How Long Will This Take?
Key Reassurances
- Most cases are completed in 1–2 stages (2–4 hours total)
- The waiting between stages is when your tissue is being thoroughly examined
- 100% margin examination is what makes the 99% cure rate possible
- You can bring entertainment, snacks, and a companion
- More stages simply means the cancer grew irregularly. Not that it’s more dangerous
A Typical Mohs Surgery Timeline
Here is what a typical Mohs surgery day looks like:
| Phase | Duration | What Happens |
|---|---|---|
| Check-in & Preparation | 15–30 min | Paperwork, marking the tumor, surgical area preparation |
| Stage 1: Excision | 10–20 min | Tumor removal under local anesthesia |
| Stage 1: Processing | 30–45 min | Your tissue is mapped, frozen, cut, stained, and examined |
| Results & Decision | 5 min | Surgeon reviews slides; if clear → reconstruction. If residual → Stage 2 |
| Stage 2 (if needed) | 10–20 min | Additional tissue removed only where cancer remains |
| Stage 2: Processing | 30–45 min | Same meticulous examination repeated |
| Reconstruction | 20–60 min | Wound closure once all margins are clear |
| Discharge | 15 min | Wound care instructions, follow-up scheduling |
The Waiting IS the Cure
The waiting between stages is often the hardest part for patients. But here is the key insight: the waiting is what makes Mohs surgery superior to every other skin cancer treatment.
During those 30–45 minutes, your surgeon is personally examining every millimeter of your tissue margin under the microscope. This is 100% margin evaluation, compared to approximately 0.1% with standard pathology. This is why the cure rate is 99%. The wait is not wasted time. It is the most thorough cancer check possible.
Practical Tips
- Bring a book, tablet, or downloaded podcasts/audiobooks
- Bring a phone charger. You will have time to use it
- A companion can keep you company and help pass the time
- Light snacks and water are welcome (eat breakfast before your appointment)
- Wear comfortable, button-front clothing that doesn’t need to go over your head
- Ask your surgeon how many stages are typical for your type of tumor
How Many Stages Will I Need?
Most skin cancers are cleared in 1–2 stages. The number of stages depends on the tumor type, size, location, and whether it has been previously treated. Your surgeon can give you a general estimate, but the exact number is only known once all margins are confirmed clear under the microscope.
What the Evidence Shows
- Approximately 70–80% of Mohs cases are cleared in 1–2 stages
- Average total clinic time: 2–4 hours
- Each additional stage adds approximately 45–60 minutes
- More stages does NOT mean the cancer is more serious. It means it was growing in an irregular pattern
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About This Article
Author: Dr. Yehonatan Kaplan, M.D., Fellow ACMS
Last Medical Review:
Audience: Patients
Clinic: Kaplan Clinic · DermUnbound Research Program