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Dive into the research topics where Stephen N. Snow is active.

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Featured researches published by Stephen N. Snow.


Journal of The American Academy of Dermatology | 1992

Eccrine porocarcinoma of the face

Stephen N. Snow; George T. Reizner

Eccrine porocarcinoma is a rare tumor of the skin. We report a case on the chin that was successfully treated with Mohs surgery. In our review of the worlds literature 105 cases were compiled. The tumor most often occurs in the elderly and affects men more frequently than women. It may develop from a preexisting benign poroma and may also appear as a verrucous or nodular, ulcerative growth. Approximately 50% of the tumors occur on the lower extremities; the leg is the most common site. Microscopically the tumor demonstrates both intraepidermal and dermal invasion and is capable of forming satellite lesions and in-transit metastases when lymphatic vessels are invaded. The local recurrence and regional metastatic rates are both approximately 20%. Distant metastasis occurs in 12% of cases. The mortality rate is more than 65% when regional nodes are involved.


The Journal of Urology | 1985

Microscopically Controlled Surgery in the Treatment of Carcinoma of the Penis

Frederic E. Mohs; Stephen N. Snow; Edward M. Messing; Michael E. Kuglitsch

Complete removal of carcinoma of the penis can be achieved by excision of the neoplasm layer by layer and microscopic examination of the entire undersurface of each layer by the systematic use of frozen sections. Microscopic guidance provides substantial assurance of eradication of the primary cancer, and permits preservation of maximal amounts of normal tissue and normal functions. In a series of 29 consecutive cases of squamous cell carcinoma of the penis the 5-year cure rate among the 25 determinate cases was 68 per cent. The fact that in this series only 1 patient had cancer limited to the prepuce is evidence that circumcision usually is successful for neoplasms so limited. The primary carcinoma was eradicated in 23 of the 25 lesions (92 per cent).


Cancer Prevention Research | 2010

A randomized, double-blind, placebo-controlled phase 3 skin cancer prevention study of {alpha}-difluoromethylornithine in subjects with previous history of skin cancer.

Howard H. Bailey; KyungMann Kim; Ajit K. Verma; Karen Sielaff; Paul O. Larson; Stephen N. Snow; T Lenaghan; Jaye L. Viner; Jeff Douglas; Nancy E. Dreckschmidt; Mary Hamielec; Marcia Pomplun; Harry Sharata; Puchalsky D; Er Berg; Thomas C. Havighurst; Paul P. Carbone

Preclinical studies have shown that the inhibition of ornithine decarboxylase (ODC) by α-difluoromethylornithine (DFMO) and resultant decreases in tissue concentrations of polyamines (putrescine and spermidine) prevents neoplastic developments in many tissue types. Clinical studies of oral DFMO at 500 mg/m2/day revealed it to be safe and tolerable and resulted in significant inhibition of phorbol ester–induced skin ODC activity. Two hundred and ninety-one participants (mean age, 61 years; 60% male) with a history of prior nonmelanoma skin cancer (NMSC; mean, 4.5 skin cancers) were randomized to oral DFMO (500 mg/m2/day) or placebo for 4 to 5 years. There was a trend toward a history of more prior skin cancers in subjects randomized to placebo, but all other characteristics including sunscreen and nonsteroidal anti-inflammatory drug use were evenly distributed. Evaluation of 1,200 person-years of follow-up revealed a new NMSC rate of 0.5 events/person/year. The primary end point, new NMSCs, was not significantly different between subjects taking DFMO and placebo (260 versus 363 cancers, P = 0.069, two-sample t test). Evaluation of basal cell (BCC) and squamous cell cancers separately revealed very little difference in squamous cell cancer between treatment groups but a significant difference in new BCC (DFMO, 163 cancers; placebo, 243 cancers; expressed as event rate of 0.28 BCC/person/year versus 0.40 BCC/person/year, P = 0.03). Compliance with DFMO was >90% and it seemed to be well tolerated with evidence of mild ototoxicity as measured by serial audiometric examination when compared with placebo subjects. The analysis of normal skin biopsies revealed a significant (P < 0.05) decrease in 12-0-tetradecanoylphorbol-13-acetate–induced ODC activity (month 24, 36, and 48) and putrescine concentration (month 24 and 36 only) in DFMO subjects. Subjects with a history of skin cancer taking daily DFMO had an insignificant reduction (P = 0.069) in new NMSC that was predominantly due to a marked reduction in new BCC. Based on these data, the potential of DFMO, alone or in combination, to prevent skin cancers should be explored further. Cancer Prev Res; 3(1); 35–47


Journal of The American Academy of Dermatology | 1994

Giant basal cell carcinoma: Report of two cases and review of the literature

William J. Sahl; Stephen N. Snow; Norman S. Levine

Only 10% of all basal cell carcinomas are located on the trunk. Giant basal cell carcinomas are rare and are preferentially located on the trunk. We report two giant basal cell carcinomas of the trunk, one of which was fatal. Our review also includes a summary of previously reported cases of giant basal cell carcinoma. An analysis of these cases discloses an interesting feature of large basal cell carcinoma: Once giant basal cell carcinomas reach a critical mass, they demonstrate extremely aggressive behavior.


Journal of The American Academy of Dermatology | 1994

Second-intention healing of exposed facial-scalp bone after Mohs surgery for skin cancer: Review of ninety-one cases

Stephen N. Snow; Mark A. Stiff; Ricardo Bullen; Frederic E. Mohs; Wei-Hsiung Chao

BACKGROUND Second-intention healing over exposed bone is considered by some to be subject to the complications of pain, infection, and nonhealing. OBJECTIVE Our purpose was to determine would healing by second intention over exposed scalp or facial bone after Mohs micrographic surgery for skin cancer. METHODS The chart records of all patients treated between 1981 and 1992 for skin cancer that resulted in exposed bone were identified. RESULTS There were 115 wounds in 91 patients that were managed by second-intention healing, or partial closure, or both. Three cases of soft tissue infection occurred adjacent to nasal and sinus areas. The overall complication rate was 5.4% (6 of 112 cases) and consisted of localized soft tissue infections (2.7%) and poor wound healing (2.7%). There were no cases of osteomyelitis. Second-intention wound healing was successful in 95% of the wounds. CONCLUSION The outpatient management of exposed bone after Mohs surgery is relatively safe. Relative risk factors for development of complications include (1) a history of previous x-radiation treatment for skin cancer, (2) manipulation of the operative site, and (3) an open defect located near the nose or exposed sinus cavity.


Dermatologic Surgery | 1998

Angiosarcoma of the Head and Neck Managed by a Combination of Multiple Biopsies to Determine Tumor Margin and Radiation Therapy: Report of Three Cases and Review of the Literature

Ricardo Bullen; Paul O. Larson; Anya Landeck; Stephen Nychay; Stephen N. Snow; Paul G. Hazen; Timothy J. Kinsella; John Lamond

background. Cutaneous angiosarcoma (AS) is a rare, often multicentric vascular tumor of the head and neck region with a rather poor prognosis. The original clinical size of the tumor rarely correlates to the degree of microscopic tissue invasion. Treatment by surgical excision sometimes requires very wide excision. Treatment by radiation or electron beam appears less mutilating but its efficacy is not well documented. objective. To present our experience with a combined surgical delineation of tumor margins followed by radiation treatment. methods. We treated three patients with extensive AS of the scalp and face. Prior to radiation, in two cases the tumor margins were determined by grid‐pattern punch biopsies. In the third patient, the tumor margins were determined by Mohs mapping system. All three patients then received radiation either by rotational arc electron beam (n = 2) and standard radiation. results. One patient developed two local recurrences in non‐irradiated areas plus a metastatic cervical node, all of which responded to additional electron beam. The patient has no evidence of disease (NED) after 30 months of observation. The other two patients were treated by electron beam and radiation have NED at 5 and 1 years follow‐up, respectively. conclusions. Local control of AS of the scalp may be achieved by assessment of the tumor margin by peripheral biopsies or Mohs technique followed by electron beam and radiation.


Cancer Prevention Research | 2012

A Phase III Skin Cancer Chemoprevention Study of DFMO: Long-term Follow-up of Skin Cancer Events and Toxicity

Sarah M. Kreul; Thomas C. Havighurst; KyungMann Kim; Eneida A. Mendonça; Gary S. Wood; Stephen N. Snow; Abbey L Borich; Ajit K. Verma; Howard H. Bailey

Decreasing the incidence of nonmelanoma skin cancer (NMSC) is of great importance in regards to future healthcare services. Given the previously reported preventive effects of α-difluoromethylornithine (DFMO) in skin and colon cancer trials, we determined appropriate cause to update the clinical data on the subjects from the recently reported randomized, double-blind, placebo-controlled phase III skin cancer prevention study of DFMO. Our intention was to retrospectively assess the further incidence of skin cancer, other malignancies, and adverse events of patients accrued to our phase III skin cancer prevention study of DFMO. Clinical records of 209 University of Wisconsin (UW) Health subjects were reviewed, and 2,092.7 person years of on study (884.3 person years) and poststudy (1,208.4 person years) follow-up for these patients were assessed for new NMSC events and recurrence rates from the on study period, the poststudy period, and the two study periods combined. No evidence of increased significant diagnoses or serious adverse events was observed in the DFMO participants. The initially observed, marginally significant reduction (P = 0.069) in NMSC rates for DFMO subjects relative to placebo continued without evidence of rebound. Event rates after discontinuation from study for total NMSCs (DFMO 0.236 NMSC/person/year, placebo 0.297, P = 0.48) or the subtypes of basal cell carcinomas (BCC; DFMO 0.179 BCC/person/year, placebo 0.190, P = 0.77) and squamous cell carcinomas (SCC; DFMO 0.057 SCC/person/year, placebo 0.107, P = 0.43) are listed. Follow-up data revealed a persistent but insignificant reduction in new NMSCs occurring in DFMO subjects without evidence of latent or cumulative toxicity relative to placebo subjects. Cancer Prev Res; 5(12); 1368–74. ©2012 AACR.


Cancer Prevention Research | 2010

A randomized, double-blind, placebo-controlled phase 3 skin cancer prevention study of DFMO in subjects with previous history of skin cancer

Howard H. Bailey; KyungMann Kim; Ajit K. Verma; Karen Sielaff; Paul O. Larson; Stephen N. Snow; T Lenaghan; Jaye L. Viner; J Douglass; Nancy E. Dreckschmidt; Mary Hamielec; Marcia Pomplun; Harry Sharata; Puchalsky D; Er Berg; Thomas C. Havighurst; Paul P. Carbone

Preclinical studies have shown that the inhibition of ornithine decarboxylase (ODC) by α-difluoromethylornithine (DFMO) and resultant decreases in tissue concentrations of polyamines (putrescine and spermidine) prevents neoplastic developments in many tissue types. Clinical studies of oral DFMO at 500 mg/m2/day revealed it to be safe and tolerable and resulted in significant inhibition of phorbol ester–induced skin ODC activity. Two hundred and ninety-one participants (mean age, 61 years; 60% male) with a history of prior nonmelanoma skin cancer (NMSC; mean, 4.5 skin cancers) were randomized to oral DFMO (500 mg/m2/day) or placebo for 4 to 5 years. There was a trend toward a history of more prior skin cancers in subjects randomized to placebo, but all other characteristics including sunscreen and nonsteroidal anti-inflammatory drug use were evenly distributed. Evaluation of 1,200 person-years of follow-up revealed a new NMSC rate of 0.5 events/person/year. The primary end point, new NMSCs, was not significantly different between subjects taking DFMO and placebo (260 versus 363 cancers, P = 0.069, two-sample t test). Evaluation of basal cell (BCC) and squamous cell cancers separately revealed very little difference in squamous cell cancer between treatment groups but a significant difference in new BCC (DFMO, 163 cancers; placebo, 243 cancers; expressed as event rate of 0.28 BCC/person/year versus 0.40 BCC/person/year, P = 0.03). Compliance with DFMO was >90% and it seemed to be well tolerated with evidence of mild ototoxicity as measured by serial audiometric examination when compared with placebo subjects. The analysis of normal skin biopsies revealed a significant (P < 0.05) decrease in 12-0-tetradecanoylphorbol-13-acetate–induced ODC activity (month 24, 36, and 48) and putrescine concentration (month 24 and 36 only) in DFMO subjects. Subjects with a history of skin cancer taking daily DFMO had an insignificant reduction (P = 0.069) in new NMSC that was predominantly due to a marked reduction in new BCC. Based on these data, the potential of DFMO, alone or in combination, to prevent skin cancers should be explored further. Cancer Prev Res; 3(1); 35–47


Dermatologic Surgery | 2009

Hidradenomas and a Hidradenocarcinoma of the Scalp Managed Using Mohs Micrographic Surgery and a Multidisciplinary Approach: Case Reports and Review of the Literature

Regina Yavel; Molly Hinshaw; Venkat Rao; Gregory K. Hartig; Paul M. Harari; Daniel Stewart; Stephen N. Snow

&NA; The authors have indicated no significant interest with commercial supporters.


Journal of Oncology | 2010

Cutaneous Adenoid Cystic Carcinoma with Perineural Invasion Treated by Mohs Micrographic Surgery—A Case Report with Literature Review

Yaohui G. Xu; Molly Hinshaw; B. Jack Longley; Humza Ilyas; Stephen N. Snow

We report a 58-year-old woman with cutaneous adenoid cystic carcinoma arising on the chest treated with Mohs micrographic surgery. The patient remained tumor-free at 24-month follow-up. To date, only six other cases of cutaneous adenoid cystic carcinoma were reportedly managed by Mohs surgery. Cutaneous adenoid cystic carcinoma has low potential for distant metastasis but is notorious for its aggressive infiltrative growth pattern, frequent perineural invasion, and high risk of local recurrence after excision. We propose that Mohs surgery is an ideal method to achieve margin-free removal of cutaneous adenoid cystic carcinoma. A brief literature review is provided.

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Frederic E. Mohs

University of Wisconsin-Madison

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Paul O. Larson

University of Wisconsin-Madison

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David Madjar

University of Wisconsin-Madison

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Howard H. Bailey

University of Wisconsin-Madison

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KyungMann Kim

University of Wisconsin-Madison

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Molly Hinshaw

University of Wisconsin-Madison

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Thomas C. Havighurst

University of Wisconsin-Madison

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Ajit K. Verma

Stord/Haugesund University College

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Anya Landeck

University of Wisconsin-Madison

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