common skin tumors like basal- and squamous - cell carcinoma present a serious problem in modern medicine . it is confirmed that a variety of biological consequences such as increases in skin cancer or cataract may result from the increased uv exposure due to ozone depletion and atmospheric ozone hole . uv radiation may also be produced by artificial sources , for example by quartz lamps frequently used in tanning parlors . carcinogenesis of skin tumors is very often associated with chronic exposure to uv radiation , and frequent sunburns in childhood may lead to skin cancer in later age . uv - a and uv - b radiation are responsible for photoaging , an accelerated aging of skin . photoaging is characterized by loss of skin elasticity , roughness , deep wrinkles and pigmentations . one of the most common malignant skin tumors is basal cell carcinoma ( bcc ) . bcc most commonly occurs in middle - aged and elderly persons ( 5070 years old ) , mainly in caucasians who were exposed to sunlight radiation . one of the most important biological features is low degree of malignancy and low rate of local growth ; however , over time it may contribute to local destruction of surrounding tissues , resulting in deep ulcerations . bcc is mainly located on the skin exposed to uv light , especially on the head , neck and limbs . these lesions more often recur after incomplete surgical treatment , but generally bcc has a good prognosis . surgery , cryosurgery , electrodissection and co2 laser therapy are typical treatment methods [ 48 ] . photodynamic therapy ( pdt ) comprises 2 main agents : light and a specific chemical compound called a photosensitizer . photosensitizers have a high affinity to malignant cells and after absorption of energy from light they shift into an excited state . a photosensitizer in the excited state causes photochemical reactions that lead to necrosis and apoptosis in pathological tissues . for many years pdt was used to detect and to treat different lesions located in the skin and mucosa [ 913 ] . photosensitizers show a high affinity to rapidly proliferating cells such as atypical and cancer cells . in the present study we used levulan as a natural precursor of porphyrins , which is metabolized in vivo into protoporphyrin ix ( pp ix ) . since 1990 , aminolevulinic acid ( ala ) as a precursor of protoporphyrin ix was frequently used in local pdt . at present , ala is successfully applied in treatment of basal cell carcinoma , squamous cell carcinoma ( scc ) , solar keratosis , and urothelial cancer of the urinary bladder [ 1416 ] . tau - like receptors of dendritic cells and macrophages under the influence of imiquimod respond with secretion of cytokines and chemokines such as interferon ( inf- , inf- ) , tnf- , and interleukins ( il-1 , il6 , and il-8 ) . moreover , imiquimod stimulates langerhans cells to present antigens of transformed cells to lymphocytes t in regional lymph nodes . using natural mechanisms of the immune system , aldara is approved for treating condyloma of the genital organs , solar keratosis and superficial form of basal cell carcinoma ( bcc ) . uniquely , imiquimod abolishes immunosuppressive phenomena generated by exogenous factors that allow precancerous and cancerous lesions to propagate . since the uses of imiquimod and pdt separately are well documented , we decided to combine both methods . the aim of our study was to evaluate the effectiveness of local photodynamic therapy supplemented with topical application of aldara in treatment of basal cell carcinoma . thirty - four patients ages 50 to 68 years were enrolled into the trial and underwent pdt treatment . all these cases were previously treated using routine methods ( cryosurgery , laser therapy or surgical excision ) without satisfactory results . lesions were located on the skin of the face ( nose , nasolabial sulcus , cheek , suborbital region ) with common bcc features : small , pearl - like nodules , with medium diameter of 0.5 cm , sometimes with erosions on the surface , with bleeding upon rubbing . some lesions were located in the scar left after previous surgical treatment . a double - blind , placebo - controlled group was used . patients were divided into 2 random groups : 10 patients were subjected to local pdt and placebo ( eucerin as vehicle cream ) , and 24 patients were subjected to pdt and imiquimod . lesions after levulan application were protected from direct light exposure using an occlusion dressing which was removed before irradiation . total time of irradiation was 30 minutes ( 215 minutes ) , wavelength was 63520 nm and total energy dose was 100 j / cm . imiquimod ( aldara ) was topically applied in 24 patients 72 hours after irradiation and then applied again twice a week before sleep for 5 weeks . ten patients received placebo ( vehicle only ) , which was applied in the same manner as imiquimod . photodynamic diagnosis ( pdd ) was used to detect and visualize suspicious sites ( including cancer lesions ) that were not seen during the routine examination using white light . it comprised local application of precursor , which , after an uptake by cancer cells and irradiation at 405 nm wavelength , emitted red fluorescence . lesions after application of precursor were covered using occlusion dressing and after 2 hours irradiated for 34 minutes . , cancer sites emitted red fluorescence and the tumor borders were found to spread beyond the area seen in the white light . the size of lesions was estimated during routine examination in white light and during the pdd session . the result of white light examination is shown in figure 1 , and the effect of the pdd session is shown in figure 2 . the size of lesion during the pdd session was found to be larger and more irregular than during the white light examination . most patients during and after pdt complained of erythema and edema that persisted for several days . patients complained of increasing symptoms such as burning sensation , itching , painful and large edema , and strong irritation of skin , with erosions , after each application of imiquimod . our study reveals that combination of pdt and aldara may increase adverse effects of pdt , such as burning and edema . due to previously mentioned reasons , 4 patients had to apply imiquimod only once a week . these adverse effects disappeared after completion of therapy with imiquimod , and treated sites scabbed . local adverse effects typical for imiquimod in the group of patients treated with pdt and placebo were not observed . results of treatment are shown in table 1 . in the group of patients who were treated using pdt and placebo , 6 patients ( 60% ) bcc located on the nose increased after 6 months in 2 patients and recurrent tumor in the scar left after previous surgical excision was observed in 1 patient ( table 1 ) . in the group of patients treated with pdt and imiquimod , 18 lesions ( 75% ) totally disappeared , and 6 lesions significantly diminished . in 1 patient small foci of previously excised bcc developed again in the scar after 10 months from the first control examination . there is ample evidence supporting the dangers of uv radiation , especially within the context of skin cancer . the popularity of sunbathing and tanning parlors , and chronic sun exposure associated with professional activity results in an increase in a high morbidity rate of skin cancer in middle - aged people . localization of lesions in the exposed parts of the body , especially on the face , is an important esthetic problem . patients who are still professionally active expect to receive dermatology treatment that gives the best cosmetic effects . the main method of skin cancer therapy for decades was surgical excision , very often associated with skin graft transplantation . c02 laser and cryosurgery were added to the arsenal of methods used against skin cancer in recent years , but each of these methods leaves scarring . unfortunately , skin cancers are very often irregular in shape and invade beyond the tumor borders that are clearly visible in routine examination . this irregular shape and difficulties in complete removal of a lesion using standard methods may result in frequent recurrences . surgical excision usually requires a margin 3 to 10 mm wide , but using dermoscopy - guided surgery this may be reduced to 2 mm . . moreover , bccs located on the nose and around the orbit are usually more aggressive than tumors located in other sites . therefore , it is very important to find an effective therapy that also yields good cosmetic effects . pdt , as a local treatment method , was used for many years with success in cases of skin precancerous lesions and skin cancers . levulan - based pdt ( levulan - pdt ) enables destruction of pathological lesions which are too small to be visible on routine examination . pdt is also responsible for destruction of vessels and induction of immunological response against cancer cells . one of many advantages of pdt is the lack of significant adverse effects ( besides burning and edema during pdt and within the next 24 hours ) . other advantages are the possibility of repeating and healing without scarring and ease of use . a clear disadvantage of levulan - pdt is weak penetration of levulan into skin . the other indication for application of levulan - pdt is a superficial lesion on the skin , such as solar keratosis . our study showed that pdd enables estimation of the true shape of a lesion and allows the microfoci of the tumor to be found . aldara is often used in dermatological lesions , such as warts , condyloma of reproductive organs and the superficial form of bcc or scc [ 2124 ] . due to its effects on immunological memory , imiquimod may protect patients against recurrences of lesions , and it is used as an additional agent in cases of incomplete surgical excision . other studies indicated that pdt in treatment of superficial bcc is effective in 7697% of cases [ 2830 ] . pdt is generally more effective in treating superficial bcc than nodular bcc . in cases of the nodular form of bcc , co2 laser surgery and pdt appear to play a synergistic role in the treatment of that lesion . in this study the bcc in that localization shows more aggressive growth with recurrences , therefore our previous efforts in bcc eradication resulted in only 60% complete responses . this combined therapy enables induction of local natural immunological mechanisms . the 75% success rate obtained in the group treated with pdt and moreover , the synergistic effect of aldara on immunological response cells seems to decrease the number of bcc recurrences ( 1 recurrence after 10 months and 1 after 15 months ; see table 1 ) . the combination of local pdt and imiquimod results in higher efficiency of bcc treatment in cases of previous unsuccessful treatment such as surgery , cryosurgery and laser therapy . there is one more important benefit from combined therapy  the high level of acceptance by treated patients . lack of adverse effects after pdt and very good cosmetic outcomes positively influence the psychological condition of a patient . patients confirmed their readiness to undergo repeated therapy in case of any recurrence , but they refused other treatment methods , such as routine surgical excision . at present , dermatological patients are younger than in the past and physical appearance is very important for such young people . in our opinion the combination of pdt with local immunomodulator seems to be an effective method of treatment in such group of patients . although this is a preliminary report , the presented modification of pdt seems to be reasonable and promising in treating basal - cell carcinoma .