The icing therapy
Especially for elderly patients with smaller, superficial tumours, another method is the treatment of icing (cryotherapy). Here, the tumour tissue is frozen with the help of liquid nitrogen at -196°C and thus destroyed, whereupon it is rejected by the body. Here too, a safety margin must be maintained. This variant is particularly suitable for tumours that are quite small and located on the surface and close to sensitive structures, for example on the eyelid. A disadvantage of this therapy is that the icing causes skin changes at the affected area from time to time, which on the one hand are optically perceived as disturbing by many and on the other hand are often reason for concern, as they cannot be clearly distinguished from a tumour recurrence.
Photodynamic Therapy
For some years now, photodynamic therapy (PDT) has also been available for the treatment of a basal cell carcinoma. Here, an ointment containing the active ingredient methyl-amino-oxo-pentanoate (MAOP) is first applied to the affected skin area, which is then absorbed by the tumor cells. In these cells, the MAOP is converted into another substance, which is the target structure of the irradiation with a special red light that follows after four hours.
Since the light is absorbed only by the cells containing this specific substance, the energy released by the light selectively destroys only the tumor cells, but not the surrounding healthy tissue. Another newer therapy option is the local treatment with creams. These contain either imiquimod or 5-fluoro-uracil as the active substance.
Imiquimod is a substance that stimulates the local body’s own immune system to attack the tumour tissue as part of an inflammatory reaction. According to previous observations, this is a gentle method that does not lead to any residual symptoms and provides a cure in about 80% of those affected. However, since it has not been practiced for a long time, it is difficult to say anything about long-term rates and a long-term risk of recurrence.
5-fluoro-uracil (5-FU) is a chemotherapeutic agent that is used systemically in various forms of cancer. When applied locally, it also causes an inflammatory reaction that leads to the death of the tumour cells. In contrast to Imiquimod, however, 5-FU is more aggressive towards healthy skin cells, which can undergo inflammatory changes as a result of its application. Both types of creams must be applied to the affected skin area over several (about 4 to 6) weeks, which can usually be done by the patient himself at home.
The treatment with ointments
Local chemo-/immunotherapy should also be considered for multiple basal cell carcinomas at multiple locations. In this case, 5-Fuorouracil in the form of an ointment is applied daily to the basaliomas over a period of approx. 4-6 weeks.
5-Fluorouracil is a cytostatic drug, a drug which inhibits the growth of tumour cells. The cytostatic drug also induces an intentional inflammatory reaction after 1-2 weeks. This serves to fight the tumour with the own immune system.
Another active substance which shows a similar mode of action is Imiquimod. The disadvantage of the therapy with cytostatic ointments are frequent allergic skin reactions of the surrounding tissue. These inflammatory reactions, which are caused by application, unsettle many patients, so that the patient often discontinues therapy early.
The chances of cure of cytostatic therapy using local ointments are strongly dependent on the growth behaviour and size of the basal cell carcinoma. Superficial basaliomas generally show a relatively high response to therapy. Imiquimod shows a chance of cure of about 80% for superficial basal cell carcinomas.
It has an immunostabilising effect and thus promotes the body’s own immune reaction against the tumour tissue. In practice, Imiquimod is commonly known under the trade name Aldara®. Besides basal cell carcinoma therapy, it is also used for the treatment of warts.
Unfortunately, none of the treatment options can safely protect the patient from the recurrence of the tumor, such a recurrence occurs in about 5 to 10% of patients. It is therefore particularly important that patients regularly present themselves to their dermatologist for follow-up checks after treatment, so that a recurrence can be detected and removed at an early stage in a given case.
