Interventions for the treatment of oral and oropharyngeal cancers: targeted therapy and immunotherapy

BACKGROUND

Oral cancers are the sixth most common cancer worldwide, yet the prognosis following a diagnosis of oral cavity or oropharyngeal cancers remains poor, with approximately 50% survival at five years. Despite a sharp increase in research into molecularly targeted therapies and a rapid expansion in the number of clinical trials assessing new targeted therapies, their value for treating oral cancers is unclear. Therefore, it is important to summarise the evidence to determine the efficacy and toxicity of targeted therapies and immunotherapies for the treatment of these cancers.

OBJECTIVES

To assess the effects of molecularly targeted therapies and immunotherapies, in addition to standard therapies, for the treatment of oral cavity or oropharyngeal cancers.

SEARCH METHODS

We searched the following electronic databases: Cochrane Oral Health Group Trials Register (to 3 February 2015), Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2015, Issue 1), MEDLINE via Ovid (1946 to 3 February 2015) and EMBASE via Ovid (1980 to 3 February 2015). We searched the US National Institutes of Health Trials Register (clinicaltrials.gov), the World Health Organization Clinical Trials Registry Platform, the American Society of Clinical Oncology conference abstracts and the Radiation Therapy Oncology Group clinical trials protocols for ongoing trials. We placed no restrictions on the language or date of publication.

SELECTION CRITERIA

We included randomised controlled trials where more than 50% of participants had primary tumours of the oral cavity or oropharynx, and which compared targeted therapy or immunotherapy, plus standard therapy, with standard therapy alone.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the results of the electronic searches, extracted data and assessed the risk of bias of the included studies. We attempted to contact study authors for missing data or clarification where necessary. We combined sufficiently similar studies in meta-analyses using random-effects models when there were at least four studies and fixed-effect models when fewer than four studies. We obtained or calculated a hazard ratio (HR) and 95% confidence interval (CI) for the primary outcomes where possible. For dichotomous outcomes, we reported risk ratios (RR) and 95% CIs.

MAIN RESULTS

Twelve trials (2488 participants) satisfied the inclusion criteria. In the included trials, 12% of participants (298 participants) had tumours of the oral cavity and 59% (1468 participants) had oropharyngeal tumours. The remaining 29% had tumours of the larynx or hypopharynx and less than 1% had tumours at other sites.No included trial was at low risk of bias; seven had an unclear risk of bias, and five had a high risk of bias. We grouped trials by intervention type into three main comparisons: standard therapy plus epidermal growth factor receptor monoclonal antibody (EGFR mAb) therapy (follow-up period 24 to 70 months); standard therapy plus tyrosine kinase inhibitors (TKIs) (follow-up period 40 to 60 months) and standard therapy plus immunotherapy (follow-up period 24 to 70 months), all versus standard therapy alone.Moderate quality evidence showed that EGFR mAb therapy may result in 18% fewer deaths when added to standard therapy (HR of mortality 0.82; 95% CI 0.69 to 0.97; 1421 participants, three studies, 67% oropharyngeal tumours, 2% oral cavity tumours).There was also moderate quality evidence that EGFR mAb may result in 32% fewer locoregional failures when added to radiotherapy (RT) (HR 0.68; 95% CI 0.52 to 0.89; 424 participants, one study, 60% oropharyngeal tumours).A subgroup analysis separating studies by type of standard therapy (radiotherapy (RT) or chemoradiotherapy (CRT)) showed some evidence that adding EGFR mAb therapy to RT may result in a 30% reduction in the number of people whose disease progresses (HR 0.70; 95% CI 0.54 to 0.91; 424 participants, one study, 60% oropharyngeal tumours, unclear risk of bias). For the subgroup comparing EGFR mAb plus CRT with CRT alone there was insufficient evidence to determine whether adding EGFR mAb therapy to CRT impacts on progression-free survival (HR 1.08; 95% CI 0.89 to 1.32; 891 participants, one study, 70% oropharyngeal tumours, high risk of bias). The high subgroup heterogeneity meant that we were unable to pool these subgroups.There was evidence that adding cetuximab to standard therapy may result in increased skin toxicity and rash (RR 6.56; 95% CI 5.35 to 8.03; 1311 participants, two studies), but insufficient evidence to determine any difference in skin toxicity and rash in the case of nimotuzumab (RR 1.06; 95% CI 0.85 to 1.31; 92 participants, one study).There was insufficient evidence to determine whether TKIs added to standard therapy impacts on overall survival (HR 0.99; 95% CI 0.62 to 1.57; 271 participants, two studies; very low quality evidence), locoregional control (HR 0.89; 95% CI 0.53 to 1.49; 271 participants, two studies; very low quality evidence), disease-free survival (HR 1.51; 95% CI 0.61 to 3.71; 60 participants, one study; very low quality evidence) or progression-free survival (HR 0.80; 95% CI 0.51 to 1.28; 271 participants, two studies; very low quality evidence). We did find evidence of an increase in skin rash (erlotinib: RR 6.57; 95% CI 3.60 to 12.00; 191 participants, one study; lapatinib: RR 2.02; 95% CI 1.23 to 3.32; 67 participants, one study) and gastrointestinal complaints (lapatinib: RR 15.53; 95% CI 2.18 to 110.55; 67 participants, one study).We found very low quality evidence from one small trial that adding recombinant interleukin (rIL-2) to surgery may increase overall survival (HR 0.52; 95% CI 0.31 to 0.87; 201 participants, 62% oral cavity tumours, 38% oropharyngeal tumours) and there was insufficient evidence to determine whether rIL-2 impacts on adverse effects.

AUTHORS' CONCLUSIONS

We found some evidence that adding EGFR mAb to standard therapy may increase overall survival, progression-free survival and locoregional control, while resulting in an increase in skin toxicity for some mAb (cetuximab).There is insufficient evidence to determine whether adding TKIs to standard therapies changes any of our primary outcomes.Very low quality evidence from a single study suggests that rIL-2 combined with surgery may increase overall survival compared with surgery alone.

The role of cetuximab in the management of head and neck cancers

INTRODUCTION

The standard of care for patients with locally-advanced head and neck cancer is chemoradiation or surgical resection followed by radiation treatment with or without chemotherapy and despite aggressive, multimodality therapies with their associated toxicities, attempts are being made to improve efficacy while reducing toxicity. Cetuximab is a chimeric mAb directed against the EGFR that showed clinical activity in squamous cell carcinoma of head and neck (SCCHN).

AREAS COVERED

Cetuximab is beneficial in recurrent and metastatic setting, as well as in the definitive setting. In a landmark study by Bonner et al., cetuximab was found to be effective in prolonging survival in conjunction with radiation treatment in locally-advanced tumors versus radiation therapy alone. The Erbitux in First-Line Treatment of Recurrent or Metastatic Head and Neck Cancer (EXTREME) trial also showed an improvement in conjunction with chemotherapy in recurrent and metastatic tumors.

EXPERT OPINION

Cetuximab is an important therapeutic option in SSCHN, and will continue to be used in metastatic and definitive settings. While cetuximab is a valuable tool in the treatment of SCCHN, more studies are needed to maximize the efficacy of this mAb in clinical settings and to identify the subpopulation of patients that truly benefit from its use.

Cetuximab may inhibit tumor growth and angiogenesis induced by ionizing radiation: a preclinical rationale for maintenance treatment after radiotherapy

BACKGROUND

The benefits of radiotherapy and cetuximab have encouraged evaluation of cetuximab after radiotherapy. The aims of this study were to preclinically evaluate the efficacy of cetuximab maintenance after radiotherapy and eventually determine its mechanisms of action.

METHODS

The A431 human carcinoma cell line was treated in culture with fractionated radiotherapy and cetuximab. The surviving cells were injected s.c. into nude mice to mimic microscopic residual disease. The animals were randomized to receive either cetuximab or saline solution. Tumor growth, cell proliferation (Ki-67), microvessel density (MVD), epidermal growth factor receptor (EGFR) and transforming growth factor (TGF-α) mRNA transcription, and vascular endothelial growth factor (VEGF) secretion were measured.

RESULTS

Tumors from irradiated cells had a faster growth rate, higher Ki-67 index, and greater angiogenesis than tumors from untreated cells. This aggressive phenotype was associated with in vitro radiation-induced extracellular signal-related kinase (ERK)-1/2 and Akt activation, greater EGFR and TGF-α transcription, and augmented VEGF secretion, all of which were inhibited by cetuximab. In cetuximab-treated mice with tumors arising from irradiated cells, time to volume was longer by a factor of 3.52, whereas the Ki-67 index and MVD were 1.57 and 1.49 times lower, respectively, a larger enhancement than seen in tumors from untreated cells. These findings suggest that cells surviving radiation may express factors that promote cell survival and induce an aggressive phenotype that may potentially be blocked by cetuximab maintenance therapy.

CONCLUSIONS

These results support the clinical evaluation of adjuvant therapy with cetuximab after radiotherapy in EGFR-dependent carcinomas.