142 ABSTRACTS

ment at 12 hours at a significant level (<0.05), 270 pa- tients would require randomization. A study evaluating the efficacy of steroids in preventing intubation (which is a relatively rare event] would need to randomize 1,480 patients to treatment and control groups. This meta-analysis provides strong support for the use of ste- roids in the treatment of hospitalized children with croup; in the absence of a randomized clinical study of sufficient size, this study provides the most reliable es- timate of the impact of steroids for this disease. This is a very useful article and it confirms the impression of experienced clinicians; it is a powerful argument for the addition of steroids to support the care of children with croup.

The Molecular Biology of Medullary Thyroid Carci- noma. BD Nelkin, AC deBustros, M Mabry, et al. JAMA 1989; 261:3130-3135

Medullary thyroid carcinoma (MTC) is an important human cancer from the point of view of the molecular abnormalities that underlie initiation and the cellular changes that promote tumor progression. The tumor can occur in different forms, both of which are inher- ited and each mediated by autosomal dominant genetic events. Most commonly, abnormalities on chromosome 10 are linked to at least one type of genetic MTC, mul- tiple endocrine neoplasia type 2. Studies from the lab- oratory of these authors using DNA from MTC tumors have suggested that a genetic mechanism involved in MTC development may be different from those changes seen in inherited cancers such as retinoblastoma. In tis- sue culture, chemical modulation or gene insertion can lead to the partial correction of cellular defects in this tumor and to a more differentiated phenotype. This is a tumor that is amenable to in vitro study. Studies with MTC cells suggest that genetic alteration of cancer cells may be achievable and act as new forms of therapeutic intervention. This is an interesting review article that emphasizes the continuing study of molecular controls for differentiation of cancer cells to produce novel agents in cancer therapy. In addition, this is a nice over- view of the newer forms of basic science techniques which are being applied to the study of head and neck tumors.

Cutaneous Angiosarcoma of the Face and Scalp. SW Barttelbort, R Stahl, S Ariyan. Plast Reconstr Surg 1989; 84:55-59

Cutaneous angiosarcoma is an infrequent but aggres- sive neoplasm which can involve skin of the face and scalp. It is a slow growing tumor which may be asymp- tomatic and characteristically infiltrates extensively into “normal skin structure.” Often, this tumor can re- cur aggressively because of its infiltrative nature. This article reviews the Yale Plastic Surgery Unit experience with a new treatment protocol based on the accurate preoperative determination of true tumor margins. Five patients were treated using this protocol. All patients were treated with a combination of surgery and radia- tion. A major problem experienced at the time of extir-

pative surgery is the difficulty in determining tumor margins. Frozen sections are distinctly unreliable be- cause they can often be falsely negative, but may turn out to be positive on permanent sections. Therefore, the use of frozen section is helpful for positive tumor mar- gin but is unreliable for negative margins. In an effort to perform more complete surgical resection, this group now performs preoperative full thickness staging biop- sies to determine the full extent of the neoplasm. Punch biopsies are performed at increasing distances from the suspected edge of the neoplasm, then analyzed by per- manent section techniques. It is important that punch biopsies be full thickness, including some of the sub- cutaneous tissue, since this helps determine the depth of surgical resection. Using these principles of treat- ment, all five patients treated had local control of neo- plasm. The authors urge the abandonment of frozen sec- tion analysis because it can be inconclusive and falsely negative. They recommend the establishment of tumor margins using careful preoperative mapping and punch biopsies. Although a rare tumor, angiosarcoma can prove to be a diagnostic and therapeutic dilemma for the head and neck surgeon. This article should be care- fully studied in conjunction with a pathologist to opti- mize resection margins in angiosarcoma.

Radiation Therapy in Recurrent Pleomorphic Adeno- ma of the Parotid. AK Dawson. Int J Radiat Oncol Biol Phys 1989; 16:819-821

Parotid gland pleomorphic adenomas can recur fol- lowing incision, depending on the type of surgical pro- cedure first performed. Enucleation is associated with a high recurrence rate, whereas superficial parotidecto- my or capsular dissection results in only 1% to 2% re- currence rates. Once a pleomorphic adenoma has re- curred, the likelihood of further recurrence may in- crease and the issue of what to do with such a tumor is problematic. The current paper examines 29 patients seen over 21 years who were treated by excision and postoperative radiation therapy following recurrence of parotid gland pleomorphic adenoma. Initially, radia- tion therapy consisted of single radium needle implant delivering 6,000 rad in 6 days. Later in the series, ex- ternal beam mega-voltage was used to 5,800 cGy in 20 fractions over 4 weeks in six patients. Twenty-two pa- tients were initially referred after excision of the first recurrence. It was found that patients were more likely to have local control of the first recurrence than of a second recurrence. Moreover, bulky disease at presen- tation was associated with a poorer control rate than small tumor size. In addition, local implant had a poorer local control rate than external beam irradiation. In this study, no complications were documented in terms of facial nerve paralysis or wound dehiscences. As is already well known, recurrent disease treated with superficial parotidectomy is associated with an increased risk of complications. For example, one study is cited in which a 12.6% incidence of permanent facial paralysis in recurrent cases was noted. Since recurrent lesions signal a high risk of the subsequent reappear- ance of tumor, the addition of external beam radiation therapy may be considered in recurrent pleomorphic