Chondrosarcoma is a malignancy rarely encountered in the head and neck. In an attempt to define this tumor's characteristics and response to therapy, all cases of chondrosarcoma treated at the University of Michigan over the past 25 years were retrospectively studied. Fourteen cases originating in the nose and paranasal sinuses, mandible, temporal bone, and larynx were reviewed. Aggressive surgical resection was the mainstay of treatment, and resulted in an overall survival of 70%, with an average follow-up of 3.5 years. Survival was highest in primary temporal bone lesions, and lowest in paranasal sinus lesions. Unresectable lesions were not cured by other modalities. This study, therefore, continued to support the crucial role of wide surgical resection in the treatment of head and neck chondrosarcoma, but conservative resection, when needed to preserve important structures, has resulted in long-term survival.

A dose of 90 CGE in accelerated fractionation prevented central recurrence in almost all cases. The median survival time was extended to 20 months, likely as a result of central control. Tumors will usually recur in areas immediately peripheral to this 90-CGE volume, but attempts to extend local control by enlarging the central volume are likely to be limited by difficulties with radiation necrosis.

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Hochberg and Pruitt have reported glioblastomas recurring within 2 cm of the primary site in 90% of patients after whole-brain radiation therapy. They suggested that computerized tomography (CT) scan accuracy would permit smaller radiation fields. A treatment protocol with smaller-field focal brain irradiation following surgical resection is reported. The first 4500 cGy of radiation is focused to within a 3-cm margin around the tumor, with a 1500-cGy boost within a 1.5-cm margin. Forty-two patients with grade III or IV astrocytoma, treated with focal brain radiation therapy were reviewed retrospectively to assess patterns of tumor recurrence. Thirty patients received intra-arterial bromodeoxyuridine (BUdR) radiosensitization with focal brain radiation therapy, and 12 patients underwent conventional focal brain radiation therapy. Tumor margin was defined on preoperative and recurrence CT scans as the contrast-enhanced area; these were traced on acetate templates and compared with each other and with the actual scans. In all 42 patients, the lesion recurred within a 2-cm margin of the original tumor. Four patients had two recurrent areas: the second area was within the 2-cm margin in two, and outside this margin in two. These results are similar to those of Hochberg and Pruitt. It is suggested that focal irradiation is now the optimal treatment for malignant astrocytoma. Since recurrences continue to be within the irradiated volumes, it appears that higher focal doses of radiation are appropriate for clinical treatment trials of malignant astrocytomas.

In vivo 3-T MR spectroscopy has sufficient spatial resolution and chemical specificity to allow distinction of recurrent tumor from radiation effects in patients with treated gliomas.