Gary L. Peck

Prevention of Skin Cancer in Xeroderma Pigmentosum with the Use of Oral Isotretinoin

To confirm reports that skin cancer can be prevented with retinoids, we conducted a three-year controlled prospective study of oral isotretinoin (also called 13-cis retinoic acid) in five patients with xeroderma pigmentosum who had a history of multiple cutaneous basal-cell or squamous-cell carcinomas. Patients were treated with isotretinoin at a dosage of 2 mg per kilogram of body weight per day for two years and then followed for an additional year, without the drug. Before, during, and after treatment, biopsies of all suspicious lesions were performed, and skin cancers were surgically removed. The patients had a total of 121 tumors (mean, 24; range, 8 to 43) in the two-year interval before treatment. During two years of treatment with isotretinoin, there were 25 tumors (mean, 5; range, 3 to 9), with an average reduction in skin cancers of 63 percent (P = 0.019). After the drug was discontinued, the tumor frequency increased a mean of 8.5-fold (range, 2- to 19-fold) over the frequency during treatment (P = 0.007). Although all patients experienced mucocutaneous toxic effects, and triglyceride, liver-function, or skeletal abnormalities developed in some, high-dose oral isotretinoin was effective in the chemoprophylaxis of skin cancers in patients with xeroderma pigmentosum.

Prolonged remissions of cystic and conglobate acne with 13-cis-retinoic acid.

Fourteen patients with treatment-resistant cystic and conglobate acne were treated for four months with oral 13-cis-retinoic acid, a synthetic isomer of naturally occurring all-trans-retinoic acid. The average dose was 2.0 mg per kilogram per day. Thirteen patients experienced complete clearing of their disease; the other had 75 per cent improvement, as determined by the number of acne nodules and cysts present before and after therapy. Prolonged remissions, currently lasting as long as 20 months after discontinuation of therapy, have been observed in all 14 patients. Clinical toxicity was limited to the skin and mucous membranes in most patients and was dose dependent and rapidly reversible upon discontinuation of therapy. The mechanism of action of 13-cis-retinoic acid in the therapy of acne probably involves a direct inhibitory effect of the drug on the sebaceous gland.

Developmental defects in gorlin syndrome related to a putative tumor suppressor gene on chromosome 9

Gorlin syndrome is an autosomal dominant disorder that predisposes to basal cell carcinomas of the skin, ovarian fibromas, and medulloblastomas. Unlike other hereditary disorders associated with cancer, it features widespread developmental defects. To investigate the possibility that the syndrome is caused by mutation in a tumor suppressor gene, we searched for loss of heterozygosity in 16 sporadic basal cell carcinomas, 2 hereditary basal cell carcinomas, and 1 hereditary ovarian fibroma and performed genetic linkage studies in five Gorlin syndrome kindreds. Eleven sporadic basal cell carcinomas and all 3 hereditary tumors had allelic loss of chromosome 9q31, and all informative kindreds showed tight linkage between the Gorlin syndrome gene and a genetic marker in this region. Loss of heterozygosity at this chromosomal location, particularly in hereditary tumors, implies that the gene is homozygously inactivated and normally functions as a tumor suppressor. In contrast, hemizygous germline mutations lead to multiple congenital anomalies.

Reduced anxiety and depression in cystic acne patients after successful treatment with oral isotretinoin

We evaluated the psychiatric morbidity and mood characteristics of a group (n = 72) of patients with cystic acne before and after treatment with one of three dosage schedules of isotretinoin. Although no excess psychiatric morbidity was observed, substantial evidence of psychologic distress was noted before treatment. Significant reductions in anxiety were observed on several measures of anxiety after treatment, with mitigation of anxiety and depression most robust in those patients with the greatest dermatologic improvement with isotretinoin.

Extraspinal Tendon and Ligament Calcification Associated with Long-Term Therapy with Etretinate

Isotretinoin, a synthetic retinoid that has been prescribed for over 500,000 patients with cystic acne, has been associated with both spinal hyperostosis and a disorder similar to diffuse idiopathic skeletal hyperostosis. We describe a syndrome of tendon and ligament calcification, primarily in extraspinal locations, that we have observed after long-term therapy for psoriasis and disorders of keratinization with etretinate, another synthetic retinoid. Of 38 patients who had received etretinate (average dose, 0.8 mg per kilogram of body weight per day; average duration, 60 months), 32 (84 percent) had radiographic evidence of extraspinal tendon and ligament calcification. The most common sites of involvement were the ankles (29 patients [76 percent]), pelvis (20 patients [53 percent]), and knees (16 patients [42 percent]); spine involvement was uncommon in this group of etretinate-treated patients. Involvement tended to be bilateral and multifocal. Fifteen (47 percent) of the 32 affected patients had no bone or joint symptoms at the sites of radiographic abnormality. Thus, tendon and ligament calcification can occur without vertebral involvement as well as in association with it (for example, as part of the spectrum of diffuse idiopathic skeletal hyperostosis). We have identified extraspinal tendon and ligament calcification as a toxic effect that is commonly associated with long-term etretinate therapy.

Isotretinoin versus placebo in the treatment of cystic acne: A randomized double-blind study

Thirty-three patients with treatment-resistant cystic and conglobate acne entered a randomized, double-blind protocol testing the efficacy of isotretinoin versus placebo. There was an overall 57% increase in the number of cystic lesions in seventeen patients who initially received placebo. Sixteen of these seventeen patients then received isotretinoin, with a resultant 98% improvement. The sixteen patients who had been randomly assigned to receive initial therapy with isotretinoin had a 95% improvement. Twenty-seven of the thirty-two patients treated with isotretinoin cleared completely. The average maximum dosage of isotretinoin received by these patients was 1.2 mg/kg/day. Eighteen patients received only one 4-month course of isotretinoin. Fifteen patients received two courses. These included twelve patients with predominantly truncal acne who responded partially to the first course, and three patients who had cleared completely after one course of therapy but had mild relapses after an average of six months off of treatment. All patients are now in remission averaging 38 months in duration. Skin biopsies and quantitative measurement of sebum production during therapy indicated a profound inhibition of sebaceous gland size and function, which may be central to the mechanism of action of isotretinoin in acne.

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.

Vertebral abnormalities associated with synthetic retinoid use

Frequent symptoms of back and neck stiffness led to a radiographic investigation of the vertebral spine in patients receiving synthetic retinoids, isotretinoin and etretinate. X-ray examination of fifty patients with various skin disorders who received retinoids for at least 2 years were compared with seventy-two age- and sex-matched untreated patients. Differences in frequencies of defined abnormalities, which included anterior spinal ligament calcification and presence of osteophyte at two or more vertebral levels in the absence of joint space narrowing, were determined for treated and untreated patients. When the entire group of treated patients was compared with the entire group of those untreated, no statistically significant differences were observed. When only patients with basal cell nevus syndrome ( BCNS ) or basal cell carcinoma (BCC) who had never received retinoid were compared with those who received isotretinoin, the frequency of the defined abnormalities was significantly higher in the treated group (P less than 0.01). This study suggests that the ingestion of isotretinoin at mean total dose of 150,060 mg for an average of 2.9 years is associated with a statistically significant increase in developing an associated ossifying diathesis in patients with BCNS or BCC, when compared with matched, untreated controls.

Synthetic Retinoids in Dermatology

Publisher Summary This chapter discusses synthetic retinoids in dermatology. Synthetic retinoids are beneficial in a variety of cutaneous disorders. Synthetic retinoids are of value in the treatment and prevention of skin cancer. Isotretinoin is the drug of choice for severe cystic acne. The development of optimum dosage schedules for acne of varying severity and for facial and truncal locations is continuing. The use of etretinate either alone or in combination with currently available therapies for psoriasis is very effective, especially for the typically treatment-resistant pustular and erythrodermic varieties. Unlike isotretinoin in acne, maintenance therapy with etretinate is necessary for most psoriatic patients. Synthetic retinoids is the most effective treatment for Dariers disease and certain other disorders of keratinization. The use of synthetic retinoids in cancer prevention and therapy for both cutaneous and internal tumors is potentially the most significant clinical use of these drugs. Chronic maintenance therapy is needed for successful chemoprevention of cancer with retinoids.

Chemoprevention of basal cell carcinoma with isotretinoin

Three patients with multiple basal cell carcinomas, due either to excessive sunlight exposure, the nevoid basal cell carcinoma syndrome, or arsenical insecticide exposure, were treated with oral isotretinoin for 2 1/2 to 4 years. Although higher doses were used initially, approximately 1.5 mg/kg/day was used for long-term therapy in all three patients. Therapeutic effects on existing tumors varied between each patient, and only nine of sixty-five lesions underwent complete clinical regression. No tumors enlarged in two patients; a few tumors enlarged slightly in the third patient, particularly during the later courses of therapy when isotretinoin was given at lower dosage. No new lesions have been observed in any of these three patients. With these encouraging preliminary data, it now may be appropriate to perform larger trials for longer periods of time to determine the usefulness of isotretinoin in the chemoprevention of basal cell carcinoma in patients with multiple tumors.