BPG: Seamless, automated and interactive visualization of scientific data

BACKGROUND

We introduce BPG, a framework for generating publication-quality, highly-customizable plots in the R statistical environment.

RESULTS

This open-source package includes multiple methods of displaying high-dimensional datasets and facilitates generation of complex multi-panel figures, making it suitable for complex datasets. A web-based interactive tool allows online figure customization, from which R code can be downloaded for integration with computational pipelines.

CONCLUSION

BPG provides a new approach for linking interactive and scripted data visualization and is available at http://labs.oicr.on.ca/boutros-lab/software/bpg or via CRAN at https://cran.r-project.org/web/packages/BoutrosLab.plotting.general.

NBN gain is predictive for adverse outcome following image-guided radiotherapy for localized prostate cancer

Despite the use of clinical prognostic factors (PSA, T-category and Gleason score), 20-60% of localized prostate cancers (PCa) fail primary local treatment. Herein, we determined the prognostic importance of main sensors of the DNA damage response (DDR): MRE11A, RAD50, NBN, ATM, ATR and PRKDC. We studied copy number alterations in DDR genes in localized PCa treated with image-guided radiotherapy (IGRT; n=139) versus radical prostatectomy (RadP; n=154). In both cohorts, NBN gains were the most frequent genomic alteration (14.4 and 11% of cases, respectively), and were associated with overall tumour genomic instability (p<0.0001). NBN gains were the only significant predictor of 5yrs biochemical relapse-free rate (bRFR) following IGRT (46% versus 77%; p=0.00067). On multivariate analysis, NBN gain remained a significant independent predictor of bRFR after adjusting for known clinical prognostic variables (HR=3.28, 95% CI 1.56–6.89, Wald p-value=0.0017). No DDR-sensing gene was prognostic in the RadP cohort. In vitro studies correlated NBN gene overexpression with PCa cells radioresistance. In conclusion, NBN gain predicts for decreased bRFR in IGRT, but not in RadP patients. If validated independently, Nibrin gains may be the first PCa predictive biomarker to facilitate local treatment decisions using precision medicine approaches with surgery or radiotherapy.

Spatial genomic heterogeneity within localized, multifocal prostate cancer

Herein we provide a detailed molecular analysis of the spatial heterogeneity of clinically localized, multifocal prostate cancer to delineate new oncogenes or tumor suppressors. We initially determined the copy number aberration (CNA) profiles of 74 patients with index tumors of Gleason score 7. Of these, 5 patients were subjected to whole-genome sequencing using DNA quantities achievable in diagnostic biopsies, with detailed spatial sampling of 23 distinct tumor regions to assess intraprostatic heterogeneity in focal genomics. Multifocal tumors are highly heterogeneous for single-nucleotide variants (SNVs), CNAs and genomic rearrangements. We identified and validated a new recurrent amplification of MYCL, which is associated with TP53 deletion and unique profiles of DNA damage and transcriptional dysregulation. Moreover, we demonstrate divergent tumor evolution in multifocal cancer and, in some cases, tumors of independent clonal origin. These data represent the first systematic relation of intraprostatic genomic heterogeneity to predicted clinical outcome and inform the development of novel biomarkers that reflect individual prognosis.

Tumour genomic and microenvironmental heterogeneity for integrated prediction of 5-year biochemical recurrence of prostate cancer: a retrospective cohort study

BACKGROUND

Clinical prognostic groupings for localised prostate cancers are imprecise, with 30-50% of patients recurring after image-guided radiotherapy or radical prostatectomy. We aimed to test combined genomic and microenvironmental indices in prostate cancer to improve risk stratification and complement clinical prognostic factors.

METHODS

We used DNA-based indices alone or in combination with intra-prostatic hypoxia measurements to develop four prognostic indices in 126 low-risk to intermediate-risk patients (Toronto cohort) who will receive image-guided radiotherapy. We validated these indices in two independent cohorts of 154 (Memorial Sloan Kettering Cancer Center cohort [MSKCC] cohort) and 117 (Cambridge cohort) radical prostatectomy specimens from low-risk to high-risk patients. We applied unsupervised and supervised machine learning techniques to the copy-number profiles of 126 pre-image-guided radiotherapy diagnostic biopsies to develop prognostic signatures. Our primary endpoint was the development of a set of prognostic measures capable of stratifying patients for risk of biochemical relapse 5 years after primary treatment.

FINDINGS

Biochemical relapse was associated with indices of tumour hypoxia, genomic instability, and genomic subtypes based on multivariate analyses. We identified four genomic subtypes for prostate cancer, which had different 5-year biochemical relapse-free survival. Genomic instability is prognostic for relapse in both image-guided radiotherapy (multivariate analysis hazard ratio [HR] 4·5 [95% CI 2·1-9·8]; p=0·00013; area under the receiver operator curve [AUC] 0·70 [95% CI 0·65-0·76]) and radical prostatectomy (4·0 [1·6-9·7]; p=0·0024; AUC 0·57 [0·52-0·61]) patients with prostate cancer, and its effect is magnified by intratumoral hypoxia (3·8 [1·2-12]; p=0·019; AUC 0·67 [0·61-0·73]). A novel 100-loci DNA signature accurately classified treatment outcome in the MSKCC low-risk to intermediate-risk cohort (multivariate analysis HR 6·1 [95% CI 2·0-19]; p=0·0015; AUC 0·74 [95% CI 0·65-0·83]). In the independent MSKCC and Cambridge cohorts, this signature identified low-risk to high-risk patients who were most likely to fail treatment within 18 months (combined cohorts multivariate analysis HR 2·9 [95% CI 1·4-6·0]; p=0·0039; AUC 0·68 [95% CI 0·63-0·73]), and was better at predicting biochemical relapse than 23 previously published RNA signatures.

INTERPRETATION

This is the first study of cancer outcome to integrate DNA-based and microenvironment-based failure indices to predict patient outcome. Patients exhibiting these aggressive features after biopsy should be entered into treatment intensification trials.

FUNDING

Movember Foundation, Prostate Cancer Canada, Ontario Institute for Cancer Research, Canadian Institute for Health Research, NIHR Cambridge Biomedical Research Centre, The University of Cambridge, Cancer Research UK, Cambridge Cancer Charity, Prostate Cancer UK, Hutchison Whampoa Limited, Terry Fox Research Institute, Princess Margaret Cancer Centre Foundation, PMH-Radiation Medicine Program Academic Enrichment Fund, Motorcycle Ride for Dad (Durham), Canadian Cancer Society.

Hotspot activating PRKD1 somatic mutations in polymorphous low-grade adenocarcinomas of the salivary glands

Polymorphous low-grade adenocarcinoma (PLGA) is the second most frequent type of malignant tumor of the minor salivary glands. We identified PRKD1 hotspot mutations encoding p.Glu710Asp in 72.9% of PLGAs but not in other salivary gland tumors. Functional studies demonstrated that this kinase-activating alteration likely constitutes a driver of PLGA.

Two phases of disulfide bond formation have differing requirements for oxygen

Disulfide bonds introduced during or shortly after protein synthesis can occur without oxygen, whereas those introduced during post-translational folding or isomerization are oxygen dependent.

Most proteins destined for the extracellular space require disulfide bonds for folding and stability. Disulfide bonds are introduced co- and post-translationally in endoplasmic reticulum (ER) cargo in a redox relay that requires a terminal electron acceptor. Oxygen can serve as the electron acceptor in vitro, but its role in vivo remains unknown. Hypoxia causes ER stress, suggesting a role for oxygen in protein folding. Here we demonstrate the existence of two phases of disulfide bond formation in living mammalian cells, with differential requirements for oxygen. Disulfide bonds introduced rapidly during protein synthesis can occur without oxygen, whereas those introduced during post-translational folding or isomerization are oxygen dependent. Other protein maturation processes in the secretory pathway, including ER-localized N-linked glycosylation, glycan trimming, Golgi-localized complex glycosylation, and protein transport, occur independently of oxygen availability. These results suggest that an alternative electron acceptor is available transiently during an initial phase of disulfide bond formation and that post-translational oxygen-dependent disulfide bond formation causes hypoxia-induced ER stress.

Parallels between the development of therapeutic drugs and cancer health disparity programs: implications for Disparities Reduction

BACKGROUND

There are analogies between the development of therapeutic drugs for cancer and the development of interventions for reducing cancer health disparities. In both cases, it can take between 12 and 15 years for the benefits to become apparent.

METHODS

The initial preclinical phase of drug development is analogous to the development of community partnerships and helping the community learn about cancer. The preclinical phase of in vitro and in vivo testing is analogous to identifying the disparities in the community. Then clinical testing begins with phase 1, toxicity, and dose-establishing studies. Analogously, community-based participatory research is used to develop disparities-reducing interventions (DRIs) within the community.

RESULTS

The phase 2 clinical studies to determine whether the drug has activity are analogous to the DRI being implemented in the community to determine whether it can cause behavioral changes that will reduce cancer health disparities. If a drug passes phase 1 and 2 studies, phase 3 clinical trials are initiated. These are controlled studies to examine the efficacy of the drug. The similar activity for disparities research is to determine whether the DRI is better than the current standard/usual practice in controlled trials. If the drug is beneficial, the final phase is the dissemination and adoption of the drug. Analogously in disparities, if the DRI is beneficial, it is disseminated and is culturally adapted to other racial/ethnic groups and finally adopted as standard practice.

CONCLUSIONS

The process of creating an effective DRI can be envisioned to have 4 stages, which can be used to aid in measuring the progress being made in reducing cancer health disparities.

Determinants of cancer health disparities: barriers to cancer prevention, screening, diagnosis and treatment

BACKGROUND

Many health disparities occur when beneficial medical interventions are not shared by all.

OBJECTIVE

To examine the barriers that cause the disparities.

METHODS

In terms of obtaining beneficial medical interventions, the individual with disparities is influenced by his/her community, healthcare provider and healthcare system. The determinants of cancer health disparities include cultural, socio-economic and environmental factors, and the effects of social injustice.

RESULTS/CONCLUSION

These factors create inadequate information and knowledge about cancer, risk-promoting behaviors, inadequate conditions for seeking medical procedures, diminished access to and use of healthcare and inadequate healthcare services. The use of patient navigators may serve to address many of these factors.

Reducing cancer health disparities: perspective of the National Cancer Institute

BACKGROUND

The National Cancer Institute created the Special Population Network (SPN) to develop cancer awareness, research and training with partnerships from community and research organizations.

METHODS

Eighteen SPNs were funded with the goals of enlisting community partnerships, enhancing training opportunities for minority scientists, and conducting pilot research projects.

RESULTS

The SPN program concluded in 2005 after achieving many major milestones.

CONCLUSION

This paper provides background information about the SPN and one of its programs, the Pacific Islander Cancer Control Network.

Cancer incidence and mortality patterns among specific Asian and Pacific Islander populations in the U.S

Objectives

We report cancer incidence, mortality, and stage distributions among Asians and Pacific Islanders (API) residing in the U.S. and note health disparities, using the cancer experience of the non-Hispanic white population as the referent group. New databases added to publicly available SEER*Stat software will enable public health researchers to further investigate cancer patterns among API groups.

Methods

Cancer diagnoses among API groups occurring from 1 January 1998 to 31 December 2002 were included from 14 Surveillance, Epidemiology, and End Results (SEER) Program state and regional population-based cancer registries covering 54% of the U.S. API population. Cancer deaths were included from the seven states that report death information for detailed API groups and which cover over 68% of the total U.S. API population. Using detailed racial/ethnic population data from the 2000 decennial census, we produced incidence rates centered on the census year for Asian Indians/Pakistanis, Chinese, Filipinos, Guamanians, Native Hawaiians, Japanese, Kampucheans, Koreans, Laotians, Samoans, Tongans, and Vietnamese. State vital records offices do not report API deaths separately for Kampucheans, Laotians, Pakistanis, and Tongans, so mortality rates were analyzed only for the remaining API groups.

Results

Overall cancer incidence rates for the API groups tended be lower than overall rates for non-Hispanic whites, with the exception of Native Hawaiian women (All cancers rate = 488.5 per 100,000 vs. 448.5 for non-Hispanic white women). Among the API groups, overall cancer incidence and death rates were highest for Native Hawaiian and Samoan men and women due to high rates for cancers of the prostate, lung, and colorectum among Native Hawaiian men; cancers of the prostate, lung, liver, and stomach among Samoan men; and cancers of the breast and lung among Native Hawaiian and Samoan women. Incidence and death rates for cancers of the liver, stomach, and nasopharynx were notably high in several of the API groups and exceeded rates generally seen for non-Hispanic white men and women. Incidence rates were lowest among Asian Indian/Pakistani and Guamanian men and women and Kampuchean women. Asian Indian and Guamanian men and women also had the lowest cancer death rates. Selected API groups had less favorable distributions of stage at diagnosis for certain cancers than non-Hispanic whites.

Conclusions

Possible disparities in cancer incidence or mortality between specific API groups in our study and non-Hispanic whites (referent group) were identified for several cancers. Unfavorable patterns of stage at diagnosis for cancers of the colon and rectum, breast, cervix uteri, and prostate suggest a need for cancer control interventions in selected groups. The observed variation in cancer patterns among API groups indicates the importance of monitoring these groups separately, as these patterns may provide etiologic clues that could be investigated by analytic epidemiological studies.

Cambodian cancer incidence rates in California and Washington, 1998-2002

BACKGROUND

Among the many diverse Asian ethnic groups living in the US, Cambodian immigrants comprise a small fraction (1.8%) of the total Asian population. Because of their small numbers, Cambodian vital statistics are often combined into Southeast Asian (SA) cancer data consisting of Vietnamese, Thais, Laotians, and Hmong.

METHODS

The 2000 Census counts were used for 2 Cambodian populations, Cambodians alone and Cambodians alone and in combination with any other racial/ethnic group for California and for Seattle (Puget Sound area), Washington. Then the cancer incidence rates were calculated using cancer cases from the California and Puget Sound cancer registries between 1998-2002. The 1998-2002 annual age-adjusted incidence rates, upper bound rates (based on the Cambodian alone population), lower bound rates (based on the Cambodians alone or in combination population) are reported and compared with the rates in the non-Hispanic White (NHW) population in these regions.

RESULTS

The top 5 cancers in Cambodian males are lung and bronchus, liver, prostate, colorectal, and stomach cancers. The sites where the rates are higher in male Cambodians than NHW males are (in ascending rank) nasopharynx, liver, stomach, myeloma, and lung and bronchus. The top 5 cancers for female Cambodians are breast, lung, colon and rectum, cervix, and thyroid. The sites where female rates are greater than NHW female rates are (in ascending rank) nasopharynx, liver, stomach, cervix uteri, oral cavity, and thyroid.

CONCLUSIONS

The challenges to address the health issues of Cambodians are complicated by historical events that caused their emigration to the US. Many of the immigrants are survivors of the holocaust in Cambodia. Health programs for Cambodians must deal with the consequences of these issues as well as cultural issues of language and religion in helping Cambodians to reduce their cancer disparities.

Measures of racial/ethnic health disparities in cancer mortality rates and the influence of socioeconomic status

OBJECTIVES

In the 1990s, U.S. cancer mortality rates declined due to reductions in tobacco use among men and beneficial cancer interventions, such as mammography and Pap smears. We examined the cancer rates by racial/ethnic group, socioeconomic status and time period to identify disparities underlying the overall mortality trend.

METHODS

We examined racial/ethnic disparities by measuring excess cancer burden [rate ratio (RR) and ratio differences (RD)] and trends in their cancer rates for nine cancer sites. The trend (T) is calculated as a ratio of the average annual cancer mortality rate for 1995-2000 relative to the rate for 1990-1994 for three levels of poverty (counties with <10% living below the poverty level, 10% - <20% and > or =20%) for the major racial/ethnic populations. We also compared the trend for each racial/ethnic SES group to the trend for lowest SES white group (TD).

RESULTS

Blacks have RR disparities relative to whites for each cancer site examined, except for female lung cancer, while the other minorities had RR disparities for cervical cancer (RR>1). There are increases in RR disparities from 1990-1994 to 1995-2000 (RD>0) for colorectal cancer, prostate cancer and breast cancer for each racial/ethnic minority. Whites and blacks had declining trends for every SES group (T<1) and positive high SES gradients (the highest SES group had the best trend and the lowest SES group had the worst trend) at each cancer site, except female lung cancer (T>1). In contrast, American Indians/Alaska natives, Hispanics and Asians/ Pacific Islanders had increasing trends for some of their cancer sites, and their trends did not have the SES gradients.

CONCLUSIONS

Increases in racial/ethnic disparities (RD>0) for colorectal, breast and prostate cancer were largest in the lowest SES groups. At some cancer sites, the highest SES group for minorities had worse trend results than the trends for the lowest SES white group (TD>0).

Determinants of cancer disparities: barriers to cancer screening, diagnosis, and treatment

There is a critical disconnect between what we discover and what we deliver to all Americans in the form of prevention, screening, detection, diagnosis, and treatment of cancer. We must identify and eliminate all barriers that prevent the benefits of research from reaching all people. Such barriers may be experienced at any point along the continuum of prevention, screening, diagnosis and treatment, and palliative care. In communities of low socioeconomic status, patient navigation has proved to be an effective intervention in promoting such timely diagnosis and treatment when applied at the point of abnormal finding. Geographic areas with excess cancer mortality should be delineated and targeted with an intense approach to providing culturally relevant education, appropriate access to screening diagnosis and treatment, and improved support systems, including navigation.

1999-2001 Cancer mortality rates for Asian and Pacific Islander ethnic groups with comparisons to their 1988-1992 rates

We report upper and lower boundary estimates of the 1999-2001 site-specific cancer mortality rates for Asian Indians, Chinese, Filipinos, Koreans, Vietnamese, Native Hawaiians, and Samoans. These rates are for the seven states (California, Hawaii, Illinois, New Jersey, New York, Texas, and Washington) that officially record mortality data for these ethnicities. The rates are based on the 2000 Census, which reports two population counts as follows: persons who identify themselves as belonging to a single ethnic group (which forms the basis for an upper boundary estimate of the rates) and persons who identify themselves as belonging to a single ethnic group or to multiple groups that include the single ethnic group (which forms the basis for a lower boundary estimate for the rates). The top five cancers for each Asian and Pacific Islander ethnic group by gender are reported. In addition, the 1988-1992 cancer mortality rates based on the 1990 Census for Chinese, Filipino, Japanese, and Native Hawaiians are determined. Their 1999-2001 and 1988-1992 rates are compared.

Special Populations Networks—How this innovative community-based initiative affected minority and underserved research programs

The Special Populations Networks (SPN) Program was created to address both community needs for cancer information and NCI's desire to obtain community-based answers to research questions and promote training opportunities for racial/ethnic minority and underserved researchers in populations with an unequal burden of cancer. The SPN program included 3 components: 1) infrastructure and capacity building combined with cancer awareness, 2) community-based research, and 3) community-centered training. The 18 SPN grantees conducted more than 1000 cancer awareness activities. More than 2000 community lay health workers were trained. Communities formalized more than 300 partnerships with Memoranda of Understanding (MOU). More than 255 pilot research project applications were submitted by junior researchers and over 135 were funded. Approximately 90% of the applications were submitted by minority junior researchers; of which more than 100 were funded. More than 290 scientific publications thus far have resulted from the work of the SPNs. In the first 3 years of the program, the SPNs also secured an additional $20 million in outside funding. The SPN program effected a paradigm shift for minority research programs by combining community-based cancer awareness, research, and training into a single program. By engaging research leaders of minority and underserved populations to aid their own, train their own, and develop research to help their own, the SPN program activated the power of their commitment to their own. That commitment was reflected in the trust and participation offered by their communities. Cancer 2006. (c) 2006 American Cancer Society.

The Asian Tobacco Education, Cancer Awareness and Research's role in tobacco and cancer control efforts in Asian American communities

PURPOSE

This article identifies the urgent needs for tobacco and cancer control in Asian American communities and the barriers that have historically prevented the development and implementation of tobacco and cancer prevention and intervention research programs among Asian Americans residing in Delaware Valley region of Pennsylvania and New Jersey. This article also presents ATECAR, the first long-term federal effort in tobacco and cancer control targeting the multi-ethnic Asian American communities in this area.

METHODS

ATECAR uses a three-pronged approach: the development of community and university infrastructure, the development of training programs for minority and underserved students so that they will pursue cancer research careers, and community-based intervention research projects.

PRINCIPAL FINDINGS

ATECAR's pioneering work redefined our understanding of Asian Americans' smoking habits and the important role of smoking, especially in newly immigrated communities.

CONCLUSION

The advent of ATECAR marks the building of a viable infrastructure that can ensure sustainability of current and future efforts in tobacco control and use.

Distinct incidence patterns among in situ and invasive breast carcinomas,with possible etiologic implications

BACKGROUND

Incidence patterns are well-established for invasive breast carcinoma (InvBC) overall and for InvBC defined by estrogen receptor (ER) expression, but are not as well-defined for breast carcinoma in situ (CIS).

METHODS

We, therefore, examined and compared the incidence patterns for CIS and InvBC in the SEER program to define these patterns and to generate etiologic hypotheses. Data were stratified by age < 50 and > or =50 years to approximate menopause.

RESULTS

During the years 1973-2000, annual age-adjusted incidence rates rose 660% for CIS and 36% for InvBC, with the most rapid increases occurring in women age > or =50 years. Age-specific incidence rate curves for CIS increased until age 50 years, and then flattened, irrespective of ER expression. On the other hand, rates for InvBC overall and for InvBC defined by ER-positive expression increased continuously with aging, whereas rates for InvBC defined by ER-negative expression flattened after 50 years. Age frequency distribution for CIS and for ER-negative InvBC demonstrated bimodal populations, with a predominant early onset peak incidence at age 50 years. Age frequency distribution for ER-positive InvBC showed bimodal populations with a predominant late-onset mode at age 71 years.

CONCLUSION

Over the last three decades, age-adjusted incidence trends differed for CIS and InvBC in the United States, possibly due to screening mammography and/or etiologic diversity. Indeed, age-specific incidence patterns suggested that carcinogenic events operating early in reproductive life had greater impact upon CIS and InvBC defined by ER-negative expression than upon InvBC overall and InvBC defined by ER-positive expression.

The Special Populations Networks for cancer awareness research and training

The Special Populations Networks (SPN) project is widely regarded as perhaps the most successful in the history of the National Cancer Institute (NCI) at performing cancer awareness, research, and training activities within minority and underserved communities throughout the United States and its territories. Key to that success is the trust established among the community, its researchers and the NCI. Composed of 18 separate grant awards, the SPN project was implemented in April 2000 to integrate the communities' need for cancer information with the NCI's need to increase cancer awareness, perform new research, and train minority junior investigators for research in populations with a disproportionate burden of cancer. To date, the 18 networks have conducted more than 1,000 awareness events, trained more than 2,000 community health aides, won 135 grants to support pilot research projects, published 130 peer-reviewed papers, and raised another $20 million to support SPN activities. Successful implementation of the SPN project required the principal investigators to establish and maintain close working relationships with key community leaders and organizations in cooperation with NCI.

Patterns in cancer incidence among American Indians/Alaska Natives, United States, 1992-1999

OBJECTIVE

Cancer is a major public health concern in American Indian and Alaska Native (AI/AN) communities. However, information on the incidence of cancer is lacking for this group. The purpose of this study is to report cancer incidence patterns for the U.S. AI/AN population.

METHODS

Age-adjusted annual cancer incidence rates for 1992 through 1999 were calculated for 12 Surveillance, Epidemiology and End Results (SEER) areas, representing a sample (42%) of the U.S. AI/AN population. Trends in cancer incidence rates for the AI/AN sample were determined using standard linear regression of log-transformed rates and were compared to those of the U.S. white population.

RESULTS

The top five incident cancers (from highest to lowest) among AI/AN males were prostate, lung and bronchus, colon and rectum, kidney and renal pelvis, and stomach cancers. Among AI/AN women, cancers of the breast, colon and rectum, lung and bronchus, endometrium, and ovary ranked highest. Four sites where cancer incidence rates are greater for AI/ANs than for whites include gallbladder (the AI/AN rate was 4.1 times the rate for white males and 2.6 times the rate for white females), liver and intrahepatic bile duct cancers (1.3 times for males and 2.3 times for females), stomach (1.2 times for males and 1.5 times for females), and kidney and renal pelvis (1.03 times for males and 1.07 times for females). The data show increasing trends for AI/AN males and females and declining trends for white males and females for colorectal, stomach, and pancreatic cancers and leukemia. Similar differences between AI/AN rates and white rates were found for urinary bladder cancers in males and gallbladder cancer in females.

CONCLUSIONS

Analysis of SEER data allowed for the determination of disparities in cancer incidence between a sample of the U.S. AI/AN population and the white population. The findings of this study provide baseline information necessary for developing cancer prevention and intervention strategies specific to the AI/AN population to address these cancer disparities.

Comparison of age-specific incidence rate patterns for different histopathologic types of breast carcinoma

OBJECTIVE

The age-specific incidence rate curve for breast carcinoma overall increases rapidly until age 50 years, and then continues to increase at a slower rate for older women. In this analysis, our objective was to compare age-specific incidence rate patterns for different morphologic types of breast carcinoma.

MATERIALS AND METHODS

We analyzed age-specific incidence rate curves by histopathologic subclassification using records from 11 standard National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) registries, diagnosed during the years 1992 to 1999. Data were examined by age <50 and > or /=50 years to simulate menopause.

RESULTS

Age-specific incidence rate curves showed three dominant patterns: (1) Rates for infiltrating duct carcinoma of no special type (duct NST), tubular, and lobular carcinomas increased rapidly until age 50 years then rose more slowly. (2) Rates for medullary and inflammatory breast carcinomas increased rapidly until age 50 years then failed to increase. (3) Rates for papillary and mucinous carcinomas increased steadily at all ages. Rate patterns varied by estrogen receptor expression but were unaffected by SEER registry, race, nodal status, or grade.

CONCLUSION

Age-specific incidence rates for breast carcinomas differed by histopathologic type. Rates that failed to increase after 50 years suggested that menopause had greater impact on medullary and inflammatory carcinomas than on duct NST, tubular, and lobular carcinomas. Menopause did not seem to have any effect on papillary or mucinous carcinomas as evidenced by steadily rising rates at all ages. Future etiologic and/or prevention studies should consider the impact of age-specific risk factors and/or exposures on different histopathologic types of breast carcinomas.

Comparison of Age-Specific Incidence Rate Patterns for Different Histopathologic Types of Breast Carcinoma

Objective: The age-specific incidence rate curve for breast carcinoma overall increases rapidly until age 50 years, and then continues to increase at a slower rate for older women. In this analysis, our objective was to compare age-specific incidence rate patterns for different morphologic types of breast carcinoma. Materials and methods: We analyzed age-specific incidence rate curves by histopathologic subclassification using records from 11 standard National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) registries, diagnosed during the years 1992 to 1999. Data were examined by age &lt;50 and ≥50 years to simulate menopause. Results: Age-specific incidence rate curves showed three dominant patterns: (1) Rates for infiltrating duct carcinoma of no special type (duct NST), tubular, and lobular carcinomas increased rapidly until age 50 years then rose more slowly. (2) Rates for medullary and inflammatory breast carcinomas increased rapidly until age 50 years then failed to increase. (3) Rates for papillary and mucinous carcinomas increased steadily at all ages. Rate patterns varied by estrogen receptor expression but were unaffected by SEER registry, race, nodal status, or grade. Conclusion: Age-specific incidence rates for breast carcinomas differed by histopathologic type. Rates that failed to increase after 50 years suggested that menopause had greater impact on medullary and inflammatory carcinomas than on duct NST, tubular, and lobular carcinomas. Menopause did not seem to have any effect on papillary or mucinous carcinomas as evidenced by steadily rising rates at all ages. Future etiologic and/or prevention studies should consider the impact of age-specific risk factors and/or exposures on different histopathologic types of breast carcinomas.

Histologic grade, stage, and survival in breast carcinoma: comparison of African American and Caucasian women

BACKGROUND

African American women have lower breast carcinoma survival rates than do Caucasian women. African American women often present with advanced-stage disease and more aggressive tumors as shown by histologic and laboratory-based prognostic factors. Aggressive tumor behavior may be responsible, at least in part, for the advanced stage and reduced survival rates.

METHODS

The authors investigated the correlation between survival and histologic grade, stage of disease, and tumor size for both African American and Caucasian women who were younger than age 50 years and age 50 years and older. The authors also investigated the distribution of grade within each stage group and the distribution of grade by tumor size. African American and Caucasian women were matched by stage, tumor size, and histologic grade. Survival was represented by 6-year breast carcinoma-specific survival rates.

RESULTS

Compared with Caucasian women, African American women, regardless of age, had proportionally more Grade III tumors and fewer Grade I and II tumors for all stages combined and for each individual stage group. Similarly, matched for tumor size, African American women had more Grade III tumors and fewer Grade I and II tumors compared with Caucasian women, except for tumors smaller than 1.0 cm. For nearly all combinations of stage and grade regardless of age, the 6-year breast carcinoma-specific survival rate was lower for African American women than for Caucasian women, although it did not always reach statistical significance.

CONCLUSIONS

Compared with Caucasian women, African American women, regardless of age, presented with proportionally more aggressive tumors for each stage of disease and for each tumor size above 1.0 cm as revealed by the histologic grade. Higher histologic grade may be a significant contributing factor to survival disadvantage for African American women.

Inflammatory breast carcinoma and noninflammatory locally advanced breast carcinoma: distinct clinicopathologic entities?

PURPOSE

Inflammatory breast carcinoma (IBC) and noninflammatory locally advanced breast carcinoma (LABC) are both associated with poor prognosis; however, whether they are distinct clinicopathologic entities remains controversial.

MATERIALS AND METHODS

To determine whether IBC and LABC were different, we compared tumor characteristics, prognosis, and age-specific incidence rate patterns in the Surveillance, Epidemiology, and End-Results program. An age of 50 years served as a surrogate marker for menopause.

RESULTS

Younger age at diagnosis, poorer tumor grade, and negative estrogen receptors (ERs) were more predictive of IBC (n = 2,237) than of LABC (n = 7,985). Breast carcinoma survival was worse for patients with IBC than for those with LABC (log-rank test, P <.0001). Age-specific incidence rates for IBC increased until 50 years and then flattened, whereas rates for LABC increased for all ages. When rates for LABC were stratified by estrogen receptor-positive (ERP) and -negative (ERN) expression, rates for ERP and ERN diverged; that is, rates for ERP increased with advancing age, whereas rates for ERN flattened after 50 years. When rates for IBC were stratified by ER expression, rates for both ERP and ERN flattened after 50 years of age.

CONCLUSION

IBC and LABC seemed to be distinct biologic entities, as indicated by different prognostic factor profiles and age-specific incidence rate patterns. Rates that increased before 50 years and then stabilized, possibly indicated that premenopausal exposures had a greater effect on maintaining rates for IBC than for LABC.

Racial disparities in breast carcinoma survival rates: seperating factors that affect diagnosis from factors that affect treatment

BACKGROUND

Black females have lower breast carcinoma survival rates compared with white females. One possible reason is that black females have more advanced-stage breast disease. Another factor may be racial differences in the utilization of cancer treatments.

METHODS

The authors determined racial differences in 6-year stage specific survival rates, adjusting for age and treatments (using estrogen receptor [ER] status), to determine whether there were racial differences in treatment. Racial differences in the stage distributions of breast disease were used to examine the impact of racial factors on breast carcinoma diagnosis.

RESULTS

For all breast carcinoma cases, the stage specific 6-year survival rates, in general, were significantly lower for black females for all stages combined and for Stages I-III in every age group. However, examination by different treatments, as measured by ER status, revealed some different results. Only black women younger than age 50 years with ER-positive tumors and women younger than age 65 years with ER-negative tumors had significantly lower stage-specific survival rates. In addition, the stage distribution analyses showed that black females of every age group had less Stage I breast disease.

CONCLUSIONS

For younger black women (younger than age 50 years), there was evidence of racial differences in treatment for both women with ER-positive tumors and women with ER-negative tumors, as indicated by their lower stage-specific survival rates. In contrast, for black females age 65 years or older with ER-positive or ER-negative tumors, the lack of a significant difference in the stage-specific survival rate suggests that Medicare may help to alleviate racial disparities in cancer treatment. Furthermore, racial differences in the stage distributions indicated the need for earlier diagnosis for black females of every age.

Trends in prostate cancer mortality among black men and white men in the United States

BACKGROUND

Prostate cancer mortality rates in the United States declined sharply after 1991 in white men and declined after 1992 in black men. The current study was conducted to investigate possible mechanisms for the declining prostate cancer mortality rates in the United States.

METHODS

The authors examined and compared patterns of prostate cancer incidence, survival rates, and mortality rates among black men and white men in the United States using the 1969-1999 U.S. prostate cancer mortality rates and the 1975-1999 prostate cancer incidence, survival, and incidence-based mortality rates from the Surveillance, Epidemiology, and End Results (SEER) Program for the U.S. population. The SEER data represent approximately 10% of the U.S. population.

RESULTS

Prostate cancer incidence and mortality rates showed transient increases after 1986, when the U.S. Food and Drug Administration approved the use of prostate specific antigen (PSA) testing. The age-adjusted prostate cancer mortality rates for men age 50-84 years, however, have dropped below the rate in 1986 since 1995 for white men and since 1997 for black men. In fact, for white men ages 50-79 years, the 1998 and 1999 rates were the lowest observed since 1950. Incidence-based mortality rates by disease stage revealed that the recent declines were due to declines in distant disease mortality. Moreover, the decrease in distant disease mortality was due to a decline in distant disease incidence, and not to improved survival of patients with distant disease.

CONCLUSIONS

Similar incidence, survival, and mortality rate patterns are seen in black men and white men in the United States, although with differences in the timing and magnitude of recent rate decreases. Increased detection of prostate cancer before it becomes metastatic, possibly reflecting increased use of PSA testing after 1986, may explain much of the recent mortality decrease in both white men and black men.

Asian and Pacific Islander Special Populations Network

This paper briefly describes four programs within the National Cancer Institute's Special Populations Network, programs designed to promote cancer awareness in minority and underserved populations. These four programs are dedicated to issues involving Asian Americans and Pacific Islanders. Of particular interest is the fact that they each have a strong community focus and are targeted to specific populations.

Rates for breast cancer characteristics by estrogen and progesterone receptor status in the major racial/ethnic groups

It has been reported that age-specific breast cancer rates vary by estrogen receptor and progesterone receptor status. We report breast cancer rates for age-at-diagnosis, stage-at-diagnosis, histological grade and type by estrogen (ER) and progesterone (PgR) receptor status in six major racial/ethnic groups. The average annual age-adjusted rates for breast cancers with estrogen receptor positive (ER+), ER-, progesterone receptor positive (PgR+), PgR-, ER+PgR+, ER+PgR-, ER-PgR+ and ER-PgR- are determined from 123,732 breast cancers with known ER status, diagnosed from 1992 to 1998 from 11 Surveillance, Epidemiology, and End Results (SEER) cancer registries. For each racial/ethnic group, their ER+ (ER+PgR+ and ER+PgR-) age-specific rates increased with age (but at a slower pace after ages 50-54) while their ER- (ER- PgR+ and ER-PgR-) age-specific rates did not increase after ages 50-54. The rank orders of the rates among the racial/ethnic groups varied by ER/PgR status. The stage I rates were greater than the stage II rates for the ER/PgR groups except for ER- and ER- PgR- cancers. The grade 2 (moderately differentiated) rates were greater than the grades 3 and 4 (poorly differentiated and undifferentiated cancers) rates for ER+ cancers, but not for ER- cancers. These results suggest that although breast cancer is a disease with enormous heterogeneity, the multiple types of breast cancer can be separated into distinct subgroups by their ER status, and perhaps by their ER/PgR status, and their cancer characteristics may be important in understanding the multiple nature of breast cancer.

The greater impact of menopause on ER- than ER+ breast cancer incidence: a possible explanation (United States)

OBJECTIVE

Analysis of 3359 Danish breast cancer cases indicated that menopause exerted a greater protective effect on estrogen-receptor negative (ER-) breast cancer than on estrogen-receptor positive (ER+) breast cancer. We examined US age-specific breast cancer rates by hormone receptor status in white and black women and men to investigate this unexpected result.

METHODS

Age-specific breast cancer incidence rates from the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute were analyzed by joint estrogen receptor and progesterone receptor (ER/PR) status of 101,140 white female and 8870 black female cases and by ER status in 706 white male and black male cases diagnosed from 1992 to 1998. Changes in the rate of increase in rates with age were identified using Poisson regression analyses.

RESULTS

For both white women and black women the age-specific rates of ER- breast cancer cease increasing after 50 years of age, but age-specific rates of ER+ breast cancer continue to increase after 50 years of age. For men the incidence of ER- cancers may increase at a slower rate than incidence of ER+ cancers in older ages. In women the black rates of ER+ cancers are greater than white rates only until age 35, but black rates of ER- cancers are greater than white rates for all ages.

CONCLUSIONS

Differences in age-specific breast cancer incidence patterns by hormone receptor status are similar for black women and white women. The incidence pattern for ER- cancers is consistent with a paracrine model for hormone-stimulated growth in normal breast tissue. The continued increase in ER+ cancers after menopause may be explained by both the paracrine growth model and an increase in the proliferation rate of ER+ cells with age.

Frequency distributions of breast cancer characteristics classified by estrogen receptor and progesterone receptor status for eight racial/ethnic groups

BACKGROUND

The National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) cancer registries have been collecting data regarding estrogen receptor (ER) and progesterone receptor (PR) status in breast cancer since 1990. The current study reports on some of these data for eight racial/ethnic groups.

METHODS

Stratified by ER and PR status, the frequency distributions of 112,588 breast cancer cases diagnosed between 1992--1997 in 11 SEER cancer registries were examined by age at diagnosis, stage at diagnosis, histologic grade, and tumor type for white, black, Hispanic, Japanese, Chinese, Filipino, Native Hawaiian, and American Indian and Alaska Native (AI/AN) females.

RESULTS

For each racial/ethnic group, the percentage of ER positive (+)/PR+ was > ER-PR- > ER+PR- > ER-PR+ tumors. For the two major ER/PR groups, the ER+PR+ tumors were different from the ER-PR- tumors in several ways. For white females, there were differences in the age distributions, stage at diagnosis, and histologic grade. For black females, the differences involved the age distributions and tumor grades. For Hispanic and Japanese females, there were differences with regard to the age distributions and tumor grades. For Filipino, Chinese, and AI/AN females, the tumor stages and grades differed. For Native Hawaiians, the histologic tumor grades were different.

CONCLUSIONS

For each racial/ethnic group, the ER/PR status appeared to divide breast cancer patients into two or more subgroups with unique tumor characteristics. In general, ER status appeared to have the greatest impact on delineating these subgroups, whereas in some cases, PR status was able to modify the subgroups further. It is hoped that reporting these tumor characteristics by ER/PR status for each racial/ethnic group will spur more investigation into the significance of ER/PR status in each racial/ethnic group.

Age-period-cohort analyses of breast-, ovarian-, endometrial- and cervical-cancer mortality rates for Caucasian women in the USA

BACKGROUND

Age-period-cohort analyses of US breast-cancer mortality rates reveal an unexpected decrease in risk for women born after 1948. Hormones are thought to play an important role in the aetiology of breast cancer and female gynaecologic cancers, and thus the evaluation of birth-cohort trends for female gynaecologic cancers may shed light on the declining breast-cancer risk among 'baby-boomers'.

METHODS

Age-period-cohort analyses are applied to US mortality rates for breast cancer, ovarian cancer, endometrial cancer and cervical cancer from 1950 through 1995.

RESULTS

Age-period-cohort analyses provide no clues regarding the declining birth-cohort risk for breast cancer in 'baby-boomers'. The birth-cohort curves for ovarian and endometrial cancers are roughly similar, and largely explained by known risk factors. The calendar-period curve for endometrial cancer reveals increased risk between 1960 and 1980, probably due to increased use of oestrogen replacement therapy. Changes in the birth-cohort curve for cervical cancer reflect, for the most part, changes in sexual activity. An unexpected significant increase in the calendar-period curve for ovarian cancer occurred around 1980.

CONCLUSION

Most of the major changes in the calendar-period and birth-cohort curves for breast cancer and female gynaecologic cancers can be explained by documented changes in known risk factors and in medical practice. The decreasing breast-cancer birth-cohort risk among 'baby-boomers' and the increasing ovarian-cancer calendar-period curve after 1980 are recent changes that require further investigation.

Nonparametric evaluation of birth cohort trends in disease rates

BACKGROUND

Although interpretation of age-period-cohort analyses is complicated by the non-identifiability of maximum likelihood estimates, changes in the slope of the birth-cohort effect curve are identifiable and have potential aetiologic significance.

METHODS

A nonparametric test for a change in the slope of the birth-cohort trend has been developed. The test is a generalisation of the sign test and is based on permutational distributions. A method for identifying interactions between age and calendar-period effects is also presented.

RESULTS

The nonparametric method is shown to be powerful in detecting changes in the slope of the birth-cohort trend, although its power can be reduced considerably by calendar-period patterns of risk. The method identifies a previously unidentified decrease in the birth-cohort risk of lung-cancer mortality from 1912 to 1919, which appears to reflect a reduction in the initiation of smoking by young men at the beginning of the Great Depression (1930s). The method also detects an interaction between age and calendar period in leukemia mortality rates, reflecting the better response of children to chemotherapy.

CONCLUSION

The proposed nonparametric method provides a data analytic approach, which is a useful adjunct to log-linear Poisson analysis of age-period-cohort models, either in the initial model building stage, or in the final interpretation stage.

Recent trends in lung cancer mortality in the United States

BACKGROUND

Previous age-period-cohort analyses of lung cancer incidence and mortality rates in the United States have demonstrated a decrease in risk by birth cohort through 1950, consistent with declining trends in smoking prevalence. This study was conducted to examine recent lung cancer trends, including trends among the cohorts born after 1950.

METHODS

Lung cancer mortality rates from 1970 through 1997 for whites aged 24--83 years and for blacks aged 30--83 years were investigated. Using age--period--cohort analyses with 2-year age and 2-year calendar-period intervals, we examined changes in the slope of the trends in birth-cohort and calendar-period effects. All statistical tests are two-sided.

RESULTS

There was an unexpected, statistically significant moderation in the rate of decrease of the birth-cohort trend in lung cancer mortality for whites born after 1950, with a corresponding smaller and statistically nonsignificant moderation for blacks. These data are consistent with smoking initiation rates: Rates of both cigarette and marijuana smoking initiation increased for children aged 12--17 years from 1965 through 1977. There was a statistically significant decrease in the slope of the calendar-period trend for lung cancer mortality in 1990 for both whites and blacks that was observed primarily in people 55 years of age and older.

CONCLUSIONS AND IMPLICATIONS

The birth-cohort pattern of lung cancer mortality after 1950 appears to reflect the early impact of teenage cigarette smoking on lung cancer risk in people under the age of 45 years, although a contribution from marijuana smoking cannot be ruled out. This result provides additional support for increasing smoking cessation and prevention programs for teenagers. The calendar-period decrease in lung cancer mortality after 1990 may reflect the long-term benefits of reductions in tobacco carcinogens in cigarettes and increases in smoking cessation beginning around 1960.

Tumor variants by hormone receptor expression in white patients with node-negative breast cancer from the surveillance, epidemiology, and end results database

PURPOSE

Hormone receptor expression (presence-positive or absence-negative) may reflect different stages of one disease or different breast cancer types. Determining whether hormone receptor expression represents one or more breast cancer phenotypes would have important paradigmatic and practical implications.

METHODS

Breast cancer records were obtained from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database. The study included 19,541 non-Hispanic white women with node-negative breast cancer. Standard tumor cell characteristics and breast cancer-specific survival were analyzed by independent estrogen receptor (ER+ and ER-), independent progesterone receptor (PR+ and PR-), and joint ERPR expression (ER+PR+, ER+PR-, ER-PR+, and ER-PR-).

RESULTS

Age frequency density plots by hormone receptor expression showed two overlapping breast cancer populations with early-onset and/or late-onset etiologies. Independent ER+ and PR+ phenotype were associated with smaller tumor sizes, better grade, and better cancer-specific survival than ER- and PR- breast cancer types. Joint ERPR phenotype exhibited biologic gradients for tumor size, grade, and cancer-specific survival, which ranked from good to worse for ER+PR+ to ER+PR- to ER-PR+ to ER-PR-.

CONCLUSION

Variations of standard tumor cell characteristics and breast cancer-specific survival by hormone receptor expression in white patients with node-negative breast cancer suggested two breast cancer phenotypes with overlapping etiologies and distinct clinical features.

Representation of Asian Americans in clinical cancer trials

PURPOSE

The objectives of this study are to analyze the accrual of Asian Americans to National Cancer Institute (NCI)-supported prevention, screening/diagnosis, and treatment trials and to determine if there is proportional ethnic representation.

METHODS

Data were obtained on all participants accrued to ongoing prevention and screening/ diagnosis trials and on all patients accrued to treatment trials from 1994 to mid-1998. In the analysis, the percentage of Asian Americans to the total number of trial participants is calculated. For treatment trials, participants were stratified into five age groups: 0-20 years, 21-44 years, 45-54 years, 55-64 years, and 65 or more years.

RESULTS

Asian Americans represented 4.8% of subjects accrued in screening/diagnosis trials, 1.8 to 2.2% of subjects in treatment trials, and 0.9% of subjects in prevention trials. Comparison of treatment trial age groups revealed that younger Asian Americans participate significantly more in treatment trials than older Asian Americans.

CONCLUSIONS

Asian American accrual in NCI-supported trials is representative of the cancer burden of Asian Americans in the United States. However, Asian Americans 65+ years are underrepresented. Their full participation in cancer trials is justified.

Annual cancer incidence rates for Hispanics in the United States: surveillance, epidemiology, and end results, 1992-1996

BACKGROUND

The expansion of the Surveillance, Epidemiology, and End Results (SEER) program and the determination of annual population estimates by county level for different racial/ethnic groups since 1990 allow the calculation of annual cancer incidence rates for Hispanics.

METHODS

Incidence rates were calculated for 11 SEER areas representing 25% of the Hispanic population. Standard regression analyses of log-transformed rates were used to determine the trends of the rates.

RESULTS

An important measure of the cancer burden among Hispanics is the rank order of their cancers. For Hispanic males, the five major cancers (in declining order) are prostate, lung and bronchus, colon/rectum, non-Hodgkin lymphoma, and stomach cancers. For Hispanic females, the top five cancers are breast, colon/rectum, lung and bronchus, cervix, and endometrial cancers. Another measure of cancer burden is their rates relative to white non-Hispanics. Hispanic males have rates greater than white non-Hispanic males for stomach (1.6 times greater) and liver and IBD cancers (2.2), whereas Hispanic females have greater rates for cervix (2.2 times greater), liver and IBD (2.0), stomach (2.1), and gallbladder cancers (3.3). Other measures of cancer burden include the trends in Hispanic rates. Hispanic males have significant declining trends for all sites, prostate cancer, and urinary bladder cancer, and an increasing trend for liver and IBD cancers. Hispanic females have significant declining trends for cervix and urinary bladder cancers.

CONCLUSIONS

The SEER cancer incidence rates and trends provide a general overview of the cancer burden among Hispanics residing in the SEER sites. This type of information is critical for determining interventions to reduce the cancer burden among Hispanics in the United States.

Polyvinyl alcohol-Fricke hydrogel and cryogel: two new gel dosimetry systems with low Fe3+ diffusion

Two new Fricke dosimeter gel systems with low diffusion rates have been developed for 3D radiation dosimetry purposes. Both systems consist of a solution of 20% (by weight) polyvinyl alcohol (PVA) in a 50 mM H2SO4 solution with 0.4 mM ferrous ammonium sulphate and xylenol orange (FX). The difference in the two gels is the way that the gelation process was initiated: either by bringing the temperature to (a) +5 degrees C or (b) -20 degrees C before returning them to room temperature. These gels are termed 'hydrogel' and 'cryogel', respectively. The hydrogel is optically transparent, and can be used with either optical or MRI detection methods for dosimetric imaging. The cryogel is rubbery in texture but opaque, so its internal Fe3+ concentration can only be measured with MRI. The hydrogel's optical attenuation coefficient is linear (r2 = 0.99) with dose from 0 to 20 Gy with a sensitivity of 0.106 cm(-1) Gy(-1) (at 543 nm). In terms of MR relaxation rate, the dose response for both the hydrogel and cryogel was linear (r2 = 0.99) with a sensitivity of 0.020 s(-1) Gy(-1) (at 1.5 T). The Fe3+ diffusion coefficient (at 20 degrees C) was measured to be 0.14 mm2 h(-1), which is significantly lower than similar preparations reported for porcine gelatin or agarose. The PVA-FX gels can be stored for long periods of time before exposure to radiation, since the auto-oxidation rate was 10 times less than that of gelatin-Fricke recipes. The new gels developed in this work are a significant improvement on previous Fricke gel systems.

Implications of stage-specific survival rates in assessing recent declines in prostate cancer mortality rates

It has been noted that the most important evidence for a benefit of early detection of prostate cancer using prostate-specific antigen (PSA) testing would be a decline in prostate cancer mortality rates to levels below those existing before diagnostic use of PSA testing. We document a decrease in U.S. prostate cancer mortality rates in white men less than 85 years of age to levels below those existing in 1986, the year use of PSA testing was approved. In fact, for men 60-79 years of age, prostate cancer mortality rates were lower in 1997 than in any year since 1950. Although it has been argued that the decrease in prostate cancer mortality rates began too soon to be explained by PSA testing, stage-specific survival rates indicate that a rapid decrease in mortality may be explained by the large number of high-grade prostate cancers detected before metastasis. If recent decreases in U.S. prostate cancer mortality rates are due to early detection using PSA testing, randomized clinical trials investigating PSA testing will show early evidence of a mortality benefit.

Polymerase chain reaction detection of Mycobacterium tuberculosis from fine-needle aspirate for the diagnosis of cervical tuberculous lymphadenitis

BACKGROUND

Despite its well-established usefulness in the diagnosis of cervical tuberculous lymphadenitis, fine-needle aspiration cytology (FNAC) has several limitations in its clinical applications, especially when the presence of acid-fast bacilli is not proven. Furthermore, fine-needle aspirate is sometimes inadequate for diagnosis, and the sensitivity and specificity of this technique for cervical tuberculous lymphadenitis has not been firmly established.

OBJECTIVE

The authors performed Mycobacterium tuberculosis polymerase chain reaction (PCR) for mycobacterial DNA sequences from the remainder of fine-needle aspirate after cytological examination and evaluated its diagnostic efficacy in clinical situations.

METHODS

Conventional diagnostic procedures including FNAC and M tuberculosis PCR were performed simultaneously in 29 cases that had been suspected to be cervical tuberculous lymphadenitis on patients' first visit. The results of FNAC and M tuberculosis PCR were compared with the clinical outcomes after several months of follow-up and pathological results from open biopsy of some cases.

RESULTS

Among the 17 cases of cervical tuberculous lymphadenitis diagnosed in clinical situations, M tuberculosis DNA was found by PCR in 13 cases (76.4%). Negative findings on PCR were achieved in 12 cases, which revealed non-granulomatous lymphadenopathy.

CONCLUSION

From these results, we conclude that M tuberculosis PCR using the remainder of aspirate for cytological examination is a very useful tool for the diagnosis of cervical tuberculous lymphadenitis, and its clinical application with FNAC could reduce the necessity for open biopsy.

Cl--dependent and Cl--independent Na+/ HCO3- acid extrusion in cultured rat cerebellar astrocytes

It is still uncertain whether the Na+-dependent Cl--HCO3- exchanger (NCBE) is expressed in mammalian astrocytes. Using fluorescent indicators to monitor the intracellular pH (pHi) and intracellular Na+ or Cl- levels, the NCBE in cultured rat cerebellar astrocytes was examined in detail. In nominally bicarbonate-free (Hepes-buffered) medium, a marked pHi recovery from internal acid load was seen which could be blocked completely by 30 microM HOE 694, a specific Na+-H+ exchanger isoform 1(NHE-1) inhibitor, at a pHi above 6.9. These conditions were therefore used to block NHE activity in CO2/HCO3-buffered media when the NCBE was being studied at pHi above 6.9. After internal acid loading in completely Cl--free bicarbonate-buffered medium (containing HOE 694), the rates of pHi recovery and transient Na+ influx were considerably slowed, and the Cl--dependent acid extrusion was both Na+- and 4,4-diisothiocyano-stilbene-disulphonic acid (DIDS)-sensitive. Moreover, a HCO3-dependent Cl- efflux during internal acid injection was seen. These results suggest that the NCBE is present in astrocytes. Following repetitive internal acid loading by addition of 5% CO2 to internal Cl- depleted cells, a similar rate of pHi recovery was consistently seen, suggesting Cl--independent pHi regulation also occurred in astrocytes. Moreover, this pHi recovery was completely blocked in the absence of sodium or on addition of DIDS, confirming that the Na+-HCO3 cotransporter (NBC) is present. Thus, the present study provides evidence that both the NCBE and NBC play important roles in acid extrusion in cultured mammalian astrocytes.

Measurement of Gd-DTPA diffusion through PVA hydrogel using a novel magnetic resonance imaging method

Polyvinyl alcohol-cryogel (PVA-C) is a hydrogel that is an excellent tissue mimic. In order to characterize mass transfer in this material, as well as to demonstrate in principle the ability to noninvasively measure solute diffusion in tissue, we measured the diffusion coefficient of the magnetic resonance (MR) contrast agent gadolinium diethylene triaminopentaacetic acid (Gd-DTPA) through PVA-C using a clinical MR imager. The method involved filling thick-walled rectangular PVA-C "cups" with known concentrations of Gd-DTPA solutions. Then by using a fast inversion recovery spin echo MR imaging protocol, a signal "null" contour was created in the MR image that corresponded to a second, known concentration of Gd-DTPA. By collecting a series of MR images through the PVA-C wall as a function of time, the displacement of this second known isoconcentration contour could be tracked. Application of Fick's second law of diffusion yielded the diffusion coefficient. Seven separate experiments were performed using various combinations of initial concentrations of Gd-DTPA within the PVA-C cups (3.2, 25.6, or 125 mM) and tracked isoconcentrations contours (0.096, 0.182, or 0.435 mM Gd-DTPA). The experimental results and the predictions of Fick's law were in excellent agreement. The diffusivity of Gd-DTPA through 10% PVA hydrogel was found to be (2.6 +/- 0.04) x 10(-10) m(2)/s (mean +/- s.e.m.). Separate permeability studies showed that the diffusion coefficient of Gd-DTPA through this hydrogel did not change with an applied pressure of up to 7.1 kPa. Accurate measurements could be made within 30 min if suitable Gd-DTPA concentrations were selected. Due to the excellent repeatability and fast data acquisition time, this technique is very promising for future in vivo studies of species transport in tissue.

Breast cancer trends of black women compared with white women

OBJECTIVE

To investigate why breast cancer mortality rates have decreased in the 1990's for white women but not for black women.

DESIGN

Racial differences in breast cancer incidence, survival, and mortality rates were examined using regression methods and age-period-cohort models.

SETTING

United States breast cancer mortality rates from 1970 through 1995, breast cancer incidence rates from 1980 through 1995, and 3-year survival rates from 1980 through 1993. The incidence and survival data are from the Surveillance, Epidemiology, and End Results Program, representing 11% of the US population, of the National Cancer Institute, Bethesda, Md.

RESULTS

For both white and black women aged 30 to 39 years, breast cancer mortality rates began decreasing in 1987. For white women aged 40 to 79 years, breast cancer mortality rates declined after 1989, and for black women aged 40 to 69 years, mortality rates ceased increasing in the middle to late 1980s. Birth cohort trends were similar by race, but calendar period trends and survival rates differed.

CONCLUSIONS

Declines in mortality rates in women younger than 40 years reflect a favorable birth cohort trend for women born after 1948 and likely reflect changes in risk factors. The increased early detection of breast cancer by mammography and improvements in breast cancer treatment appear to be contributing to the improving mortality trends in older women, although black women appear to have benefited less than white women from early detection and treatment advances. In addition, substantial increases in survival rates for white women with regional disease have contributed to their declining mortality rates and likely reflect an increasing use of beneficial adjuvant therapy.