November is Mouth Cancer Action Month, and the Cochrane Oral Health Group has a range of systematic reviews dedicated to the topic. Mouth cancer can affect anybody; in the UK more than 6,700 people were diagnosed with the condition last year, and more than 2,000 people died from the disease, more than testicular and cervical cancer combined. Here’s what the evidence says…
Limited evidence that screening programmes can be effective
A review on Screening programmes for the early detection and prevention of oral cancer found that a visual examination as part of a population-based screening programme can reduce the mortality rate of the disease in people who are at high risk. However, the evidence was limited to one study with a high risk of bias. The review concluded that more randomized controlled trials on the efficacy of screening programmes are needed. These should be of high quality and should report according to CONSORT guidance.
Diagnosing potentially malignant disorders
The Oral Health Group’s first published review on diagnostic test accuracy was Clinical assessment to screen for the detection of oral cavity cancer and potentially malignant disorders in apparently healthy adults. It looked at the diagnostic accuracy of conventional oral examination, vital rinsing, light-based detection, biomarkers and mouth self-examination for the early detection of potentially malignant disorders or cancers of the lip and mouth. 13 relevant studies were identified. There were a lot of differences between the studies, which made comparisons difficult. However, it was concluded that when the prevalence of the disease is reported at 1-5% of the population, the “Index tests” under review were better at classifying the absence of potentially malignant disorders in people who didn’t have the disease than they were at detecting its presence in diseased individuals. The advice for dentists and other dental care professionals is to remain vigilant for signs of mouth cancer when performing routine oral examinations.
Oral cancer treatments: chemotherapy and radiotherapy can increase overall survival
Three of the Group’s reviews look at treatments for oral cavity and oropharyngeal cancer. They considered chemotherapy, radiotherapy and surgical treatment. The chemotherapy review found that its use resulted in improvements in overall survival of between 8% and 22%. It also found that chemotherapy given at the same time as radiotherapy is more effective than chemotherapy given before radiotherapy, and may reduce the need for surgery. Radiotherapy also resulted in improved survival, however new methods of giving radiotherapy (accelerated fractionation or hyperfractionation) may be associated with increased side effects. The studies in the surgical review focused on patients with cancers in the oral cavity. They did not show that surgery to remove the lymph nodes in the neck, which appear to be cancer-free, at the same time as the cancer is removed is associated with longer survival, but there is evidence that early neck surgery reduces recurrence of the cancer. Neither is there evidence that removal of all the lymph nodes in the neck results in longer survival compared to selective surgical removal of affected lymph nodes. Although removal of lymph nodes from the neck is associated with significant adverse effects related to appearance and functions such as eating, drinking and speaking, the studies in this review did not measure quality of life.
- British Dental Health Foundation, Mouth Cancer Action Month
- Brocklehurst P, Kujan O, O’Malley LA, Ogden G, Shepherd S, Glenny AM. Screening programmes for the early detection and prevention of oral cancer. Cochrane Database of Systematic Reviews 2013, Issue 11. Art. No.: CD004150. DOI: 10.1002/14651858.CD004150.pub4.
- Walsh T, Liu JLY, Brocklehurst P, Glenny AM, Lingen M, Kerr AR, Ogden G, Warnakulasuriya S, Scully C. Clinical assessment to screen for the detection of oral cavity cancer and potentially malignant disorders in apparently healthy adults. Cochrane Database of Systematic Reviews 2013, Issue 11. Art. No.: CD010173. DOI: 10.1002/14651858.CD010173.pub2.
- Furness S, Glenny AM, Worthington HV, Pavitt S, Oliver R, Clarkson JE, Macluskey M, Chan KKW, Conway DI. Interventions for the treatment of oral cavity and oropharyngeal cancer: chemotherapy. Cochrane Database of Systematic Reviews 2011, Issue 4. Art. No.: CD006386. DOI: 10.1002/14651858.CD006386.pub3
- Glenny AM, Furness S, Worthington HV, Conway DI, Oliver R, Clarkson JE, Macluskey M, Pavitt S, Chan KKW, Brocklehurst P, The CSROC Expert Panel. Interventions for the treatment of oral cavity and oropharyngeal cancer: radiotherapy. Cochrane Database of Systematic Reviews 2010, Issue 12. Art. No.: CD006387. DOI: 10.1002/14651858.CD006387.pub2
- Bessell A, Glenny AM, Furness S, Clarkson JE, Oliver R, Conway DI, Macluskey M, Pavitt S, Sloan P, Worthington HV. Interventions for the treatment of oral and oropharyngeal cancers: surgical treatment. Cochrane Database of Systematic Reviews 2011, Issue 9. Art. No.: CD006205. DOI: 10.1002/14651858.CD006205.pub3.