A case control study on the effectiveness of breast cancer screening by clinical breast examination in Japan

Diagnostic Accuracy of Breast Medical Tactile Examiners (MTEs): A Prospective Pilot Study

Background

The usefulness of clinical breast examination (CBE) in general and in breast cancer screening programs has been a matter of debate. This study investigated whether adding vision-impaired medical tactile examiners (MTEs) improves the predictiveness of CBE for suspicious lesions and analyzed the feasibility and acceptability of this approach.

Methods

The prospective study included 104 patients. Physicians and MTEs performed CBEs, and mammography and ultrasound results were used as the gold standard. Sensitivity and specificity were calculated and logistic regression models were used to compare the predictive value of CBE by physicians alone, MTEs alone, and physicians and MTEs combined.

Results

For CBEs by physicians alone, MTEs alone, and both combined, sensitivity was 71, 82, and 89% and specificity was 55, 45, and 35%, respectively. Using adjusted logistic regression models, the validated areas under the curve were 0.685, 0.692, and 0.710 (median bootstrapped p value (DeLong) = 0.381).

Conclusion

The predictive value for a suspicious breast lesion in CBEs performed by MTEs in patients without prior surgery was similar to that of physician-conducted CBEs. Including MTEs in the CBE procedure in breast units thus appears feasible and could be a way of utilizing their skills.

A comparison of clinicopathological characteristics and long-term survival outcomes between symptomatic and screen-detected breast cancer in Japanese women

BACKGROUND

Several studies from other countries have reported that patients with screen-detected breast cancer have better survival than those with symptomatic breast cancer. However, no such comparison has been performed in Japan. Therefore, we aimed to compare the clinicopathological characteristics and survival rates between symptomatic and screen-detected breast cancer in Japanese women.

METHODS

From January 2000 to December 2004, 977 and 182 women with symptomatic or screen-detected breast cancer, respectively, underwent surgery at a single Japanese hospital. We retrospectively reviewed these patients' clinicopathological data. Likelihood of death was estimated using the Kaplan-Meier method and the log-rank test. Multivariate analysis including mode of detection, tumor size, lymph node status, hormone receptor status, and adjuvant therapy administration was performed using the Cox proportional hazards model.

RESULTS

Screen-detected breast cancer was associated with increased rate of breast-conserving surgery, non-invasive carcinoma, smaller tumor size, decreased lymph node involvement, increased hormone receptor positivity, and decreased adjuvant chemotherapy administration. Compared to women with symptomatic tumors, those with screen-detected tumors had improved overall and breast cancer-specific survival rates. Factors associated with survival in univariate analysis were screen detection, tumor size, lymph node status, progesterone receptor status, and adjuvant chemotherapy administration.

CONCLUSIONS

Breast cancer screening in Japanese women has led to increases in the rates of breast-conserving surgery, hormone receptor positivity, and survival rates along with reductions in axillary lymph node dissection and adjuvant chemotherapy administration.

A meta-analysis of mammographic screening with and without clinical breast examination

Mammographic screening with clinical breast examination has been recommended in Japan since 2000. Although mammographic screening without clinical breast examination has not been recommended, its introduction is anticipated. The efficacies of mammographic screening with and without clinical breast examination were evaluated based on the results of randomized controlled trials. PubMed and other databases for studies published between 1985 and 2014 were searched. The study design was limited to randomized controlled trials to evaluate mortality reduction from breast cancer. Five studies were eligible for meta-analysis of mammographic screening without clinical breast examination. The relative risk for women aged 40-74 years was 0.75 (95% confidence interval, 0.67-0.83). Three studies evaluated the efficacy of mammographic screening with clinical breast examination. The relative risk for women aged 40-64 years was 0.87 (95% confidence interval, 0.77-0.98). The number needed to invite was always lower in mammographic screening without clinical breast examination than in mammographic screening with clinical breast examination. In both screening methods, the number needed to invite was higher in women aged 40-49 years than in women aged 50-70 years. These results suggest that mammographic screening without clinical breast examination can afford higher benefits to women aged 50 years and over. Although evidence of the efficacy of mammographic screening without clinical breast examination was confirmed based on the results of the randomized controlled trials, a Japanese study is needed to resolve local problems.

Is clinical breast examination effective in Japan? Consideration from the age-specific performance of breast cancer screening combining mammography with clinical breast examination

BACKGROUND

There is controversy about the value of clinical breast examination (CBE) in breast cancer screening programs that include mammography.

METHODS

In Fukui Prefecture, a screening combining mammography with CBE was employed on 62,447 women from 2004 to 2009. We examined the sensitivity and specificity of mammography alone, and mammography and CBE together for each age group (40-49, 50-59, 60-69, and 70-79).

RESULTS

167 breast cancers and 49 false-negative cancers were detected during 5 years. For the combined screening, the sensitivities were 73.1, 74.1, 78.3, and 86.5 %, and the specificities were 83.8, 87.5, 89.8, and 90.9 % in the groups of 40-49, 50-59, 60-69, and 70-79 years, respectively. In the mammography-specific analysis, sensitivity decreased to 69.8 % (-3.3 %), 66.7 % (-7.7 %), 77.3 % (-1.0 %), and 83.8 % (-2.7 %) in the groups of 40-49, 50-59, 60-69, and 70-79 years, respectively. There were greater reductions in the groups of 40-49 and 50-59 years than in those of 60-69 and 70-79 years, but there was no statistically significant decrease. Specificity generally increased with increasing age and there was a significant improvement in specificity among all age groups, except that of 70-79 years.

CONCLUSIONS

Our findings suggest that there is a trade-off between sensitivity and specificity associated with CBE added to mammography. This tendency is greater in those 40-50 years of age than in those 60-70 years of age. We consider that CBE may be omitted from breast cancer screening among women aged 60 and 70 years. Furthermore, another modality to complement mammography screening in younger Japanese women is expected.

Effect of screening mammography on breast cancer survival in comparison to other detection methods: a retrospective cohort study

The effectiveness of screening mammography (SMG) on mortality has been established in randomized controlled trials in Western countries, but not in Japan. This study evaluated the effectiveness by comparing the survival based on detection methods. The survivals were estimated by the Kaplan-Meier method. Breast cancer patients diagnosed from 1 January 1989 to 31 December 2000 were determined using the Miyagi Prefectural Cancer Registry and follow-up was performed from the date of the diagnosis until the date of death or the end of follow-up, 31 December 2005. The hazard ratios (HR) and 95% confidence interval (CI) of breast cancer death based on the detection methods were estimated by the Cox proportional-hazard regression model. The mean age of the 7513 patients was 55.7 years (range, 15.0-99.3). The 5-year survival associated with the SMG group, the clinical breast examination (CBE) group, and the self-detection group was 98.3%, 94.3%, and 84.8%, respectively. The HR (95% CI) of deaths from breast cancer was 2.50 (1.10-5.69) for patients in the CBE group and 6.57 (2.94-14.64) for the self-detection group in comparison to the SMG group. In women aged 50-59, the HRs were 1.64 (0.58-4.62) among the CBE group and 3.74 (1.39-10.03) among the self-detection group, and the HRs for the CBE and self-detection groups in women aged 60-69 were 2.96 (0.68-12.83) and 9.51 (2.36-38.26), respectively. After adjusting for stage, the HRs dropped remarkably. Screening mammography may be more effective in the elderly group and be able to reduce the mortality of breast cancer in Japan.

Cost-effectiveness analysis of screening modalities for breast cancer in Japan with special reference to women aged 40-49 years

Although the introduction of screening mammography in Japan would be expected to reduce mortality from breast cancer, the optimal screening modality in terms of cost-effectiveness remains unclear. We compared the cost-effectiveness ratio, defined as the cost required for a life-year saved, among the following three strategies: (1) annual clinical breast examination; (2) annual clinical breast examination combined with mammography; and (3) biennial clinical breast examination combined with mammography for women aged 30-79 years using a hypothetical cohort of 100 000. The sensitivity, specificity and early breast cancer rates were derived from studies conducted from 1995 to 2000 in Miyagi Prefecture. The treatment costs were based on a questionnaire survey conducted at 13 institutions in Japan. We used updated parameters that were needed in the analysis. Although the effectiveness of treatment in terms of the number of expected survival years was highest for annual combined modality, biennial combined modality had a higher cost-effectiveness ratio, followed by annual combined modality and annual clinical breast examination in all age groups. In women aged 40-49 years, annual combined modality saved 852.9 lives and the cost/survival duration was 3 394 300 yen/year, whereas for biennial combined modality the corresponding figures were 833.8 and 2 025 100 yen/year, respectively. Annual clinical breast examination did not confer any advantages in terms of effectiveness (815.5 lives saved) or cost-effectiveness (3 669 900 yen/year). While the annual combined modality was the most effective with respect to life-years saved among women aged 40-49 years, biennial combined modality was found to provide the highest cost-effectiveness.

How relevant is breast cancer screening in the Asia/Pacific region?

Nationwide breast cancer screening with mammography is well-established in many western countries. Many studies have shown its benefit in mortality reduction. However, breast cancer screening in Asia has been slow to implement, as it was perceived that the breast cancer incidence was low and the parenchyma of Asian women was difficult to assess mammographically. With changing disease patterns, breast cancer is now one of the most common cancers amongst women in Asia. Breast cancer screening has become an important and relevant health problem. However, apart from biological differences between western and Asian women, cultural and economic considerations need to be addressed. This paper looks at the various issues pertaining to the feasibility and relevance of population-based screening in the Asia/Pacific region.

Outcome of screening by clinical examination of the breast in a trial in the Philippines

The value of screening by Clinical Examination of the Breast (CBE) as a means of reducing mortality from breast cancer (BC) is not established. The issue is relevant, as CBE may be a suitable option for countries in economic transition, where incidence rates are on the increase but limited resources do not permit screening by mammography. Our aims were to assess whether mass screening by CBE carried out by trained para-medical personnel is feasible in an urban population of a low-income country, and its efficacy in reducing BC mortality. Our study was designed as a randomised controlled trial of the effect on BC mortality of 5 annual CBE carried out by trained nurses. The target population was women aged 35-64 years, resident in 12 municipalities of the National Capital Region of Manila, Philippines. The units of randomization were the 202 health centres (HC) within the selected municipalities. During 1995 nurses and midwives were recruited and trained in performing CBE. The first round of screening took place in 1996-1997. The intervention however showed a refractory attitude of the population with respect to clinical follow-up and was discontinued after the completion of the first screening round. Cases of breast cancer occurring in the study population during 1996-1999 were identified by the 2 local population-based registries. In the single screening round 151,168 women were interviewed and offered CBE, 92% accepted (138,392), 3,479 were detected positive for a lump and referred for diagnosis. Of these only 1220 women (35%) completed diagnostic follow-up, whereas 42.4% actively refused further investigation even with home visits, and 22.5% were not traced. Of 53 cases that occurred among screen-positive women in the 2 years after CBE only 34 were diagnosed through the intervention. Eighty cases occurred among screen-negative women. The test sensitivity for CBE repeated annually was 53.2%. The actual sensitivity of the programme was 25.6% and positive predictive value 1%. Screen-detected cases were non-significantly less advanced than the others. Previous studies have shown that most breast cancer cases in the Philippines present at advanced stages and have an unfavourable outcome. Although CBE undertaken by health workers seems to offer a cost-effective approach to reducing mortality, the sensitivity of the screening programme in the real context was low. Moreover, in this relatively well-educated population, cultural and logistic barriers to seeking diagnosis and treatment persist and need to be addressed before any screening programme is introduced.

Mammographic screening for non-palpable breast cancer in Japan

In Japan, mammography was endorsed for breast cancer screening in women aged 40 and over by the Ministry of Health, Labor and Welfare in 2004. The spread of mammographic screening has caused an increase in the incidence of non-palpable breast cancer. Precision reading for mammography is necessary to detect non-palpable breast cancer. When mass and focal asymmetric density is noted, it is important to analyze the density, density gradient, internal structure, margin and associated findings. Calcifications are classified by morphology and distribution mainly. It is necessary to distinguish secretor-type calcifications from necrotic-type calcifications. The Iwate Cancer Association performed a population-based screening program for breast cancer using mammography combined with clinical breast examination of 42,065 women in Iwate Prefecture from 1999 to 2003. A total of 2,329(5.7%)women were recalled and the 112 cases(0.27%) of cancer were detected in 114 breasts. Of 114 breast cancers, 40 (35%) were non-palpable and 74(65%) were palpable. The early breast cancer (stage 0 and I) rate of the non-palpable group was significantly higher than that of the palpable group (90% and 47%, p = 0.0003). The node-negative rate of the non-palpable group was significantly higher than that of the palpable group (92% and 68%, p = 0.011). It is expected that mammographic screening will be expanded and that the mortality rate from breast cancer in Japan will decrease, as in Europe and the United States.

Cancer burden and trends in the Asian Pacific Rim region

This paper describes the current cancer burden and time trends, discusses dominant risk factors and prevention and control strategies, and makes future projections for the top eight cancers (stomach, lung, liver, colon/rectum, esophagus, breast, cervix, and leukemia) in the Asian Pacific Rim region. The future cancer trends through to the year 2050 are projected based on population dynamics, including population growth and ageing. In 2000, the Asian Pacific Rim had over 3 million new cancer cases, over 2 million cancer deaths, and 5.4 million people living with cancer. In 2050, 7.8 million new cancer cases and 5.7 million deaths from cancer are projected. The current cancer burden and the future projection provide facts that cancer is and will be a very serious public health problem in the Asian Pacific Rim region and will assist public health officers and cancer researchers in the design and establishment of public health policies, prioritization of future research, and application of current knowledge in the prevention and control of cancer.

Genetic predisposition to breast cancer: a surgical perspective

BACKGROUND

Molecular alterations in proto-oncogenes, tumour suppressor genes, and genes that function in DNA damage recognition and repair are considered to be hallmarks of a carcinogenic process, including breast carcinogenesis.

METHODS

A computer-assisted search of the English literature (Medline database, 1990-1999) was performed, followed by a manual search of the reference list of pertinent articles retrieved.

RESULTS

Hereditary breast cancer accounts for 5-10 per cent of all breast cancer cases. About 90 per cent of hereditary breast cancers involve mutation of the BRCA1 and/or BRCA2 genes. Other cancer-related genes (including myc, c-erbB2, Tsg101 and Mdgi) are involved in breast carcinogenesis, but they do not give rise to familial breast cancer syndromes. Risk estimation is the most important clinical implication. Management options for the high-risk mutation carriers include cancer surveillance and preventive strategies (prophylactic surgery or chemoprevention).

CONCLUSION

Despite inadequate knowledge about the genetic predisposition to breast cancer and its clinical implications, the demand for genetic testing is likely to expand rapidly. In addition to risk estimation, cancer surveillance and preventive strategies, gene therapy offers a new and theoretically attractive approach to breast cancer management.