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An educational aid, not advice for your case. For a superficial or low-risk basal cell carcinoma there is a genuine choice, and it is usually summarised in a way that hides what is being traded. Answer four questions and this sets out, for your situation, what the randomised trials found about cure rate, about how the result looks, and about what each treatment does to your skin while it works, quoted word for word with the study it came from. It gives no score and makes no prediction about you.
Answer the 4 questions and the statement that applies to that combination appears here, quoted word for word from Thomson et al., interventions for basal cell carcinoma of the skin (Cochrane Database of Systematic Reviews, 2020) and the sources listed below, with a plain line on what it means and the questions to take to your surgeon.
Without JavaScript, every statement the aid can show is listed further down the page. This is an educational aid, not advice.
The aid picks from these 15 cards; each quotes its source word for word. Read them all here, with or without the questions above.
“Overall, surgical interventions have the lowest recurrence rates. ... Non-surgical treatments, when used for low-risk BCC, are less effective than surgical treatments, but recurrence rates are acceptable and cosmetic outcomes are probably superior.”
“Five-year success rates for imiquimod were 82.5% (170/206) compared with 97.7% (173/177) for surgery (relative risk of imiquimod success = 0.84, 95% confidence interval = 0.77-0.91, P < 0.001).”
What this means: This card is shown whatever you answer, because everything else is measured against it. The SINS trial randomised 501 people in the UK with a primary nodular or superficial basal cell carcinoma at a low-risk site between imiquimod cream and excision with a 4 mm margin, and followed them for five years. Roughly one person in six treated with the cream needed something else; roughly one in forty treated with surgery did. That is the size of the trade, and it is a real trade rather than a formality, because the non-surgical options buy other things.
“Five years after treatment, the probability of tumor-free survival was 62.7% for methyl aminolevulinate photodynamic therapy (95% CI = 55.3-69.2), 80.5% for imiquimod (95% CI = 74.0-85.6), and 70.0% for 5-fluorouracil (95% CI = 62.9-76.0).”
“Cryotherapy - 'superficial' type BCCs can be frozen with liquid nitrogen. This will generate a wound that will usually heal with a scar. Creams - these can be applied to the skin to destroy 'superficial' type BCCs. The two commonly used are imiquimod cream and 5-fluorouracil cream.”
What this means: A superficial basal cell carcinoma is the one where the alternatives to surgery genuinely compete. The Dutch trial randomised 601 patients between the three and followed them for five years, and the order was clear: imiquimod first, fluorouracil second, photodynamic therapy third. Imiquimod is used once daily for six weeks; fluorouracil twice daily for four weeks; photodynamic therapy is two hospital visits. Freezing is also offered and leaves a scar of its own.
“MAL-PDT may result in more recurrences compared to SE at three years (36.4% versus 0%, respectively) (RR 26.47, 95% CI 1.63 to 429.92; 1 study; 68 participants with low-risk nBCC in the head and neck area; low-certainty evidence).”
“Participants were randomized to imiquimod 5% cream once daily (superficial basal cell carcinoma, 6 weeks; nodular basal cell carcinoma, 12 weeks) or excisional surgery (4-mm margin).”
What this means: A nodular basal cell carcinoma is a lump rather than a patch, so a treatment that works on the surface has further to reach. Photodynamic therapy did badly against surgery for nodular disease in the head and neck, although that comparison rests on a single small study and the Cochrane authors graded it low certainty. Imiquimod was tested on nodular disease in SINS, but for twelve weeks rather than six. The British Association of Dermatologists reserves creams and photodynamic therapy for superficial lesions, so if yours is nodular ask specifically what the evidence is for that subtype.
“'High risk' BCCs are more likely to come back after treatment. They include BCCs that are large, have unclear edges, have grown back despite previous treatment, or are classified as 'infiltrative' or 'morphoeic' sub-type. ... For high risk BCCs, the following treatments are most likely to be offered: Surgery (excision) - the BCC is cut out with a surrounding area (margin) of normal skin, as described above. The margins of the skin sample can be tested to confirm whether the BCC has been fully removed.”
“Most studies (48/52) included only low-risk BCC (superficial (sBCC) and nodular (nBCC) histological subtypes).”
What this means: If the word used about your basal cell carcinoma is infiltrative, morphoeic or recurrent, or if the edges are not clearly visible, the comparison between creams and surgery does not apply to you: almost all of the randomised evidence was collected in low-risk lesions. The point of an excision or of Mohs here is that somebody can look at the edges of what was taken out and say whether the cancer is all gone, which is exactly what curettage, freezing and creams cannot do.
“You may be recommended Mohs surgery if: It is difficult to see the edges of the skin cancer and so there would be a chance of not removing it fully if a standard surgical removal was performed. You have a skin cancer in an area where it is important to try and preserve unaffected skin and deeper tissue, if possible (for example, on eyelids, nose, ears, lips and around the mouth).”
“For primary BCC, the 10-year cumulative probabilities of recurrence were 4.4% after MMS and 12.2% after SE (Log-rank test chi-square 2.704, p=0.100). For recurrent BCC, cumulative 10-year recurrence probabilities were 3.9% and 13.5% for MMS and SE, respectively (Log-rank 5.166, p=0.023).”
What this means: The Dutch trial randomised 408 primary and 204 recurrent high-risk facial basal cell carcinomas and followed them for ten years. For a lesion that had already come back once, Mohs clearly did better; for a first lesion the difference pointed the same way but did not reach statistical significance. The other reason for Mohs on a face is not the cure rate at all: checking the edges as it goes means less normal skin is taken, which changes what the reconstruction has to do.
“It can take up to 3 hours to get your result. You may need another stage of surgery if any skin cancer was left behind. This means that you could be in hospital for up to a day, although this can vary. ... More than one set of local anaesthetic injections are often needed for Mohs. It can be a long and tiring day.”
“In 90% of cases the skin cancer is removed after 1-2 stages of Mohs surgery. Some people may need more stages.”
What this means: You arrive, the lesion is marked and photographed, you are given local anaesthetic and the tumour is taken out, the wound is dressed and you wait in a recovery bay while the sample is read under a microscope. If anything is left, you are numbed again and another layer comes out. You do not know at the start how many stages there will be or how big the wound will end up, and the wound is only closed once the surgeon is satisfied. The leaflet also says you will need someone to drive you home, that public transport is not advised afterwards, and to bring something to do.
“Surgery (curettage and cautery) - the BCC is scraped off (a process known as curettage) and then the skin surface is sealed using heat (cautery). Often the curettage and cautery are repeated a few times back-to-back to clear all the affected skin. Although it is usually not possible to test the edges of the sample to confirm that the BCC has been fully removed (such as with an excision), this procedure is generally considered effective for treating a low-risk BCC.”
“You don't have any stitches with this type of surgery. The area will scab over. Your doctor will tell you how to look after your wound and when to remove the dressing.”
What this means: One appointment, local anaesthetic, no stitches and no return visit to have them out, and a round pale scar where the scab falls off. The price is that no pathologist can confirm the edges are clear, which is why it is offered for low-risk lesions on the body rather than for anything high-risk or anything on the face where the edges are hard to see.
“At 3 years, 178 (84%) of 213 participants in the imiquimod group were treated successfully compared with 185 (98%) of 188 participants in the surgery group (RR 0.84, 98% CI 0.78-0.91; p<0.0001). ... Although excisional surgery remains the best treatment for low-risk basal-cell carcinoma, imiquimod cream might still be useful.”
“For high-risk facial BCC (high-risk histological subtype or located in the facial 'H-zone' or both), there may be slightly fewer recurrences with Mohs micrographic surgery (MMS) compared to surgical excision (SE) at three years (1.9% versus 2.9%, respectively) ... and at five years (3.2% versus 5.2%, respectively).”
What this means: You said the cure rate matters most, so this is the straight answer rather than a balanced one: excision, or Mohs where the site or the subtype calls for it. Nothing else measured in a randomised trial comes close for a basal cell carcinoma, and the SINS authors wrote that sentence themselves.
“The most common adverse events were itching (211 patients in the imiquimod group vs 129 in the surgery group) and weeping (160 vs 81). ... 12 (5%) participants in the imiquimod group withdrew because of adverse events compared with four (2%) in the surgery group.”
“Most imiquimod treatment failures occurred in year 1.”
What this means: Two things are worth knowing before choosing the cream. The first is that the treatment is visible: itching, weeping and inflammation over the weeks it is working, which on a face is public in a way a dressing is not. The second is more encouraging. Nearly all the failures happened in the first year, so a lesion that clears and stays clear through the first year is unlikely to fail later.
“However, imiquimod may result in greater numbers of good/excellent cosmetic outcomes compared to SE when observer-rated (60.6% versus 35.6%, respectively) (RR 1.70, 95% CI 1.35 to 2.15; 1 study, 344 participants; low-certainty evidence). ... There may be little to no difference in the number of participant-rated good/excellent cosmetic outcomes (RR 1.00, 95% CI 0.94 to 1.06; 1 study, 326 participants).”
“MAL-PDT probably results in greater numbers of participant- (RR 1.18, 95% CI 1.09 to 1.27; 97.3% versus 82.5%) or observer-rated (RR 1.87, 95% CI 1.54 to 2.26; 87.1% versus 46.6%) good/excellent cosmetic outcomes at one year compared to SE.”
What this means: This is the honest counterweight to the cure-rate card, and it is not a small effect. Doctors looking at the results rated photodynamic therapy nearly twice as likely to look good as surgery, and imiquimod clearly better than surgery. Patients rating their own results were less impressed by the difference for imiquimod but agreed strongly about photodynamic therapy. Notice also what surgery scored on the observer ratings: a good or excellent result in roughly a third to a half. A scar is the usual outcome of an operation, not a complication of one.
“Participants were randomly assigned (1:1) ... to receive either imiquimod 5% cream once daily for 6 weeks (superficial) or 12 weeks (nodular), or surgical excision with a 4 mm margin.”
“Mohs surgery takes longer to do (half a day on average) than standard excision. More than one set of local anaesthetic injections are often needed for Mohs. It can be a long and tiring day. ... There are usually longer waiting lists for Mohs surgery compared to standard excision.”
What this means: A standard excision is usually a single appointment under local anaesthetic, with stitches out at the GP surgery one or two weeks later. Curettage and cautery is one appointment and no stitches. A cream is six to twelve weeks of daily treatment at home with review afterwards. Photodynamic therapy is two hospital visits. Mohs is most of a day, plus a longer wait to get it. The fastest option and the most certain option are not always the same one, and neither is the least disruptive.
“Based on one study of 347 participants with high- and low-risk primary BCC of the face, radiotherapy may result in more recurrences compared to SE under frozen section margin control at three years (5.2% versus 0%, respectively) ... Radiotherapy probably results in a smaller number of good participant- (RR 0.76, 95% CI 0.63 to 0.91; 50.3% versus 66.1%) or observer-rated (RR 0.48, 95% CI 0.37 to 0.62; 28.9% versus 60.3%) good/excellent cosmetic outcomes compared to SE, when measured at four years, where dyspigmentation and telangiectasia can occur.”
“Radiotherapy - X-ray radiation is projected onto the BCC, and this treatment is repeated over a number of days/weeks. This treatment is usually delivered by the oncology team. Radiotherapy is not suitable for people with genetic skin cancer syndromes as it can increase the number of BCCs.”
What this means: Radiotherapy avoids an operation, which is exactly why it is used where surgery would be disfiguring or where someone cannot have an anaesthetic. It is not a free choice: in the one randomised comparison it recurred more often than margin-controlled excision, the skin it treats changes colour and develops fine visible vessels over years, and it means several visits over days or weeks rather than one. It is also not offered to people with a genetic skin cancer syndrome.
“In some cases, it may be reasonable not to treat the BCC at all - for example, if the BCC is growing slowly on a non-critical area of the body or if the person would be unable to tolerate or recover from treatment due to other health issues.”
“BCCs very rarely spread to other parts of the body and are almost never a danger to life.”
What this means: You said you wanted to avoid an operation, so this belongs on the list rather than being left for someone to raise at the end. It is a choice for a slow-growing lesion on a part of the body where nothing important is nearby, and for someone whose other health problems make treatment the bigger burden. It is not a choice for a lesion near the eye, nose, ear or lip, where growth causes damage that is hard to repair, and it is a decision to make with the team rather than by not going back.
“BCCs are also more likely to come back in people with weak immune systems. In these cases, it is important to make sure that the BCC has been completely removed.”
“SCC is 150 times more common in transplant recipients than in the general population and is the most frequent type of skin cancer in organ transplant patients. ... BCCs are up to 10 times more common in organ transplant recipients compared with the general population.”
What this means: Two things follow. First, the British Association of Dermatologists says that in people with weakened immune systems it is important to be sure the basal cell carcinoma has been completely removed, which argues for a treatment whose margins can be checked rather than a cream. Second, the far bigger risk for you is not this lesion but the next ones, and above all squamous cell carcinoma, so the conversation should also cover how often your skin is checked, daily SPF 50 all year, and whether your immunosuppression itself is worth reviewing with your transplant team.
“For BCCs, the 3-year cumulative risk is 44%, also at least a 10-fold increase in incidence compared with the rate in a comparable general population.”
“Some skin cancers have a low risk of coming back. For example, if you have an early stage basal cell carcinoma (BCC) or a low risk squamous cell carcinoma (SCC) you might have: a single follow up appointment and then no further follow up appointments.”
What this means: This card is shown whatever you answer. In the pooled studies, 44 of every 100 people who had a basal cell carcinoma had another one within three years, because the whole area of skin took the same ultraviolet damage. It is also why follow-up for a low-risk lesion is often a single appointment and then discharge: the surveillance is handed to you, and what you are asked to do is check your own skin monthly and go back for any mark that is growing, changing, bleeding or not healing, including a change where this one was treated.
Each combination of answers maps to a fixed set of cards, and every card quotes the statement it implements with the page it was read from; nothing is scored or inferred. Where the sources disagree, both are quoted. The mapping is data in the OnCo repository and is tested against every combination of answers. Checked 2026-09-25.
This is an educational aid to prepare for a conversation with your surgical team. It is not medical advice, and it cannot see your scans or your history. OnCo is orientation, not medical advice.