Systematic review
Intensity-modulated radiation therapy for head and neck cancer: Systematic review and meta-analysis

https://doi.org/10.1016/j.radonc.2013.11.010Get rights and content

Abstract

Background and purpose

Intensity-modulated radiation therapy (IMRT) provides the possibility of dose-escalation with better normal tissue sparing. This study was performed to assess whether IMRT can improve clinical outcomes when compared with two-dimensional (2D-RT) or three-dimensional conformal radiation therapy (3D-CRT) in patients with head and neck cancer.

Methods and materials

Only prospective phase III randomized trials comparing IMRT with 2D-RT or 3D-CRT were eligible. Combined surgery and/or chemotherapy were allowed. Two authors independently selected and assessed the studies regarding eligibility criteria and risk of bias.

Results

Five studies were selected. A total of 871 patients were randomly assigned for 2D-RT or 3D-CRT (437), versus IMRT (434). Most patients presented with nasopharyngeal cancers (82%), and stages III/IV (62.1%). Three studies were classified as having unclear risk and two as high risk of bias. A significant overall benefit in favor of IMRT was found (hazard ratio – HR = 0.76; 95% CI: 0.66, 0.87; p < 0.0001) regarding xerostomia scores grade 2–4, with similar loco-regional control and overall survival.

Conclusions

IMRT reduces the incidence of grade 2–4 xerostomia in patients with head and neck cancers without compromising loco-regional control and overall survival.

Section snippets

Study design

This was a systematic review carried out in accordance with The Cochrane Collaboration Handbook of Interventions Systematic Reviews [7]. The manuscript was prepared using the PRISMA Statement as a reporting guide [8].

Criteria for considering studies for this review

Only prospective phase III randomized trials were considered. Eligible trials had to compare IMRT with 2D-RT or 3D-CRT in previously untreated patients, with non-metastatic head and neck cancers.

Patients were treated with radiotherapy either primarily or combined with surgery or

Study selection and characteristics of the included studies

Six papers corresponding to five studies fulfilled the eligibility criteria [16], [17], [18], [19], [20], [21]. The flowchart of the retrieved studies and the main characteristics of the included studies are presented in Fig. 1 and Table 1, respectively.

In these five studies, 871 patients were randomly assigned for 2D-RT or 3D-CRT (437), versus IMRT (434). Except for Gupta et al. [19], [20], all studies compared 2D-RT with IMRT. Three studies included only patients with nasopharynx cancers [16]

Discussion

Head and neck tumors are curable even for locally advanced presentations, either with surgery or RT alone or with combined treatments (surgery, RT and chemotherapy). Usually, loco-regional control is directly related to survival since these tumors tend to grow locally rather than metastasize. The head and neck anatomy favors RT in the sense that high doses can be safely delivered to this site. However, more sensitive structures like the parotid glands may suffer the effect of high radiation

Financial disclosure/acknowledgements

None to declare.

Conflict of interest statement

None to declare.

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