Two articles caught my attention in the Nov. 25 issue -- one, about evidence that whole brain irradiation can be eliminated in patients with CNS lymphoma (here); and the other that hippocampus-sparing radiotherapy supports preservation of memory (here). The latter article contains the word PCI -- i.e., prophylactic cranial irradiation.
Briefly, prophylactic cranial irradiation was introduced several decades ago to reduce the risk of metastatic disease in the brain in patients with limited small-cell lung cancer, whose cancer is in complete remission after treatment with chemotherapy and thoracic irradiation. Meta-analysis of trials have shown that prophylactic cranial irradiation can improve overall survival at three years from 15 percent to 18 percent and 15 percent to 20 percent.1,2 However, because this prophylaxis is associated with substantial side effects and impact on quality of life, the question arises whether the benefits outweigh the risks. The prophylaxis, though, has for years been offered to patients with limited small-cell lung cancer.
Regarding hippocampus sparing, though: Although it may help preserve memory, the result is not absolute and does not prevent other side effects of prophylactic cranial irradiation.
High response rates have been reported in patients with small-cell lung cancer with various systemic therapies.3 It was encouraging to read in the OT article that chemo-immune therapy can replace whole brain irradiation in CNS lymphoma.
Prophylactic cranial irradiation was brought to my attention in the middle of last year and, reviewing treatment for limited small cell lung cancer, it is noteworthy that little has changed in the past 20 years. Moreover, the question arises whether patients always receive an informed consent at the time of discussion of this prophylaxis. Among survivors are patients who declined the prophylaxis and who were treated with effective local control at diagnosis of brain metastatic disease.
In changes to therapy, it is crucial to ascertain that systemic upfront therapy is adequate.
1. Arriagada et al: Annals of Oncology 2002;13:748-754.
2. Auperin et al: NEJM 1999;341:476-484.
3. Crivellari et al: The Oncologist 2007;12:79-89.
Marlies Van Hoef, MD, PhD, MBA