Radiation oncology in undergraduate medical education: a literature review.

PURPOSE: To review the published literature pertaining to radiation oncology in undergraduate medical education. METHODS AND MATERIALS: Ovid MEDLINE, Ovid MEDLINE Daily Update and EMBASE databases were searched for the 11-year period of January 1, 1998, through the last week of March 2009. A medical librarian used an extensive list of indexed subject headings and text words. RESULTS: The search returned 640 article references, but only seven contained significant information pertaining to teaching radiation oncology to medical undergraduates. One article described a comprehensive oncology curriculum including recommended radiation oncology teaching objectives and sample student evaluations, two described integrating radiation oncology teaching into a radiology rotation, two described multidisciplinary anatomy-based courses intended to reinforce principles of tumor biology and radiotherapy planning, one described an exercise designed to test clinical reasoning skills within radiation oncology cases, and one described a Web-based curriculum involving oncologic physics. CONCLUSIONS: To the authors' knowledge, this is the first review of the literature pertaining to teaching radiation oncology to medical undergraduates, and it demonstrates the paucity of published work in this area of medical education. Teaching radiation oncology should begin early in the undergraduate process, should be mandatory for all students, and should impart knowledge relevant to future general practitioners rather than detailed information relevant only to oncologists. Educators should make use of available model curricula and should integrate radiation oncology teaching into existing curricula or construct stand-alone oncology rotations where the principles of radiation oncology can be conveyed. Assessments of student knowledge and curriculum effectiveness are critical.

Malignant epithelioid cranial nerve sheath tumor: case report of a radiation response.

Malignant epithelioid nerve sheath tumors (MESs) especially those involving intracranial cranial nerves are rare and thought to be radioresistant. We report a case of a MES involving the Vth and VIIth cranial nerves responsive to radiotherapy. A 41-year-old man with progressive left facial weakness underwent an MRI that disclosed an enhancing lesion involving both V3 cranial nerve and the distal VIIth nerve. Biopsy confirmed a malignant epithelioid schwannoma. The tumor was resected but residual tumor was present at the cut end of the infraorbital nerve, within the oral cavity and at the brainstem. Positive excision margins were irradiated to 60 Gy/30 fractions by a wedge pair technique extending from the inferior orbit to C2. Tumor was controlled for 38 months and then radiographic recurrence was resected from the infratemporal fossa outside the irradiated field.A new primary MES tumor developed at 69 months at the C1/C2 root levels at the lower edge of the previously irradiated field. It was subtotally resected but by 77 months residual tumor had grown inferiorly down to C5 so this area was re-irradiated with a complicated 7-field approach to spare spinal cord. Initially the tumor responded but ultimately progressed posteriorly where radiation dose was limited by spinal cord tolerance. New involvement of the Xth cranial nerve was noted. The patient expired from brainstem compression 7 years after initial radiotherapy. The long-term control of the original tumor despite positive margins argues for the use of radiotherapy in the treatment of these tumors.

Orienting and defensive behaviors elicited by superior colliculus stimulation in rats: effects of 5-HT depletion, uptake inhibition, and direct midbrain or frontal cortex application.

Electrical or chemical stimulation of the superior colliculus (SC) in rats produces orienting and defensive responses. Defensive behaviors are modulated by serotonin (5-hydroxytryptamine, 5-HT), and serotonergic fibers provide a dense innervation of the SC. Here, we examined the role of 5-HT in modulating the behavioral responses of rats elicited by electrical SC stimulation. Low-intensity (107+/-12 microA) stimulation of the SC elicited orienting head movements, while higher intensities (204+/-20 microA) produced running and jumping responses. Treatment with the 5-HT depletor p-chlorophenylalanine (300 mg/kg/day x 3, i.p.) lowered current thresholds to elicit orienting and running by 40 and 21%, respectively. Conversely, concurrent administration of the 5-HT uptake inhibitor fluoxetine (10 mg/kg, i.p.) and the 5-HT(1A) receptor antagonist WAY 100635 (0.5 mg/kg, s.c.) increased threshold currents to produce head and running movements by 41 and 18%, respectively. We investigated the anatomical substrate of this inhibitory effect of 5-HT with intracerebral 5-HT application by means of reverse microdialysis. Application of 5-HT (1-50 mM) into the midbrain immediately adjacent to the SC stimulation electrode resulted in a pronounced (approximately four-fold for 50 mM 5-HT) dose- and time-dependent increase in stimulation thresholds to elicit head movements. Application of 5-HT into the frontal cortex (up to 100 mM) had no significant effect on SC-evoked behavioral responses. These results show that 5-HT exerts an inhibitory influence over orienting and defensive behaviors initiated in the mammalian SC. It appears that this inhibitory effect is mediated, to a large extent, by a direct action of 5-HT at the level of the midbrain.