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

Surgical treatments for oral cavity (mouth) and oropharyngeal (throat) cancers*

Key messages

• In people with mouth cancer, elective removal of neck lymph nodes at the same time as primary tumour removal, compared with the removal of neck lymph nodes only when they become cancerous, probably increases survival and reduces recurrence, but may increase the risk of unwanted effects.
• Future studies of surgical treatment of mouth and throat cancers should report findings according to primary tumour location and measure quality of life and illness or disability associated with treatment.

What is the background to the review?

Oral cavity (mouth) and oropharyngeal (throat) cancers are becoming more common and are very difficult to cure. Treatment can involve surgery, chemotherapy, radiotherapy, or a combination of these. For people with mouth cancer, the removal of the lymph nodes (small glands that filter cancer cells and other foreign substances) is sometimes part of the treatment; this is known as neck dissection. Surgeons sometimes remove lymph nodes that appear cancer free while removing the original tumour (elective neck dissection). Other surgeons adopt a 'watch and wait' approach, removing lymph nodes when they become cancerous. The type of dissection can be radical neck dissection, where all the lymph nodes are removed, or selective neck dissection, where only diseased nodes are removed. One way to determine whether the lymph node is diseased is to perform a lymph node biopsy.

What did we want to find out?

We wanted to know which surgical treatments are most likely to result in people with mouth and throat cancers living longer (overall survival), living longer without symptoms (disease‐free survival), and not having the cancer come back at the same site (locoregional recurrence) or spread to other sites (recurrence). We also wanted to know if the different treatments have unwanted effects.

What did we do?

We searched for studies that randomly allocated people with mouth or throat cancer to different types of surgical treatment. We summarised the characteristics and findings of relevant studies and assessed our confidence in the results.

What did we find?

We included 15 studies (four new studies in this update) that evaluated nine comparisons of different treatments. No studies compared different approaches to cutting out the original (primary) tumour. The studies involved 2820 participants.

Main results

Five studies evaluated removal of the primary tumour, comparing elective neck dissection with the 'watch and wait approach' in people with mouth cancer. The results show that elective neck dissection probably leads to longer overall and disease‐free survival and less locoregional recurrence, but more unwanted effects.

Two studies compared radical neck dissection versus selective neck dissection in people with mouth cancer. It is unclear which treatment provides better outcomes.

Two trials evaluated a more limited neck dissection (superselective) versus selective neck dissection; we were unable to use the data reported.

One study compared a more selective neck dissection (supraomohyoid) and a modified radical neck dissection. We were unable to use the data reported. The modified radical neck dissection group had more complications, more pain, and poorer shoulder function, but we are very uncertain about the results.

In one study, all the people in one group had a lymph node biopsy and only had neck lymph nodes removed if the biopsy was positive, while all people in the other group had neck lymph nodes removed without a biopsy. There may be no difference between these two approaches in terms of overall survival, disease‐free survival, and locoregional recurrence. No unwanted effects were reported.

One study evaluated using a special scan (positron emission tomography‐computed tomography (PET‐CT)) after combined chemotherapy and radiotherapy to guide decisions about neck dissection, versus a planned neck dissection before or after chemoradiotherapy. There is probably no difference between these approaches in terms of overall survival or locoregional recurrence. There may be no difference in unwanted effects, but we are very uncertain about the results.

One trial suggested that surgery plus radiotherapy may result in better overall survival than radiotherapy alone, but we are very uncertain about the results. Surgery may result in more thickened scar tissue. There may be no difference with regard to other unwanted effects.

One study compared surgery versus radiotherapy in people with throat cancer. There may be no difference in overall survival, disease‐free survival, or unwanted effects, but we are very uncertain about the results.

One study compared surgery followed by radiotherapy versus chemotherapy. People receiving surgery and radiotherapy may live longer without symptoms, but we are very uncertain about the results.

What are the limitations of the evidence?

We are moderately confident that elective neck dissection at the same time as removal of the main tumour improves survival and reduces recurrence. Not all studies provided information about everything that we were interested in.

We are moderately confident that PET‐CT does not improve survival or reduce recurrence. There are too few studies to be certain about the results.

We have little confidence in results from other comparisons due to too few studies and limited information within them.

How up to date is this evidence?

The evidence is current to 9 February 2022.

*This is a plain language summary of a review that is published in the Cochrane Library. You can access the full report here: https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD006205.pub5/full#CD006205-abs-0002