Induction chemotherapy followed by radical chemoradiotherapy for patients with stage IV non-metastatic nasopharyngeal carcinoma: 11-Year Experience in a tertiary centre.

INTRODUCTION: T4 nasopharyngeal carcinoma (NPC) with close proximity to critical organs at risk (OARs) is usually underdosed during radiotherapy in order to respect radiation constraints. N3 disease has high risk of distant metastasis. Induction chemotherapy (IC) provides advantages of sparing of OARs during subsequent chemoradiotherapy (CCRT) and early eradication of micrometastasis. However, factors predicting successes of IC in this patient group are not well-studied. METHODS: 104 T4 or N3 NPC patients were retrospectively reviewed during 2007-2018. They were planned for IC followed by CCRT using intensity-modulated radiotherapy. RESULTS: In the whole group, five-year failure-free survival (FFS), locoregional failure-free survival (LRFS), distant failure-free survival (DFFS) and overall survival (OS) were 40.9%, 45.7%, 46.9% and 53.6% respectively. Isolated marginal failure rate was 5% (4/80) among patients with primary tumours located close to critical OARs. Pre-IC gross tumour volume primary (GTVp) total volume > 110 cm3 correlated with worse five-year LRFS (OR 6.37, P = 0.008), DFFS (OR 8.89, P = 0.003) and OS (OR 50.12, P < 0.001). In the T4 subgroup, IC improved D100% GTVp from 61.39 Gy to 64.71 Gy (P < 0.001) and V100% GTVp from 98.78% to 99.28% (P < 0.001). CONCLUSION: Our study demonstrated improved dosimetric parameters and low isolated marginal failure rate. It supported the use of IC and CCRT for tumours located close to critical OARs. Further research is warranted to compare predictive roles of pre- and post-IC tumour volumes. For high-risk patients being defined by pre-IC volume or other prognostic models, treatment escalation should be considered.

Radiation-induced temporo-mandibular joint disorder in post-radiotherapy nasopharyngeal carcinoma patients: assessment and treatment.

Nasopharyngeal carcinoma (NPC) is endemic in southern China, and its incidence in Hong Kong is relatively high. Radiotherapy is the mainstay treatment for NPC due to its relatively high radiosensitivity and deep-seated anatomical position, which is not readily accessible by surgery. Although the technique of radiotherapy in NPC has been advancing and offers promising treatment outcome, complications around the irradiation areas are inevitable and the quality of life of the post-radiotherapy patients is often compromised. Trismus, which is defined as the restricted mouth opening or jaw movement due to the disorder of temporo-mandibular joint (TMJ), is one of the possible late complications for radiotherapy of NPC and is found in 5-17% of the post-radiotherapy (post-RT) patients. Trismus at early stage may only affect the speech, but in severe cases nutritional intake and oral hygiene condition may deteriorate seriously. This article reviewed the possible causes of radiation-induced TMJ damage, the various assessments including imaging modalities and possible treatments. The conclusion is that the availability of simple, yet effective examinations for trismus is essential for delaying the progression and restoring TMJ functions. Although there is no absolutely effective treatment for trismus, many supportive, restorative and palliative management are possible under different clinical situations.