CTF Structured Abstract: Oral cancer

Canadian Task Force on Preventive Health Care

Structured Abstract

Please note: In 2003, the CTF updated its Grades of Recommendations to include an "I Recommendation" for situations where insufficient evidence exists to allow a recommendation to be made. (Formerly, these situations were captured under a "C Recommendation".) This change is not retroactive, and all "C Recommendations" made prior to 2003 have not been reevaluated in light of the new "I" recommendation grade. For a discussion of these recommendation grades, please link to the 2003 article in the Canadian Medical Association Journal here.

Preventive Health Care, 1999 Update: Prevention of Oral Cancer Mortality

Prepared by Robert J. Hawkins, DDS, Faculty of Dentistry, University of Toronto, Ontario, Elaine Wang, MDCM, MSc, FRCP (C), Dept. of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, and James L. Leake, DDS, DDPH, MSc, FRCD(C), Faculty of Dentistry, University of Toronto, Ontario

These recommendations were finalized by the Task Force in January 1999

Objective
Burden of Suffering
Options
Outcomes

Evidence
Values
Benefits, Harms, and Costs

Recommendations
Validation
Sponsors

Objective

To evaluate the role of counselling and screening to prevent oral cancer and to establish evidence based guidelines.

Burden of Suffering

In 1996, the estimated incidence and number of deaths from oral cancer in Canada were 3,090 and 1,070, respectively. Death from oral cancer accounted for 1.7% of all cancer deaths. From 1987 to 1991, the number of new cases per year ranged from 2,837 to 3,017, while the number of deaths was 960 to 1,026. 1n 1993 the potential years of life lost due to oral cancer was 17,000. 71% of all cases were found among men aged 50 and over. For this group, the probability of developing oral cancer increased from age 50 to 90 from 0.2% to 1.7%.

Five-year survival rates of 50% or less are often reported for patients and have not improved substantially since the 1960s, as nodal involvement and metastases generally occur prior to diagnosis. Mortality and morbidity are both high in advanced stages and treatment may lead to impaired function, pain or disfigurement. Chewing ability may be compromised by the disease or therapy. Financial costs are generally high, because rehabilitation and prosthetic replacements are often required following treatment.

Options

Counselling to modify risk factors such as tobacco use or alcohol consumption; population-based screening for cancer or precancer; screening by clinical examination.

Outcomes

Survival rates following therapy for oral cancer, progression of precancerous lesions to malignancy, complications of disease and therapy, and costs of disease and screening. Rates of smoking cessation and alcohol reduction.

Evidence

MEDLINE and CANCERLIT databases were searched from 1966 to 1999 using the MeSH and text terms mouth neoplasms, oral cancer, precancer, screening, population surveillance, therapy, smoking cessation, alcohol reduction, and evaluation studies. Reference lists of key papers were reviewed and manual searches of relevant journals were conducted. Only English language journals were reviewed.

Recommendations were graded as:

A Good evidence to support the recommendation that the condition be specifically considered in a PHE.

B Fair evidence to support the recommendation that the condition be specifically considered in a PHE.

C Poor evidence regarding inclusion or exclusion of the condition in a PHE, but recommendations may be made on other grounds.

D Fair evidence to support the recommendation that the condition be specifically excluded from consideration in a PHE.

E Good evidence to support the recommendation that the condition be specifically excluded from consideration in a PHE.

Quality of evidence was rated according to 5 levels:

I Evidence from at least 1 properly randomized controlled trial (RCT).

II-1 Evidence from well-designed controlled trials without randomization.

II-2 Evidence from well-designed cohort or case-control analytic studies, preferably from more than 1 centre or research group.

II-3 Evidence from comparisons between times or places with or without the intervention. Dramatic results in uncontrolled experiments could also be included here.

III Opinions of respected authorities, based on clinical experience, descriptive studies or reports of expert committees.

Values

The 9-member Task Force of experts in family medicine, geriatric medicine, pediatrics, psychiatry and epidemiology used an evidence-based method for evaluating the effectiveness of preventive health care interventions. Recommendations were not based on cost-effectiveness of options. Patient preferences were not discussed.

Background papers providing critical appraisal of the evidence and tentative recommendations prepared by the chapter author were pre-circulated to the members. Evidence for this topic was presented and deliberated upon in a 2-day meeting in May 1998. Consensus was reached on final recommendations.

Benefits, Harms, and Costs

Health care provider counselling has been shown to increase smoking cessation rates over 6 to 12 months, with physicians reporting counselling more often than dentists. 70% to 80% of physicians have reported offering counselling, while 30% to 40% of dentists report the same. 3 case-control studies indicated that smoking cessation decreases the odds ratio of developing oral cancer. Following 10 years of cessation, the odds ratio of ex-smokers becomes equal to non-smokers. Following 10 years of follow-up, a study in India found a decrease in the incidence of precancerous lesions among the intervention cohort in comparison to the control group in response to an anti-tobacco education program.

To date, only one study has been conducted to assess the link between screening and prevention of oral cancer. This non-controlled study of cancer screening in Cuba included approximately 13 million examinations over a 6-year period from 1984-1990. Although the proportion of cancers detected increased from 24% to 49%, there was no change in oral cancer incidence or mortality over the study period. However, the short duration of the study may have precluded any improvements.

Surgical removal is the standard therapy for localized lesions. When surgical removal is made difficult due to the location or extent of the lesion, other therapies to consider include: 13-cis-retinoic acid (13cRA), beta-carotene, and bleomycin. 13cRA has been shown to be more effective than beta-carotene, but is more commonly associated with side effects. Bleomycin has been shown to be more effective than a placebo, but there are no trials comparing bleomycin and 13cRA. No controlled studies have evaluated surgery or radiotherapy for early stage malignant lesions.

Recommendations

Recommendation grade [A, B, C, D, E] and level of evidence [I, II-1, II-2, II-3, III] are indicated after each recommendation. Citations in support of individual recommendations are identified in the guideline text.

There is good evidence to include counselling for smoking cessation in the periodic health examination [A, I, II-2]. No specific recommendation was made for alcohol reduction counselling for the prevention of oral cancer; however, counselling for problem drinking may be indicated for other conditions.
There is fair evidence to exclude population screening for oral cancer by clinical examination [D, II-2].
There is insufficient evidence to include or exclude opportunistic screening for oral cancer by clinical examination of asymptomatic patients [C, II-2]

Validation

This report was externally peer reviewed. The US Department of Health and Human Services, Agency for Health Care Policy and Research agrees with smoking cessation counselling recommendation of this report. The screening recommendations in this report are consistent with those of the US Preventive Services Task Force and the UK Working Group on Oral Cancer. Both indicate screening for high-risk groups. The American Cancer Society recommends routine screening for asymptomatic persons over age 20. Although no official statements have been made, dental organizations support the concept of oral cancer screening.

A	Good evidence to support the recommendation that the condition be specifically considered in a PHE.
B	Fair evidence to support the recommendation that the condition be specifically considered in a PHE.
C	Poor evidence regarding inclusion or exclusion of the condition in a PHE, but recommendations may be made on other grounds.
D	Fair evidence to support the recommendation that the condition be specifically excluded from consideration in a PHE.
E	Good evidence to support the recommendation that the condition be specifically excluded from consideration in a PHE.

I	Evidence from at least 1 properly randomized controlled trial (RCT).
II-1	Evidence from well-designed controlled trials without randomization.
II-2	Evidence from well-designed cohort or case-control analytic studies, preferably from more than 1 centre or research group.
II-3	Evidence from comparisons between times or places with or without the intervention. Dramatic results in uncontrolled experiments could also be included here.
III	Opinions of respected authorities, based on clinical experience, descriptive studies or reports of expert committees.