PubMed Health⌕ Search

Biomedical subjects

L Tabár

Publications and source records attributed to L Tabár.

At least 19 recordsLinked to original sources
PubMed2003

Mammography and breast cancer: the new era.

OBJECTIVES: To review the evidence demonstrating that early detection of breast cancer substantially decreases death from the disease, and to demonstrate that the significant change in the outcome of breast cancer patients results from a combination of early detection and surgical removal of breast cancer, as treatment of the late stage disease provides little impact on ultimate outcome. METHOD: Review results of the randomized controlled trials of mammographic screening and the published results of service screening. RESULTS: Both randomized controlled trials and service screening, when performed properly, provide unequivocal evidence demonstrating that arresting the disease in its preclinically detectable phase has significant impact on outcome. Primary emphasis should be upon preventing breast cancer from developing to metastatic disease. CONCLUSIONS: Numerous scientific trials have repeatedly and convincingly confirmed that breast cancer is progressive rather than a systemic disease from its inception. Progression of breast cancer can be arrested through detection and treatment at an early phase. The time at which disease progression is arrested has significant impact on clinical outcome, making mammographic screening a key factor in the control of breast cancer.

Adult↗
PubMed2003

Quantifying the potential problem of overdiagnosis of ductal carcinoma in situ in breast cancer screening.

The relevance of detection of ductal carcinoma in situ (DCIS) in a breast cancer screening programme, and the extent of overdiagnosis of non-progressive lesions, remains controversial. It was the purpose of this paper to estimate the incidence of non-progressive, 'overdiagnosed' DCIS. We defined non-progressive DCIS (DCIS(0)) as DCIS which could not have progressed to invasive disease if left untreated. Progressive DCIS (DCIS(1)) was defined as DCIS which has the propensity to progress to invasive disease. We fitted a Markov process model of the incidence of progressive and non-progressive DCIS, the transition of the former to preclinical invasive disease and the subsequent progression to clinical symptomatic cancer. We used data from the Swedish Two-County Trial and from service screening programmes in the UK, Netherlands, Australia and the USA to estimate the incidence of progressive and non-progressive DCIS, and the detection rates of each at the first and subsequent screening. Average incidence of non-progressive DCIS was 1.11 per 100000 per year. Average incidence of progressive DCIS was 2.1 per 1000 per year. At prevalence screen, 37% of DCIS cases were estimated to be non-progressive. A woman attending prevalence screen has a 19 times greater chance of having a progressive DCIS or an invasive tumour diagnosed than of having a non-progressive DCIS diagnosed. At incidence screen, only 4% of DCIS cases were estimated to be non-progressive. A woman attending an incidence screen has a 166 times higher probability of having a progressive DCIS or invasive lesion diagnosed than of having a non-progressive DCIS diagnosed. There is an element of overdiagnosis of DCIS in breast cancer screening, but the phenomenon is small in both relative and absolute terms.

Adult↗
PubMed2002

Oral contraceptive use and mammographic patterns.

High-risk mammographic patterns represent an increased risk of contracting breast cancer and may be used as a surrogate endpoint for the disease. We examined the relationship between oral contraceptive (OC) use and mammographic patterns among 3218 Norwegian women, aged 40-56 years. Information on ever OC use, duration, and age of first OC use and other epidemiological data were obtained through questionnaires. The mammograms were categorized into five groups. Patterns I-III were combined into a low-risk group and patterns IV and V into a high-risk group. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using logistic regression and adjusted for age, menopausal status, parity, age at first birth, and body mass index. Women who reported ever having used OCs were 20% more likely (OR 1.27, 95% CI 1.0-1.6) to have high-risk mammographic patterns compared with those reporting never having used OCs. There was no dose response between different measures of OC use and high-risk patterns. Among nulliparous women, ever OC users were four times more likely (OR 4.65, 95% CI 2.1-10.3) to have high-risk patterns compared with never users. Our findings suggest that, especially among nulliparous women, ever OC use may exert its effect on breast cancer risk through changes in breast tissue, which can be observed on a mammogram.

Adult↗
PubMed2001

Beyond randomized controlled trials: organized mammographic screening substantially reduces breast carcinoma mortality.

BACKGROUND: The efficacy of mammographic screening in the reduction of breast carcinoma mortality has been demonstrated in randomized controlled trials. However, the evaluation of organized screening outside of research settings (so-called "service screening") faces unique methodologic and conceptual challenges. The current study describes the evaluation of organized mammography screening in a clinical setting and demonstrates the benefit obtained from service screening in two Swedish counties. METHODS: In the group of subjects ages 20--69 years, there were 6807 women diagnosed with breast carcinoma over a 29-year period in 2 counties in Sweden and 1863 breast carcinoma deaths. All patients were classified from patient charts based on their screening status (i.e., whether they had been invited to undergo screening and whether they actually had undergone screening). The number of women who lived in the 2 counties during the 29-year study period was provided by the Central Bureau of Statistics. Breast carcinoma-specific mortality was compared across three time periods: 1) 1968--1977, when no screening was taking place because mammography had not been introduced; 2) 1978--1987, the approximate period of the Two-County randomized controlled trial of screening in women ages 40--74 years; and 3) 1988--1996, when all women in the 2 counties ages 40--69 years were invited to undergo screening (service screening). When comparing breast carcinoma mortality in screened women with that in women diagnosed before screening was introduced, a correction for self-selection bias was incorporated to prevent overestimation of the benefit of screening. RESULTS: The mortality from incident breast carcinoma diagnosed in women ages 40-69 years who actually were screened during the service screening period (1988--1996) declined significantly by 63% (relative risk [RR] = 0.37; 95% CI, 0.30--0.46) compared with breast carcinoma mortality during the time period when no screening was available (1968--1977). The mortality decline was 50% (RR = 0.50; 95% CI, 0.41--0.60) when breast carcinoma mortality among all women who were invited to undergo screening (nonattendees included) was compared with breast cancer mortality during the time period when no screening was available (1968--1977). The reduction in mortality observed during the service screening period, adjusted for selection bias, was 48% (RR = 0.52; 95% CI, 0.43--0.63). No significant change in breast carcinoma mortality was observed over the three time periods in women who did not undergo screening. This group included women ages 20--39 years because these individuals were never invited to undergo screening, and women ages 40--69 years who did not undergo screening (not invited during the randomized trial or invited during the second and third time periods but declined). CONCLUSIONS: Regular mammographic screening resulted in a 63% reduction in breast carcinoma death among women who actually underwent screening. The policy of invitation to organized screening with mammography appears to have reduced breast carcinoma mortality by 50% in these 2 counties.

Adult↗
PubMed2001

A treatment scale for axillary management in breast cancer.

BACKGROUND: We have investigated a method, the Kaufman axillary treatment scale (KATS), to help assign patients with a clinically negative axilla to one of three current options of axillary management: standard axillary dissection, sentinel node sampling followed by axillary dissection if the sentinel node is positive, or no axillary surgery at all. The KATS score uses preoperative data to guide the choice of axillary treatment. METHODS: The KATS score is calculated by adding the preoperative values of tumor size, patient age, and pathologic grade. Values range from 1 to 4 for size (1 to 9 mm, 10 to 14 mm, 15 to 19 mm, and 20 to 30 mm), 1 to 3 for age (70 years and over, 50 to 69 years, less than 50 years), and 1 to 2 for grade (low or not low) to calculate the score. The KATS score ranges from 3 to 9. We have applied this score against the SEER (Surveillance, Epidemiology, and End Results) tumor registry of 529 patients with invasive breast cancer with known pathologic data. We then validated it by applying it to our own set of 190 patients using preoperative data. The chi-square test and logistic regression analysis were used for P values (all two sided), univariate and multivariate analysis, odds ratio and confidence intervals utilizing SPSS statistics software. RESULTS: In the SEER database using American Joint Committee on Cancer pathologic size alone, no sizable group was identified with a positive node rate neither below 8% (T1a) nor above 48% (T2). KATS scores of 3 and 4 (68 patients, group 1) identify patients with an average node positive rate of 4.4% (P <0.02, group 1 versus 2). Those patients with KATS scores of 5, 6, and 7 (341 patients, group 2) carry an average node positive rate of 22% (P <0.001, group 2 versus 3). KATS scores of 8 and 9 (120 patients, group 3) identify patients with an average node positive rate of 50% (P <0.001, group 3 versus 1). Similar results were found on our own group of 190 patients using preoperative available data. KATS scores of 3 or 4 (11 patients, group 1) had no positive nodes. Group 2 (100 patients, KATS score 5, 6, and 7) had an average 30% node positive rate. Group 3 (79 patients, KATS score 8 and 9) had 61% node positive rate. The KATS score allows the clinician to separate patients into three axillary management groups. Group 1 are those patients who may need no axillary surgery at all. Group 2 are patients who would benefit from sentinel node mapping. Group 3 has a node positive rate (61%) similar to that of clinically palpable nodes (since not all clinically palpable nodes are positive). Group 3 patients may be considered for standard axillary dissection, similar to the palpable node patient. If group 3 patients have sentinel node mapping, more than half of these patients require axillary dissection and the impact of false negative sentinel node procedures may become clinically significant. CONCLUSIONS: An axillary treatment score has been developed to aid in the triage of patients toward reasonable axillary treatment choices for the benefit of the patient. The KATS score is a guideline and not a mandate. The KATS score attempts to use breakpoints that are both clinically practical and validated by scientific data. Like many other attempts to categorize patients, there is a continuum of data points along any variable. The treating physician utilizing the full array of available data on each patient makes the final clinical decision of axillary management.

Age Factors↗
PubMed2000

A novel method for prediction of long-term outcome of women with T1a, T1b, and 10-14 mm invasive breast cancers: a prospective study.

BACKGROUND: Women with small mammographically detected breast cancers generally have good long-term outcomes, but a few with T1a (1-5 mm) and T1b (6-10 mm) tumours will eventually die from breast cancer. We investigated whether women at high risk of breast-cancer death could be identified with mammographic criteria and differentiated from women with small cancers of the breast and good outcomes. METHODS: We prospectively applied mammographic classifications of tumour type to a consecutive series of 343 mammograms of invasive breast cancers of size 1-14 mm. Classifications were: stellate (spiculated) mass with no calcifications; circular or oval lesions with no calcifications; spiculated or circular lesions with non-casting-type calcifications; and casting-type calcifications. FINDINGS: 20-year survival for women with 1-14 mm invasive tumours with casting-type calcifications was 55%. 14% of 138 women with 1-9 mm tumours had casting-type calcifications on mammography, which accounted for 73% of all breast-cancer deaths (p<0.001). T1a, T1b, and 10-14 mm tumours with casting-type calcifications behaved as if they were larger lesions, since the rate of death was similar to that for women with advanced high-grade tumours. Most women who died were node-negative. The long-term survival of women who had tumours of 1-9 mm with no casting-type calcifications was about 95%. INTERPRETATION: Mammographic classification seemed to reliably predict good and bad long-term outcomes for survival in tumours of 14 mm or smaller, and especially for those smaller than 10 mm. The implications for therapy are substantial.

Breast Neoplasms↗
PubMed2000

The pressing need for better histologic-mammographic correlation of the many variations in normal breast anatomy.

Mammography screening calls for a reevaluation of the working relationship between physicians dealing with the diagnosis and treatment of breast diseases. In this new era, histologic-mammographic correlation needs to be extended to correctly describe the deceptive mammographic findings that correspond to variations in normal breast tissue. Progress in histologic-mammographic correlation can only be made by overcoming the limitations inherent to the traditional histologic technique by examining a histologic specimen of greater length, width, and depth. There are several distinct advantages to using the large-section histology technique in the diagnosis of breast diseases. The subgross (three-dimensional) histology technique serves to bridge the gap that separates the pathologist and radiologist, bringing them to a common ground for a better understanding of breast morphology. These improvements in communication between the members of the diagnostic team will serve to optimize the sensitivity and specificity of breast cancer diagnosis.

Breast↗
PubMed2000

The Swedish Two-County Trial twenty years later. Updated mortality results and new insights from long-term follow-up.

The benefit of invitation to mammographic screening observed in this trial is maintained as a highly significant 32% reduction in breast cancer mortality. Mammographic screening for breast cancer continues to save lives after up to 20 years. Screening derives this benefit by improving the distribution of tumors diagnosed with respect to prognostic categories based on node status, size, and histology of tumors. There is potential for modern screening programs with shorter interscreening intervals to achieve even greater improvements in prognostic category and greater reductions in breast cancer mortality. Mammography can discriminate a subpopulation of high-risk cases, those displaying casting-type calcifications on the mammogram, among very small tumors, with fundamental implications for diagnosis and treatment.

Adult↗
PubMed2000

A new era in the diagnosis of breast cancer.

The regular use of high-quality mammography on asymptomatic women enables most breast cancers to be detected in the preclinical phase. Earlier detection dramatically rearranges the spectrum of breast cancer outcomes, resulting in better control of breast cancer. The new era requires a shift in thinking and a re-evaluation of the traditional diagnostic and therapeutic approaches to breast diseases. Tumors are smaller, less often node-positive, and have a more favorable malignancy grade. The challenge for diagnosticians is to find as many breast cancers as possible in the preclinical phase. The challenge for therapists is to adapt the treatment guidelines accordingly, in order to avoid over-treatment.

Adult↗
PubMed1999

The natural history of breast carcinoma: what have we learned from screening?

BACKGROUND: The availability of breast carcinoma data from trials of mammographic screening provides an opportunity to study the natural history of breast carcinoma. METHODS: The Swedish Two-County study is a randomized, controlled trial of mammographic screening for breast carcinoma in which 77,080 women were randomized to receive an invitation to mammographic screening and 55,985 were randomized to receive no invitation. During the trial, a total of 2468 breast carcinoma cases were diagnosed. The authors examined the effect of screening on the pathologic attributes of the tumors diagnosed, mortality and survival from breast carcinoma, and the consequences of arresting tumor development by screening. RESULTS: Screening reduces mortality from breast carcinoma largely through its effect in detecting tumors at a smaller size, decreasing the probability of lymph node metastases, and reducing the opportunity for worsening of the grade of malignancy of the tumor. CONCLUSIONS: Breast carcinoma is not a systemic disease at its inception, but is a progressive disease and its development can be arrested by screening. The point at which the tumor's progression is arrested is crucial. Detection of small (<15 mm) and lymph node negative invasive tumors will save lives and confer an opportunity for less radical treatment. Tumor progression in the preclinical phase occurs more rapidly in women age <50 years, suggesting the need for a shorter screening interval for this group.

Adult↗
PubMed1999

10-Year results after sector resection with or without postoperative radiotherapy for stage I breast cancer: a randomized trial.

PURPOSE: To study the long-term effectiveness of postoperative radiotherapy after sector resection for breast cancer in a randomized trial in which mammography is a major pathway to diagnosis. PATIENTS AND METHODS: Three hundred eighty-one women with a unifocal breast cancer < or = 20 mm in diameter on the preoperative mammogram and without histopathologic signs of axillary metastases were treated by sector resection plus axillary dissection. Of these patients, 184 women were randomized to receive postoperative radiotherapy to the breast (XRT group), and 197 women received no further treatment (non-XRT group). RESULTS: The local recurrence rate was 8.5% (95% confidence interval [CI], 3.9% to 13.1%) in the XRT group and 24.0% (95% CI, 17.6% to 30.4%) in the non-XRT group (P =.0001). Survival free from regional and distant recurrence was 83. 3% in the XRT group (95% CI, 77.5% to 89.1%) and 80.0% in the non-XRT group (95% CI, 73.9% to 86.1%) (P =.23). Overall survival was 77.5% in the XRT group (95% CI, 70.9% to 84.1%) and 78% in the non-XRT group (95% CI, 71.7% to 84.3%) (P =.99). A subgroup analysis suggested that women older than 55 years of age without comedo or lobular carcinomas had a low risk of local recurrence of 6.1% (95% CI, 0.1% to 9.1%) in the XRT-group and 11.0% (4.0% to 18.0%) in the non-XRT group (P =.16). CONCLUSION: Sector resection plus radiotherapy resulted in an absolute reduction in local recurrence of 16% at 10 years compared with surgery alone. Women older than 55 years of age without comedo or lobular carcinomas may have a low risk of local recurrence. Postoperative radiotherapy was not shown to reduce distant recurrences or improve overall survival.

Breast Neoplasms↗
PubMed1997

The Tabár classification of mammographic parenchymal patterns.

The purpose of this study was to describe one method of classification, based on anatomic-mammographic correlations, developed by Tabár. We also wanted to examine how the mammograms categorized as low- and high-risk according to Tabár and Wolfe criteria related to each other and to three selected risk factors for breast cancer. The study materials are based on questionnaires and mammograms from 3,640 Norwegian women, aged 40-56 years, participating in the third Tromsö study. The mammograms were categorized into five groups. Line drawings and their pathologic correlates of the five patterns are described in detail. The Tabár classification is based on anatomic-mammographic correlations, following three-dimensional (thick slice technique) histopathologic-mammographic comparisons, rather than simple pattern reading (Wolfe classification). For analysis patterns I-III (Tabár) and N1 and P1 (Wolfe) were grouped into low-risk groups and patterns IV and V (Tabár) and P2 and DY Wolfe) into high-risk groups. The overall agreement on high-risk versus low risk for the two classifications was 54% with a kappa-value of 0.22. The study displays that the strength of association between high-risk mammographic patterns and the three selected risk factors parity, number of children and age at first birth is of greater magnitude when the Tabár instead of the Wolfe classification is applied. More patients are needed to compare the classification directly with the risk of cancer. This study indicates that further development of the classification of mammograms may increase the usefulness of mammographic patterns in research and clinical practice.

Adult↗
PubMed1997

Risk factors for local recurrence after conservative treatment in stage I breast cancer. Definition of a subgroup not requiring radiotherapy.

BACKGROUND: Risk factors for local recurrence after breast-conserving treatment of early breast cancer have not previously been evaluated in settings where mammography has been a major pathway to diagnosis of both primary tumour and recurrences or in patients treated surgically by a formal sector resection. PATIENTS AND METHODS: Three hundred eighty-one women with stage 1 primary breast cancer were randomised after a standardised sector resection to either a course of postoperative radiotherapy to 54 Gy to the breast (XRT group) or to surgery alone (non XRT group). At five years, 43 local recurrences, six of them in the XRT group, appeared. Patient characteristics collected from the medical records, histopathological characteristics determined by re-examination of slides, and mammographic characteristics from the pre-operative mammograms were evaluated as risk factors for recurrence by univariate and multivariate Cox proportional hazards models. Results are reported as relative hazards (RH) with 95% confidence intervals (95% CI). RESULTS: In the univariate analysis comedo cancer, RH 3.5 (95%, CI 18 6.7), lobular cancers RH 2.8 (95% CI 1.1 7.1), mammographic appearance as circular/oval shaped density, RH 2.3 (95% CI 1.1 4.51, and mammographic appearance as a stellate lesion with microcalcifications inside the lesion, RH 3.8 (95% CI 1.1-13.0) were identified as risk factors for local recurrence. Age, with a RH of 0.97 (95% CI 0.94 0.99) for each increasing year was inversely associated with risk. A multivariate analysis, which also took postoperative radiotherapy into account, only showed comedo cancers with a RH 2.6 (95% CI 1.3-5.0) and mammographic appearance of a stellate lesion with microcalcification inside the lesion RH 4.5 (95% CI 1.1-17.6) to be statistically significant. The estimates for age RH 0.98 (95% CI 0.95 1.01 and lobular cancers RH 2.5 (95%, CI 0.98 6.6) were marginally changed, with widened CIs. Patients > 60 years of age, without comedo or lobular carcinomas were found to be at low risk 15.9% at five years in Kaplan Meyer estimate) of local recurrence, even without postoperative radiotherapy. CONCLUSION: Low age, comedo and lobular cancers and mammographic appearance of the tumour as a stellate lesion with microcalcifications inside the lesion indicate an increased risk for local recurrence after sector resection in stage 1 tumours at five years. Patients > 60 years of age without comedo or lobular cancers are at low risk for local recurrence at five years even without postoperative radiotherapy.

Combined Modality Therapy↗
PubMed1997

Recent results from the Swedish Two-County Trial: the effects of age, histologic type, and mode of detection on the efficacy of breast cancer screening.

The effect of mammographic screening in reducing mortality from breast cancer is known to be smaller and more delayed in women aged 40-49 than in women over 50. In this study, we investigated how these phenomena relate to histology-specific breast cancer incidence and mortality. The data are from 2,468 women with breast cancer who participated in the Swedish Two-County Trial. The overall relative breast cancer mortality of invited to noninvited women aged 40-49 was 0.87, and the relative mortality from poorly differentiated (grade 3) ductal carcinoma was 0.95. These results were not statistically significant. The corresponding relative risks for invited women aged 50-74 were a statistically significant 0.65 and 0.61. We conclude that in this trial, with a two-year interscreening interval, the smaller and later effect of invitation to screening on breast cancer mortality in women 40-49 years old is due to the failure of screening to reduce mortality from grade 3 ductal carcinoma in this age group.

Adult↗
PubMed1997

Updated overview of the Swedish Randomized Trials on Breast Cancer Screening with Mammography: age group 40-49 at randomization.

The purpose of this overview is to estimate more precisely the long-term effect of mammography screening by adding four more years of follow-up to women aged 40-49 years in the four Swedish trials on mammography screening. Data from the four, trials were merged and linked to the Swedish Cancer and Cause of Death Register for 1958-1993 and 1951-1993 respectively to identify date of breast cancer diagnosis and cause and date of death. The invited and control groups comprised 48,569 and 40,247 women respectively. At the December 1993 follow-up, 602 and 482 breast cancer cases were identified in the two groups respectively, of which 104 and 111 had breast cancer as the underlying cause of death. This corresponds to a relative risk (RR) of 0.77 (95% CI: 0.59-1.01) for the two groups. In the 40-44 age group at randomization, 94% of breast cancer patients in the study and 89% in the control group were diagnosed before the age of 50; however, among breast cancer deaths in this age group, only two in the invited and five in the control group died after age 50. At follow-up of women 40-44 years at randomization 208 women in the invited and 184 in the control group were reported to the Cancer registry with breast cancer. Out of these 195 (94%) and 163 (89%) respectively were reported before the age of 50. Further, the relative risk for the age group 40-44 years at randomization by age at follow-up was 1.11, 0.51 and 0.46 for the age groups 45-49, 50-54, and 55-59 at follow-up. This study shows a 23% reduction in the breast cancer mortality in women 40-49 years at randomization achieved from a median trial time of 7.0 years, a median follow-up time of 12.8 years, and a screening interval of 18-24 months. Almost all of the effect in the 40-44 year age group at randomization was due to screening before the age of 50.

Adult↗
PubMed1997

Markov models of breast tumor progression: some age-specific results.

Researchers have noted that mammographic screening has a reduced effect on breast cancer mortality in women in their forties compared to older women. Explanations for this include poorer sensitivity in younger women due to denser breast tissue, as well as more rapid tumor progression, giving a shorter mean sojourn time (the average duration of the preclinical screen-detectable period). To test these hypotheses, we developed a series of Markov-chain models to estimate tumor progression rates and sensitivity. Parameters were estimated using tumor data from the Swedish two-county trial of mammographic screening for breast cancer. The mean sojourn time was shorter in women aged 40-49 compared to women aged 50-59 and 60-69 (2.44, 3.70, and 4.17 years, respectively). Sensitivity was lower in the 40-49 age group compared to the two older groups (83%, 100%, and 100%, respectively). Thus, both rapid progression and poorer sensitivity are associated with the 40-49 age group. We also modeled tumor size, node status, and malignancy grade together with subsequent breast cancer mortality and found that, to achieve a reduction in mortality commensurate with that in women over 50, the interscreening interval for women in their forties should be less than two years. We conclude that Markov models and the use of tumor size, node status, and malignancy grade as surrogates for mortality can be useful in design and analysis of future studies of breast cancer screening.

Adult↗