Clinical and laboratorv studies
`
`Topical photodynamic therapy with endogenous
`porphyrins after application of 5-aminolevulinic acid
`
`An alternative treatment modality for solar keratoses, superficial
`squamous cell carcinomas, and basal cell carcinomas?
`
`Peter Wolf, MD, Edgar Rieger, MD, and Helmut Ked, MD Graz, Austria
`
`Background: Topical photodynamic therapy with endogenous porphyrins consists of irradi(cid:173)
`ation of a tumor with visible light after the application of exogenous 5-aminolevulinic acid.
`Objective: To assess the effectiveness of this modality, patients with precancerous conditions
`and various skin cancers were treated.
`Methods: Thirteen patients with 70 skin lesions were enrolled. Standard treatment involved
`the topical application of 20% 5-aminolevulinic acid in an oil-in-water emulsion. The emul(cid:173)
`sion was applied under an occlusive dressing for 4 to 8 hours before exposure to photoacti(cid:173)
`vating light.
`Results: We observed a complete response after a single treatment for all 9 solar keratoses,
`5 of 6 early invasive squamous cell carcinomas, and 36 of 37 superficial basal cell carcino(cid:173)
`mas. Only 1 of 10 noduloulcerative basal cell carcinomas completely resolved. Eight cutane(cid:173)
`ous metastases of malignant melanoma were therapeutic failures.
`Conclusion: Topical photodynamic therapy with endogenous porphyrins is effective for su(cid:173)
`perficial epithelial skin tumors.
`(J AM ACAD DERMATOL 1993;28:17-21.)
`
`Photodynamic therapy (PDT), also known as
`photochemotherapy or photoradiation therapy, is
`effective for many forms of malignant
`tumors,
`including skin cancers. 1-6 Photoactivation of photo(cid:173)
`sensitizing porphyrins, which selectively accumulate
`in malignant cells, leads to the release of cytotoxic
`substances and causes tumor destruction with min(cid:173)
`imal damage to surrounding normal tissue. I-3 Un(cid:173)
`fortunately, when given systemically in PDT, the
`porphyrin compounds, hematoporphyrin derivative
`(HPD), or a mixture of its active components, com(cid:173)
`mercially known as Photofrin II, lead to generalized
`skin photosensitivity for at least 4 weeks.3,4, 7 The
`risk of serious accidental phototoxic reactions is the
`main reason that PDT by intravenous injection of
`porphyrins is not used much more widely.
`Recently, Kennedy et a1.8 described a novel
`method oftopical PDT and showed favorable results
`in the treatment of selected superficial nonmela-
`
`From the Department of Dermatology, University of Graz.
`Accepted for publication May 20, 1992.
`Reprint requests: Helmut Kerl, MD, Department of Dermatology,
`University of Graz, Auenbruggerplatz 8, A-8036 Graz, Austria.
`16/1/39537
`0190-9622/93/$1.00 + .10
`
`noma skin cancers. 5-Aminolevulinic acid (5·ALA)
`was used, which is a precursor of endogenous
`porphyrins in the biosynthetic pathway for heme.9
`Topically applied to skin cancers, 5-ALA in aqueous
`solution passes readily through abnormal keratin
`and is metabolized by the tumor cells to photosen(cid:173)
`sitizing concentrations of porphyrins.8 The 5-ALA(cid:173)
`induced photosensitivity is restricted to the abnor(cid:173)
`mal epidermis. Subsequent exposure to photoacti(cid:173)
`vating light selectively destroys skin cancers.
`We describe our evaluation of the effectiveness of
`PDT after topical application of 5-ALA to epithelial
`precancerous lesions and various skin cancers.
`
`PATIENTS
`Thirteen patients (3 women and 10 men) between 39
`and 89 years ofage (average 66 years) participated in this
`study after giving signed informed consent. Patients with
`multiple skin lesions were preferentially enrolled. There
`were 70 lesions including 37 superficial basal cell carci(cid:173)
`nomas in 4 patients, 34 lesions on the trunk and 3 on the
`face; 10 noduloulcerative basal cell carcinomas in 5
`patients, 8 lesions on the face and 2 on the trunk; 9 solar
`keratoses in 3 patients, all on the face or scalp; 6 early in(cid:173)
`vasive squamous cell carcinomas (superficial squamous
`17
`
`

`

`18 Wolf et a1.
`
`cell carcinomas with focal invasion of the papillary der(cid:173)
`mis) in 3 patients, 3 on the face of 1patient, 20n the trunk
`of a patient with Bowen's disease, 1 on the back of the
`hand of a patient with xeroderma pigmentosum (XP); 8
`cutaneous metastases in 1 patient with advanced malig(cid:173)
`nant melanoma, 5 melanotic and 3 amelanotic lesions, all
`on the left leg.
`The greatest diameter of the lesions ranged from 0.5 to
`3.0 em for superficial basal cell carcinomas, from 0.5 to
`5.0 em for noduloulcerative basal cell carcinomas, from
`1 to 2 em for solar keratoses, from 1 to 6 em for early in(cid:173)
`vasive squamous cell carcinomas, and from 0.1 to 1 em for
`cutaneous metastases of malignant melanoma.
`Biopsies were always performed on single lesions before
`the treatment but, if the patient had more than two, bi(cid:173)
`opsy was done on only a representative lesion.
`
`MATERIAL AND METHODS
`Therapeutic light source
`
`A Leitz Pradovit slide projector (Leitz, Wetzlar, Ger(cid:173)
`many) equipped with a Philips 250 W lamp (24 Y, Phil(cid:173)
`ips, Germany) provided the source of irradiation. The to(cid:173)
`tal irradiance (i.e., full emitted spectrum before filtration)
`at 10 cm and 30 em from the lens as measured by a cal(cid:173)
`ibrated photodiode BPW 34 was 100 and 50 mWjcm2,
`respectively. Certain irradiations were performed with a
`Schott RG 570 long-wave-pass red color glass filter to
`eliminate wavelengths less than 570 nm.
`
`Procedure
`Standard treatment involved the topical application of
`20% 5-ALA (Fluka Chemie AG, Buchs, Switzerland)
`dissolved in Doritin (Chemofux, Vienna, Austria), a pro(cid:173)
`prietary oil-in-water emulsion. The emulsion was applied
`under occlusive dressing to the tumors and approximately
`1em of adjacent skin to allow penetration of 5-ALA into
`the tissue and synthesis of endogenous porphyrins. The
`presence of endogenous porphyrins in the tumors was es(cid:173)
`timated by the visual evaluation of the characteristic red
`fluorescence of porphyrins under Wood's light in a dark(cid:173)
`ened room. Fluorescence of the tumors could be observed
`as early as 1 hour after application of 5-ALA, but the in(cid:173)
`tensity of the fluorescence was maximal at 4 to 6 hours,
`and then gradually decreased. Most tumors were exposed
`to photoactivating light 4 hours after application of 5(cid:173)
`ALA. The remainder were irradiated at 6 or 8 hours af(cid:173)
`ter application. Exposure times for solar keratoses and
`superficial basal cell carcinomas were either 5 minutes at
`100 mWj crn2 or its equivalent, 10 minutes at 50 mW/
`cm2, to unfiltered light (dosage 30 joules/cm2) or 10 or
`20 minutes, respectively, to red light (produced by filtra(cid:173)
`tion through RG 570). For two solar keratoses a dose as
`high as 100 joules/cm2 of unilltered light was given.
`Noduloulcerative basal cell carcinomas and squamous
`
`Journal of the
`American Academy of
`Dermatology
`
`cell carcinomas and metastases of malignant melanoma
`were exposed either 15 minutes at 100 mWjcm2 to un(cid:173)
`filtered light (dosage 90 joules/cm2) or 30 minutes to red
`light at 100 mW/cm2 (before filtration).
`Photographs were taken of all lesions before and after
`treatment. Tumor response was evaluated at 4 and/or 8
`weeks after treatment. Complete tumor response was de(cid:173)
`fined as absence of clinically evident tumor at the site of
`treatment. In cases in which the clinical assessment was
`uncertain, punch biopsies were performed. A partial tu(cid:173)
`mor response was defined as marked reduction in tumor
`size as determined by clinical evaluation.
`
`SELECTED CASE REPORTS
`Case 1 (see also Wolf and Kerl lO). A 47-year-old
`woman with XP had a hyperkeratotic plaque of 1.5 em
`in diameter on the dorsum of her left hand (Fig. 1, A). A
`biopsy specimen indicated superficial squamous cell car(cid:173)
`cinoma. The lesion was exposed 30 minutes to red light
`at 100 mWjcm2 4 hours after application of 5-ALA.
`Peak erythema and edema of the exposed area were ab(cid:173)
`normally delayed (72 hours, normal 8 to 24 hours).
`Erythema persisted for more than 2 weeks. The reaction
`on the adjacent skin was unusually strong with blistering.
`Four weeks later there was no sign of residual tumor.
`Erythema ofthe adjacent skin gradually resolved, leaving
`residual hyperpigmentation. There was no clinical evi(cid:173)
`dence of tumor recurrence 6 months later (Fig. 1, B).
`Case 2. A 59-year-old man, occupationally exposed to
`arsenic, had 32 superficial basal cell carcinomas on the
`trunk. In addition, he had a 1 em ulcerative basal cell
`carcinoma on the right cheek. Biopsies were performed on
`two representative lesions on the lower back, two on the
`chest, and the lesion on the right cheek before therapy
`(Fig. 2, A). All tumors were exposed to 30 joulesJcm2 of
`unfiltered light 6 hours after application of 5-ALA. Im(cid:173)
`mediately after exposure, the lesions became erythema(cid:173)
`tous and edematous. Within 2 days the lesions developed
`a thin crust. Adjacent normal skin showed only moderate
`erythema. When the patient was reexamined 4 weeks
`later, there were only slight residual erythema or hypo(cid:173)
`pigmented spots but no evidence of tumor in the treated
`areas. Three biopsies were performed on the back at the
`site of treated tumors. Histologic examination revealed
`fibrosis with an inflammatory cell
`infiltrate and no
`evidence of residual basal cell carcinoma (Fig. 2, B). Af(cid:173)
`ter 8 weeks complete healing of all lesions with good cos(cid:173)
`metic results had occurred.
`
`RESULTS
`Clinical response
`The treatment was well tolerated by all patients
`without local anesthetics. Mild to strong stinging or
`burning was always said to occur at the site of pho-
`
`

`

`Volume 28
`Number 1
`January 1993
`
`Topical photodynamic therapy 19
`
`Fig. 1. Case 1. A, Superficial squamous cell carcinoma
`on back of left hand of patient with xeroderma pigmen(cid:173)
`tosum. B, Six months after therapy.
`
`Fig. 2. Case 2. A, Photomicrograph of superficial basal
`cell carcinoma on back before therapy. B, Complete re(cid:173)
`gression of tumor 4 weeks after therapy.
`
`toirradiated areas during but not after exposure to
`photoactivating light. Pain was diminished when
`tumors were treated with r~d light. The treated le(cid:173)
`sions normally became erythematous, edematous or
`vesiculated during or immediately after therapy and
`later crusted with healing in 2 to 4 weeks. In general,
`the exposed areas of adjacent skin showed only a
`mild reaction to the treatment. However, patients
`with extensive sun-damaged skin on the face and the
`patient with XP had an unusually strong reaction in
`adjacent skin. Only limited areas were treated in
`these patients at one time, to minimize the skin re(cid:173)
`action.
`The response of the tumors to the topical PDT
`after application of 5-ALA is summarized in Table
`I. When examined 4 to 8 weeks after a single treat(cid:173)
`ment a complete response was observed for all solar
`keratoses, 5 of 6 early invasive squamous cell carci(cid:173)
`nomas, 36 of 37 superficial basal cell carcinomas,
`but only 1 of 10 noduloulcerative basal cell carcino(cid:173)
`mas. Partial tumor response was observed for all
`
`other nonmelanoma skin cancers. There was no ob(cid:173)
`servable difference in tumor response with 100
`illW / cm2 irradiance for 5 or 10 minutes or 50
`illW / cm2 for 10 or 20 minutes. In some cases of
`partial tumor response after a single PDT weekly
`repeated treatments were performed up to 3 times.
`However, only in one case (superficial basal cell
`carcinoma on the abdomen) was a partial tumor re(cid:173)
`sponse followed by complete tumor eradication.
`In amelanotic cutaneous metastases of malignant
`melanoma only superficial tumor necrosis was ob(cid:173)
`served in posttreatment biopsy specimens; in melan(cid:173)
`otic metastases the treatment was ineffective (both
`types were exposed to the same dose of red light).
`The nonresponding tumors were excised or treated
`with radiotherapy.
`
`Follow-up
`The longest available follow-up is with the first
`two patients who entered the study. They have
`reached 12 months of follow-up; the median fol-
`
`

`

`20 Wolf et al.
`
`Table I. Tumor response to topical photodynamic
`therapy with unfiltered visible light (full
`spectrum) and red light
`
`TuDHlf type
`
`Superficial BCC
`Noduloulcerative BCC
`Solar keratosis
`Superficial SCC
`Metastases of MM
`
`Unfiltered
`light
`
`32 (32)*
`I (5)
`9 (9)
`4 (5)
`
`Red
`light
`
`4 (5)
`0(5)
`
`1 (1)
`0(8)
`
`Bee, Basalcell carcinoma; MM, malignantmelanoma;See, squamous
`cell carcinoma.
`"Numbers indicate complete tumor responses; numbers in parentheses
`indicate total of treated tumors.
`
`low-up in all patients is 7 months (range 3 to 12).
`There was one recurrent superficial basal cell carci(cid:173)
`noma; no recurrence was observed in the other
`tumors.
`
`DISCUSSION
`This study suggests that superficial epithelial car(cid:173)
`cinomas of the skin are highly sensitive to PDT af(cid:173)
`ter topical application of 5-ALA. A complete re(cid:173)
`sponse was observed for all treated solar keratoses,
`5 of 6 early invasive squamous cell carcinomas, and
`36 of 37 superficial basal cell carcinomas. Neither
`generalized photosensitivity nor other severe adverse
`reactions were noted and the patients' acceptance of
`the treatment modality was good. There was only
`one recurrent tumor (superficial basal cell carcino(cid:173)
`ma).
`Noduloulcerative basal cell carcinomas did not
`respond well to the therapy. Only 1 of 10 tumors
`completely resolved. The results of our clinical trial
`are in agreement with the study of Kennedy et al. 8
`They also observed complete response for nearly all
`treated superficial lesions, including solar keratoses,
`selected superficial basal cell carcinomas, and either
`in situ or early invasive squamous cell carcinomas,
`but only partial response for most noduloulcerative
`basal cell and thick squamous cell carcinomas. The
`ineffectiveness of the treatment in noduloulcerative
`basal cell carcinomas and cutaneous metastases of
`malignant melanoma may be because these lesions
`were partly or completely covered by normal epi(cid:173)
`dermis that did not allow penetration of 5-ALA and
`subsequent production of endogenous porphyrins. In
`melanotic metastases, pigment within the lesions
`may also have prevented adequate light penetra(cid:173)
`tion.11-13
`
`Journal of the
`American Academy of
`Dermatology
`
`In the biosynthetic pathway for heme, 5-ALA is
`a precursor of photoactivable porphyrins, including
`uroporphyrins, coproporphyrins, and protoporphy(cid:173)
`rins.9, 14 However, protoporphyrin IX CPp IX) has
`been shown to be the main active photosensitizer
`after treatment with exogenous 5-ALA.8, 15-17 Red
`fluorescence and phototoxic damage is characteris(cid:173)
`tic for tissues accumulating 5-ALA-induced Pp IX
`when exposed to appropriate wavelengths of photo(cid:173)
`activating light.8, 14, 15, 17
`PDT normally includes the intravenous adminis(cid:173)
`tration of a photosensitizer and the subsequent ex(cid:173)
`posure of tumors to appropriate wavelengths of
`light.1-6 Unfortunately, the photosensitizers in com(cid:173)
`mon use, HPD or Photofrin II, persist in the skin for
`several weeks to several months after injection,
`which results in generalized photosensitivity. 1, 3, 4, 7
`In contrast, the skin photosensitivity caused by top(cid:173)
`ical application of 5-ALA is restricted to the tumor
`and vanishes within 24 hours after treatment. 15
`Most clinical applications of PDT have used red
`light (630 nm) to treat tumors because of the in(cid:173)
`creased ability of longer wavelengths to penetrate
`tissues compared with shorter wavelengths of visible
`light, that is, the optical penetration depth is about
`8 to 10 mm at 630 nm compared with 1 to 2 mm at
`400 to 500 nm. I-6 However, 5-ALA-induced pho(cid:173)
`tosensitivity has a porphyrin-like spectrum with
`maximum excitation at 410 nm (Soret band) and
`three smaller peaks in the visible range (at 510,545,
`and 580 nm).16 Because for thin skin lesions the
`depth of penetration of shorter wavelengths of visi(cid:173)
`ble light was effective,3 most superficial skin tumors
`in our study were treated by full-spectrum visible
`light (400 to 760 nm) rather than by red light with
`wavelengths longer than 570 nm (produced through
`the Schott RG 570 filter). In the treatment of
`superficial basal cell carcinomas, full-spectrum vis(cid:173)
`ible light was effective in all 32 lesions, and red light
`in 4 of 5 treated lesions (see Table I); however,
`shorter exposure times could be given with full(cid:173)
`spectrum visible light. Both were ineffective in the
`treatment of nodulou1cerative basal cell carcinomas.
`Phototoxic damage in PDT is believed to be me(cid:173)
`diated via cytotoxic substances, mainly excited sin(cid:173)
`glet oxygen. 2, 3 The main targets of PDT are cell
`membranes.2,3 However, the mechanism of tissue
`destruction in topical PDT with endogenous por(cid:173)
`phyrins may be different from the mechanism in
`PDT after the intravenous injection of HPD or
`Photofrin II. In addition to direct tumor cell cyto-
`
`

`

`Volume 28
`Number 1
`January 1993
`
`toxicity and inflammatory response, vascular effects
`including endothelial cell damage, blood cell aggre(cid:173)
`gation, reduction and/or cessation ofblood flow, and
`hemorrhage are believed to contribute to the effec(cid:173)
`tiveness of the latter treatment. 2 In 5-ALA-induced
`PDT, however, we observed in posttreatment biopsy
`specimens (24 and 48 hours after treatment) epi(cid:173)
`dermal necrosis and acute dermal inflammation and
`edema, but vascular damage was not noted.
`
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`