Adaptive radiotherapy for head and neck cancers: Fact or fallacy to improve therapeutic ratio?

Modern standards of precision radiotherapy, primarily driven by the technological advances of intensity modulation and image guidance, have led to increased versatility in radiotherapy planning and delivery. The ability to shape doses around critical normal organs, while simultaneously "painting" boost doses to the tumor have translated to substantial therapeutic gains in head and neck cancer patients. Recently, dose adaptation (or adaptive radiotherapy) has been proposed as a novel concept to enhance the therapeutic ratio of head and neck radiotherapy, facilitated in part by the onset of molecular and functional imaging. These contemporary imaging techniques have enabled visualisation of the spatial molecular architecture of the tumor. Daily cone-beam imaging, besides improving treatment accuracy, offers another unique angle to explore radiomics - a novel high throughput feature extraction and selection workflow, for adapting radiotherapy based on real-time tumor changes. Here, we review the existing evidence of molecular and functional imaging in head and neck cancers, as well as the current application of adaptive radiotherapy in the treatment of this tumor type. We propose that adaptive radiotherapy can be further exploited through a systematic application of molecular and functional imaging, including radiomics, at the different phases of planning and treatment.

Mobile cauda equina schwannomas.

Although very rare, cases of cauda equina tumours migrating several levels have been known to occur. We report two cases of cauda equina schwannomas which migrated from its primary site, one caudally and the other one rostrally as confirmed by magnetic resonance imaging perioperatively. The first patient was a 27-year-old man and the second a 41-year-old man; both presented with back pain. This report aims to remind clinicians that certain tumours attached to the roots in the lumbar spinal canal may migrate.

Microsurgical treatment for spinal tumours.

INTRODUCTION: Although spinal tumours are amenable to total surgical excision, the factors determining the outcome are diverse. This study re-evaluates aspects of the disease that contribute to their outcome. METHODS: Ninety-three consecutive patients with spinal cord tumours that underwent microsurgical excision between February 1992 and February 2002 were retrospectively studied. All patients underwent magnetic resonance imaging and had histological confirmation of spinal tumours. RESULTS: There were 44 men and 49 women with a mean age of 49.05 years (range 6 to 83 years). The location of the tumours was cervical in 37 cases, thoracic in 41 cases, lumbosacral in 13 cases, and multilevel in two cases. The mean tumour size was 2.2 cm (range 0.8 to 7 cm) and mean duration of symptoms was 10.8 months. Complete excision was achieved in 72 cases and incomplete removal in 15 cases. The mean follow-up period was 21.45 months (range 3 days to 8 years). Immediate post-operative improvement was noted in 40 (43 percent) patients, 24 (25.4 percent) improved within six months, 13 (14 percent) improved after six months, 12 (12.9 percent) had no improvement and four patients died. The duration of symptoms and the completeness of excision were factors that correlated with post-operative improvement (p-value is less than 0.05). Age, gender, size, histological type, presenting symptoms, spinal level affected and axial location of tumour did not correlate with the outcome. CONCLUSION: Microsurgical excision of spinal cord tumours is a safe and effective procedure, and post-operative outcome is correlated to duration of symptoms and the extent of tumour resection.