1 Basic principles of postoperative pathological diagnosis report of breast cancer
(1) The pathological histological diagnosis report should include all the contents related to the treatment and prognosis of the patient as far as possible, such as the size of the tumor (including macroscopic examination and microscopic tumor size), histological type, histological grading, tumor involvement and the condition of the cut edge and lymph nodes. Therefore, we should try to observe all the tumor tissues, and take the tumor peri-tumor, other quadrants and surgical margins for observation. Zhang Keyun, Department of Radiology, Wuxi Eighth People’s Hospital
(2) The molecular pathology diagnosis report includes the immunohistochemical detection of ER, PR, HER-2 and Ki-67, etc.
(3) Histopathological types should be accurately reported, such as mucinous carcinoma, tubular carcinoma and invasive micropapillary carcinoma.
(4) The pathological diagnosis report of carcinoma in situ should report the nuclear grade (low, medium or high grade) and the presence or absence of necrosis (pimple-like necrosis or punctate necrosis) as well as the surgical margins, and whether microinfiltration is found, etc.
(5) Please refer to the section on clinical guidelines for breast-conserving treatment for sampling and reporting of breast-conserving specimens.
(6) The name or type of benign paracancerous lesion should be reported if necessary.
2 Content and specifications of the pathological diagnosis report
2.1 General items
(1) Pathology number (search number).
(2) Patient’s name, birth date (age), sex, bed number, hospitalization number.
(3) Date of surgery, date of pathology retrieval.
2.2 Status of surgical specimens
(1) Left and right side.
(2) Specimen type (e.g. breast-conserving surgery specimen, modified radical surgery specimen, local breast expansion plus axillary lymph node dissection specimen, modified radical surgery specimen after neoadjuvant chemotherapy, etc.) For patients after neoadjuvant chemotherapy, in order to ensure accurate pathological sampling, it is recommended that the skin of the patient’s lesion site be tattooed and marked before neoadjuvant chemotherapy, and pathological assessment is referred to our “Pathological diagnosis of breast cancer after neoadjuvant chemotherapy Expert Consensus”.
(3) Macroscopic examination (including tumor size or scope, texture, boundary, color, etc.).
3 Histopathological diagnosis
3.1 Primary foci
3.1.1 Histological type
Including the histological type of the tumor and other lesions present in the peri-tumor breast tissue.
3.1.2 Histologic grading
Grading is based on 3 indicators: the presence of glandular duct formation, morphology of the nucleus and nuclear division image. The modified Scarff-Bloom-Richardson grading system is recommended.
3.1.3 Tumor size
The tumor size involved in breast cancer staging refers to the size of invasive cancer. The following points should be noted when measuring: (1) If the tumor tissue has both invasive and in situ cancer components, the size of the tumor should be based on the measurement of the invasive component. (2) Carcinoma in situ with microinfiltration: when microinfiltration is present, it should be indicated in the report and the maximum diameter of the microinfiltrating foci should be measured; if it is multifocal microinfiltration, the size of the infiltrating foci cannot be cumulative, but the multifocal microinfiltration should be indicated in the report and the maximum diameter of the largest infiltrating foci should be measured. (3) For more than two multiple tumor lesions occurring in the same quadrant that can be determined by the naked eye, it should be indicated as multifocal tumor in the pathology report, and the size should be measured separately. (4) For more than two multiple tumor lesions occurring in different quadrants that can be determined by the naked eye, they should be indicated as multicentric tumors in the pathology report, and the size should be measured separately. (5) If the tumor tissue consists entirely of ductal carcinoma in situ, its extent should also be measured as accurately as possible.
3.1.4 Extent of tumor involvement and surgical margins
The extent of tumor involvement includes nipple, areola, skin, fat, vasculature (lymphatic vessels, veins, arteries), nerves and pectoral muscle. The incision margin includes peripheral margin, lateral skin margin and basal margin.
3.2 Lymph node status
3.2.1 Regional lymph nodes
Report the total number of lymph nodes and the number of metastases in each group sent for examination.
3.2.2 Biopsy of anterior lymph nodes
If there is metastatic cancer in the lymph nodes, the size of the metastatic cancer foci should be reported as much as possible to determine the isolated tumor cells (ITC), micrometastasis, and macrometastasis. It should be noted that lymph nodes containing only ITC are not counted in the number of positive lymph nodes, but should be counted as pN0(i+).
4 Immunohistochemical test content
(1) Immunohistochemical staining for ER, PR, HER-2 and Ki-67 should be performed for all invasive breast cancer and non-invasive cancer, and further in situ hybridization should be performed for cases with HER-2 of ++. HER-2 testing refers to China’s “Guidelines for HER-2 Testing in Breast Cancer” (2014 edition).
(2) All invasive breast cancers should be tested for Ki-67, and the percentage of positive staining cells in the cancer cells should be reported.
(3) Laboratories performing immunohistochemistry and molecular pathology testing for breast cancer should establish a complete and effective internal quality control and certification system. Units that are not equipped for testing should properly prepare specimens and provide them to a pathology laboratory with relevant qualifications for testing.
5 Signature of pathologist, date of report