ventricular dP/dt max but caused a significant increase in hindlimb perfusion pressure of 40+/-9 and 50+/-14 mmHg, respectively. Respiration was unaffected. NMDA (n=6), applied to the ventral surface, caused significant increases in both left ventricular dP/dt max and hindlimb perfusion pressure of 1,950+/-349 mmHg s(-1) and 69+/-17 mmHg respectively, with no associated change in left ventricular end-diastolic pressure. The amplitude of respiratory movements increased. It is concluded that activation of 5-HT2 receptors at the level of the rostral ventrolateral medulla (RVLM) excites sympathetic premotor neurons and/or their antecedents controlling hindlimb vascular resistance but not those controlling the inotropic effects on the left ventricle.

Is hereditary site-specific ovarian cancer a distinct genetic condition?

It is not clear if hereditary site-specific ovarian cancer exists as a genetic entity distinct from the hereditary breast-ovarian cancer syndrome. We have identified a large Ashkenazi Jewish kindred with 8 cases of ovarian carcinoma and no cases of breast cancer. Initially, linkage analysis for this kindred generated a negative LOD score to BRCA1, but subsequent mutation and haplotype analysis of key individuals demonstrated a BRCA1 185delAG mutation segregating with all but 1 of the ovarian cancer cases. This observation has important implications for genetic counselling of families with site-specific ovarian cancer. Hereditary site-specific ovarian cancer is likely to be a variant of the hereditary breast-ovarian cancer syndrome, attributable to either BRCA1 or BRCA2. We consider women from these families to be at increased risk of breast cancer and counsel them accordingly.

Carmustine, Ara C, cyclophosphamide and etoposide with autologous bone marrow transplantation in relapsed or refractory lymphoma: a dose-finding study.

The purpose of this study was to define the dose-limiting non-hematologic toxicity of carmustine, Ara C, cyclophosphamide and etoposide (BACE). Between October 1986 and March 1990, 37 patients with relapsed or refractory lymphoma received escalating doses of combination chemotherapy followed by autologous bone marrow transplant (ABMT). Twenty patients with Hodgkin's disease (HD) and 17 patients with intermediate or high grade non-Hodgkin's lymphoma (NHL) initially received conventional-dose therapy with either a 7 week course of modified MACOP-B or a single dose of cyclophosphamide (CY) at 2 g/m2 depending on prior therapy and response. Regardless of response, patients then received escalating doses of BACE, toxicity permitting. Ten patients obtained complete responses (CR) and 12 patients were partial responders (PR), CR+PR (75%) with modified MACOP-B and 7 (64%) patients obtained PR with CY. The maximum-tolerated dose (MTD) for BACE was determined to be carmustine 700 mg/m2, Ara C 1500 mg/m2, CY 150 mg/kg and etoposide 1500 mg/m2. When Ara C was escalated from 1500 mg/m2 to 3000 mg/m2 holding the other drugs at the prior doses, the next two patients died secondary to diffuse alveolar damage. Overall and event-free survivals are identical with 14 of 37 patients (38%) alive with a median follow-up of 61 months (range 38-79 months). Ten patients were treated at the MTD, none of whom died a toxic death and 3 (30%) are alive with a median follow-up of 42 months (range 38-52 months). We defined the MTD and BACE showing pulmonary toxicity to be the dose-limiting non-hematologic toxicity.(ABSTRACT TRUNCATED AT 250 WORDS)

The epidemiology of ovarian cancer.

The epidemiologic data collected to date have provided some important and provocative clues as to the etiology of ovarian cancer. The recognition of familial clustering of this disease has led to exciting advances in understanding the genetics involved. The contribution of endocrine factors has been well documented in the epidemiologic literature, leading to important insights into the process of carcinogenesis. Clearly, additional information is needed to further explain the interplay of genetic, physiologic, and life style factors, to lead to a better understanding of the disease, and ultimately to a means of prevention and control.

Specific worry about breast cancer predicts mammography use in women at risk for breast and ovarian cancer.

This longitudinal study examined predictors of mammography use among women with a family history of breast cancer participating in a risk assessment and surveillance program (N = 213). Assessed were background variables (age, prior mammography utilization), cognitive variables (perceived vulnerability), and affective variables (cancer worry and general distress). Results of logistic regression analyses predicting adherence 1 year after baseline contact, in which variables of prior utilization, feelings of vulnerability, and general distress were controlled for, indicated that cancer worry and age were significant predictors of mammography adherence. Results suggest that moderate levels of cancer worry facilitate, rather than undermine, adherence. The results have implications for the construction of educational messages that should be designed to acknowledge feelings of cancer-specific worry and to provide guidance in health protective behaviors.

Ovarian cancer risk counseling: a guide for the practitioner.

Epithelial ovarian cancer is the most common gynecologic cancer diagnosed in women in the United States, with over 20,000 newly diagnosed cases per year. Over 70% of these patients present with advanced, stage III or IV disease, resulting in more than 13,000 deaths each year. This figure is all the more tragic given the long-term disease-free survival of approximately 85% for early stage disease. The natural history of the disease is poorly understood but is characterized by an insidious onset with vague, non-specific symptoms (which are commonly overlooked), and a high but often transient response to current surgical and chemotherapeutic approaches. It is commonly associated with a prolonged and painful death accompanied by repeat bowel obstructions, malnutrition, and immunologic compromise. In addition to the pain and suffering and loss of life of those affected with the disease, there is a profound and long-lasting impact on the entire family who experience the loss.

The use of smokeless tobacco among basic airmen.

Abstract The use of smokeless tobacco, including both snuff and chewing tobacco, is enjoying a resurgence in popularity in the United States, particularly among teenage males. In order to assess the prevalence of these habits among young Air Force recruits, we administered a questionnaire to a random sample of 1,954 basic airmen at Lackland Air Force Base, Texas, to obtain information on frequency, types, intensity, and duration of smokeless tobacco use in this population. We found that 14.9 percent of the males reported using snuff for an average of 104 minutes per day. Chewing tobacco was reported among 11.1 percent of males with an average daily exposure of 72.1 minutes. The average duration of use of both snuff and chewing tobacco prior to entry into the Air Force was four years. Highest usage for both products was seen among Caucasian males. Users of both types of smokeless tobacco products were also more likely to be cigarette smokers than those who did not use either product.

Quantitative studies of the vasculature of the carotid body in the chronically hypoxic rat.

The carotid bodies of rats made chronically hypoxic by breathing 12% O2 in a normobaric chamber (inspired PO2 91 mmHg) were compared with those of controls. Serial 5-microm sections of the organs were examined using an interactive image analysis system. The total volume of the carotid bodies was increased by 64%. The total vascular volume rose by 103% and was likely due to an increase in size of the large vessels (>12 microm lumen diameter) because the small vessel (5-12 microm lumen diameter) volume did not increase significantly while the small vessel density tended to decrease. The extravascular volume was increased by 57%. Expressed as a percentage of the total volume of the organ, the total vascular volume did not change, but the small vessel volume was significantly decreased from 7.83 to 6.06%. The large vessel volume must therefore have been increased. The proportion occupied by the extravascular volume was virtually unchanged (84 vs 82%). In accordance with these findings, the small vessel endothelial surface area per unit carotid body volume was diminished from 95.2 to 76.5 mm-1, while the extravascular area per small vessel was increased from 493 to 641 microm(2) or by 30%. In conclusion, the enlargement of the carotid body in chronic hypoxia is most likely due to an increase in total vascular volume, mainly involving the "large" vessels, and to an increase in extravascular volume. This is in contrast to our previously published findings indicating that in the spontaneous insulin-dependent diabetic rat the enlargement of the carotid body is due solely to an increase in extravascular volume.