Excision — Surgical Tissue Removal

Surgical excision is the mechanical resection and extraction of pathological tissue from the body. Depending on the clinical objective, excisions range from minor out-patient procedures to complex, deep-tissue operations. In an excisional biopsy, an entire suspicious lesion is extracted for diagnostic histological analysis, distinguishing it from an incisional biopsy, which samples only a cross-section.

In therapeutic oncology, the standard technique is wide local excision. This approach involves removing the macroscopic tumour along with an intentional boundary of surrounding, clinically healthy tissue known as the surgical margin. Securing negative margins ensures that residual microscopic malignant cells are not left behind in the operative bed, decreasing the probability of local disease relapse.

Excision is frequently the most decisive step toward curing early-stage solid tumours. The completeness of an excision directly influences future care: achieving 'clean' or 'negative' margins suggests the entire local tumour has been cleared. Conversely, if pathologically examined margins are 'positive'—meaning cancer cells reach the outermost cut edge—a patient may require a re-excision or supplementary radiation therapy to prevent recurrence, making precise surgical planning critical.

Prior to excision, clinical imaging such as ultrasound, MRI, or mammography maps the precise boundaries of the lesion. Following excision, the removed tissue specimen is oriented with surgical sutures, inked with coloured dyes by the pathologist, and analysed under a microscope. The pathologist reports tumour size, histologic grade, and the distance in millimetres between malignant cells and the inked margins.

Excision is employed across virtually all solid tumours. It is the primary local treatment for cutaneous malignancies, including melanoma, basal cell carcinoma, and squamous cell carcinoma of the skin. It is also central to breast-conserving surgery (lumpectomy or wide local excision), soft tissue sarcomas, thyroid nodules, and superficial bladder or oral lesions.

If histological assessment reveals clear margins, the patient may safely proceed to planned surveillance or planned adjuvant therapies like chemotherapy or hormone treatment. If margins are close or positive, the surgical team may recommend an immediate re-excision to take more tissue. In many cancers, such as breast cancer, wide local excision is paired with regional sentinel lymph node biopsy and adjuvant radiotherapy.