The Difference Of Age Related Lobular Involution Between Benign And Malignant Breast Diseases

PurposePrimary purpose:To study whether there are differences between of age related lobular involution between benign and malignant breast diseases, and aid to explore the association between the extent of age related lobular involution and breast cancer.Second purpose:To verify the correlation between lobular involution and age.Participants and methods:Cases who had benign or malignant breast disease diagnosed via surgical excision at the breast department of the second hospital of Shandong University between December 2004, and February,2010 were included by the following criterion. All the corresponding biopsy samples were reviewed by one pathologist and lobular involution extent of the background tissue were evaluated by Vierkant' standard, in which involution was categorized as none (0% TDLUs involuted), mild(1%-24% TDLUs involuted), moderate(25%-74% TDLUs involuted)or complete (≥75% TDLUs involuted). Results were documented as 0,1,2 and 3 respectively.Group A:Cases who were diagnosed breast cancer and underwent breast conserving surgery were included in this group. And cases who were diagnosed breast benign disease were included in this group and 1:2 pairwised with above malignant cases by age to study whether there were any differences between malignant and benign breast diseases. Lobular involution of the 4 incisions of malignant cases were evaluated respectively to study whether there were any differences between different samples from the same invidiual. And also this group was used to verify the correlation between lobular involution and age.Group B:Cases who were diagnosed breast cancer and breast benign disease in bilateral breasts respectively at the same time were included in this group. Lobular involution of the 2 samples were evaluated to study whether there were any differences between malignant and benign breast diseases.Results: Lobular involution is a physiological process and in this study we found high concordance of lobular involution values across multiple areas of breast tissue in women undergoing breast conserving surgery (ICC=0.646 95%CI=0.358-0.877).There was a moderate positive correlation between lobular involution extent and age (Spearman correlation coefficient/rs=0.434, p=0.049), and lobular involution extent undergoes gradually increase as aging. And the correlation trend is more obvious beyond 50-year old:56.0% cases over 50 underwent complete involution while no cases below 50. We found no significant statistic differences in lobular involution extent between pairwised cases from Group A (p=1.000).However,wild statistic differences were observed in Group B analysis of malignant and benign disease of the same individual (ICC=0.438, 95%CI=-0.078-0.867).Conclusion:Lobular involution is a physiological process and there is high concordance of lobular involution values across multiple areas of breast tissue. Any random samples can be employed to evaluate the lobular involution status of an individual. There is a clear positive correlation trend between lobular involution extent and age, and the correlation trend is more obvious beyond 50-year old indicating the fact that the 50-year is an important cutpoint in the involuting process. The fact indicate us that we should not only pay attention to the characteristic of the tumor but also the lobular involution of breast tissue for breast disease cases above 50.Those who undergo abnormal involution may carry a higher breast cancer risk and should receive more enhanced follow-up. In this study, we found no difference between malignant and benign breast diseases in pairwised groups but wild differences in the same individual. Take the small sample size and no immune-histochemistry result in consideration, it's not proper to reach the conclusion that there is no differences between malignant and benign breast diseases in lobular involution extent. More large sample-size and comprehensive study are needed to interpret the fact. Compared to the clear pathological conception and conclusion, the relationships between lobular involution and breast cancer risk factors or breast cancer risk are undefined and more molecular level study are needed.