A resection margin or surgical margin is the margin of apparently non-tumorous tissue around a tumor that has been surgically removed, called "resected", in surgical oncology. The resection is an attempt to remove a cancer tumor so that no portion of the malignant growth extends past the edges or margin of the removed tumor and surrounding tissue. These are retained after the surgery and examined microscopically by a pathologist to see if the margin is indeed free from tumor cells (called "negative"). If cancerous cells are found at the edges (called "positive") the operation is much less likely to achieve the desired results. [1] : sections 1-2
The size of the margin is an important issue in areas that are functionally important (i.e., large vessels like the aorta or vital organs) or in areas for which the extent of surgery is minimized due to aesthetic concerns (i.e., melanoma of the face or squamous cell carcinoma of the penis). [2] The desired size of margin around the tumour can vary. In resections for breast cancer, there appears to be a difference between European and American radiation oncologists, with the former preferring larger margins of over 5 mm. [1] : section 2
Residual tumour at the primary site after treatment (it does not address the surgical margin as commonly believed) is classified by the pathologist as (AJCC 8th Edition):
The Margin Status following tumour resection (AJCC 8th Edition):
Apart from traditional methods looking at stained "shaves" (thin slices of tissue removed from the edge of the margin) or smeared and stained imprints, more recent techniques used to assess margins include x-rays with compression, frozen specimens, and new techniques such as intraoperative fluorescence imaging, Raman spectroscopy, optical coherence tomography and quantitative diffuse reflectance spectroscopy. [3] [1] : sections 5-6
Surgical margin in a surgery report defines the visible margin or free edge of "normal" tissue seen by the surgeon with the naked eye. Surgical margin as read in a pathology report defines the histological measurement of normal or unaffected tissue surrounding the visible tumor under a microscope on a glass mounted histology section. [4] [5] A "narrow" surgical margin implies that the tumor exists very close to the surgical margin, and a "wide" surgical margin implies the tumor exists far from the cut edge or the surgical margin. Narrow surgical margin using the bread loafing technique suggests that residual cancer might be left due to false negative error. A surgeon often will perform a second surgery if a narrow surgical margin is noted on a pathology report.
This determination is made with the full understanding of "false negative error" intrinsic in the bread loafing technique of histology (also known as POMA - a term used by the NCCN). [6] The higher the false negative error is, the higher the recurrence rate of a cancer or tumor at the surgical margin. This is due to the misreading of a pathology specimen as being clear of residual tumor when there is actually residual tumor left where the specimen was not cut and mounted on the histology slide. The "false negative error" is very low in the CCPDMA method of histology processing, and can be very high in the bread loafing (POMA) method of histology processing. [6] In the bread loafing method of processing, one will note a high false negative error rate with narrow surgical margin; and one will note a low false negative error with a wide surgical margin [7] Surgical margin has a much less significant effect on the false negative error rate of CCPDMA methods, allowing the surgeon to routinely use very narrow surgical margins (1 to 2 mm for non-melanoma skin cancer). [7] The worldwide extent of inadequate resection of the tumor is illustrated in following Table showing the percentage of positive surgical margins for the most common cancer types.
Cancer type (solid tumours only) | Estimated new cases * | Incidence * | Positive margins |
---|---|---|---|
Breast | 2,261,419 | 12% | 20–70% |
Trachea, lung, and bronchus | 2,206,771 | 11% | 5–17% |
Prostate | 1,414,259 | 7% | 7–75% |
Colorectal | 1,931,590 | 10% | 12–58% |
Urinary bladder | 573,278 | 3% | 0–25% |
Kidney and renal pelvis | 431,288 | 2% | 7–11% |
Uterine corpus | 417,367 | 2% | 4–17% |
Pancreas | 495,773 | 3% | 18–85% |
Thyroid | 586,202 | 3% | 10–11% |
Lip, oral cavity | 377,713 | 2% | 5–43% |
A Krukenberg tumor refers to a malignancy in the ovary that metastasized from a primary site, classically the gastrointestinal tract, although it can arise in other tissues such as the breast. Gastric adenocarcinoma, especially at the pylorus, is the most common source. Krukenberg tumors are often found in both ovaries, consistent with its metastatic nature.
Carcinoma is a malignancy that develops from epithelial cells. Specifically, a carcinoma is a cancer that begins in a tissue that lines the inner or outer surfaces of the body, and that arises from cells originating in the endodermal, mesodermal or ectodermal germ layer during embryogenesis.
A bone tumor is an abnormal growth of tissue in bone, traditionally classified as noncancerous (benign) or cancerous (malignant). Cancerous bone tumors usually originate from a cancer in another part of the body such as from lung, breast, thyroid, kidney and prostate. There may be a lump, pain, or neurological signs from pressure. A bone tumor might present with a pathologic fracture. Other symptoms may include fatigue, fever, weight loss, anemia and nausea. Sometimes there are no symptoms and the tumour is found when investigating another problem.
Basal-cell carcinoma (BCC), also known as basal-cell cancer, is the most common type of skin cancer. It often appears as a painless raised area of skin, which may be shiny with small blood vessels running over it. It may also present as a raised area with ulceration. Basal-cell cancer grows slowly and can damage the tissue around it, but it is unlikely to spread to distant areas or result in death.
Histopathology refers to the microscopic examination of tissue in order to study the manifestations of disease. Specifically, in clinical medicine, histopathology refers to the examination of a biopsy or surgical specimen by a pathologist, after the specimen has been processed and histological sections have been placed onto glass slides. In contrast, cytopathology examines free cells or tissue micro-fragments.
Melanoma, also redundantly known as malignant melanoma, is a type of skin cancer that develops from the pigment-producing cells known as melanocytes. Melanomas typically occur in the skin, but may rarely occur in the mouth, intestines, or eye. In women, they most commonly occur on the legs, while in men, they most commonly occur on the back. About 25% of melanomas develop from moles. Changes in a mole that can indicate melanoma include an increase in size, irregular edges, change in color, itchiness, or skin breakdown.
Sex cord–gonadal stromal tumour is a group of tumors derived from the stromal component of the ovary and testis, which comprises the granulosa, thecal cells and fibrocytes. In contrast, the epithelial cells originate from the outer epithelial lining surrounding the gonad while the germ cell tumors arise from the precursor cells of the gametes, hence the name germ cell. In humans, this group accounts for 8% of ovarian cancers and under 5% of testicular cancers. Their diagnosis is histological: only a biopsy of the tumour can make an exact diagnosis. They are often suspected of being malignant prior to operation, being solid ovarian tumours that tend to occur most commonly in post menopausal women.
Dermatofibrosarcoma protuberans (DFSP) is a rare locally aggressive malignant cutaneous soft-tissue sarcoma. DFSP develops in the connective tissue cells in the middle layer of the skin (dermis). Estimates of the overall occurrence of DFSP in the United States are 0.8 to 4.5 cases per million persons per year. In the United States, DFSP accounts for between 1 and 6 percent of all soft tissue sarcomas and 18 percent of all cutaneous soft tissue sarcomas. In the Surveillance, Epidemiology and End Results (SEER) tumor registry from 1992 through 2004, DFSP was second only to Kaposi sarcoma.
Fibrosarcoma is a malignant mesenchymal tumour derived from fibrous connective tissue and characterized by the presence of immature proliferating fibroblasts or undifferentiated anaplastic spindle cells in a storiform pattern. Fibrosarcomas mainly arise in people between the ages of 25–79 It originates in fibrous tissues of the bone and invades long or flat bones such as the femur, tibia, and mandible. It also involves the periosteum and overlying muscle.
Ameloblastoma is a rare, benign or cancerous tumor of odontogenic epithelium much more commonly appearing in the lower jaw than the upper jaw. It was recognized in 1827 by Cusack. This type of odontogenic neoplasm was designated as an adamantinoma in 1885 by the French physician Louis-Charles Malassez. It was finally renamed to the modern name ameloblastoma in 1930 by Ivey and Churchill.
Lentigo maligna is where melanocyte cells have become malignant and grow continuously along the stratum basale of the skin, but have not invaded below the epidermis. Lentigo maligna is not the same as lentigo maligna melanoma, as detailed below. It typically progresses very slowly and can remain in a non-invasive form for years.
The frozen section procedure is a pathological laboratory procedure to perform rapid microscopic analysis of a specimen. It is used most often in oncological surgery. The technical name for this procedure is cryosection. The microtome device that cold cuts thin blocks of frozen tissue is called a cryotome.
Mohs surgery, developed in 1938 by a general surgeon, Frederic E. Mohs, is microscopically controlled surgery used to treat both common and rare types of skin cancer. During the surgery, after each removal of tissue and while the patient waits, the tissue is examined for cancer cells. That examination dictates the decision for additional tissue removal. Mohs surgery is the gold standard method for obtaining complete margin control during removal of a skin cancer using frozen section histology. CCPDMA or Mohs surgery allows for the removal of a skin cancer with very narrow surgical margin and a high cure rate.
Undifferentiated pleomorphic sarcoma (UPS), also termed pleomorphic myofibrosarcoma, high-grade myofibroblastic sarcoma, and high-grade myofibrosarcoma, is characterized by the World Health Organization (WHO), 2020, as a rare, poorly differentiated neoplasm, i.e. an abnormal growth of cells that have an unclear identity and/or cell of origin. WHO classified it as one of the undifferentiated/unclassified sarcomas in the category of tumors of uncertain differentiation. Sarcomas are cancers known or thought to derive from mesenchymal stem cells that typically develop in bone, muscle, fat, blood vessels, lymphatic vessels, tendons, and ligaments. More than 70 sarcoma subtypes have been described. The UPS subtype of these sarcomas consists of tumor cells that are poorly differentiated and may appear as spindle-shaped cells, histiocytes, and giant cells. UPS is considered a diagnosis that defies formal sub-classification after thorough histologic, immunohistochemical, and ultrastructural examinations fail to identify the type of cells involved.
Radical surgery, also called radical dissection, is surgery that is more extensive than "conservative" surgery.
Surgical pathology is the most significant and time-consuming area of practice for most anatomical pathologists. Surgical pathology involves gross and microscopic examination of surgical specimens, as well as biopsies submitted by surgeons and non-surgeons such as general internists, medical subspecialists, dermatologists, and interventional radiologists.
Skin biopsy is a biopsy technique in which a skin lesion is removed to be sent to a pathologist to render a microscopic diagnosis. It is usually done under local anesthetic in a physician's office, and results are often available in 4 to 10 days. It is commonly performed by dermatologists. Skin biopsies are also done by family physicians, internists, surgeons, and other specialties. However, performed incorrectly, and without appropriate clinical information, a pathologist's interpretation of a skin biopsy can be severely limited, and therefore doctors and patients may forgo traditional biopsy techniques and instead choose Mohs surgery. There are four main types of skin biopsies: shave biopsy, punch biopsy, excisional biopsy, and incisional biopsy. The choice of the different skin biopsies is dependent on the suspected diagnosis of the skin lesion. Like most biopsies, patient consent and anesthesia are prerequisites.
Epithelial-myoepithelial carcinoma of the lung is a very rare histologic form of malignant epithelial neoplasm ("carcinoma") arising from lung tissue.
Complete circumferential peripheral and deep margin assessment (CCPDMA) is the preferred method for the removal of certain cancers, especially skin cancers.
Bread loafing is a common method of processing surgical specimens for histopathology. The process involves cutting the specimen into 3 or more sections. The cut sections are mounted by embedding in paraffin or frozen medium. The cut edge is then thinly sliced with a microtome or a cryostat. The thin slices are then mounted on a glass slide, stained, and covered with another layer of glass.