Mistletoe is a semiparasitic plant that grows on several types of common trees such as apple, oak, pine, and elm. Mistletoe extract has been used since ancient times to treat many ailments (see Question 1).
Mistletoe is one of the most widely studied complementary and alternative medicine therapies in people with cancer. In certain European countries, preparations made from European mistletoe are among the most prescribed drugs for patients with cancer (see Question 1).
Most investigators have previously recommended treatment according to the guidelines given above for standard treatment of children with Langerhans cell histiocytosis. It is unclear, however, whether adult LCH responds as well as the childhood form of the disease. In addition, the drugs used in the treatment of children appear to be less well-tolerated in adults. Excessive neurologic toxicity from vinblastine, for example, prompted closure of the LCH-A1 trial.
Treatment of pulmonary LCH
It is difficult to judge the effectiveness of various treatments for pulmonary LCH as patients can recover spontaneously or have stable disease without treatment. Smoking cessation is mandatory in view of the apparent causal effect of smoking in pulmonary LCH. It is not known if steroid therapy is efficacious in the treatment of adult pulmonary LCH because reported case series did not control for smoking cessation. Most adult patients with LCH have gradual disease progression with continued smoking. The disease may regress or progress with the cessation of smoking.
Lung transplant may be necessary for adults with extensive pulmonary destruction from LCH. This multicenter study reported 54% survival at 10 years posttransplant with 20% of patients having recurrent LCH that did not impact survival; longer follow-up of these patients is needed. The best strategy for follow-up of pulmonary LCH includes physical examination, chest radiographs, lung function tests, and high-resolution computed tomography (CT) scans.
Treatment of bone LCH
Similar to children, adults with single-bone lesions should undergo curettage of the lesion followed by observation, with or without intralesional corticosteroids. Extensive or radical surgery leading to loss of function and disfigurement is contraindicated at any site, including the teeth or jaw bones. Systemic chemotherapy will cause bone lesions to regress and the involved teeth and jaw bones cannot reform. For those failing chemotherapy, low-dose radiation therapy may be indicated and should be tried prior to any radical surgery leading to extensive loss of function and disfigurement. Radiation therapy is also indicated for impending neurological deficits from vertebral body lesions or visual problems from orbital lesions. A German cooperative radiation therapy group reported on a series of 98 adult LCH patients, most of whom (60 of 98) had only bone lesions, and 24 had multisystem disease including bone, treated with radiation therapy.[Level of evidence: 3iiiDiv] Of 89 evaluable patients, 77% achieved a complete remission, 9% developed an infield recurrence, and 15.7% (14 of 89) experienced a progression outside the radiation field(s).