Elective neck dissection versus observation for early-stage oral squamous cell carcinoma: Systematic review and meta-analysis

INTRODUCTION

Oral squamous cell carcinoma (OSCC) is the seventh most common cancer globally, and has been identified as a growing health concern. This study aims to evaluate the current literature comparing elective neck dissection to observation in the treatment of early-stage tongue SCC, focusing on nodal recurrence, overall survival, disease specific survival statistics from randomised controlled trials comparing the two interventions.

METHODS

Systematic review and meta-analysis was conducted according to PRISMA guidelines. The odds ratio (OR) was used as a summary statistic.

RESULTS

From 8 studies, there was a total of 372 cases of recurrence, 98 (15.1%) in END group and 274 (41.5%) in the Observation group. There was a significantly lower rate of recurrence in the END group compared to observation (OR 0.25, 95% CI 0.16-0.39, I² = 54%, P < 0.00001). END was associated with higher overall survival rates when compared with observation (OR 1.95, 95% CI 1.40-2.73, I² = 14%, P < 0.0001). END was also associated with higher disease-specific survival compared with observation (OR 1.88, 95% CI 1.21-2.93), I² = 47%, P = 0.005), with no significant heterogeneity noted.

CONCLUSIONS

END was associated with significantly lower recurrence rates and higher overall and disease-specific survival compared to a conservative observation approach in early-stage oral SCC with clinically N0 neck.

Transneuronal degeneration of thalamic neurons following deafferentation: quantitative studies using [3H]thymidine autoradiography

Transneuronal degeneration of thalamic neurons following partial deafferentation was studied using [3H]thymidine autoradiography. Timed-pregnant female Sprague-Dawley rats received systemic injections of [3H]thymidine on embryonic day (E) 13, 14 and/or 15. On the day of birth, pups were anesthetized by hypothermia and subjected to unilateral enucleation, unilateral removal of the inferior colliculus or sham lesion. Animals were sacrificed on postnatal day 10 or 30 and the brains processed for autoradiography. Material from sham-lesioned animals demonstrates that neurons destined for the dorsal lateral geniculate nucleus (LGd) undergo final mitoses on E13, 14 and 15. Neurons in the ventral medial geniculate nucleus (MGv) undergo final mitoses on E13 and 14. Thirty days following neonatal unilateral eye removal, the contralateral LGd displays a loss of approximately 30-35% of [3H]thymidine labeled neurons. Neonatal unilateral removal of the inferior colliculus results in a loss of approximately 30-40% of labeled neurons in MGv. For both LGd and MGv, shorter survival times reveal less severe cell loss. Late generated (E15) LGd neurons show less severe loss following enucleation than do earlier generated neurons. These results document the degree of cell loss in sensory thalamic nuclei following deafferentation and demonstrate that [3H]thymidine autoradiography provides a useful quantitative method for assessing anterograde transneuronal cell loss in targeted populations of neurons in the developing central nervous system.