Intense p53 staining is a valuable prognostic indicator for poor prognosis in medulloblastoma/central nervous system primitive neuroectodermal tumors

Intense p53 immunostaining may predict for a poor prognosis in central nervous system primitive neuroectodermal tumor of childhood.

BACKGROUND

Medulloblastoma is a common childhood primary brain tumor. Potential prognostic indicators for patients with local disease are age, extent of resection, and gender. However, none of these are well established. Immunohistologic staining is a potentially useful means to identify high-risk patients. The purpose of this clinical pathologic study was to investigate the prognostic significance of GFAP, synaptophysin, Ki-67, and p53 immunostaining in medulloblastoma/central nervous system primitive neuroectodermal tumors (CNS PNETs.)

MATERIALS AND METHODS

The records of 40 patients with CNS PNETs were reviewed. Their surgical specimens were immunostained for p53, glial fibrillary acidic protein (GFAP), synaptophysin, and Ki-67. The p53 specimens were scored blindly for the intensity of staining of nuclei (intense vs weak) and the quantity of cells stained. The Ki-67, GFAP, and synaptophysin specimens were analyzed for quantity of cells stained.

RESULTS

Ten patients' specimens stained intensely for the p53 protein. Eleven had weakly staining nuclei. Nineteen specimens had no staining. The patients with specimens that stained intensely had a statistically significant decreased disease free survival (P = 0.03). Mere presence or quantity of p53 nuclear staining did not correlate with disease free survival. Immunohistochemical staining for Ki-67, GFAP, and synaptophysin did not correlate with disease free survival. Clinical parameters of age, gender, and extent of resection also did not approach statistical significance for disease free survival.

CONCLUSION

Intense nuclear staining for p53 was the only variable in this clinical pathologic study that reached statistical significance for disease free survival. This suggests that intense staining for p53 may be the most important prognostic indicator for non-metastatic CNS PNETs. p53 Immunostaining with antibodies against p53 in CNS PNETs should be studied in a multi-institutional setting with larger numbers of patients.

Contamination of the pleural surfaces in childhood sarcoma. Use of colloidal P-32 to reduce radiation dose to the whole lung

Children with pulmonary sarcomas who have diffuse contamination of the pleural cavity present a difficult management problem for the radiation oncologist. Doses required to control even microscopic disease exceed lung tolerance. We report on the use of intracavity colloid P-32 in an attempt to treat the pleural surface and spare normal lung parenchyma and tissues of the chest wall. Three children--18 months, 12 years, and 3 years of age--had spillage of pulmonary sarcomas into the chest cavity. All children were treated with systemic chemotherapy. Initially, 0.5 mCi of technetium sulfur colloid (99mTc-sulfur colloid) was instilled into the pleural space to ascertain even distribution of isotope. This was then followed by installation of 5.0 mCi of colloidal P-32. Uniform distribution was then confirmed by bremsstrahlung scanning. All three patients are in complete remission 3.5 years, 3 years, and 1 year after treatment, respectively. The major toxicity was asymptomatic pleural thickening, which could be confused with disease. This was confirmed histologically to be fibrous in the first patient. The process diminished or stabilized with time in all 3 patients over the period of observation. In this small series, intrapleural colloidal P-32 appeared to be safe and well tolerated and would be expected to be less toxic than wide-field external beam in the treatment of spilled pulmonary sarcomas.

The reirradiation of recurrent bronchogenic carcinoma with external beam irradiation

Symptomatic local failure following thoracic irradiation for bronchogenic carcinoma presents a clinical challenge to the Radiation Oncologist. We retrospectively evaluated the efficiency of reirradiation with external beam radiation of 30 patients. The median dose of initial irradiation was 6,000 cGy in 6 weeks. The median time following initial irradiation to recurrence was 12 months. The median dose of retreatment was 3,030 cGy in 3 weeks. Of the symptomatic patients, 88% and 70% subjectively responded to initial irradiation and to reirradiation, respectively. Retreatment toxicity included radiation esophagitis (6 patients), dry desquamation (4 patients), and symptomatic radiation pneumonitis (1 patient). Based on this study, doses of external beam radiation in the range of 2,000-3,000 cGy in 2 to 3 weeks appear safe and effective in reirradiating recurrent bronchogenic carcinoma.

Clinical presentation, treatment, and outcome of trilateral retinoblastoma

In this report, three new cases of trilateral retinoblastoma are presented. The clinical presentation, treatment, and outcome of the patients are described and compared with those of 32 cases that have been previously reported in the literature. A positive family history was obtained in 68% of the patients. The mean age at diagnosis of bilateral retinoblastoma was 7.2 months. The mean age at diagnosis of trilateral disease was 39.7 months, resulting in a mean latent interval of 32.6 months. The mean time from diagnosis of trilateral retinoblastoma to death was 6.6 months, and all patients died with spinal metastases. The patients who received no therapy survived an average of 1.3 months after the diagnosis of trilateral disease. The patients who received any form of definitive therapy survived 9.7 months. Five patients who had complete or dramatic response to therapy by computed tomography scans had local intracranial tumor present at autopsy. Therefore, more aggressive local therapy may be warranted.

Skin cancer in patients with chronic radiation dermatitis

The cases of 76 patients with chronic radiation dermatitis resulting from low-dose ionizing radiation for benign disease were reviewed retrospectively for risk factors leading to the development of neoplasia. The patients were studied with respect to original hair color, eye color, sun reactive skin type, benign disease treated, area treated, age at treatment, and age at development of first skin cancer. Analysis of data showed 37% of patients had sun-reactive skin type I, 27% had type II, and 36% had type III. Types IV through VI were not represented. There appeared to be an overrepresentation of types I and II. Increased melanin pigmentation may therefore be either directly or indirectly protective against the development of skin cancers in patients who have received low-dose superficial ionizing radiation for benign disease. The sun-reactive skin type of patients with chronic radiation dermatitis may be used as a predictor of skin cancer risk when the total dose of ionizing radiation is not known.

The palliation of osseous metastasis with 32P or 89Sr compared with external beam and hemibody irradiation: a historical perspective

Radiation is an effective modality for palliation of osseous metastases. In patients with a limited number of lesions, local external beam irradiation is the most expedient method of delivering radiation therapy. Complete or partial relief of pain will occur in 80-90% of patients. When metastases are widespread or when new sites continue to appear, localized external irradiation becomes logistically difficult. In such cases, hemibody irradiation has been effective with an overall response rate of 85%. However, nausea, vomiting, diarrhea, and bone marrow and pulmonary toxicity may complicate therapy. In these cases, an effective alternative is systemic phosphorus-32 (32P) or strontium-89 (89Sr). Relief of pain in the range of 60-90% has been reported. Toxicity of 32P is largely that of bone marrow suppression, while 89Sr appears to be relatively marrow-sparing. In this review, we consider systemic 32P or 89Sr as viable options to external beam or hemibody irradiation in the presence of numerous bone metastases.

A comparison of lung metastases and natural killer cell activity in daily fractions and weekly fractions of radiation therapy on murine B16a melanoma

C57BL/6J male mice were inoculated with 5 X 10(5) B16a melanoma cells. Seven days post-inoculation, when the tumor had grown to 8.0-10.0 mm in diameter, 120 tumor-bearing mice were randomly divided into three groups: (1) sham-irradiated controls, (2) mice receiving 200 cGy five times a week for 6 weeks, and (3) mice receiving 800 cGy once a week for 4 weeks. Thirty mice in each group were sacrificed 47 days postinoculation. Ten mice in each group were observed for the survival time data. The primary tumor was significantly smaller and the number of lung metastases were significantly fewer in mice treated with 800 cGy once a week compared to mice treated with 200 cGy five times a week. When natural killer (NK) cell activity was assessed against YAC-1 tumor targets, it was found to be significantly higher in mice treated with a single large weekly dose of irradiation. These results show that B16a melanoma responds more favorably to a single large dose of irradiation administered once a week compared to the smaller conventional fraction administered five times a week. This beneficial effect correlates with an increase in NK activity, indicating that there may be a causal relationship.