Highlighted review: Surgical treatments for oral cavity (mouth) and oropharyngeal (throat) cancers

Vishal M Bulsara, Helen V Worthington, Anne‐Marie Glenny, Janet E Clarkson, David I Conway, Michaelina Macluskey

Plain language summary: Surgical treatments for oral cavity (mouth) and oropharyngeal (throat) cancers

Review question
We evaluated clinical trials of surgical treatments for oral and oropharyngeal cancers to find out which were most likely to result in people with these cancers living longer (overall survival). living longer without symptoms (disease‐free survival), and not experiencing a recurrence of the cancer at the same site or spread to other sites.

We also wanted to find out how different treatments affect disease symptoms, quality of life, time in hospital, complications, side effects and cost.

Background
Oral cancer is among the most common cancers worldwide, with more than 400,000 new cases diagnosed in 2012. The treatment of these cancers can involve surgery, chemotherapy, radiotherapy, or a combination of two or all three therapies.

This topic area was identified as a priority by an expert working group for oral and maxillofacial surgery in 2014. Authors working with Cochrane Oral Health conducted this review, which is an update of a review originally published in 2007 and first updated in 2011. The evidence is current to 20 December 2017.

Study characteristics
We included 12 trials (five new for this update) that investigated the success of surgical treatment for oral cancers. The studies involved 2300 participants, 2148 of whom had mouth cancers. The trials included seven comparisons of different treatment options. None of them compared different surgical approaches for cutting out the primary tumour.

Key results
The findings of the studies are mixed and it is not possible to draw firm conclusions about the optimal surgical approach for mouth and throat cancers.

Surgical removal of the lymph nodes in the neck that appear to be cancer‐free, at the same time as the cancer is removed did not seem to be associated with longer survival in two studies whose results were combined. Another study, however, suggested there may be a benefit of early neck surgery in terms of overall survival and 'disease‐free survival' (length of time after primary treatment without signs and symptoms of disease). One study found cancer recurrence at or around the same site was less likely with the early surgery, while three other studies did not favour either treatment.

There was no evidence that removal of all the lymph nodes in the neck resulted in longer survival compared to selective surgical removal of affected lymph nodes.

One study evaluated use of a special scan (positron‐emission tomography‐computed tomography (PET‐CT)), after a combination of chemotherapy and radiotherapy, to guide decisions about neck dissection, and found no difference in mortality (death) compared with undertaking a planned neck dissection before or after chemoradiotherapy.

There were a number of other surgical approaches compared in the studies, but we were unable to use the results in this review.

Although removal of lymph nodes from the neck is known to be associated with significant negative effects related to appearance and functions such as eating, drinking and speaking, the studies reported poorly on these side effects and did not measure quality of life accurately enough or in large enough numbers to be included in any of our analyses.

Certainty of the evidence
The certainty of the evidence was very low as there were few studies for each comparison and they were at risk of bias because of the way they were designed. Some comparisons and outcomes had no useable results.

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Citation: Bulsara VM, Worthington HV, Glenny AM, Clarkson JE, Conway DI, Macluskey M. Interventions for the treatment of oral and oropharyngeal cancers: surgical treatment. Cochrane Database of Systematic Reviews 2018, Issue 12. Art. No.: CD006205. DOI: 10.1002/14651858.CD006205.pub4.