SEARCH

SEARCH BY CITATION

Keywords:

  • oral neoplasms;
  • familial risk;
  • tobacco;
  • alcohol drinking;
  • risk factors

Abstract

  1. Top of page
  2. Abstract
  3. Material and methods
  4. Results
  5. Discussion
  6. Acknowledgements
  7. References

Scanty data are available on familial risk in oral and pharyngeal cancer. The relationship between oral and pharyngeal cancer and family history of cancer in first-degree relatives was investigated using data from a multicentric case-control study conducted in Italy and Switzerland between 1992 and 2005 on 956 cases aged less than 79 years, with histologically confirmed incident oral and pharyngeal cancer, and 2362 controls admitted to hospital for acute, nonneoplastic conditions. Logistic regression models conditioned on sex, age, study centre, and including terms for education, tobacco smoking, alcohol drinking, and number of siblings were used to estimate the odds ratios (OR) of oral and pharyngeal cancer. The multivariate ORs were similar for a family history of oral and pharyngeal cancer (2.6, 95% confidence interval, CI, 1.5–4.5) and laryngeal cancer (3.8, 95% CI, 2.0–7.2). The OR was 3.1 (95% CI, 2.0–4.8) for oral and pharyngeal cancer and laryngeal cancer combined. The OR was 7.1 (95% CI, 1.3–37.2) for subjects with 2 or more first-degree relatives with oral and pharyngeal/laryngeal cancers. Significant increases in risk were also observed for a family history of melanoma (OR = 5.8; 95% CI, 1.3–26.4) and lung cancer (OR = 1.4; 95% CI, 1.0–2.0). Compared to subjects without family history, nonsmokers, and non or moderate drinkers, the OR was 42.6 for current smokers, heavy drinkers with family history. History of oral and pharyngeal cancer and laryngeal cancer is a strong determinant of oral and pharyngeal cancer risk, independent from tobacco and alcohol. © 2007 Wiley-Liss, Inc.

Incidence and mortality from oral and pharyngeal cancer vary widely across the world.1, 2 This variation depends mostly on differences in exposure to tobacco and alcohol, the 2 major risk factors for oral and pharyngeal cancer. However, genetic factors may also contribute to explain the observed differences in rates.2

Only a few epidemiologic studies have assessed familial risks in oral and pharyngeal cancer. A case-control study from the United States on 487 cases found odds ratios (OR) of 1.2 (95% confidence interval (CI), 0.7–2.3) in subjects with a family history of oral and pharyngeal cancer, and of 1.6 (95% CI, 0.7–3.8) for a family history of cancers of the esophagus and larynx.3 Another case-control study from Puerto Rico on 342 oral and pharyngeal cancers showed ORs of 2.5 (95% CI, 0.8–8.0) in subjects reporting a first-degree relative with oral and pharyngeal cancer, and of 2.6 (95% CI, 1.4–4.8) in those reporting upper aerodigestive tract cancers.4 A record-linkage study on the Utah Population Database, which includes ∼1 million individuals, found a standardized incidence ratio of oral and pharyngeal cancer of 1.8 (95%, 0.5–4.0) for subjects with a first-degree relative with cancer at the same site (8 observed versus 4.4 expected cases).5

The familial aggregation of oral and pharyngeal cancers, however, may have different genetic and environmental correlates in different populations, including the prevalence of various susceptibility genes and the exposure to various environmental factors. Thus, to provide further data on the issue, we have examined the relation between family history of oral and pharyngeal cancer/laryngeal cancer and the risk of oral and pharyngeal cancer and other cancers using data from a large multicentric case-control study conducted in Italy and Switzerland.

Material and methods

  1. Top of page
  2. Abstract
  3. Material and methods
  4. Results
  5. Discussion
  6. Acknowledgements
  7. References

Data were derived from a case-control study of oral and pharyngeal cancer conducted between 1992 and 2005 in the greater Milan area and the provinces of Pordenone in northern Italy, of Rome and Latina in central Italy, and in the Swiss Canton of Vaud.6, 7 Data collection started and ended later in Milan. However, the same questionnaires and selection criteria were used in all centers.

Cases consisted of 956 patients under age 79 years admitted to major teaching and general hospitals in the areas under study with incident, histologically-confirmed carcinoma of the oral cavity and pharynx (median age 58 years, range 22–78). Controls were 2362 subjects under age 79 years (median age 58 years, range 19–79), selected among patients admitted to the same hospitals as cases for a wide spectrum of acute, nonneoplastic conditions, unrelated to known risk factors for oral and pharyngeal diseases, tobacco and alcohol consumption, and long-term modifications of diet. Seventeen percent of controls were admitted for traumas, 33% for other orthopedic disorders, 25% for surgical conditions, and 25% for miscellaneous other illnesses, including eye, nose, ear, skin or dental disorders. Less than 5% of cases and controls contacted refused to participate.

Centrally trained interviewers interviewed cases and controls during their hospital stay, using a structured questionnaire that included information on socio-demographic characteristics, anthropometric measures, lifestyle habits (including tobacco smoking and alcohol drinking), a validated food frequency section, and personal medical history. Informed consent was obtained prior to the interview from the patients and from the hospitals, in respect to the legislation in force. The subjects were specifically asked how many sisters and brothers they had, and whether their parents, siblings, children, grandparents or spouse had ever had cancer (excluding nonmelanoma skin cancer). For each relative with a history of cancer, the subject was asked to report the vital status of the relative at the time of interview, his/her current age or the age at death, the site of the tumour and the age at cancer diagnosis. In the present analysis, we considered the history of cancer in first-degree relatives only, i.e., parents, siblings and children. On account of recall and classification difficulties, some sites were combined (i.e., the whole intestinal tract, Hodgkin and non-Hodgkin lymphomas, cervix and corpus uteri). No verification of the cancer diagnoses in the relatives was performed.

Statistical analysis

We estimated the OR and the corresponding 95% CIs of oral and pharyngeal cancer according to history of cancer at selected sites in first-degree relatives using conditional multiple logistic regression models.8 The models were conditioned on sex, age and study centre, and included terms for education, tobacco smoking, alcohol drinking, and number of brothers and sisters.

Results

  1. Top of page
  2. Abstract
  3. Material and methods
  4. Results
  5. Discussion
  6. Acknowledgements
  7. References

Table I gives the distribution of 956 cases and 2362 controls according to center, age, sex and selected covariates. By design, the proportion of women was higher in controls than in cases, and the age distribution was similar in cases and controls. Cases reported higher tobacco and alcohol consumption.

Table I. Distribution of 956 Oral and Pharyngeal Cancer Cases and 2362 Controls According to Center, Sex, Age and Selected Covariates (Italy and Switzerland, 1992–20051)
 Cases (%)Controls (%)
  • 1

    The sum may not add up to the total because of some missing values.

  • 2

    1 Cigar equals 3 cigarettes, 1 g of pipe tobacco equals 1 cigarette.

  • 3

    Ex-smokers were subjects who had stopped smoking for at least 1 year.

Center
 Pordenone494 (51.7)1053 (51.6)
 Milano207 (21.6)590 (28.4)
 Roma104 (10.9)438 (22.1)
 Vaud151 (15.8)281 (11.9)
Sex
 Male781 (81.7)1546 (65.5)
 Female175 (18.3)816 (34.5)
Age (years)
 <50199 (20.8)585 (24.8)
 50–59336 (35.2)703 (29.7)
 60–69328 (34.3)789 (33.4)
 70–7993 (9.7)285 (12.1)
 Range (median)22–78 (58)19–79 (58)
Education (years)  
 <7497 (52.3)1159 (49.1)
 7–11279 (29.3)722 (30.6)
 ≥12175 (18.4)480 (20.3)
Smoking habit2
 Never smoker113 (11.8)990 (42.0)
 Ex-smoker3239 (25.0)716 (30.3)
 Current smoker  
  1–19 cigarettes/day240 (25.1)367 (15.6)
  ≥20 cigarettes/day363 (38.1)286 (12.1)
Alcohol consumption
 <21 drinks/week262 (27.5)1477 (62.6)
 21–34 drinks/week113 (11.8)410 (17.4)
 ≥35 drinks/week430 (45.1)337 (14.3)
 Ex drinkers149 (15.6)137 (5.8)
Sisters (number)
 0228 (23.9)586 (24.8)
 1316 (33.0)698 (29.5)
 2177 (18.7)484 (20.5)
 ≥3233 (24.4)594 (25.2)
Brothers (number)
 0260 (27.2)558 (23.6)
 1287 (30.0)782 (33.1)
 2180 (18.8)450 (19.1)
 ≥3229 (24.0)572 (24.2)

Table II presents the relation between oral and pharyngeal cancer risk and several aspects of family history of oral and pharyngeal cancer and/or laryngeal cancer. The ORs of oral and pharyngeal cancer according to family history of oral and pharyngeal cancer and laryngeal cancer were similar (OR = 3.0 and 3.2, respectively). The OR for oral and pharyngeal cancer and laryngeal cancer combined was 3.1. The ORs became 2.6, 3.8 and 3.1, respectively, for oral and pharyngeal cancer, laryngeal cancer and oral and pharyngeal/laryngeal cancers after adjustment for education, smoking, alcohol and number of brothers and sisters. No substantial differences emerged according to the type of relative and the age of the relative at diagnosis of oral and pharyngeal/laryngeal cancers, while the adjusted OR was 7.1 (95% CI, 1.3–37.2) for those with 2 or more first-degree relatives affected.

Table II. Odds Ratio of Oral and Pharyngeal Cancer According to Family History of Oral and Pharyngeal Cancer, Laryngeal and Oral and Pharyngeal/Laryngeal Cancers in First-Degree Relatives in a Multicenter Study From Italy and Switzerland, 1992–2005
 Family history of oral and pharyngeal cancerFamily history of laryngeal cancerFamily history of oral and pharyngeal cancer /laryngeal cancer
Cases:ControlsOR1 (95% CI)2OR3 (95% CI)2Cases:ControlsOR1 (95% CI)2OR3 (95% CI)2Cases:ControlsOR1 (95% CI)2OR3 (95% CI)2
  • 1

    ORs conditioned on sex, age and study centre.

  • 2

    95% Confidence interval.

  • 3

    Further adjusted for education, smoking, alcohol and number of brothers and sisters when appropriate.

  • 4

    Reference category: no family history.

  • 5

    Subjects with both a sibling and parent/child affected were 3 cases for a family history of oral and pharyngeal cancer, 2 cases and 2 controls for a family history of laryngeal cancer and 6 cases and 2 controls for a family history of oral and pharyngeal cancer/laryngeal cancer.

No915:23281414925:23391414885:23051414
Yes41:343.0 (1.9–4.9)2.6 (1.5–4.5)31:233.2 (1.8–5.6)3.8 (2.0–7.2)71:573.1 (2.2–4.6)3.1 (2.0–4.8)
Type of relative5
 Parent/child25:193.1 (1.7–5.9)2.3 (1.1–4.8)17:132.6 (1.2–5.6)3.0 (1.3–6.9)42:322.9 (1.8–4.8)2.6 (1.5–4.7)
 Sibling19:152.9 (1.4–6.1)3.0 (1.3–7.0)16:123.0 (1.4–6.6)3.8 (1.5–9.5)35:272.9 (1.7–5.1)3.4 (1.8–6.7)
Age of youngest affected relative
 <55 years13:103.3 (1.4–8.1)3.1 (1.1–8.8)9:73.1 (1.1–8.9)3.9(1.2–13.3)22:173.3 (1.7–6.6)3.5 (1.6–7.9)
 ≥55 years28:242.9 (1.6–5.2)2.4 (1.2–4.6)22:163.2 (1.6–6.3)3.8 (1.8–7.9)49:403.0 (2.0–4.7)3.0 (1.8–4.9)
Number of affected relatives
 138:342.8 (1.7–4.7)2.4 (1.4–4.3)27:203.0 (1.7–5.6)3.7 (1.9–7.3)63:542.9 (2.0–4.3)2.9 (1.9–4.6)
 ≥23:04:34.4(0.9–21.6)5.0(0.8–32.3)8:37.7 (1.9–30.9)7.1(1.3–37.2)

Table III gives the distribution of cases and controls according to family history of oral and pharyngeal cancer in separate strata of age, tobacco and alcohol consumption, and the corresponding ORs. No clear differences in risk emerged between strata of covariates. The tests for interaction were not significant for any of the strata considered.

Table III. Odds Ratio of Oral and Pharyngeal Cancer According to Family History of Oral and Pharyngeal Cancer/Laryngeal Cancers in Strata of Selected Covariates (Italy and Switzerland, 1992–2005)
StratumFamily history of oral and pharyngeal cancer/laryngeal cancer
(Cases:Controls)OR1 (95% CI)2OR3 (95% CI)2
NoYes
  • 1

    ORs conditioned on sex, age and study centre. Reference category: no family history.

  • 2

    95% Confidence interval.

  • 3

    Further adjusted for education, smoking, alcohol and number of brothers and sisters when appropriate.

  • 4

    Former smokers since less than five years were included in the “current” smokers category.

Age (years)
 <60 years498:126037:283.6 (2.1–6.1)3.6 (1.9–6.8)
 ≥60 years387:104534:292.7 (1.6–4.6)2.7 (1.5–4.8)
Smoking4
 Never/former241:152921:422.3 (1.3–4.1)2.2 (1.2–4.0)
 Current644:77450:154.6 (2.5–8.6)4.8 (2.5–9.4)
Alcohol (drinks/week)
 <21251:144211:351.8 (0.9–3.7)2.1 (1.0–4.3)
 21 to <3599:40014:105.9 (2.5–13.9)6.6 (2.7–16.3)
 ≥35399:32631:112.1 (1.0–4.3)2.0 (1.0–4.3)

The joint effect of smoking, drinking and family history of oral and pharyngeal cancer is shown in Figure 1. Compared to the lowest risk category, i.e., never/ex smokers (former smokers since less than 5 years were included in the “current” smokers category), drinkers of <21 drinks/week without family history, the risk was increased in those with one or more factors in the highest risk category. Moreover, in each combination of smoking and drinking habits, a family history of oral and pharyngeal/laryngeal cancers increased the risk of oral and pharyngeal cancer. The OR was 1.9 (95% CI, 0.8–4.5) for nonsmokers, moderate drinkers with family history of oral and pharyngeal/laryngeal cancers, 11.7 (95% CI 8.8–15.6) for current smokers and heavy drinkers without family history, and 42.6 (95% CI 18.2–99.8) for smokers and heavy drinkers who also reported a first degree relative with oral and pharyngeal /laryngeal cancers.

thumbnail image

Figure 1. Odds ratios (and 95%, CI) of oral and pharyngeal cancer according to smoking and drinking and family history of oral, pharyngeal and laryngeal cancer. *number of cases: controls. # Former smokers since less than 5 years were included in the “current” smokers category. ORs conditioned on sex, age and study centre and adjusted for education and number of brothers and sisters when appropriate.

Download figure to PowerPoint

Table IV shows the number of cases and controls with history of other selected cancers in first-degree relatives, and the corresponding ORs. A significant increase in oral and pharyngeal cancer was observed with a family history of melanoma (OR = 5.8; 95% CI, 1.3–26.4) and lung cancer (OR = 1.4; 95% CI, 1.0–2.0). None of the other cancer sites showed a significant association. The OR was 1.3 (95% CI, 1.1–1.6) for all cancer sites combined, and 1.1 (95% CI, 0.9–1.4) for all sites except oral cavity, pharynx and larynx.

Table IV. Odds Ratio of Oral and Pharyngeal Cancer According to Family History of Selected Cancers in First-Degree Relatives (Italy and Switzerland, 1992–2005)
Cancer siteSubjects with family history (%)OR1 (95% CI)2OR3 (95% CI)2
CasesControls
  • 1

    ORs conditioned on sex, age and study centre. Reference category: no family history.

  • 2

    95% Confidence interval.

  • 3

    Further adjusted for education, smoking, alcohol and number of brothers and sisters when appropriate.

  • 4

    p < 0.05

Oral cavity and pharynx41 (4.3)34 (1.4)3.04(1.9–4.9)2.64(1.5–4.5)
Larynx31 (3.4)23 (1.0)3.24(1.8–5.6)3.84(2.0–7.2)
Esophagus12 (1.3)26 (1.1)1.1 (0.5–2.2)1.1 (0.5–2.6)
Stomach54 (5.7)89 (3.8)1.54(1.0–2.2)1.3 (0.9–2.0)
Intestines35 (3.7)79 (3.3)1.2 (0.8–1.8)1.2 (0.8–1.9)
Liver34 (3.6)68 (2.9)1.4 (0.9–2.2)1.4 (0.8–2.3)
Pancreas10 (1.1)48 (2.0)0.5 (0.3–1.0)0.6 (0.3–1.4)
Lung75 (7.9)125 (5.3)1.54(1.1–2.1)1.4 (1.0–2.0)
Melanoma6 (0.6)3 (0.1)6.04(1.4–25.7)5.84(1.3–26.4)
Breast41 (4.3)85 (3.6)1.2 (0.8–1.8)1.3 (0.8–2.0)
Cervix and corpus Uteri19 (2.0)43 (1.8)1.2 (0.7–2.1)1.1 (0.6–2.0)
Prostate12 (1.3)28 (1.2)1.0 (0.5–2.0)1.5 (0.7–3.3)
Bladder9 (0.9)17 (0.7)1.5 (0.6–3.6)1.0 (0.4–2.6)
Kidney0 (0)16 (0.7)
Brain11 (1.2)34 (1.4)0.7 (0.4–1.5)0.6 (0.3–1.4)
Lymphomas4 (0.4)10 (0.4)1.3 (0.4–4.5)0.9 (0.2–4.1)
Leukaemias17 (1.9)41 (1.7)1.0 (0.6–1.8)1.0 (0.5–2.0)
All sites348 (36.4)703 (29.8)1.44(1.2–1.6)1.34(1.1–1.6)
All sites excluding oral cavity, pharynx and larynx299 (31.3)663 (28.1)1.24(1.0–1.4)1.1 (0.9–1.4)

Discussion

  1. Top of page
  2. Abstract
  3. Material and methods
  4. Results
  5. Discussion
  6. Acknowledgements
  7. References

In this study, a family history of oral and pharyngeal cancer and/or, laryngeal cancer in first-degree relatives was directly and strongly associated with the risk of oral and pharyngeal cancer, and the risk was higher when 2 or more relatives were affected, and independent from alcohol and tobacco consumption. The risk of oral and pharyngeal cancer was also increased in subjects with a family history of cancers of the lung and skin melanoma.

With reference to potential sources of bias, we excluded from the control group all diagnoses potentially associated with the increased risk of oral and pharyngeal cancer, such as tobacco and alcohol related conditions.9 Moreover, the almost complete participation has likely reduced selection bias. Information on family history was self reported, and it is possible that cases of oral and pharyngeal cancer may tend to recall a family history of oral and pharyngeal cancer or other cancers more accurately than controls. Several studies, however, have shown that the recall of cancer in first-degree relatives is satisfactory and comparable in cases and controls, while the recall of cancer in second-degree relatives is less reliable.10–12 Therefore, we only considered first-degree relatives in our analysis. In a reproducibility analysis in our population, the Kappa of agreement between 2 interviews was >0.8 for family history of digestive tract cancers in first degree relatives.13 Moreover, family history of most cancer sites was not associated with an increased risk of oral and pharyngeal cancer in this study, suggesting that no major recall bias of cancer in general has affected our results. With reference to confounding, we allowed for tobacco and alcohol, the major risk factors for oral and pharyngeal cancer, education as a social class indicator, and for number of brothers and sisters.

Our findings of an elevated risk of oral and pharyngeal cancer in subjects with family history of oral and pharyngeal/laryngeal cancers are in broad agreement with other reports, although our point estimate is somewhat higher than in other studies.3–5

An inherited component of susceptibility to oral and pharyngeal cancer has been suggested by case reports of families with multiple affected members,14–16 by epidemiologic studies indicating familial tendency to oral and pharyngeal cancer or other cancers of upper aerodigestive tract,1, 17–23 by segregation analysis in first-degree relatives,24 by elevated risks associated with polymorphic genes involved in the metabolism of tobacco and alcohol (i.e., ALDH2),25–29 and by elevated risks associated with genes involved in DNA repair maintenance of genetic stability.30, 31

Familial aggregation of oral and pharyngeal cancers may also be due to shared environmental exposure to the main risk factors, i.e., alcohol and tobacco. However, the risk of oral and pharyngeal cancer was only moderately increased in individuals with a family history of lung cancer, and not related to a family history of cancer at other sites related to alcohol or alcohol and tobacco (i.e., esophagus or liver),9, 32 suggesting that tobacco and alcohol cannot totally explain this association. Our finding for a family history of lung cancer is consistent with the results of case-control studies from the United States3 (OR = 1.2) and Puerto Rico4 (OR = 1.2).

We found an association with family history of melanoma. Although the point estimate of the OR was around 6, this estimate was based on 6 cases and 3 controls only, with a lower confidence limit of 1.3. This association has not to our knowledge been previously reported, and needs therefore independent confirmation. In fact, given the multiple tests performed, this result may be due to chance.

The analysis of the joint effect with alcohol and tobacco found that family history was also a risk factor in nonsmokers and non or moderate drinkers. The ORs of family history in the low exposure category of smoking and drinking was 1.9, while the OR for high exposure to tobacco and alcohol in subjects without family history was 11.7. The OR of those with family history and high exposure to alcohol and tobacco predicted by assuming an additive effect would be 13, and 22 by assuming a multiplicative model.33 Our point estimate of 42.6 suggests, if anything, a multiplicative or a supra-multiplicative effect. In agreement with a study from Puerto Rico,4 compared to the lowest risk category, i.e., light smokers and light drinkers without family history, the OR was 1.8 for light smokers and drinkers with family history of oral and pharyngeal cancer/laryngeal cancer, 12.2 for heavy smokers heavy drinkers without family history, and 60.4 for those who were heavy smokers, heavy drinkers and also reported a first degree relative with upper aerodigestive tract cancer.

Thus, our study adds further and more precise quantification on the association of family history of cancer and oral and pharyngeal cancer and is, to our knowledge, the first comprehensive epidemiologic information on family history of cancer at several sites and risk of oral and pharyngeal cancer. Our results show that the best way to prevent oral and pharyngeal cancer is to avoid alcohol and tobacco exposure, even in subjects with a family history of this neoplasm. There is ample scope for prevention of oral and pharyngeal cancer, a neoplasm that has shown little sign of improvement in survival over the last few years.34

Acknowledgements

  1. Top of page
  2. Abstract
  3. Material and methods
  4. Results
  5. Discussion
  6. Acknowledgements
  7. References

The authors thank C. Pasche and F. Lucchini for the Swiss data collection and validation, and Ms. I. Garimoldi for editorial assistance.

References

  1. Top of page
  2. Abstract
  3. Material and methods
  4. Results
  5. Discussion
  6. Acknowledgements
  7. References
  • 1
    La Vecchia C,Tavani A,Franceschi S,Levi F,Corrao G,Negri E. Epidemiology and prevention of oral cancer. Oral Oncol 1997; 33: 30212.
  • 2
    La Vecchia C,Lucchini F,Negri E,Levi F. Trends in oral cancer mortality in Europe. Oral Oncol 2004; 40: 4339.
  • 3
    Goldstein AM,Blot WJ,Greenberg RS,Schoenberg JB,Austin DF,Preston-Martin S,Winn DM,Bernstein L,McLaughlin JK,Fraumeni JF,Jr. Familial risk in oral and pharyngeal cancer. Eur J Cancer B Oral Oncol 1994; 30: 31922.
  • 4
    Brown LM,Gridley G,Diehl SR,Winn DM,Harty LC,Otero EB,Fraumeni JF,Jr,Hayes RB. Family cancer history and susceptibility to oral carcinoma in Puerto Rico. Cancer 2001; 92: 21028.
  • 5
    Goldgar DE,Easton DF,Cannon-Albright LA,Skolnick MH. Systematic population-based assessment of cancer risk in first-degree relatives of cancer probands. J Natl Cancer Inst 1994; 86: 16008.
  • 6
    Negri E,Franceschi S,Bosetti C,Levi F,Conti E,Parpinel M,La Vecchia C. Selected micronutrients and oral and pharyngeal cancer. Int. J Cancer 2000; 86: 1227.
  • 7
    Levi F,Pasche C,La Vecchia C,Lucchini F,Franceschi S,Monnier P. Food groups and risk of oral and pharyngeal cancer. Int. J Cancer 1998; 77: 7059.
  • 8
    Breslow NE,Day NE. Statistical methods in cancer research, vol. I. The analysis of case-control studies. Lyon: IARC Scientific Publication no. 32, 1980.
  • 9
    Franceschi S,Talamini R,Barra S,Baron AE,Negri E,Bidoli E,Serraino D,La Vecchia C. Smoking and drinking in relation to cancers of the oral cavity, pharynx, larynx, and esophagus in northern Italy. Cancer Res 1990; 50: 65027.
  • 10
    Koch M,Gaedke H,Jenkins H. Family history of ovarian cancer patients: a case-control study. Int J Epidemiol 1989; 18: 7825.
  • 11
    Theis B,Boyd N,Lockwood G,Tritchler D. Accuracy of family cancer history in breast cancer patients. Eur J Cancer Prev 1994; 3: 3217.
  • 12
    Eerola H,Blomqvist C,Pukkala E,Pyrhonen S,Nevanlinna H. Familial breast cancer in southern Finland: how prevalent are breast cancer families and can we trust the family history reported by patients? Eur J Cancer 2000; 36: 11438.
  • 13
    Bravi F,Bosetti C,Negri E,Lagiou P,La Vecchia C. Family history of cancer provided by hospital controls was satisfactorily reliable. J Clin Epidemiol 2007; 60: 1715.
  • 14
    Ankathil R,Mathew A,Joseph F,Nair MK. Is oral cancer susceptibility inherited? Report of five oral cancer families. Eur J Cancer B Oral Oncol 1996; 32: 637.
  • 15
    Tashiro H,Abe K,Tanioka H. Familial occurrence of cancer of the mouth. J Oral Maxillofac Surg 1986; 44: 3223.
  • 16
    Hara H,Ozeki S,Shiratsuchi Y,Tashiro H,Jingu K. Familial occurrence of oral cancer: report of cases. J Oral Maxillofac Surg 1988; 46: 1098102.
  • 17
    Bondy ML,Spitz MR,Halabi S,Fueger JJ,Schantz SP,Sample D,Hsu TC. Association between family history of cancer and mutagen sensitivity in upper aerodigestive tract cancer patients. Cancer Epidemiol Biomarkers Prev 1993; 2: 1036.
  • 18
    Copper MP,Jovanovic A,Nauta JJ,Braakhuis BJ,de Vries N,van der Waal I,Snow GB. Role of genetic factors in the etiology of squamous cell carcinoma of the head and neck. Arch Otolaryngol Head Neck Surg 1995; 121: 15760.
  • 19
    Foulkes WD,Brunet JS,Kowalski LP,Narod SA,Franco EL. Family history of cancer is a risk factor for squamous cell carcinoma of the head and neck in Brazil: a case-control study. Int J Cancer 1995; 63: 76973.
  • 20
    Foulkes WD,Brunet JS,Sieh W,Black MJ,Shenouda G,Narod SA. Familial risks of squamous cell carcinoma of the head and neck: retrospective case-control study. Br Med J 1996; 313: 71621.
  • 21
    Yu GP,Zhang ZF,Hsu TC,Spitz MR,Schantz SP. Family history of cancer, mutagen sensitivity, and increased risk of head and neck cancer. Cancer Lett 1999; 146: 93101.
  • 22
    Jefferies S,Eeles R,Goldgar D,A'Hern R,Henk JM,Gore M. The role of genetic factors in predisposition to squamous cell cancer of the head and neck. Br J Cancer 1999; 79: 8657.
  • 23
    Mork J,Moller B,Glattre E. Familial risk in head and neck squamous cell carcinoma diagnosed before the age of 45: a population-based study. Oral Oncol 1999; 35: 3607.
  • 24
    De Andrade M,Amos CI,Foulkes WD. Segregation analysis of squamous cell carcinoma of the head and neck: evidence for a major gene determining risk. Ann Hum Genet 1998; 62: 50510.
  • 25
    Harty LC,Caporaso NE,Hayes RB,Winn DM,Bravo-Otero E,Blot WJ,Kleinman DV,Brown LM,Armenian HK,Fraumeni JF,Jr,Shields PG. Alcohol dehydrogenase 3 genotype and risk of oral cavity and pharyngeal cancers. J Nat Cancer Inst 1997; 89: 1698705.
  • 26
    Park JY,Schantz SP,Stern JC,Kaur T,Lazarus P. Association between glutathione S-transferase pi genetic polymorphisms and oral cancer risk. Pharmacogenetics 1999; 9: 497504.
  • 27
    Jourenkova-Mironova N,Mitrunen K,Bouchardy C,Dayer P,Benhamou S,Hirvonen A. High-activity microsomal epoxide hydrolase genotypes and the risk of oral, pharynx, and larynx cancers. Cancer Res 2000; 60: 5346.
  • 28
    Oshan AF,Weissler MC,Watson MA,Bell DA. GSTM1, GSTT1, GSTP1, CYP1A1, and NAT1 polymorphisms, tobacco use, and the risk of head and neck cancer. Cancer Epidemiol Biomarkers Prev 2000; 9: 18591.
  • 29
    Lewis SJ,Smith GD. Alcohol, ALDH2, and esophageal cancer: a meta-analysis which illustrates the potentials and limitations of a Mendelian randomization approach. Cancer Epidemiol Biomarkers Prev 2005; 14: 196771.
  • 30
    Sturgis EM,Castillo EJ,Li L,Zheng R,Eicher SA,Clayman GL,Strom SS,Spitz MR,Wei Q. Polymorphisms of DNA repair gene XRCC1 in squamous cell carcinoma of the head and neck. Carcinogenesis 1999; 20: 21259.
  • 31
    Berwick M,Vineis P. Markers of DNA repair and susceptibility to cancer in humans: an epidemiologic review. J Nat Cancer Inst 2000; 92: 87497.
  • 32
    Pelucchi C,Gallus S,Garavello W,Bosetti C,La Vecchia C. Alcohol and tobacco use and cancer risk for upper aero-digestive tract and liver. Alcohol Res Health 2006; 29: 1938.
  • 33
    Rothman KJ,Greenland S. Modern epidemiology. Philadelphia: Lippincott-Raven, 1998.
  • 34
    Franceschi S,Levi F,La Vecchia C. Decline in 5-year survival rates for cancer of head and neck. Lancet 1992; 340: 47.