Breast lesions particularly breast cancer causes some 20.0% of cancer death among females  . Breast cancer is the commonest cause of death in middle-aged women in western countries. Currently, one of every nine women in United States of America would develop breast cancer in their life time  . And virtually remain stable over the past thirty years, now being about 27 per one lac. In developing countries, it accounts for 1% to 3.0% of death  . Specifically, in Bangladesh, breast lesions particularly breast cancer is common clinical problem. In Bangladesh, remarkable increase of breast cancer has occurred in recent year. National Institute of cancer research from 1996 to 2000 showed cervical cancer ranked 1st and breast cancer ranked 2nd and the management of patients with carcinoma breast can be improved if a definitive diagnosis is obtained preoperatively by Radiological Examination  .
The result of this study was to focus a new approach to reduce the frequency of unnecessary biopsies. Gray scale ultrasonography (USG) can detect breast mass very early due to visualization of marginal contour, calcification and echo-pattern of very small mass  . It can contribute to the survival benefit obtained by early breast cancer detection  . For developing country like Bangladesh Gray scale ultrasonography can be an easy, non ionizing, non invasive, time relieving, low cost diagnostic tool which can reduce unnecessary biopsies and surgical procedures and thus reducing morbidity and financial burden to the patient.
The purpose of this study was to assess the overall diagnostic accuracy of Gray scale USG to identify the malignant breast lesion.
This study was performed in the Department of Radiology and Imaging at Banghabandhu Sheikh Mujib Medical University (BSMMU), Dhaka from July 2008 to June 2009 for a period of one (01) year. Patients presented with palpable breast lesions who were admitted in the surgery units of BSMMU and were diagnosed clinically as having solid breast lumps were selected as study population. The objective of the study was discussed in details with the patients before their decision to enroll themselves into the study. A detailed clinical history was taken from the patients about their symptoms like lump, duration of complains, pain, nipple discharge, nipple retraction etc. Relevant physical examinations were also done in all the cases. The patients were underwent Gray scale sonography by standard procedure  . Malignancy of breast lesions was detected pre-operatively. The findings were also interpreted first by the investigator and to eliminate bias the findings were confirmed by a radiologist of the department. Excision biopsy or mastectomy was done in all cases. Their postoperative findings were noted and were correlated with sonological findings. Tissues of surgically removed tumors were sent to the Department of Pathology. Their histopathology reports were collected and were then correlated with the gray scale sonography findings. All this information was collected in a pre-designed data collection sheet. All the collected data was compiled and tabulated on master sheet. Statistical analyses were carried out by using the Statistical Package for Social Sciences version 16.0 for Windows (SPSS Inc., Chicago, Illinois, USA). A descriptive analysis was performed for all data. The quantitative observations were indicated by frequencies and percentages. Chi-square test and test of validity was done for color Doppler sonographic findings in evaluation of benign and malignant breast lesion. A p value was considered to be statistically significant if <0.05. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy were calculated for the test by standard formula  .
Twenty three cases found truly malignant and 4 (four) cases were found benign as confirmed by histopathology; while of the 23 benign cases (USG diagnosis), 22 were found benign as detected by FNAC and 1(one) were found malignant which was confirmed by excisional biopsy. So, finally 28 cases were diagnosed malignant and 22 cases were benign. Thus, out of 50 cases 22 patients diagnosed as benign and 28 cases were diagnosed as malignant after performing excisional biopsy. In malignant and benign tumor more than 1.4 cm was found in 18 cases in each. Irregular margin was found more in malignant tumor than benign which was 16 (80%) and 10 (38.47%) cases respectively (Table 1).
The patients suspected as malignant or benign lesion in breast by gray scale sonology were correlated with histopathological diagnosis. Out of the 50 cases 27 (54%) cases were malignant and 23 (46%) cases were benign in histopathological findings. On the other hand, 24 (48%) cases were suspected as malignant and
Table 1. Distribution of all parameters compared to histopathological report (n = 50).
rests of the 26 (52%) cases were suspected as benign in gray scale sonography. Among the 24 cases, which were suspected as malignant by gray scale sonology, one case was benign in histopathological examination. Four (4) cases were found malignant in histopathology among the suspected benign cases, which were diagnosed by gray scale sonography (Table 2).
Sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 85.2%, 95.0%, 95.8%, 84.6% and 90.0% respectively (Table 3).
Figure 1. ROC curve of the gray scale sonography.
Table 2. Association between gray scale sonography and histopathology in evaluation of malignant and benign lesion (n = 50).
Table 4. Area under the curve.
The test result variable(s): Gray Scale Sonography has at least one tie between the positive actual state group and the negative actual state group. Statistics may be biased. a. Under the nonparametric assumption; b. Null hypothesis: true area = 0.5.
Ultrasonography in Gray scale has been shown to be effective modality in detection breast malignancy. Gray scale evaluation has become an important investigation and is considered as most important complementary method to mammography. Thus it could be concluded that Gray scale sonography increase chance of detection of malignancy. This method prospective study was carried out in the department of Radiology and Imaging, BSMMU, hospital in collaboration with the departments of surgery and pathology department of BSMMU during the period of July 2008 to June 2009.
Gray scale Ultrasonography is very useful in the differentiation between benign and malignant breast masses     . The distribution and morphology of lesions in solid breast masses seen at Gray scale ultrasound is a potentially important feature to be considered along with other sonographic criteria to predict the likelihood of malignancy  . Characteristic sonographic findings of benign tumors include a round or oval, slightly hypo echoic lesion with smooth borders, homogeneous internal echo, no central posterior acoustic shadowing andnormal surrounding tissue      . The typical features of malignancy include irregular shape, irregular margins, hypoechogenicity and central posterior acoustic shadowing.
Validity of gray scale sonography of diagnostic modality in evaluation of suspected malignant lesion has been calculated by sensitivity, specificity, positive and negative predictive values. The validity of gray scale sonography and histopathological findings were correlated by calculating sensitivity, specificity, accuracy, positive and negative predictive values by using the standard formula.
Preoperative detection of breast malignancy by Gray scale sonography and its validity by determining sensitivity, specificity, accuracy, positive predictive value and negative predictive value. The age of patients ranged from 25 to 69 years. They were divided into 5 age groups. Maximum numbers of patients with solid breast lesions were found in the 50 - 59 years age group. Among the 50 patients 46% (23 cases) were proved to be benign lesions and 54% (27 cases) were diagnosed as malignant lesions. Sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) were 92.59%, 86.95%, 90%, 89.28% and 90.90% respectively. Similar result is reported in other studies   .
The study findings indicate that Gray scale sonographyis sensitive, specific and accurate diagnostic tool then they used as a single modality in detection of malignant breast lesions. Limitations of the study were short period, small sample size, inflammatory lesions in breast that give increase RI index. Gray scale sonography were performed by a single radiologist of the department, so there was chance of bias. There are some limitation of this study. This is a single centred study. Furthermore sample size is small. Updated and technologically advanced USG is not used.
Gray scale sonography of solid breast lesions is a sensitive, specific and accurate modality in detecting malignant solid breast lesions. In the present study, it is observed that Gray scale evaluation has a high sensitivity and accuracy. So, it can be concluded that gray scale sonography can be used as a sensitive diagnostic tool in the detection of malignant solid breast lesions. However, further research on this subject may be encouraged on large number of patients in multiple tertiary levels.