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Context.-For the treatment of a single metastasis to the brain, surgical resection combined with postoperative radiotherapy is more effective than treatment with radiotherapy alone. However, the efficacy of postoperative radiotherapy after complete surgical resection has not been established. Objective.-To determine if postoperative radiotherapy resulted in improved neurologic control of disease and increased survival. Design.-Multicenter, randomized, parallel group trial. Setting.-University-affiliated cancer treatment facilities. Patients.-Ninety-five patients who had single metastases to the brain that were treated with complete surgical resections (as verified by postoperative magnetic resonance imaging) between September 1989 and November 1997 were entered into the study. Interventions.-Patients were randomly assigned to treatment with postoperative whole-brain radiotherapy (radiotherapy group, 49 patients) or no further treatment (observation group, 46 patients) for the brain metastasis, with median followup of 48 weeks and 43 weeks, respectively. Main Outcome Measures.-The primary end point was recurrence of tumor in the brain; secondary end points were length of survival, cause of death, and preservation of ability to function independently. Results.-Recurrence of tumor anywhere in the brain was less frequent in the radiotherapy group than in the observation group (9 [18%] of 49 vs 32 [70%] of 46; PϽ.001). Postoperative radiotherapy prevented brain recurrence at the site of the original metastasis (5 [10%] of 49 vs 21 [46%] of 46; PϽ.001) and at other sites in the brain (7 [14%] of 49 vs 17 [37%] of 46; PϽ.01). Patients in the radiotherapy group were less likely to die of neurologic causes than patients in the observation group (6 [14%] of 43 who died vs 17 [44%] of 39; P = .003). There was no significant difference between the 2 groups in overall length of survival or the length of time that patients remained functionally independent. Conclusions.-Patients with cancer and single metastases to the brain who receive treatment with surgical resection and postoperative radiotherapy have fewer recurrences of cancer in the brain and are less likely to die of neurologic causes than similar patients treated with surgical resection alone.

The domestication of citrus, is poorly understood. Cultivated types are selections from, or hybrids of, wild progenitor species, whose identities and contributions remain controversial. By comparative analysis of a collection of citrus genomes, including a high quality haploid reference, we show that cultivated types were derived from two progenitor species. Though cultivated pummelos represent selections from a single progenitor species, C. maxima, cultivated mandarins are introgressions of C. maxima into the ancestral mandarin species, C. reticulata. The most widely cultivated citrus, sweet orange, is the offspring of previously admixed individuals, but sour orange is an F1 hybrid of pure C. maxima and C. reticulata parents, implying that wild mandarins were part of the early breeding germplasm. A wild “mandarin” from China exhibited substantial divergence from C. reticulata, suggesting the possibility of other unrecognized wild citrus species. Understanding citrus phylogeny through genome analysis clarifies taxonomic relationships and enables sequence-directed genetic improvement.