Basal cell carcinoma treatment
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The following methods are employed in the treatment of basal cell carcinoma (BCC):
- Mohs surgery: Mohs surgery (or Mohs micrographic surgery) is an outpatient procedure in which the tumor is surgically excised and then immediately examined under a microscope. It is often claimed to have the highest cure rate of 97% to 99.8% by some individuals. The base and edges are microscopically examined to verify sufficient margins before the surgical repair of the site. If the margins are insufficient, more is removed from the patient until the margins are sufficient. It is also used for squamous cell carcinoma; however, the cure rate is not as high as Mohs surgery for basal cell carcinoma.
- Chemotherapy: Some superficial cancers respond to local therapy with 5-fluorouracil, a chemotherapy agent. Topical treatment with 5% Imiquimod cream, with five applications per week for six weeks has a reported 70-90% success rate at reducing, even removing, the BCC [basal cell carcinoma]. Both Imiquimod and 5-fluorouracil has received FDA approval for the treatment of superficial basal cell carcinoma. Off label use of imiquimod on invasive basal cell carcinoma has been reported. Imiquimod may be used prior to surgery in order to reduce the size of the carcinoma. One can expect a great deal of inflammation with this treatment. Chemotherapy often follows Mohs surgery to eliminate the residual superficial basal cell carcinoma after the invasive portion is removed. Removing the residual superficial tumor with surgery alone can result in large and difficult to repair surgical defects. One often waits a month or more after surgery before starting the Imiquimod or 5-fluorouracil to make sure the surgical wound has adequately healed. Some individual advocate the use of curettage (see EDC below) first, then followed by chemotherapy. These experimental procedure likely will result in better cure rate than one alone, but is not standard of care.
- Immunotherapy: Immunotherapy research suggests that treatment using Euphorbia peplus, a common garden weed, may be effective. Australian biopharmaceutical company Peplin is developing this as topical treatment for BCC. Imiquimod or Aldara is an immunotherapy but is listed here under chemotherapy.
- Radiation: Radiation therapy is appropriate for all forms of BCC as adequate doses will eradicate the disease. Although radiotherapy is generally used in older patients who are not candidates for surgery, it is also used in cases where surgical excision will be disfiguring or difficult to reconstruct (especially on the tip of the nose, and the nostril rims). The use of radiotherapy below the elbows and knees is not recommended as the blood supply to these areas is more easily affected by the radiation. Radiation treatment often takes as few as 5 visit to as many as 25 visits for radiation therapy. Usually, the more visits scheduled for therapy, the less complication or damage is done to the normal tissue supporting the tumor. Cure rate can be as high as 95% for small tumor, or as low as 80% for large tumors. Usually, recurrent tumors after radiation are treated with surgery, and not with radiation. Further radiation treatment will further damage normal tissue, and the tumor might be resistance to further radiation.
- Photodynamic Therapy: Photodynamic therapy is a new modality for treatment of basal-cell carcinoma, which is administrated by application of photosensitizers to the target area. When these molecules are activated by light, they become toxic, therefore destroy the target cells. Methyl aminolevulinate is approved by EU as a photosensitizer since 2001. This therapy is also used in other skin cancer types.
- Cryosurgery: Cryosurgery is an old modality for the treatment of many skin cancers. When accurately utilized with a temperature probe and a cryotherapy instruments, it can result in very good cure rate. Disadvantage is lack of margin control, tissue necrosis, over or under treatment of the tumor, and long recovery time. Several textbooks are published on the therapy, and a few physicians still apply the treatment to selected patients.
- Electrodessication and curettage: or EDC. One utilize a round knife, or curette, to scrape away the soft cancer. The next step is to burn the skin with an electric current. This further soften the skin, allowing for the knife to cut more deeply with the next layer of curettage. The cycle is repeated, with a safety margin of curettage of normal skin around the visible tumor. This cycle is repeated 3 to 5 times, and the free skin margin treated is usually 4 to 6 mm. Cure rate is very much user dependent and depends on the size and type of tumor. Infiltrative or morpheaform BCC's can be difficult to eradicate with EDC. Reserved only for non cosmetically important areas like the trunk. Some physicians believe that it is acceptable to utilize EDC on the face of elderly patients over the age of 70. However, with increasing life expectancy, such an objective criteria can not be supported. The cure rate can be low or high, depending on the aggressiveness of the EDC and the free margin treated.
- Standard surgical excision with either frozen section histology, or fixed tissue pathology. The cure rate for this method, whether done by a plastic surgeon, family doctor, or dermatologist is totally dependent on the surgical margin. A dermatoscope dermatoscopy can help an experienced surgeon accurately identify the visible tumor that the naked eye can not see. The narrower the free margin (skin removed that is free of visible tumor) the higher the recurrence rate. With special margin controlled processing and frozen section histology, a surgeon can assure a high cure rate approaching Mohs surgery. However, most standard excisions done in a plastic surgeon or dermatologist's office are sent to an outside laboratory for standard bread loafing method of processing. This method has a high "false negative" cure rate, due to the random sampling of the tumor. It is likely that less than 5% of the surgical margin is examined, as each slice of tissue is only 6 micron thick, and only about 3 to 4 sections are obtained. Usually, the rule of thumb is if a 4 mm free margin is obtained around a small tumor (less than 6mm), or a wider 6 mm free margin is obtained around a larger tumor (greater than 6mm), the cure rate is very high - 95% or better. Unfortunately, for cosmetic reasons, many doctors take only very small surgical margins 1-2 mm, especially when facial tumor is being removed. A pathology report from such a case indicating "margins free of residual tumor", often is inaccurate, and a high recurrence rate of up to 50% might occur. When in doubt, a patient should demand that either Mohs surgery or frozen section histology is utilized when dealing with a tumor on the face. The pathologist processing the frozen section specimen should cut multiple sections through the block to minimize the false negative error rate. Or one should simply process the tissue utilizing a method approximating the Mohs method (described in most basic histopathology text books) during frozen section processing. Unfortunately, these methods are difficult when applied to frozen sections; and is very tedious to process. When not utilizing frozen section, the surgeon will have to wait a week or more, before informing the patient if more tumor is left, or if the surgical margin is too narrow. And a second surgery must be performed to remove the residual or potential residual tumor.
Treating surgeons will recommend one of these modalities as appropriate treatment depending on the tumor size, location, patient age, and other variables.
- The Skin Cancer Foundation - The Skin Cancer Foundation Seal of Recommendation
- Peplin's skin cancer gel trial a success - Breaking News - Business - Breaking News
- Peng Q et al (Jan 2008) "Lasers in Medicine" Rep. Prog. Phys. 71 056701