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Prognostic and Predictive Factors in Breast Cancer; assessments and applications
Dr. I.O. Ellis & Dr. Ch. Elston
I-MACROSCOPIC EXAMINATION OF BIOPSY AND RESECTION SPECIMENS
Diagnostic Biopsy/Excision Specimens from Symptomatic Lesions
Increasing use of the triple approach to diagnosis with a consequent policy of non intervention following a benign diagnosis has led to a reduction in the need and use of surgical biopsy for benign conditions. In those patients choosing surgical excision for a benign condition or where there is uncertainty to the final diagnosis, surgeons in the United Kingdom are now endeavouring to remove the lesion with the minimum amount of surrounding tissue, usually less than 20 grams of tissue being resected to ensure the minimum cosmetic defect.
With such small resections it is usually possible to block the entire specimen after serially slicing at 3 - 5 mm intervals. If a discrete lesion is identified on the cut surface and this corresponds to the description of the lesion given on the request form this should be sampled. In cases where no discrete lesion is seen on gross examination Schnitt and Wang have demonstrated that sampling should be concentrated on the fibrous parenchymal component of the specimen and that submitting every grossly benign breast biopsy in its entirely is not cost effective. They indicate that over 75% of tumours of macroscopically invisible carcinomas or areas of atypical hyperplasia can be identified by taking five tissue blocks and the vast majority can be identified if ten blocks are sampled. There appears therefore to be no value in taking more than 10 blocks from a macroscopically benign specimen.
Because of the small size of these specimens assessment of the excision margin is usually irrelevant as it will inevitably be extremely close to any lesion detected. It is not our routine practice to comment on the site and involved excision margins in such excision specimens and re-excision is mandatory should a malignant tumour be identified.
Diagnostic Biopsy/Excision Specimens from Mammographic Screening Lesions
Biopsies of mammographically detected lesions may provide especial difficulty in histological interpretation and consequently require optimal fixation and careful handling. The surgeon should be discouraged from cutting the specimen before sending it to the pathologist and should ideally mark it with sutures in order to obtain proper orientation. Sutures are preferable to metal staples which often retract into the specimen, thus becoming impossible to recognise, and may obscure microcalcifications. A code of orientation for the sutures needs to be established and indicated on the request form. Fig 1.1
Palpable lesions detected in screening programmes may be dealt with by conventional methods and there is no especial virtue in specimen radiography, except in known carcinomas to determine the relationship to excision margin assuming that there is no doubt that the radiological and palpable lesions are one and the same.
Confirming excision of abnormality
After excision, the intact specimen - with the guide wire in situ - must be x-rayed. Ideally this procedure is carried out by the staff of the radiological department, so that the radiologist or surgeon can determine whether the relevant lesion has been resected. It may be necessary on medico-legal grounds for centres to name consultants responsible for confirming that mammographic lesions have been removed. Ideally those consultants should be the radiologists who interpreted the clinical mammograms. A good working relationship between pathologists, surgeons and radiologists is essential. Two copies of the specimen radiography at this time could be taken with benefit, one for the department of radiology and one for the pathologist.
If mammographic abnormality not identified
Clearly there will be a few occasions when the mammographic abnormality cannot be identified in the specimen. This may result from the excision of a lesion producing only architectural change in the clinical mammogram or from unsuccessful surgical localisation. Detailed pathological examination should still be undertaken even in the latter case and the findings communicated to the surgeon. Clinical mammography can subsequently be repeated to determine if the lesion is still present in the breast.
Specimens should be examined within 2-3 hours if received fresh. Samples for oestrogen receptor determination must be snap frozen in liquid nitrogen within 30 minutes of excision if a ligand binding assay is used. However, it should be remembered that oestrogen receptor status can now be determined accurately on standard formalin-fixed, paraffin-embedded sections.
In order to demonstrate adequacy of excision, the entire surface of the specimen should be painted with India ink, radiolucent pigments, dyed gelatin or other suitable material. Selection of appropriate blocks is described on following sections. An appropriate period of drying must be allowed if spread of the chosen reagent is to be avoided.
Large blocks and sections are used in some laboratories where they are found to be of value in identifying screen-detected lesions as well as in determining their size, extent of spread and adequacy of excision. They facilitate orientation by obviating the need for mental reconstruction of the overall picture from several separate sections. They also reduce the number of blocks required. Other workers, however, have encountered problems in achieving adequate fixation and good cytological detail in addition to the technical difficulties of cutting large sections and the problems in storing them. Although these drawbacks can be overcome, large blocks are not regarded as essential for examining specimens from screened women and their use should depend on local preference.
Therapeutic excision specimens
Such specimens arise in patients who have had a pre-operative diagnosis of carcinoma achieved through triple approach assessment. Patients will have had mammographic assessment of the extent of the disease and will have been deemed suitable for conservation therapy following appropriate counselling. The surgeon aims to achieve excision with an adequate surrounding margin of uninvolved breast tissue. For this reason these specimens are usually much larger than a surgical excision purely for diagnosis. In our Unit intraoperative specimen radiography is routinely used to determine the relationship of the principle tumour mass to the radial excision margins. The surgeon resects a cylinder of breast tissue from the dermis to the deep fascia and unless there is macroscopic gross involvement of the superficial or deep margins, re-excision will be concentrated on radial margins (medial, lateral, superior, inferior) should the lesion appear close on the specimen radiograph. Immediate re-excision of the relevant area is then carried out and a separate specimen submitted for histological examination.
In our Unit the main specimen is orientated using a standard convention of sutures; long - lateral, medium - medial, short - superficial, loop - anterior. Specimen excision surfaces are marked using India ink. Following marking the tumour mass is incised in the fresh state and sampled if appropriate (for archival storage). Immediate incision ensures rapid fixation of the tumour. This is necessary to achieve good preservation for histological assessment of tumour morphology and for oestrogen receptor assessment on paraffin sections.
After fixation the specimen is sampled as indicated in Figs 1.2 and 1.3. A series of radial tumour blocks are taken to include the peripheral margin of the tumour. This is required for assessment of histological type, histological grade and vascular invasion. These blocks may, in a smaller specimen, also encompass the radial resection margins. The distance from the tumour edge to the radial margin is measured to the nearest millimetre using the Vernier Scale on the microscope stage. If invasive carcinoma extends within 5 mm and in situ carcinoma within 10 mm of a radial margin or the shave specimens are involved, then appropriate re-excision will be carried out. In addition shave blocks are taken from the radial resection margins as indicated in the diagram.
T = Tumour
Tumour Blocks (T)
SR = Superior Radial
4 from exposed faces of incised tumour quadrans
MR = Medial Radial
IR = Inferior Radial
Radial margin blocks (................R)
LR = Lateral Radial
SMS = Superomedial Shave
4 blocks to include (if possible) a radial margin (superior, inferior, medial and inferior) and tumour edge
IMS = Inferiomedial Shave
Shave margin blocks (................S)
ILS = Inferolateral Shave
SLS = Superolateral Shave
Blocks of peripheral margin faces. Concentrate on fibrous breast tissue rather than adipose tissue
Re-excision of the biopsy cavity and surrounding tissues may be carried in patients having a prior diagnostic biopsy in which a diagnosis of carcinoma has been made or those with previous therapeutic excisions in which there is involvement of a margin. Block selection may be difficult in such samples and it is essential that the specimen is orientated accurately by the surgeon at the time of resection. The extent of sampling depends on the amount of tissue resected. It is currently our policy to concentrate the examination on shave excision samples from the peripheral radial margin of the re-excision specimen. The cavity margin can also be sampled to identify any residual carcinoma.
Naked Eye Examination
Macroscopic examination of mastectomy specimens should ideally be undertaken in the fresh state within 2 hours of removal and tumours incised before fixation to allow adequate penetration of fixative. The favoured method of examination is by slicing the breast from the deep surface in the sagittal plane after measuring the dimensions. The slices should be about 10 mm thick and may be left joined by the skin or separated completely and arranged in order. The size of the breast should be recorded. The maximum diameter of the main lesion should be measured and the distance from the nearest margin of excision determined as for biopsies (see earlier).
Blocks of tumour (the number depending on tumour size as above) should be taken to include the periphery and should always be sufficient to represent the maximum extent of the lesion noted macroscopically. Blocksof the nearest excision margin should be taken if tumour is suspected to reach it on macroscopic examination. Painting with India ink or pigments may be helpful as in local excision specimens. If the tumour has been removed previously, then 3-4 blocks should be taken from the cavity wall. The breast slices should be examined by careful naked eye inspection and palpation. Blocks should be taken from any suspicious areas, noting the quadrant in which they are located. At least one block should be taken from each quadrant and ideally two from the nipple - sections in the sagittal plane and a coronal section through the junction with the areola.
Axillary Dissection Specimens
Axillary contents received with mastectomy or biopsy specimens should be examined carefully to maximise lymph node yield. This is usually achieved by cutting the specimen into thin slices which are then examined by careful inspection and palpation. The use of clearing agents may increase lymph node yield but are time-consuming and expensive of reagents and are not regarded as essential. The axillary contents can be divided into three levels if the surgeon has marked the specimen appropriately.
Pathological examination should be performed on all lymph nodes received and the report should state the total number and the number containing metastases. A representative complete section of any grossly involved lymph node is adequate. For nodes greater than 5 mm in maximum dimension, three slices should be taken and processed in a single block. Nodes less than 5 mm should be embedded in their entirety. They can be processed in groups. Detection of metastatic deposts can be increased by examination at two or more levels or through use of immunocytochemistry.