Hearing the word “cancer” in a dermatology clinic tends to flatten everything else the doctor says for the next few minutes. Most skin cancers, though, sit at the more manageable end of the oncology spectrum, and many are dealt with in a day surgery room under local anaesthetic. Singapore’s national cancer registry has long recorded non-melanoma skin cancers among the tumours with the highest survival figures, which reflects how treatable they generally are when picked up early¹.

What throws people is the range of options presented. One person leaves with a tube of cream, another is booked for a procedure that takes several hours with pauses in between, and a third has a simple excision with stitches. None of that inconsistency is arbitrary. Skin cancer treatment is chosen according to what the tumour is, how big it has grown, where it sits on the body, and how it has behaved so far.

The diagnosis comes first

Nothing is decided before a biopsy result. Three diagnoses account for the overwhelming majority of cases, and they behave quite differently.

• Basal cell carcinoma (BCC) is the most common. It grows slowly and rarely spreads elsewhere, though it can burrow locally and damage nearby structures if ignored for years.
• Squamous cell carcinoma (SCC) grows faster and carries a real, if modest, risk of spreading, which rises with size, depth, and location.
• Melanoma is less common but the most serious, and it is managed surgically with margins based on tumour thickness².

The biopsy also reveals the growth pattern. A superficial BCC sitting in the upper layers is a very different proposition from an infiltrative or morphoeic one sending microscopic strands sideways under apparently normal skin.

Topical therapy: Creams with a narrow remit

Prescription creams have a place, though a specific one. Imiquimod works by prompting a local immune response against abnormal cells, while 5-fluorouracil interferes with cell replication. Both are applied at home over several weeks, and both produce a period of redness, crusting, and discomfort that patients need to be warned about in advance.

A randomised trial comparing imiquimod, fluorouracil, and photodynamic therapy for superficial BCC found imiquimod performed best of the three at one year, with reasonable outcomes across all arms³. The important qualifier is the word superficial. These creams do not reliably reach tumours that extend into the dermis, and dermatology guidelines position them as options for low-risk superficial lesions where surgery is unsuitable or declined⁴.

Topical therapy also leaves no specimen to examine, so nobody can confirm that every abnormal cell has gone. Follow-up examination becomes the safety net instead of a pathology report.

Surgical excision: The standard workhorse

Straightforward excision remains the most common approach. The tumour is cut out with a pre-determined margin of normal-looking skin around it, the wound is closed, and the whole specimen goes to the laboratory for the margins to be checked afterwards. For a small, well-defined BCC on the trunk or a limb, this is efficient and highly effective.

The limitation shows up when a margin comes back positive. That means the patient returns for a second procedure, having already had the area closed and healed.

Mohs surgery: Checking the margins as you go

Mohs micrographic surgery reorganises that sequence. The surgeon removes a thin layer of tissue, maps it, and processes it on site while the patient waits. If abnormal cells appear at an edge of the map, only that specific direction is taken further. The cycle repeats until the margins read clear, and reconstruction happens only once that point is reached.

Two things follow from this:

• The first is precision about margins, because the surgeon is looking at almost the entire deep and peripheral surface of what was removed instead of sampling it.
• The second is tissue conservation, which is why the technique is favoured on the face, where every millimetre of skin around an eyelid, nose, or lip carries functional consequences.

A randomised trial comparing Mohs surgery with standard excision for facial BCC followed patients for ten years and reported lower recurrence in the Mohs arm, with the difference most pronounced for recurrent tumours⁵. The trade-off is time. A Mohs day involves waiting between stages, and the process requires an on-site laboratory and a surgeon trained in both the excision and the histology reading.

Where each option tends to fit

Curettage with electrodessication, cryotherapy, and radiotherapy each retain a role in selected cases, particularly for frail patients or for lesions in awkward positions.

What the dermatologist is weighing up

Several factors sit behind the recommendation, and a good consultation makes them explicit:

• Tumour type and growth pattern from the biopsy
• Size and depth, plus whether the borders are clearly visible
• Anatomical site, since the face, ears, and genital area carry higher recurrence rates
• Whether this is a first tumour or a recurrence
• Cosmetic and functional consequences of the reconstruction
• General health, medication, and how well the person tolerates longer procedures

Immunosuppressed patients, including transplant recipients, generally need a lower threshold for definitive surgery, since their tumours can behave more aggressively.

The follow-up is part of the treatment

Clearing one tumour does not reset the risk. Anyone who has developed one skin cancer carries a meaningfully higher chance of developing another given the concept of field cancerization, so scheduled checks continue long after the wound heals. Much of the work of preventing skin cancer recurrence happens in those appointments, where the treated site and the rest of the skin are examined at set intervals.

Daily sun protection sits alongside the monitoring. Singapore records consistently high ultraviolet levels through the year, which makes shade, clothing, and sunscreen a practical part of aftercare instead of general advice.

Conclusion

Any new lesion that bleeds, crusts repeatedly, or refuses to heal deserves a proper look rather than a wait-and-see approach. At Angeline Yong Dermatology, Dr Angeline Yong provides diagnosis, biopsy, and surgical management, including Mohs micrographic surgery, alongside non-surgical options where they are appropriate. Book a consultation to have the lesion examined and to discuss what the pathology means for your next steps.

References

National Registry of Diseases Office. (2026). Singapore cancer registry annual report 2023. Health Promotion Board.

Swetter, S. M., Tsao, H., Bichakjian, C. K., Curiel-Lewandrowski, C., Elder, D. E., Gershenwald, J. E., Guild, V., Grant-Kels, J. M., Halpern, A. C., Johnson, T. M., Sober, A. J., Thompson, J. A., Wisco, O. J., Wyatt, S., Hu, S., & Lamina, T. (2019). Guidelines of care for the management of primary cutaneous melanoma. Journal of the American Academy of Dermatology, 80(1), 208–250. https://doi.org/10.1016/j.jaad.2018.08.055

Arits, A. H., Mosterd, K., Essers, B. A., Spoorenberg, E., Sommer, A., De Rooij, M. J., van Pelt, H. P., Quaedvlieg, P. J., Krekels, G. A., van Neer, P. A., Rijzewijk, J. J., van Geest, A. J., Steijlen, P. M., Nelemans, P. J., & Kelleners-Smeets, N. W. (2013). Photodynamic therapy versus topical imiquimod versus topical fluorouracil for treatment of superficial basal-cell carcinoma: a single blind, non-inferiority, randomised controlled trial. The Lancet. Oncology, 14(7), 647–654. https://doi.org/10.1016/S1470-2045(13)70143-8

Work Group, Invited Reviewers, Kim, J. Y. S., Kozlow, J. H., Mittal, B., Moyer, J., Olencki, T., & Rodgers, P. (2018). Guidelines of care for the management of basal cell carcinoma. Journal of the American Academy of Dermatology, 78(3), 540–559. https://doi.org/10.1016/j.jaad.2017.10.006

van Loo, E., Mosterd, K., Krekels, G. A., Roozeboom, M. H., Ostertag, J. U., Dirksen, C. D., Steijlen, P. M., Neumann, H. A., Nelemans, P. J., & Kelleners-Smeets, N. W. (2014). Surgical excision versus Mohs’ micrographic surgery for basal cell carcinoma of the face: A randomised clinical trial with 10 year follow-up. European journal of cancer (Oxford, England : 1990), 50(17), 3011–3020. https://doi.org/10.1016/j.ejca.2014.08.018