Outcome After Radiation Therapy for Langerhans Cell Histiocytosis Is Dependent on Site of Involvement.

PURPOSE: To characterize the efficacy and safety of radiation therapy in a contemporary Langerhans cell histiocytosis (LCH) cohort and to explore whether there are sites at higher risk for local recurrence. PATIENTS AND METHODS: Between 1995 and 2015 we identified 39 consecutive LCH patients who were treated primarily with radiation therapy. Patients were staged by single/multisystem involvement and established risk organ criteria. In 46 irradiated lesions, clinical and radiologic responses were evaluated at multiple time points after radiation therapy. Patient demographics, treatment, and local failure were compared by site of lesion. RESULTS: Median age at radiation therapy was 35 years (range, 1.5-67 years). Twelve patients had multisystem involvement, and of those, 5 patients had disease in organs considered to be high risk. The following sites were irradiated: bone (31), brain (6), skin (3), lymph node (3), thyroid (2), and nasopharynx (1). Median dose was 11.4 Gy (range, 7.5-50.4 Gy). At a median follow-up of 45 months (range, 6-199 months), local recurrence or progression was noted in 5 of 46 lesions (11%). There were no local failures of the 31 bone lesions evaluated, whereas the 3-year freedom from local failure in the 15 non-bone lesions was 63% (95% confidence interval 32-83%; P=.0008). Local failures occurred in 2 of 3 skin lesions, in 2 of 6 brain lesions, and 1 of 3 lymph node lesions. Deaths were recorded in 5 of 39 patients (13%), all of whom were adults with multisystem disease. CONCLUSION: Radiation therapy is a safe and effective measure for providing local control of LCH involving the bone. Whereas bone lesions are well controlled with low doses of radiation, disease in other tissues, such as the skin and brain, may require higher doses of radiation or additional treatment modalities.

New staging system for nasopharyngeal carcinoma. Long-term outcome.

We report prognostic determinants and survival found after a long follow-up of 182 patients in North America in a prospective collaborative study. All patients were under observation since enrollment, and all were treated with modern equipment and techniques at major medical centers. Use of Cox regression methods identified five disease-related characteristics significantly associated with survival. These form the basis of the new staging system. A second system including antibody-dependent cellular cytotoxicity was developed because a high antibody-dependent cellular cytotoxicity titer correlated with good prognosis. The two new systems are better predictors of outcome than are the traditional staging systems. The unique World Health Organization 2 and 3 morphologic forms of nasopharyngeal carcinoma appear to be chronic diseases, because the risk of death does not level off with time, as it does for most other cancers.