Treatment of keratoacanthomas with oral 13-cis-retinoic acid

Oral Isotretinoin and Its Uses in Dermatology: A Review

In 1982, the Food and Drug Administration (FDA) of the United States of America approved isotretinoin (13-cis-retinoic acid), a retinoid derivative of vitamin A, to treat severe recalcitrant acne vulgaris. Apart from its prescribed use for severe acne, evidence suggests that isotretinoin is commonly used off-label to treat mild-to-moderate acne, inflammatory skin conditions, genodermatoses, skin cancer, and other skin disorders. This is due to its anti-inflammatory, immunomodulatory, and antineoplastic properties. Some "off-label" use is successful, while others are ineffective. Therefore, this information is essential to clinicians for deciding on the appropriate use of isotretinoin. In this article, we aim to review the most updated evidence-based data about the use of oral isotretinoin in dermatology.

Oral isotretinoin for the treatment of dermatologic conditions other than acne: a systematic review and discussion of future directions

While isotretinoin has been the gold-standard of therapy for severe acne since its approval in 1982, its anti-inflammatory properties makes it a potentially applicable and versatile therapy for a wide variety of dermatologic conditions yet to be explored. This systematic review comprehensively recounts the success of oral isotretinoin in non-acne cutaneous diseases and provide insight into future directions of isotretinoin utility. A systematic literature review was performed using PubMed. Search terms included "isotretinoin" OR "accutane" AND "skin" OR "dermatology" OR "hair" OR "nails" OR "rosacea" OR "psoriasis" OR "pityriasis rubra pilaris" OR "condyloma acuminata" OR "granuloma annulare" OR "darier's disease" OR "non-melanoma skin cancer" OR "frontal fibrosing alopecia" OR "cutaneous lupus erythematosus" OR "hidradenitis suppurativa" OR "photodamaged skin" OR "skin aging" OR "wart" OR "flat warts" OR "plane warts" OR "lichen planus" OR "dissecting cellulitis" OR "folliculitis decalvans" OR "sebaceous hyperplasia" OR "cutaneous t-cell lymphoma" OR "mycosis fungoides." A total of 169 studies discuss the use of oral isotretinoin for 16 non-acne dermatologic conditions, the most common being non-melanoma skin cancers (0.2-8.2 mg/kg/day), cutaneous T-cell lymphomas (0.5-2 mg/kg/day), and rosacea (0.22-1 mg/kg/day). Inflammatory conditions such as rosacea, granuloma annulare, and hidradenitis suppurativa benefit from lower oral isotretinoin dosage of 0.3-1 mg/kg/day, whereas, hyperkeratotic diseases such as psoriasis and pityriasis rubra pilaris, consistently respond better to higher dosages of up to 2-4 mg/kg/day for lesion clearance. Recurrence of disease following discontinuation of isotretinoin have been reported for rosacea, psoriasis, granuloma annulare, Darier's disease, dissecting cellulitis, and non-melanoma skin cancers. Disease exacerbation was reported in some patients with hidradenitis suppurativa. Off-label isotretinoin is an effective treatment choice for dermatological conditions beyond acne. Further prospective, randomized human trials are needed to clarify when and how to prescribe off-label isotretinoin for maximum efficacy and safety.

Consensus on the use of oral isotretinoin in dermatology - Brazilian Society of Dermatology

BACKGROUND

Isotretinoin is a synthetic retinoid, derived from vitamin A, with multiple mechanisms of action and highly effective in the treatment of acne, despite common adverse events, manageable and dose-dependent. Dose-independent teratogenicity is the most serious. Therefore, off-label prescriptions require strict criteria.

OBJECTIVE

To communicate the experience and recommendation of Brazilian dermatologists on oral use of the drug in dermatology.

METHODS

Eight experts from five universities were appointed by the Brazilian Society of Dermatology to develop a consensus on indications for this drug. Through the adapted DELPHI methodology, relevant elements were listed and an extensive analysis of the literature was carried out. The consensus was defined with the approval of at least 70% of the experts.

RESULTS

With 100% approval from the authors, there was no doubt about the efficacy of oral isotretinoin in the treatment of acne, including as an adjunct in the correction of scars. Common and manageable common adverse events are mucocutaneous in nature. Others, such as growth retardation, abnormal healing, depression, and inflammatory bowel disease have been thoroughly investigated, and there is no evidence of a causal association; they are rare, individual, and should not contraindicate the use of the drug. Regarding unapproved indications, it may represent an option in cases of refractory rosacea, severe seborrheic dermatitis, stabilization of field cancerization with advanced photoaging and, although incipient, frontal fibrosing alopecia. For keratinization disorders, acitretin performs better. In the opinion of the authors, indications for purely esthetic purposes or oil control are not recommended, particularly for women of childbearing age.

CONCLUSIONS

Approved and non-approved indications, efficacy and adverse effects of oral isotretinoin in dermatology were presented and critically evaluated.

Spontaneous tumour regression in keratoacanthomas is driven by Wnt/retinoic acid signalling cross-talk

A fundamental goal in cancer biology is to identify the cells and signalling pathways that are keys to induce tumour regression. Here we use a spontaneously self-regressing tumour, cutaneous keratoacanthoma (KAs), to identify physiological mechanisms that drive tumour regression. By using a mouse model system that recapitulates the behaviour of human KAs, we show that self-regressing tumours shift their balance to a differentiation programme during regression. Furthermore, we demonstrate that developmental programs utilized for skin hair follicle regeneration, such as Wnt, are hijacked to sustain tumour growth and that the retinoic acid (RA) signalling pathway promotes tumour regression by inhibiting Wnt signalling. Finally, we find that RA signalling can induce regression of malignant tumours that do not normally spontaneously regress, such as squamous cell carcinomas. These findings provide new insights into the physiological mechanisms of tumour regression and suggest therapeutic strategies to induce tumour regression.

Keratoacanthoma as a postoperative complication of skin cancer excision

BACKGROUND

Keratoacanthomas usually occur spontaneously as a single rapidly growing tumor on sun-exposed skin. Multiple keratoacanthomas are rarely seen. Keratoacanthomas may also develop after trauma, laser resurfacing, radiation therapy, and at the donor site after skin grafting.

OBJECTIVE

We report 6 cases of keratoacanthomas that developed in and around healing and healed surgical sites after treatment of skin cancer. These tumors developed 1 to 3 months after surgery and were sometimes multiple.

METHODS

We performed follow-up examinations of patients' wounds after the treatment of skin cancer. Histological examination of nodules developing in the margins of healing wound sites and in the scars of healed wound sites after Mohs micrographic surgery revealed keratoacanthomas.

RESULTS

The tumors presented as a rapidly growing nodule or nodules, with the typical morphology and pathology of keratoacanthoma. One patient developed multiple keratoacanthomas at surgical and nonsurgical sites. These nodules were treated by a combination of excision, curettage and electrodesiccation, and oral isotretinoin, 4 mg/d.

CONCLUSION

Keratoacanthoma must be considered in the differential diagnosis of a rapidly growing nodule within or around the surgical site after skin cancer surgery.

Ferguson Smith type multiple keratoacanthomas and a keratoacanthoma centrifugum marginatum in a woman from Japan

We report a case of multiple keratoacanthomas on the sun-exposed skin of a 37-year-old woman from Japan. She had experienced 4 similar episodes of evolution and involution of multiple keratoacanthomas during a period of 10 years since she was 27 years old. She was given the diagnosis of Ferguson Smith type keratoacanthoma. This is the seventh Japanese case of Ferguson Smith type keratoacanthoma described in detail in the literature. In addition, the patient was found to have an annular, coral reef-like eruption on the front of her neck, which was diagnosed as a keratoacanthoma centrifugum marginatum. A combination of different variants of keratoacanthoma in 1 patient is uncommon, and only 2 patients with the same combination of lesions, as that seen in our patient, have been reported. Our patient was treated by a relatively low dose (0.5 mg/kg body weight) of etretinate. Both variants of keratoacanthoma showed good response to the treatment. Effectiveness of etretinate for treating keratoacanthoma centrifugum marginatum has only been reported in a few cases. Our patient had no relapse during a period of 15 months after cessation of etretinate treatment.

Periocular keratoacanthoma: clinical features, pathology, and management

PURPOSE

To review the clinical features and results of surgical treatment of keratoacanthoma of the eyelids.

DESIGN

Retrospective, interventional case series.

PARTICIPANTS

Ten patients.

METHODS

Chart review of all eyelid keratoacanthomas treated between 1992 and 2001.

MAIN OUTCOME MEASURES

Adequate excision, recurrence rate, and complications.

RESULTS

Patient ages ranged from 27 to 78 years, with a mean age of 59 years. Six patients were male and four were female. The lesion was found on the lower lid in five patients, upper lid in two, medial canthus in two, and lateral canthus in one. The maximum diameter of the lesion varied from 2 to 25 mm, with a mean of 7.2 mm. All lesions were treated by surgical excision, with frozen-section control of margins in five cases. All lesions were excised completely with clear resection margins, and there were no cases of recurrence. The only complication was a minor wound infection in one patient. Mean follow-up was 34.5 months.

CONCLUSIONS

Because of the aggressive nature and uncertain relationship to squamous cell carcinoma, we recommend excision of periocular keratoacanthoma. Surgical excision of eyelid keratoacanthoma provides good results and a very low risk of recurrence. Frozen-section control of margins should be used in selected cases to ensure complete excision.

A case of multiple keratoacanthoma centrifugum marginatum: response to oral etretinate

The patient was a 48-year-old man who had a history of colonic polyps. About 18 months before, a dark reddish nodule had appeared on his right forearm. By peripheral growth, this lesion had formed a crateriform prominence with central healing. Similar symptoms multiplied and expanded, the largest being about the size of a child's head. Given both the clinical and histologic evidence, a diagnosis of keratoacanthoma centrifugum marginatum (KCM) was made. Oral etretinate was administered, and an involution of verrucous plaque began after 4 weeks. After 8 weeks, the lesions faded, leaving pigmentation in some areas. This is a rare disorder, only 30 such cases having been reported worldwide, and the present case was the third in which oral etretinate was found to be effective.

Intralesional corticosteroid treatment of multiple eruptive keratoacanthomas: case report and review of a controversial therapy

BACKGROUND

Use of intralesional corticosteroids in the management of keratoacanthomas has been reported in older literature. Yet this therapy is no longer a commonly considered treatment option.

OBJECTIVE

To report management of a therapeutically challenging patient with multiple eruptive keratoacanthomas with intralesional corticosteriod treatment to revive awareness of this treatment option.

METHODS

A 55-year-old female with frequent episodes of multiple eruptive keratoacanthomas was treated with intralesional corticosteroids and methotrexate.

RESULTS

Intralesional corticosteroids successfully treated eruptive keratoacanthomas with complete regression and minimal scarring within 2-4 weeks.

CONCLUSION

Despite its limitations, intralesional corticosteroids may have a role in the treatment of select keratoacanthomas.

Uses of vitamins A, C, and E and related compounds in dermatology: a review

Vitamins have been increasingly used as prophylactic and therapeutic agents in the management of skin disorders. The current literature is replete with studies that promote the potential benefits of these compounds and attempt to elucidate their mechanisms of action. We review the literature and discuss the roles, safety, and efficacy of vitamins A, C, and E and related compounds in cutaneous health and disease.

Effects of topical treatment with fenretinide (4-HPR) and plasma vitamin A levels in patients with actinic keratoses

Eighteen patients with facial actinic keratoses were treated with the retinoid fenretinide (4-HPR), applied topically twice-daily for 3 months. After 3 months of treatment, complete regression was observed in 56% and partial regression in 44% of cases. Eight patients relapsed within 3 months after drug discontinuation. Six months later, only two patients (11%) showed a treatment response (complete regression). Blood samples showed that 4-HPR was not absorbed and no local or distant adverse effects were observed. Baseline plasma retinol levels were lower than in healthy subjects, thus suggesting that reduced retinol levels might be involved in this pathology. These encouraging preliminary results suggest the need for further studies to evaluate the best dosage schedules and duration of 4-HPR topical application in actinic keratoses.

Epidermal differentiation enhances CRABP II expression in human skin

The cellular retinoic acid-binding proteins (CRABP I and II) are thought to mediate the effects of retinoic acid on target cells. We have used riboprobes complementary to CRABP I and II mRNAs to study the expression of these messages in normal and abnormal human skin. CRABP II was expressed predominantly in the suprabasal layers of the epidermis, with stronger expression in newborn than in sun-protected adult skin. Interestingly, the epidermis adjacent to or overlying squamous cell or basal cell carcinomas also showed strong expression, whereas the tumor cells were negative, with the exception of more differentiated cells surrounding the "keratin pearls" within squamous cell carcinomas. CRABP II mRNA was also found in the more differentiated cells of the hair follicles, in the outer root sheath. CRABP I message was undetectable in the epidermis or in the dermis of normal skin but was detected in the cells of the papillary dermis surrounding basal and squamous cell carcinomas. These data suggest that increased levels of CRABP II mRNA accompany keratinocyte differentiation in vivo.

Treatment of a recurrent keratoacanthoma with oral isotretinoin

BACKGROUND

Keratoacanthoma is a benign epithelial tumor that occurs on the sun-exposed skin of elderly people. Development of KAS on functionally and cosmetically important areas such as the face poses the therapeutic challenge to minimize functional and cosmetic damage. Oral isotretinoin (Accutane, Roche Laboratories) has been reported to be an effective treatment of multiple as well as solitary keratoacanthomas.

CASE REPORT

A 45-year-old man with a large keratoacanthoma on the nasal ala, recurrent after surgical excision, was treated with 1 mg/kg/day (80 mg/day) oral isotretinoin (Accutane). Cessation of tumor progression was evident within 1 week after initiation of therapy, and tumor regression was evident within 2 weeks. Tumor size diminished rapidly over the ensuing weeks and complete resolution at 12 weeks was confirmed by biopsy.

CONCLUSION

An initial trial of oral isotretinoin is an alternative to immediate surgical excision for the treatment of large keratoacanthomas in instances when tumor removal would cause considerable cosmetic deformity.

13-cis-retinoic acid and hepatic steatosis in rats

The effect of administration of 13-cis-retinoic acid (100 mg/kg diet) on lipid metabolism was examined in male rats fed either a 20% casein + 0.3% methionine diet, a 20% casein diet, a 10% casein + 0.3% methionine diet, or a 10% casein + 0.6% methionine diet for 10 days. Hepatic triglyceride concentrations of rats fed either 10% casein diet were 3-fold greater than animals receiving diets containing 20% casein. The addition of 13-cis-retinoic acid to the diet further increased the total hepatic lipid (43-56%) and triglyceride (approximately 2-fold) concentrations in rats fed the 10% casein diets. 13-cis-Retinoic acid supplementation did not alter the total liver lipid or triglyceride concentrations in rats fed either of the 20% casein diets. Thus, under specific dietary conditions, the administration of 13-cis-retinoic acid resulted in a marked accumulation of hepatic lipids which did not appear to be related to the total methionine content of the diet nor to the hepatic concentrations of S-adenosylmethionine and glutathione. In addition, all four groups of 13-cis-retinoic acid-fed rats exhibited elevations in the concentration of serum triglycerides, and 10-20% reductions in serum cholesterol concentrations.

Etretinate therapy of solar-related kerato acanthoma

Nineteen patients with a total of 22 keratoacanthomas were treated in this trial with 1 mgm/kg/day of etretinate for six weeks. The patients had predominantly solitary keratoacanthoma, all associated with severe solar damage. There was a provision for reduction of dose and also for extension of length of treatment time for lesions which had responded but had not completely disappeared at the end of six weeks. Sixteen of the nineteen patients cleared without recurrence. Two patients had therapy stopped because of side effects and in these, further treatment was required. These side effects were severe paronychia and elevation of serum lipids. Other side effects were almost exclusively muco-cutaneous. Keratoacanthomas on the head, neck and upper limbs had cleared completely at the end of six weeks therapy, with a variable degree of ridged scarring. Lesions on the lower legs almost invariably required treatment times which were longer than six weeks and could be up to twelve weeks. Etretinate therapy of solar related keratoacanthoma should be considered for large lesions, multiple lesions, lesions in areas which are difficult to treat, and lesions in patients unsuited for destructive therapy or surgery.

Retinoids and photodamage

Extensive well-controlled clinical studies performed over the past 5 years have demonstrated a consistent, dose-dependent, statistically significant improvement in the appearance of photodamaged skin after 3-6 months of daily treatment with topical 0.001-0.1% tretinoin cream. Clinical changes included decreases in surface roughness, irregular pigmentation, fine and coarse wrinkling, and sallowness. Actinic keratoses have also been reported to decrease in size and number. Blinded analysis of biopsies from more than 500 subjects showed that there was compaction of the stratum corneum, an increase in the number of granular layers, thickening of the epidermis and a decrease in epidermal melanin. There were no detectable histological changes in any dermal parameters. The specific cellular mechanisms by which retinoic acid (RA) exerts its beneficial effect on photodamaged skin are currently the subject of intensive investigation. It is well established that RA enters the nucleus where it binds to an RA receptor (RAR), and that the RA-RAR complex then binds to specific RA response elements in the DNA, modulating the expression of target genes. It is thus likely that RA improves at least some aspects of photoageing by modifying cellular differentiation programmes, as retinoids have been shown to do during embryogenesis, in malignantly transformed cells and in skin affected by certain dermatoses.

Retinoids in cancer prevention and therapy

Retinoids are a class of compounds structurally related to vitamin A. In preclinical studies, all-trans retinoic acid (tretinoin), 13-cis retinoic acid (isotretinoin) and the aromatic retinoids etretinate and acitretin have preventive and therapeutic effects on carcinogen-induced premalignant and malignant lesions. Clinically, chemoprevention with isotretinoin and etretinate has been tested with some degree of success in such indications as basal cell carcinomas, squamous cell carcinomas, superficial bladder tumors and second primary tumors in patients with squamous cell carcinoma of the head and neck. Limited therapeutic success has also been achieved with retinoid treatment of precancerous and cancerous conditions of the skin, oral cavity, larynx, lung, bladder and vulva. Dramatic therapeutic effects have been observed in the treatment of acute promyelocytic leukemia with tretinoin, which leads to very high rate of complete remission. Excellent results were recently reported in the treatment of squamous cell carcinomas of the skin and cervix with a combination of isotretinoin and recombinant interferon alfa-2a (rIFN alfa-2a, Roferon-A). The mechanism of action of retinoids is through modulation of cell proliferation and differentiation. Retinoids vary in their capacity to induce differentiation and to inhibit proliferation in a series of human transformed hematopoietic and epithelial cell lines. Some cytokines potentiate the retinoid-induced cell differentiation and act synergistically with retinoids to inhibit cell proliferation. The pattern of synergism is dependent upon the combination and tumor cell line tested. The discovery of nuclear retinoid receptors has contributed substantially to the understanding of the mechanism of action of retinoids at the molecular level. Further understanding of the molecular biology of retinoids is expected to contribute to a rational design of new retinoids in the future, which in turn may result in improvements in the prevention and therapy of cancer.

Biology of cutaneous squamous cell carcinoma

Nonmelanoma skin cancer is the leading cause of cancer in the United States. Cutaneous squamous cell carcinoma is second only to basal cell carcinoma in prevalence and its incidence is increasing. The biology of squamous cell carcinoma is reviewed under the broad areas of etiology, immunobiology, biochemistry, metastatic potential, and therapy, with emphasis on prevention, diagnosis, and management.

Treatment of keratoacanthomas with intralesional methotrexate

Multiple modalities exist for the treatment of keratoacanthoma. Excisional surgery is currently the treatment of choice for the majority of keratoacanthomas. This can result in functional and cosmetic defects when large or strategically located lesions are treated. An effective nonsurgical treatment would be desirable in such cases. Intralesional therapy, particularly with 5-fluorouracil, has been shown to be effective in the treatment of keratoacanthomas. Systemic methotrexate has been tried, with variable success. We report an open, noncontrolled study of nine consecutive patients with unusually large or strategically located solitary keratoacanthomas treated successfully with intralesional methotrexate. All lesions responded promptly, with complete resolution after a mean of 3.0 weeks and a mean of 1.7 injections. No side effects occurred, and scarring was minimal. We concluded that intralesional methotrexate is a simple and effective modality for the treatment of select keratoacanthomas and may offer greater efficacy, a more rapid response, decreased pain, and lower cost compared with intralesional 5-fluorouracil.

Argon laser treatment of small keratoacanthomas in difficult locations

Seventeen patients (mean age, 64.7 years) with solitary keratoacanthomas (KA) located on the face and auricles were treated with the argon laser. All lesions were less than 10 mm in diameter and had been present for 2-10 weeks (mean, 3.8 weeks). The diagnosis was made clinically and was confirmed by histology. The lesions were treated with the argon laser using the continuous exposure technique with a power setting of 4.5 watts (W) and a beam diameter of 1 mm. Complete re-epithelialization occurred within 14-21 days. Excellent treatment results were achieved in 65% of the patients. Thirty-five percent healed with mild scarring. During a follow-up period of 2 years no recurrences were noted. The use of the argon laser for removal of small KAs in difficult locations, which would often require invasive surgery, appears to be an effective additional treatment modality.

Multiple keratoacanthomas after megavoltage radiation therapy

Multiple keratoacanthomas developed on the face of a woman after radiation therapy to the nasal sinuses. Treatment with isotretinoin appeared to shorten her recovery period.

Multiple keratoacanthomas treated with oral retinoids

Multiple eruptive keratoacanthoma of Witten and Zak is a rare disorder characterized by numerous small, eruptive tumors and larger, more typical keratoacanthomas. Affected patients have features of Grzybowski-type keratoacanthomas and Ferguson Smith type. Two patients with multiple keratoacanthomas were treated with oral retinoids. Both patients had hundreds of follicular papules on the trunk and extremities. Less common lesions included nodules with central horn-filled craters more characteristic of classic keratoacanthomas. Retinoid therapy resulted in regression of the larger, more typical keratoacanthomas in both patients. The small follicular keratoacanthomas remained unaffected. Thus oral retinoids are only partially beneficial for the treatment of the Grzybowski type or the Witten and Zak type of multiple eruptive keratoacanthomas.

Keratoacanthoma necessitating metacarpal amputation

Keratoacanthoma is usually considered a benign self-limiting lesion. First described in 1888 by Hutchinson, it most commonly involves the face and hands. It is usually controlled by complete soft tissue excision. A variant, subungual keratoacanthoma, affects bone by pressure erosion of the distal phalangeal tip. We report a case of keratoacanthoma clinically involving a metacarpal and phalanges with a radiologic and physical appearance at variance with previous reports. After multiple recurrences following erosion and cryosurgery, as well as attempted digit salvage with Mohs' surgery, ray amputation was required. The world literature pertaining to keratoacanthoma is reviewed and discussed.

The future of topical therapy for cutaneous aging

The elements of cutaneous aging have been well described and include changes of intrinsic or chronologic aging as well as changes of extrinsic or environmental aging. We also include male pattern alopecia in this category. The current dominance of tretinoin in cutaneous aging therapy is likely to be challenged by newer classes of retinoids, by topical antiandrogens, and by alternative treatments for proliferative lesions.

Taste and olfactory disturbances after treatment for acne with isotretinoin, a 13-cis-isomer of retinoic acid

We report an olfactory disturbance after acne treatment with isotretinoin. A disturbance in taste was also reported by the patient. Examination of the nose showed no pathological findings. A CT scan was done to exclude a tumor or a lesion at the lamina cribrosa. Taste and smell examinations were performed and verified the lost qualities.

Current surgical management of skin cancer in dermatology

Skin cancer has become a major public health problem in the United States and worldwide. Epidemiologic studies confirm a continued increase in the number of basal cell carcinomas, squamous cell carcinomas, and malignant melanomas. Dermatologists, the primary caretakers of the skin, manage skin cancer with various modalities that have been time tested and found reliable, including excision, electrosurgery, cryosurgery, and Mohs micrographic surgery. Extirpative procedures for basal cell carcinoma and squamous cell carcinoma are considered with attention to cure, restoration of function, and cosmesis--in that order. The dermatologic management of melanoma is critical because early diagnosis and treatment of thin lesions has been the only effective improvement in melanoma management in the last several decades. Wide excision, with a 1-3-cm margin, of thin stage I melanoma has moved surgical management from the operating room to the outpatient surgical setting. Management of these increasingly common problems, as reviewed here, is principally responsible for the growth of surgical practice as a subspecialty of dermatology.

Effect of oral isotretinoin on dysplastic nevi

We previously reported a favorable histologic response of dysplastic nevi to topical tretinoin in three patients. To investigate the anticancer and cancer preventive effects of retinoids we have examined the effect of systemic isotretinoin on dysplastic nevi. After confirmatory baseline biopsies, eleven patients with the dysplastic nevus syndrome were treated with oral isotretinoin, 40 mg twice a day for 4 months. At completion of therapy, at least three previously identified and photographed clinically typical dysplastic nevi were rephotographed and removed for histologic evaluation. Eight patients completed the full course of medication. There were no clinical changes in the dysplastic nevi in these patients. Posttherapy biopsy specimens in six volunteers revealed most of the remaining lesions to be dysplastic nevi. The majority of lesions biopsied in two subjects showed normal, benign nevi only. This proportion of clinically typical dysplastic nevi that prove to be normal nevi histologically (28%) is not significantly different from that reported by others. Oral isotretinoin does not appear to have a significant biologic effect on the clinical or histologic appearance of dysplastic nevi in the treatment schedule employed.

Vitamin A derivatives in the prevention and treatment of human cancer

Vitamin A is essential for normal cellular growth and differentiation. A vast amount of laboratory data have clearly demonstrated the potent antiproliferative and differentiation-inducing effects of vitamin A and the synthetic analogues (retinoids). Recent in-vitro work has led to the exciting proposal that protein kinase-C may be centrally involved in many of retinoids' anticancer actions including the effects on ornithine decarboxylase induction, intracellular polyamine levels, and epidermal growth factor receptor number. Several intervention trials have clearly indicated that natural vitamin A at clinically tolerable doses has only limited activity against human neoplastic processes. Therefore, clinical work has focused on the synthetic derivatives with higher therapeutic indexes. In human cancer prevention, retinoids have been most effective for skin diseases, including actinic keratosis, keratoacanthoma, epidermodysplasia verruciformis, dysplastic nevus syndrome, and basal cell carcinoma. Several noncutaneous premaligancies, however, are currently receiving more attention in retinoid trials. Definite retinoid activity has been documented in oral leukoplakia, laryngeal papillomatosis, superficial bladder carcinoma, cervical dysplasia, bronchial metaplasia, and preleukemia. Significant therapeutic advances are also occurring with this class of drugs in some drug-resistant malignancies and several others that have become refractory, including advanced basal cell cancer, mycosis fungoides, melanoma, acute promyelocytic leukemia, and squamous cell carcinoma of the skin and of the head and neck. This report comprehensively presents the clinical data using retinoids as anticancer agents in human premalignant disorders and outlines the ongoing and planned studies with retinoids in combination and adjuvant therapy.

Treatment and prevention of basal cell carcinoma with oral isotretinoin

Twelve patients with multiple basal cell carcinomas resulting from varying causes were treated with high-dose oral isotretinoin (mean daily dosage: 3.1 mg/kg/day) for a mean of 8 months. Of the 270 tumors monitored in these patients, only 8% underwent complete clinical and histologic regression. All patients developed moderate to severe acute toxicities, leading five patients to withdraw from the study. Retinoid skeletal toxicity was identified in two patients who were examined after long-term therapy. Lower doses of isotretinoin (0.25 to 1.5 mg/kg/day) were ineffective for chemotherapy but demonstrated a chemopreventive effect in a subset of three patients who received these lower doses for 3 to 8 years. Two of these three patients have been observed after discontinuation of therapy. In one patient with a history of arsenic exposure, only one new tumor has appeared in a 27-month posttreatment observation period; in the other patient with the nevoid basal cell carcinoma syndrome, 29 new tumors have appeared within a 13-month period. This suggests that the need for long-term maintenance therapy with isotretinoin for chemoprevention of basal cell carcinoma may depend on the underlying cause of the skin cancers.

Keratoacanthomas treated with Mohs' micrographic surgery (chemosurgery). A review of forty-three cases

A series of forty-three keratoacanthomas were treated with Mohs' micrographic surgery with the use of the fresh-tissue technic. Of forty-two keratoacanthomas followed from 6 to 24 months, one aggressive keratoacanthoma recurred, yielding an overall recurrence rate of 2.4%. Micrographic surgery is an expedient treatment that allows for complete microscopic examination of the keratoacanthoma, maximum preservation of normal tissue, and a high degree of assurance of cure.

13-cis-retinoic acid in the treatment of oral leukoplakia

13-cis-Retinoic acid has been reported to be effective in treating oral leukoplakia. We randomly assigned 44 patients with this disease to receive 13-cis-retinoic acid (24 patients) or placebo (20), 1 to 2 mg per kilogram of body weight per day for three months, and followed them for six months. There were major decreases in the size of the lesions in 67 percent (16 patients) of those given the drug and in 10 percent (2 patients) of those given placebo (P = 0.0002); dysplasia was reversed in 54 percent (13 patients) of the drug group and in 10 percent (2 patients) of the placebo group (P = 0.01). The clinical response to the drug correlated with the histologic response in 56 percent (9 of 16) of the patients evaluated. Relapse occurred in 9 of 16 patients two to three months after treatment ended. The toxic effects of the drug were acceptable in all but two patients. Cheilitis, facial erythema, and dryness and peeling of the skin were common; conjunctivitis and hypertriglyceridemia also occurred. All adverse reactions could be reversed by reducing the dose or temporarily discontinuing the drug. We conclude that 13-cis-retinoic acid, even in short-term use, appears to be an effective treatment for oral leukoplakia and has an acceptable level of toxicity.