BASAL CELL CARCINOMA PDT
A NON-SURGICAL OPTION FOR FACIAL AND COSMETIC-ZONE BCC

Not all basal cell carcinomas are equal candidates for PDT. Understanding the BCC subtypes and size limits that respond well to PDT — and those that do not — is fundamental to patient selection.

“A 15 mm superficial BCC on the nose of an elderly patient who values cosmetic outcome is a perfect PDT indication. A 25 mm infiltrative BCC with deep dermal involvement in the same location is not.”

• Superficial BCC — Best PDT Indication

  Superficial BCC (sBCC) is the most suitable PDT indication. The tumour is confined to the epidermis and superficial dermis, where PDT light penetration easily reaches all tumour cells. PDT achieves 5-year recurrence-free rates of 70–80% for sBCC — comparable to surgical excision with good cosmetic superiority. Most sBCC on the face, trunk, and limbs are suitable.

• Nodular BCC — Suitable with Pre-Treatment Curettage

  Nodular BCC (nBCC) extends deeper into the dermis — beyond standard PDT light penetration depth (~5 mm). PDT for nBCC requires pre-treatment curettage (gentle scraping of the tumour to thin it to <2 mm depth) under local anaesthetic before cream application. With curettage, MAL-PDT achieves 5-year recurrence-free rates of 60–75% for nBCC <20 mm.

• Aggressive BCC Subtypes — PDT NOT Recommended

  Morphoeic (sclerosing) BCC, infiltrative BCC, basosquamous BCC, and micronodular BCC have infiltrative growth patterns that extend beyond visible margins and deep into dermis. PDT cannot reliably achieve complete clearance for these subtypes. Surgical excision (ideally Mohs micrographic surgery) is the standard for aggressive subtypes regardless of location.

• Size Limit: Generally <20 mm Diameter

  PDT outcomes decline for BCCs larger than 20 mm diameter and are significantly reduced beyond 30 mm. For larger BCCs, surgical excision with margin assessment provides better tumour control. For very large BCCs, fractionated radiotherapy or combined surgical-PDT approaches may be considered.

Published recurrence rates and comparative data from major BCC-PDT studies.

The cosmetic outcome advantage of PDT over surgery is most dramatic on the face — particularly the cosmetically sensitive "H-zone" (nose, periorbital, forehead, ears). This drives patient preference for PDT in these locations.

• Nose BCCs: Avoiding Deforming Surgery

  BCC on the nose is one of the most challenging surgical locations. Excision with adequate margins on the ala nasi, nasal tip, or nasal sidewall often requires complex flap reconstruction. PDT for superficial and selected nodular nasal BCCs achieves good tumour control without flap surgery — preserving nasal shape and avoiding visible scarring. For small superficial BCCs on the nose, PDT 5-year recurrence rates are comparable to excision with substantially better cosmetic outcomes.

• Periorbital BCCs: Avoiding Eyelid Deformity

  BCCs near the eyelid margins, medial canthus, and lateral canthus carry high risk of surgical deformity — ectropion, entropion, and lagophthalmos from eyelid distortion. PDT for appropriate periorbital BCCs avoids these functional complications. Careful technique is required to protect the eye during light delivery (protective eye shields).

• Scalp BCCs in Bald Patients

  Surgical excision on the bald scalp creates prominent scars with no hair coverage. PDT heals without scarring — leaving only minor pigmentation change at most. For multiple superficial BCCs on the bald scalp, PDT can treat several lesions in a single session.

• Large Superficial BCCs on the Trunk and Limbs

  Large superficial BCCs (15–30 mm) on the trunk or limbs that would require substantial excision and closure with a scar respond well to PDT — typically healing with minimal cosmetic footprint. Patient preference for avoiding surgery is a valid basis for choosing PDT for these lesions when the clinical situation is appropriate.

The standard protocol for MAL-PDT (Metvix) for basal cell carcinoma, including the curettage step for nodular BCC.

1. 1

   Step 1: Biopsy Confirmation

   Histological confirmation of BCC subtype and depth assessment. Superficial BCC: no additional preparation beyond scale removal. Nodular BCC: curettage planned before cream application.

2. 2

   Step 2: Local Anaesthetic and Curettage (Nodular BCC Only)

   For nodular BCC: local anaesthetic injected around the tumour. Gentle curettage removes tumour tissue to <2 mm depth — thinning the nodule to within PDT light penetration range. Haemostasis with pressure. This step is not needed for superficial BCC.

3. 3

   Step 3: Surface Preparation

   Treatment area cleaned. Any residual scale removed. BCC marked with a pen to ensure cream covers the full tumour plus 5 mm margin.

4. 4

   Step 4: MAL Cream Application

   Metvix cream applied 1 mm thick over tumour plus 5 mm margin. Covered with occlusive film dressing. 3-hour incubation under the dressing.

5. 5

   Step 5: Red LED Light Delivery

   Dressing removed. Red LED lamp at 630 nm delivers 37–75 J/cm² for 7–8 minutes. Protective eye shields placed if treating near the eyes. Cooling air reduces discomfort.

6. 6

   Step 6: Second Session (1 Week Later)

   Standard BCC-PDT protocol uses 2 sessions 1 week apart. The second session treats residual tumour and improves overall clearance rates significantly.

7. 7

   Step 7: Response Assessment and Long-Term Follow-Up

   Clinical assessment at 3 months confirms initial response. Long-term follow-up at 12 months and then annually for 5 years — BCC recurrence most common in years 1–3 and requires prompt retreatment (re-excision, repeat PDT, or Mohs surgery).

Related PDT topics and resources.

Frequently Asked Questions

Common questions about PDT for basal cell carcinoma.