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The Skin Doctor

Doctor-led comparison of the three field treatments for actinic keratosis and selected superficial skin cancers — Efudix (5-fluorouracil), Aldara (imiquimod) and photodynamic therapy. Explains why the PDT version matters (conventional vs daylight vs laser-assisted), what head-to-head trials show, and the downtime, cost and practical factors that decide which approach suits which patient.

Field therapy

Efudix vs Aldara vs PDT: Choosing a Field Treatment

Doctor-led comparison of the three field treatments for actinic keratosis and selected superficial skin cancers — Efudix (5-fluorouracil), Aldara (imiquimod) and photodynamic therapy. Explains why the PDT version matters (conventional vs daylight vs laser-assisted), what head-to-head trials show, and the downtime, cost and practical factors that decide which approach suits which patient.

Portrait of Dr Christopher Irwin

By Dr Christopher Irwin, MBChB, FRACGP, MMed (Skin Cancer), FACAM, MSCCA

Last reviewed 2026-07-10 · 9 min read · Editorial policy

Quick answer

Efudix (5-fluorouracil), Aldara (imiquimod) and photodynamic therapy (PDT) all treat a field of sun-damaged skin rather than single spots. Among the options compared in the landmark four-way randomised trial — which included the two creams and conventional PDT, but not laser-assisted PDT — Efudix was the most effective for actinic keratosis. (1) But “PDT” is not one treatment: laser-assisted PDT, a newer protocol tested in separate randomised trials, has reported the highest clearance of any field treatment (~92% for AK, ~93.8% for Bowen’s) in a single in-clinic session with about 5–7 days of healing. (7,8,9) Aldara retains particular strengths in superficial BCC and selected Bowen’s disease. (5,6) The comparison table below is the heart of this page; the right option still depends on your diagnosis, the site, cost and the downtime you can manage — decided in consultation, after uncertain lesions are biopsied. This page is patient information, not a recommendation.

If you have been told you have actinic keratosis (sun spots), Bowen’s disease (SCC in situ) or a superficial BCC, there is usually more than one reasonable way to treat it. Patients often arrive having heard of one option — a “chemo cream”, a cream that “uses your immune system”, or a light treatment — and want to know how they compare.

This guide puts the three main field treatments side by side, using the published head-to-head evidence, so the conversation with your doctor starts from an informed place. It is general information: the comparison changes with your diagnosis, and no cream or procedure should be started without one.

Why “field” treatment at all?

Sun-damaged skin is rarely damaged in just one spot. The skin around a visible lesion has usually received the same lifetime UV dose and carries the same DNA changes — a concept called field cancerisation. (10) Treating the whole at-risk area, rather than freezing spots one by one, aims to clear the invisible damage and reduce the cycle of new lesions. (For a fuller explanation of field cancerisation and why we treat the field at all, see our field therapy overview.)

All three options below are field treatments. They differ in how they destroy abnormal cells, how long treatment takes, what the recovery looks like and what the evidence shows for each diagnosis.

The three options in one line each

  • Efudix (5-fluorouracil) — a topical chemotherapy cream applied at home for 2–6 weeks; it preferentially damages rapidly dividing abnormal cells.
  • Aldara (imiquimod) — an immune-activating cream applied at home over several weeks; it prompts your own immune system to clear abnormal cells.
  • Laser-assisted PDT — a single in-clinic session: fractional laser helps a photosensitising cream penetrate, then red light activates it to destroy abnormal cells.

What the head-to-head evidence shows

Actinic keratosisSCC in situ (Bowen’s)Course & downtimeCost pattern
Efudix (5-fluorouracil)Most effective field cream — 74.7% sustained success at 12 months (1,2)~50–85% clearance reported (3,4)Once/twice-daily cream, 2–6 weeks; weeks of visible reaction, then further weeks to settleLow — prescription cream used at home
Aldara (imiquimod)53.9% sustained success at 12 months (1)~73% clearance in the randomised trial (6)Cream several times weekly, ~6 weeks (protocol varies); weeks of reaction, sometimes flu-like symptomsLow–moderate — prescription cream used at home
Laser-assisted PDT~92% complete clearance in randomised trials (7,8)~93.8% clearance (9)Single in-clinic session; heals in about 5–7 daysHigher — in-clinic procedure

Three important caveats on that table:

  1. The PDT row is laser-assisted PDT specifically. The landmark four-way trial that crowned Efudix the best field cream compared it against conventional cream-and-lamp PDT — laser-assisted PDT was not in that trial. The next section unpacks why the PDT version matters so much.
  2. Numbers are not directly interchangeable. They come from different trials, sites and definitions of clearance — they are a guide to the pattern, not a precise scorecard.
  3. Superficial BCC is its own conversation. Imiquimod has the strongest cream evidence there — 80.5% of patients remained tumour-free at five years in a randomised trial, versus 70.0% for 5-fluorouracil. (5,11) Surgery still offers the highest cure rate for suitable lesions, and laser-assisted PDT for non-melanoma skin cancer is discussed separately.

Not all PDT is the same

Every form of photodynamic therapy shares the same principle: a photosensitising cream (ALA or MAL) is taken up preferentially by abnormal cells, then activated by light, destroying those cells. What differs between versions is how deeply the cream penetrates and how it is activated — and the results differ accordingly. When you read or hear a claim about “PDT”, the first question is always which PDT.

Conventional PDT (cream + red lamp)

The photosensitiser is applied under a dressing for around three hours, then activated with a red LED lamp in clinic. This is the version included in the four-way NEJM trial — where it achieved 37.7% sustained success for actinic keratosis at 12 months, well behind Efudix’s 74.7%. (1) The illumination step can also be genuinely painful. Effective for selected lesions, but for field treatment of AK the trial evidence puts it behind the leading cream.

Daylight PDT (cream + natural daylight)

The same photosensitiser, activated instead by about two hours of ordinary outdoor daylight. Randomised trials — including an Australian study — show clearance similar to conventional PDT for thin (grade I) actinic keratoses, with substantially less pain; most patients describe it as nearly painless. (12,13) Its place is gentle treatment of thin, widespread facial and scalp AKs; it is weather-dependent and less suited to thicker lesions.

Laser-assisted PDT (fractional laser + cream + light)

The newest refinement — and the protocol we use at The Skin Doctor. A fractional ablative laser first creates microscopic channels in the skin so the photosensitiser penetrates deeper and more evenly before light activation. In randomised trials this lifts complete clearance to around 92% for actinic keratosis and 93.8% for Bowen’s disease — the strongest published results in the PDT family — with healing in about 5–7 days after a single session. (7,8,9) You can read how the session works step by step on our laser-assisted PDT page.

So when this page compares “PDT” against the creams, the table row refers to the laser-assisted protocol. A comparison based on conventional PDT would look quite different — which is exactly why the four-way cream trial and the laser-assisted trials both matter and neither tells the whole story alone.

How to think about the choice

In practice, the decision usually comes down to five questions:

1. What exactly is being treated?

The diagnosis drives everything. Widespread actinic keratosis favours Efudix or laser-assisted PDT. (1,7) Biopsy-confirmed Bowen’s disease can suit any of the three depending on site and size. (3,4,6,9) Superficial BCC shifts the cream conversation toward imiquimod. (5,11) Anything with diagnostic uncertainty gets biopsied before field treatment is even discussed.

2. How much downtime can you take?

The creams work over weeks — and they look like it. Efudix in particular produces a red, crusted, sometimes weeping reaction that many patients describe as dramatic (our week-by-week Efudix timeline shows what to expect and when). Laser-assisted PDT concentrates the discomfort into a single session with roughly 5–7 days of healing. If you cannot take weeks of visible facial reaction — for work, care responsibilities or events — that often decides it.

3. Will you actually do the course?

Efudix and Aldara only work if applied consistently to schedule, and stopping early reduces clearance. If daily application for a month or more is unrealistic, a single in-clinic session may serve you better — an honest self-assessment here is worth more than any efficacy percentage.

4. What does cost look like?

The creams are prescription medications, varying in cost depending on the area treated — from around $60–70 AUD up to more than $200 AUD. LA-PDT is an in-clinic procedure and costs more per session. Set against that: a failed or abandoned cream course has its own costs, and some patients pay for the shorter downtime. Fees are disclosed at booking and discussed before anything is decided.

5. What happened last time?

If an area has already failed one field treatment, or the reaction was intolerable, that history matters — switching modality is common and reasonable, planned with your doctor.

Can the options be combined?

Yes — they are complementary rather than competing. A common pattern is a cream for smaller or lower-risk fields and laser-assisted PDT for extensive damage, or PDT where a cream course previously failed. Sequencing is individual and planned at review; it is not something to improvise at home.

Talk it through before you decide

A 20-minute skin review is enough to examine the area, confirm what is being treated, and walk through these trade-offs for your situation — including whether field treatment is needed at all yet.

Frequently asked questions

  • Is Efudix or Aldara better for actinic keratosis (sun spots)?
    In head-to-head randomised trials, 5% fluorouracil (Efudix) cleared actinic keratosis more effectively than imiquimod (Aldara) — in the largest trial, 74.7% of Efudix patients had sustained success at 12 months versus 53.9% with imiquimod. That is why Efudix is often the first-choice cream for AK. Aldara still has a role in selected situations, and the right choice depends on your diagnosis, the site and your circumstances.
  • Is PDT better than Efudix?
    It depends entirely on which PDT. In the large four-way randomised trial, conventional (cream-and-lamp) PDT cleared fewer actinic keratoses at 12 months than Efudix (37.7% vs 74.7% sustained success). Laser-assisted PDT — where fractional laser pre-treatment helps the photosensitiser penetrate — was not in that trial, and has separately reported around 92% clearance in randomised trials, delivered in a single in-clinic session with days rather than weeks of downtime. The trade-off is cost and clinic attendance versus a low-cost cream you use at home.
  • What is daylight PDT and is it as good?
    Daylight PDT uses the same photosensitising cream, activated by about two hours of ordinary outdoor daylight instead of a clinic lamp. Randomised trials, including an Australian study, show clearance similar to conventional PDT for thin (grade I) actinic keratoses with substantially less pain — most patients find it nearly painless. It suits thin, widespread facial and scalp sun damage; it is weather-dependent and less suited to thicker lesions, and its published results sit below those of laser-assisted protocols.
  • Which treatment has the least downtime?
    Laser-assisted PDT generally has the shortest recovery — most skin settles in around 5–7 days after a single session. Efudix and Aldara both produce weeks of visible redness and crusting during the course, plus a further healing period after stopping. If you cannot take extended social or work downtime, that difference often drives the decision.
  • Can I switch from one treatment to another?
    Yes — these options are not mutually exclusive. If a cream is not tolerated, or an area does not clear fully, your doctor may adjust the plan or use a different approach for the next round. Some patients use a cream for smaller areas and laser-assisted PDT for extensive field damage. Any switch should be planned with your doctor rather than done on your own.
  • Do I need a biopsy before field treatment?
    Any lesion where there is diagnostic uncertainty — or any lesion that could be an invasive cancer rather than a pre-cancer or in-situ change — should be biopsied first. Field treatments are only appropriate once the diagnosis is confirmed as suitable, which is why treatment starts with a proper skin assessment.
  • Are these treatments subsidised or expensive?
    Efudix and Aldara are prescription creams and are generally the lower-cost options. Photodynamic therapy is an in-clinic procedure and costs more per session. Fees and any rebates are individual — they are disclosed when you book and discussed at your consultation before any decision is made.

References

  1. Jansen MHE, Kessels JPHM, Nelemans PJ, et al. Randomized trial of four treatment approaches for actinic keratosis. N Engl J Med. 2019;380(10):935-946. At 12 months, sustained success was highest with 5% fluorouracil (74.7%), then imiquimod (53.9%), MAL-PDT (37.7%) and ingenol mebutate (28.9%).
  2. Krawtchenko N, Roewert-Huber J, Ulrich M, Mann I, Sterry W, Stockfleth E. A randomised study of topical 5% imiquimod vs. topical 5-fluorouracil vs. cryosurgery in immunocompetent patients with actinic keratoses: a comparison of clinical and histological outcomes including 1-year follow-up. Br J Dermatol. 2007;157(Suppl 2):34-40.
  3. Morton CA, Birnie AJ, Eedy DJ. British Association of Dermatologists' guidelines for the management of squamous cell carcinoma in situ (Bowen's disease) 2014. Br J Dermatol. 2014;170(2):245-260.
  4. Bath-Hextall FJ, Matin RN, Wilkinson D, Leonardi-Bee J. Interventions for cutaneous Bowen's disease. Cochrane Database of Systematic Reviews. 2013;(6):CD007281.
  5. Geisse J, Caro I, Lindholm J, Golitz L, Stampone P, Owens M. Imiquimod 5% cream for the treatment of superficial basal cell carcinoma: results from two phase III, randomized, vehicle-controlled studies. J Am Acad Dermatol. 2004;50(5):722-733.
  6. Patel GK, Goodwin R, Chawla M, et al. Imiquimod 5% cream monotherapy for cutaneous squamous cell carcinoma in situ (Bowen's disease): a randomized, double-blind, placebo-controlled trial. J Am Acad Dermatol. 2006;54(6):1025-1032.
  7. Choi SH, Kim KH, Song KH. Efficacy of ablative fractional laser-assisted photodynamic therapy with short-incubation time for the treatment of facial and scalp actinic keratosis: 12-month follow-up results of a randomized, prospective, comparative trial. J Eur Acad Dermatol Venereol. 2015;29(8):1598-1605.
  8. Choi SH, Kim TH, Song KH. Efficacy of iontophoresis-assisted ablative fractional laser photodynamic therapy with short incubation time for the treatment of actinic keratosis: 12-month follow-up results of a prospective, randomised, comparative trial. Photodiagnosis Photodyn Ther. 2017;18:105-110.
  9. Ko DY, Kim KH, Song KH. A randomized trial comparing methyl aminolaevulinate photodynamic therapy with and without Er:YAG ablative fractional laser treatment in Asian patients with lower extremity Bowen disease: results from a 12-month follow-up. Br J Dermatol. 2014;170(1):165-172.
  10. Braakhuis BJ, Tabor MP, Kummer JA, Leemans CR, Brakenhoff RH. A genetic explanation of Slaughter's concept of field cancerization: evidence and clinical implications. Cancer Res. 2003;63(8):1727-1730.
  11. Jansen MHE, Mosterd K, Arits AHMM, et al. Five-year results of a randomized controlled trial comparing effectiveness of photodynamic therapy, topical imiquimod, and topical 5-fluorouracil in patients with superficial basal cell carcinoma. J Invest Dermatol. 2018;138(3):527-533.
  12. Rubel DM, Spelman L, Murrell DF, et al. Daylight photodynamic therapy with methyl aminolevulinate cream as a convenient, similarly effective, nearly painless alternative to conventional photodynamic therapy in actinic keratosis treatment: a randomized controlled trial. Br J Dermatol. 2014;171(5):1164-1171.
  13. Lacour JP, Ulrich C, Gilaberte Y, et al. Daylight photodynamic therapy with methyl aminolevulinate cream is effective and nearly painless in treating actinic keratoses: a randomised, investigator-blinded, controlled, phase III study throughout Europe. J Eur Acad Dermatol Venereol. 2015;29(12):2342-2348.

Related

Portrait of Dr Christopher Irwin

By Dr Christopher Irwin, MBChB, FRACGP, MMed (Skin Cancer), FACAM, MSCCA

Last reviewed 2026-07-10 · Editorial policy