The most important thing to remember about the Mohs procedure is that it is a precise surgery that spares healthy tissue and obliterates the cancer in one sitting. The standard excision aims to remove the cancer entirely, but the excision size is an "over-estimate" that includes the surrounding normal tissue to prevent re-excisions.
Table 2 is a comparison chart of the standard excision and Mohs excision. The images also compare the relative size of tissue trauma resulting from each procedure.
Table 2. Standard Excision vs. Mohs Excision.| Standard Excision | Mohs Excision |
| One large piece of tissue is removed all at once | Small amounts of tissue are removed in stages |
| The wound is stitched up, and the patient is sent home to wait for the results | The wound is left open until the excised tissue is evaluated and removed the same day |
| Excision size is estimated; it must be larger than the tumor to have clear margins, and a large amount of healthy tissue is removed | Excision is precise, and healthy tissue is spared |
| Orientation is less accurate | Precise orientation of tissue is maintained throughout the entire process |
| 3–5 mm margins | 1–2 mm margins |
| Scar is larger | Scar is smaller |
| Tissue is fixed in formalin for paraffin processing; evaluation may not be done for several days | Tissue is frozen and cryosectioned for rapid evaluation |
| About 1% of the margin is evaluated, depending on the grossing protocols | 100% of the margin is evaluated |
| If the original excision shows a tumor in the margins, a new excision must be made around the scar | Excisions are continued in stages until all affected tissue is removed; no re-excisions are needed |
| Skin cancer cure rate 89–92% | Skin cancer cure rate above 98% |
| It may have adverse effects on function and cosmesis | Preserves function and cosmesis of area |
| Tissue is paraffin processed for permanent sections | Tissue is fresh and frozen-sectioned; no tissue is retained (typically) for permanent sections |
