Snuff dipping and oral cancer in Sudan: a retrospective study

Survival analysis of Sudanese oral squamous cell carcinoma patients with field of cancerization

BACKGROUND

The late presentation and diagnosis of OSCC account for the large number of patients with the advanced form of the disease. In Sudan, cases with delayed presentation, particularly those with risk factors such as Toombak dipping and alcohol consumption, frequently present with extensive lesions and a wide area of Field cancerization which characterized by the presence of genetic and epigenetic changes in histologically normal-appearing tissues, and have increased risk for recurrent and second primary tumors. This necessitates more aggressive treatment and is usually associated with poorer outcomes. The present study aims to investigate the survival of oral squamous cell carcinoma patients with a wide field of cancerization.

METHODS

This prospective longitudinal study includes ninety-three oral cancer patients with extensive fields of cancerization who underwent surgical treatment at Khartoum Teaching Dental Hospital (KTDH) conducted from 2019 to 2023. These patients were regularly assessed for clinical changes such as recurrence, the development of second primary tumours, and overall survival over a period of one year.

RESULTS

Out of the 93 patients, 57 (61.3%) were males, and 36 (38.7%) were females. The majority of the patients (82%) had stage IV tumours, and 62.3% had nodal metastasis. Twenty-eight (30%) patients developed recurrences, and 14 (15%) developed second primary tumours. The overall one-year survival rate was 89%, and all deceased patients passed away within 12 months. The survival rate for patients with different types of recurrences varied, with patients who had regional, local, and locoregional recurrences having survival rates of 87%, 74%, and 72%, respectively. Patients who did not experience a recurrence had a one-year survival rate of 92%. Patients who developed second primary tumours had an 86% survival rate. The survival rates for OSCC patients at stages III, IVa, and IVb were 90%, 90%, and 71%, respectively.

CONCLUSION

In this study, 62% of patients had nodal metastasis, 30% developed recurrence, and 15% developed second primary tumours. The overall one-year survival rate was 89%, although the development of recurrences and second primary tumours had a negative impact on the survival rate.

Recurrence in Oral Squamous Cell Carcinoma Associated with Wide Field of Cancerization: Analysis of 93 Cases

Background

The late presentation of oral squamous cell carcinoma (OSCC) patients in the Sudan, with advanced stages and wide field of cancerization, have a negative impact on both the morbidity and the mortality of these patients. The present study aimed to investigate the clinicopathological behavior of OSCC and predictors of development of recurrence in these patients.

Methods

This a prospective longitudinal study of 93 OSCC patients surgically treated at Khartoum Teaching Dental Hospital. Tumor's associated field of cancerization was identified. The patients were followed clinically on regular basis, for a year, for the development of recurrence.

Results

Out of the 93 patients, 57 (61.3%) were males and 36 (38.7%) were females. 82% of the patients presented with stage IV tumors, and 58 (62.4%) of the cases had nodal metastasis. Twenty-eight (30%) patients developed recurrence. Of them 17 (18.3%) had regional recurrence, eight (8.6%) had local recurrence and three (3.2%) had locoregional recurrence. Multivariate cox regression analysis showed that Toombak dipping (P.value = 0.001), tumor staging (P.value = 0.039) and presence of mucosal filed changes (P.value = 0.001) were independent predictors for local recurrence and positive pathological lymph nodes (P.value = 0.00) and extranodal extension (P.value = 0.040) were independent predictors for regional recurrence.

Conclusion

The present study showed that OSCC patients in the Sudan present with advanced lesions, mostly associated with wide field of cancerization particularly Toombak dippers. Overall recurrences were identified in 30% of the cases, regional recurrence was the commonest type followed by local recurrence.

Clinical Presentation of Wide Field of Cancerization Associated with Oral Squamous Cell Carcinoma

Background

The late presentation of oral squamous cell carcinoma (OSCC) patients in Sudan, with advanced stages and wide field of cancerization (WFC), has a negative impact on these patients. The present study aimed to investigate the different clinical presentations of mucosal changes in WFC associated with OSCC in Sudanese patients.

Methods

This a prospective longitudinal study of 93 OSCC cases. Tumor's associated field of cancerization was identified and related clinical mucosal changes were described.

Results

Out of the 93 patients, 57 (61.3%) were males and 36 (38.7%) were females. Eighty-two percent of the patients presented with stage IV tumors. Ninety-two patients had multiple sites involved in the oral cavity with overlap of sites involved. The Gingivobuccal mucosa (74.2%) was the most frequent site involved. Eighty-three (89.2%) of the lesions were surrounded by mucosal changes, of them 32 (38%) surrounded by a grizzle (mixed dark and white) discoloration and 21 (26%) were surrounded by a white-smoke discoloration followed by 17 (20%) and 13 (16%) surrounded by cotton-white and Café au lait discolorations, respectively. Forty-four (47.3%) lesions had overlapping presentations and surrounded by erythematous patches.

Conclusion

The present study showed that OSCC patients in Sudan present with advanced lesions, mostly associated with WFC, particularly the Toombak dippers. The different mucosal changes seen in the WFC associated with OSCC in these cases are in accordance with the known five mucosal presentations.

The ultra-structural, metabolomic and metagenomic characterisation of the sudanese smokeless tobacco 'Toombak'

Toombak is a smokeless tobacco produced from the Nicotiana rustica tobacco plant from Sudan. Pre-prepared and ready to buy Toombak samples were analysed using mass spectrometry (heavy metals), gas and liquid chromatography (metabolomics), 16S rRNA metagenomic sequencing (microbiome) and Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) and pH analysis. Chromium, cobalt, and copper were high in the pre-prepared form of Toombak while iron, tobacco specific nitrosamines (TSNAs), formaldehyde and acetaldehyde were high in both types. Firmicutes and Actinobacteria dominated Toombak. Samples of ready to buy Toombak showed inter-variational differences depending on place of purchase. We found Virgibacillus were increased in the pre-prepared form while Corynebacterium casei, Atopococus tabaci, Atopostipes suicloacalis, Oceanobacillus chironomi and Staphylococcus gallinarum were the most abundant species in the ready to buy forms. PICRUSt analysis highlighted increased activity of metal transport systems in the ready to buy samples as well as an antibiotic transport system. SEM-EDX highlighted large non-homogenous, irregular particles with increased sodium, while pH of samples was in the alkaline range. The final composition of Toombak is affected by its method of preparation and the end product has the potential to impart many negative consequences on the health of its users. TSNA levels observed in Toombak were some of the highest in the world while the micro-environment of Toombak supports a distinct microbiota profile.

Is toombak a risk factor for oral leukoplakia and oral squamous cell carcinoma ? A systematic review

INTRODUCTION

Toombak is a form of smokeless tobacco that is not well known in Western Society but is widely used by the Sudanese population and many others in the sub-Sahara region. However, unlike other smokeless tobacco products, information on the carcinogenic potential of toombak is scarce. The present review explored any potential epidemiological association between the use of toombak and oral leukoplakia and oral squamous cell carcinoma (OSCC).

METHODS

Databases including the Web of Science, SCOPUS, EMBASE and PubMed were searched for literature on the potential association between toombak and oral leukoplakia and OSCC. The search also included grey literature. The search period extended from 1990 to 2018. Following data mining, the study selection was conducted by two reviewers independently.

RESULTS

Eight studies that satisfied the inclusion criteria were included. Based on these results, there was a threefoldto sevenfold increased risk of developing the oral leukoplakia and oral squamous cell carcinoma among toombak users compared with non-users.

CONCLUSION

Based on the results of the systematic review, there is a strong epidemiological evidence to suggest toombak to be a major risk factor for both oral leukoplakia and OSCC. Further studies are necessary to evaluate the molecular pathway of toombak-induced oral carcinogenesis.

School workers' knowledge, attitude and behaviour related to use of Toombak: a cross sectional study from Khartoum state, Sudan

BACKGROUND

Toombak is a form of smokeless tobacco (SLT) that is locally made and consumed in Sudan and contains several carcinogenic elements. Use of Toombak has been etiologically linked to various oral diseases including oral cancer. This study aimed to obtain baseline information about the Toombak use among Sudanese school workers, as well as their knowledge about Toombak related health hazards and attitude towards their role in Toombak control. In addition, this study assessed the availability and effectiveness of control policies and preventive practices in the schools.

METHODS

A cross-sectional school-based study using one-stage stratified random sampling procedure; four schools were selected randomly from each of seven localities. A total of 239 school workers' were recruited (census) from the selected schools in Khartoum State, Sudan.

RESULTS

Of the school workers, 63% (147) were ≤40 years, half were females and 79.2% (187) were teachers. A total of 9.6% (22) school workers confirmed ever use of Toombak and the percentage of daily users amounted to 64.7% (11). Moreover, 76.2% (16) of ever Toombak users were ≥40 years and all of them were males (p < 0.001). Most of the school workers reported good knowledge, positive attitude towards their role in Toombak control and good preventive practice. Female school workers were more likely to report positive attitude towards their role in Toombak control (p < 05), and to report good knowledge. Those reporting good preventive practice in schools reported good knowledge more than two times than their counterpart (p < 0.001). Age was the strongest predictor of ever Toombak use among school workers (p < .001).

CONCLUSIONS

The use of Toombak among school workers was associated with poor knowledge, negative attitude towards their role in Toombak control and poor preventive practice, Therefore, school workers use of Toombak may reduce their motivation and use of their potential in the prevention of a major health problem caused by Toombak use and affects their role model behaviour. On the other hand, school workers engagement with preventive practices in schools' was associated with good knowledge which in turn empowers their positive attitude towards their role in Toombak control.

Oral Cancer Awareness in Sudan: Assessment of Knowledge, Attitude and Treatment Seeking Behavior

Objective:

This study was aimed to assess oral cancer awareness among a selected Sudanese population and to evaluate their knowledge and treatment seeking behavior.

Methods:

A questionnaire- based survey was performed on the general population who attended the oral cancer awareness campaigns carried between 2015 and 2016 in different geographic areas of the Sudan. It was focusing on general awareness of oral cancer, oral cancer risk factors, oral cancer clinical signs/symptoms and treatment seeking behavior. Data were entered by Microsoft excel 2007 and analyzed by SPSS (version 20) using chi square test with P value <0.05.

Result:

There were 1,370 participants, 634(46.3%) were males and 736(53.7%) were females. The responses of participants revealed that 66.6% have heard about oral cancer and the media was the common source of information (75.7%). Of all participants only 45.3% mentioned that they don’t have enough knowledge on oral cancer. Some participants believe that oral cancer is treatable (66.5%) whilst 30.4% respond by I don’t know. More than 80% of the respondents were aware that smokeless tobacco (toombak) is a risk factor for oral cancer. While 60.1% were aware of alcohol as a risk factor and 66.2% were aware of smoking as a risk factor. When qui square test was done, smokers were found to be the least to seek help in comparison to non-smokers. The same result was obtained from alcohol consumers but it was different in snuff dippers, as the latter response was similar to that of the non-snuff dippers.

Conclusion:

This study revealed a level of around 66.6% of oral cancer awareness in different states of Sudan. Counseling sessions should be conducted when necessary with further investigations to find out the reasons behind the continued practice of high risk habits, despite knowledge.

Differences in the Bacteriome of Smokeless Tobacco Products with Different Oral Carcinogenicity: Compositional and Predicted Functional Analysis

Smokeless tobacco (ST) products vary significantly in their oral carcinogenicity. Much is known about the differences in the chemical, but not the bacterial, constituents of these products. In this study, we explored the composition and function of the bacteriome in ST products from four countries using quantitative polymerase chain reaction (qPCR) and 16S rRNA-based next generation sequencing. The bacterial load (16S rRNA copies/gram) was lowest in Swedish snus (3.4 × 10⁶) and highest in Yemeni shammah (6.6 × 10¹¹). A total of 491 species-level taxa, many of which are potentially novel, belonging to 178 genera and 11 phyla were identified. Species richness and diversity were highest for Swedish snus and lowest for Yemeni shammah. Bacillus, Paenibacillus, and Oceanobacillus spp. were the most abundant in American snuff; species of Pseudomonas, Massilia, Propionibacterium, Puniceispirillum, and Gloeothece predominated in Swedish snus. In Sudanese toombak, Facklamia, Desemzia, Atopostipes, and Lysinibacillus spp. accounted for the majority of the bacteriome. Yemeni shammah exclusively contained Bacillus spp. Functional prediction by phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) showed that genes encoding cadmium/zinc and nickel transport systems were enriched in the presumptively “high carcinogenicity” products. The bacteriome of ST products thus differed qualitatively, quantitatively, and functionally. The relevance of these differences, particularly with respect to nickel and cadmium, to oral carcinogenesis warrants further investigation.

Epidemiology of Substance Use among University Students in Sudan

Background. Youth populations are vulnerable to substance use particularly in developing countries where circumstances may be favorable for it. There is no published data on substance use among the youth in Sudan other than on tobacco use. Objectives. The aim of this study was to investigate the prevalence, circumstances, and factors associated with substance use. Methods. An institution-based survey was conducted on a sample of 500 students. Data was collected using a questionnaire designed by the WHO for student drug surveys and analyzed using IBM SPSS version 20. Results. The overall prevalence of substance use is 31%. The current prevalence of tobacco, cannabis, alcohol, amphetamines, tranquilizers, inhalants, opiates, cocaine, and heroin use was 13.7%, 4.9%, 2.7%, 2.4%, 3.2%, 1%, 1.2%, 0.7%, and 0.5%, respectively. Curiosity (33.1%) was the main reason for initiation of substance use. The main adverse effects reported were health problems (19.7%) and theft (19.7%). Peers (40.9%) were the prime source of substance use. On multivariate analysis, male sex was the principle predictor for substance use (AOR: 5.55; 95% CI: 3.38, 9.17). Conclusion. Strategies to control substance use should encompass the role of the university and parents in observing and providing education to improve awareness of substances and their consequences.

Viral infection and oral habits as risk factors for oral squamous cell carcinoma in Yemen: a case-control study

OBJECTIVE

The role of qat chewing, tobacco (shammah) dipping, smoking, alcohol drinking, and oral viral infection as risk factors for oral squamous cell carcinoma (OSCC) in Yemen was assessed.

STUDY DESIGN

A total of 60 cases of OSCC and 120 age- and gender-matched controls were analyzed with respect to demographic data, history of oral habits, and the presence of human papillomavirus (HPV)-16, HPV-18, or Epstein-Barr virus (EBV) as determined by Taqman quantitative polymerase chain reaction. Logistic regression analysis was used to identify independent predictors of the disease.

RESULTS

Shammah use was the only risk factor for OSCC, with an odds ratio of 12.6 (CI, 3.3-48.2) and 39 (CI, 14-105) for the ex-users and current users, respectively. The association of shammah use alone with OSCC exceeded that of shammah use in combination with qat chewing, smoking, or both. EBV infection, smoking, and qat chewing showed no association with OSCC, while neither HPV-16 nor HPV-18 were detected in any sample.

CONCLUSIONS

Shammah use is a major risk factor for oral cancer in Yemen.

A Case-Control Study of Oral Epithelial Proliferative Markers among Sudanese Toombak Dippers Using Micronuclei Assay, Argyrophilic Nucleolar Organizer Region, Papanicolaou and Crystal Violet Methods

The use of Toombak has been reported to play a major role in the etiology of oral cancer in Sudan. The cellular proliferative activity on the oral epithelium of 210 Toombak dippers was assessed by applying the micronuclei frequency, mean argyrophilic nucleolar organizer region (AgNOR) counts, Papanicolaou method, and 1% crystal violet stain. Participants were divided into 3 groups: 200 were apparently healthy individuals, 100 were Toombak users (cases), 100 were non-tobacco users (control) and 10 were patients with oral squamous cell carcinomas. Cytological atypia was identified among 4 (4%). Toombak users and was not found among the control group (P<0.04). The micronuclei frequencies were higher in Toombak users (1.026) than in the control group (0.356) (P<0.0001). The mean AgNOR counts in Toombak users (2.423) were higher than control group (1.303) (P<0.0001). Neither Toombak users nor control group showed mitotic figures in 1% crystal violet method. The results of this research showed that Toombak dipping is a high risk factor for increase in the cellular proliferation in the oral mucosa. The cytological proliferative marker methods used are useful for screening Toombak users.

Survey on knowledge and attitudes related to the relation between tobacco, alcohol abuse and cancer in the northern state of Sudan

BACKGROUND

The aim of this study was to determine the epidemiology of tobacco smoking, toombak dipping and alcohol consumption as risk factors for cancer in the adult population of the northern state of Sudan.

MATERIALS AND METHODS

A cross-sectional survey from March to April 2010, covering 963 adults, was performed.

RESULT

Only 207 had responded, and the male female prevalence was 20.8% and 0.73%. Out of 207 respondents, 29.5% had smoked tobacco in their lifetime, 38% were toombak dippers, while 14% were consumers of alcoholic beverages.

CONCLUSIONS

The prevalence of toombak dipping was higher than tobacco smoking among the adult population in the northern state of Sudan. Female participation in tobacco and alcohol related studies was found to suffer from major obstacles since these habits are considered as social stigma. Appreciation of the full impact of smoking on population health will definitely make a major contribution to improvement of the poor public health situation in Sudan.

Immunophenotyping of HPV Types 16 and 18 among Sudanese Patients with Oral Lesions

OBJECTIVE

The aim of this study was to screen patients with oral lesions for the presence of Human Papilloma Virus (HPV) types 16 and 18.

METHODS

Sixty patients aged between 11-80 years with a mean age of 46 years were examined using immunohistological techniques. All samples were retrieved from RICK during the period from August 2009 to August 2010. Out of 60 patients, 50 had Oral Squamous Cell Carcinomas (OSCCs) and the remaining ten had benign oral lesions, included as internal control.

RESULTS

Of the 50 patients with OSCCs, 10 (20%) showed positive immunohistochemical results for HPV types 16 and 18 of which 50% were detected among males and 50% were demonstrated among females. The ten positive findings were Immunophenotyped as follows: five were positive with HPV type 16, four with type 18 and one was positive for HPV types 16 and18. All patients with benign oral lesions were negative for HPV immunohistochemistry.

CONCLUSION

The study suggests the role of HPV 16 and 18 in the etiology of oral cancers in different parts of Sudan. However, the use of molecular techniques such as PCR are needed to confirm the results of immunohistochemistry in the role of the HPV in developing of OSCC in Sudan.

Cancer in the Sudan: an overview of the current status of knowledge on tumor patterns and risk factors

The Sudan, the largest and most diverse country in Africa, is experiencing a growing cancer problem, but little is presently known on tumor patterns, cancer epidemiology and ethnic or environmental cancer risk factors. We review here the current status of knowledge, summarizing data from local and international publications as well as primary information from the only two cancer hospitals of the country, both located in Central Sudan (Khartoum and Wad Medani). We provide frequencies reported for cancers detected in adults and children, and summarize studies on specific cancer types, as well as information on risk factors that most likely impact on tumor patterns.

A survey of oral health in a Sudanese population

Background

We aimed to assess the oral health status and risk factors for dental caries and periodontal disease among Sudanese adults resident in Khartoum State. To date, this information was not available to health policy planners in Sudan.

Methods

A descriptive population-based survey of Sudanese adults aged ≥ 16 years was conducted. After stratified sampling, 1,888 adult patients from public dental hospitals and dental health centres scattered across Khartoum State, including different ethnic groups present in Sudan, were examined in 2009-10. Data were collected using patient interviews and clinical examinations. Dental status was recorded using the DMFT index, community periodontal index (CPI), and a validated tooth wear index.

Results

Caries prevalence was high, with 87.7% of teeth examined having untreated decay. Periodontal disease increased in extent and severity with age. For 25.8% of adults, tooth wear was mild; 8.7% had moderate and 1% severe toothwear. Multivariate analysis revealed that decay was less prevalent in older age groups but more prevalent in southern tribes and frequent problem based attenders; western tribes and people with dry mouths who presented with less than18 sound, untreated natural teeth (SUNT). Older age groups were more likely to present with tooth wear; increasing age and gender were associated with having periodontal pocketing ≥ 4 mm.

Conclusions

The prevalence of untreated caries and periodontal disease was high in this population. There appear to be some barriers to restorative dental care, with frequent use of dental extractions to treat caries and limited use of restorative dentistry. Implementation of population-based strategies tailored to the circumstances of Sudanese population is important to improve oral health status in Sudan.

Adverse effects of Sudanese toombak vs. Swedish snuff on human oral cells

BACKGROUND

The high incidence of oral cancer in Sudan has been associated with the use of toombak, the local type of smokeless tobacco. However, its specific effects on human oral cells are not known. We aimed to investigate the effects of toombak on primary normal human oral keratinocytes, fibroblasts, and a dysplastic oral keratinocytic cell line, and to compare them with the effects induced by Swedish snuff.

METHOD

Aqueous extracts were prepared from moist toombak and Swedish snuff and added in serial dilutions on in vitro monolayer cultured cells. Cell viability, morphology and growth, DNA double-strand breaks (gammaH2AX staining), expression of phosphatidylserine (Annexin V staining), and cell cycle were assessed after various exposure time periods.

RESULTS

Significant decrease in cell number, occurrence of DNA double-strain breaks, morphological and biochemical signs of programmed cell death were detected in all oral cell types exposed to clinically relevant dilutions of toombak extract, although to a lesser extent in normal oral fibroblasts and dysplastic keratinocytes. G2/M-block was also detected in normal oral keratinocytes and fibroblasts exposed to clinically relevant dilutions of toombak extract. Swedish snuff extract had less adverse effects on oral cells, mainly at non-clinically relevant dilutions.

CONCLUSION

This study indicates a potential for toombak, higher than for Swedish snuff, to damage human oral epithelium. Dysplastic oral keratinocytes were less sensitive than their normal counterparts, suggesting that they might have acquired a partially resistant phenotype to toombak-induced cytotoxic effects while still being prone to DNA damage that could lead to further malignant progression.

Clinical, pathological, cellular and molecular lesions caused by oral smokeless tobacco - a review

While carcinogenicity of smokeless tobacco (ST) to humans is well established the oral lesions that precede development of cancer are less well characterized. The clinical appearances of ST-associated lesions are variable. Epidemiological studies show a strong significant association of risk with chronic daily use but population differences are noted because of various commercial products in use. Morphological features observed are some what different to oral lesions caused by smoking and oral dysplasia in ST-associated lesions is less common. Effects of ST on oral keratinocytes observed in vitro include alterations in cell proliferation, apoptosis and activation of inflammatory markers. Genetic aberrations caused by ST include activation of ras, uncommon in smokers but mutational hot spots in p53 encountered are similar to those in smokers.

Prevalence of oral cancer and potentially malignant lesions among shammah users in Yemen

The purpose of this study was to assess the prevalence of oral precancerous lesions and squamous cell carcinoma (OSCC) in Yemeni users of shammah, a traditional smokeless tobacco habit known in the Arabian Peninsula. The study group comprised 199 male and one female shammah users who were interviewed via a standardised questionnaire and clinically examined in 48 Yemeni villages and cities. Cases with oral leukoplakia (OL) or mucosal burns (MB) were compared with users without any lesion. MB were detected in 31%, of which 46.8% were located on the tongue or floor of the mouth, and OL in 27%, of which 59.2% were located in the same region. In addition, two cases (1%) of apparent OSCC were identified. Statistically significant increased OR (95% CI) of OL were (a) 6.91 (2.66-17.95) for an average duration of the respective shammah application >5min.; (b) 4.90 (1.99-12.08) for a daily frequency of those applications >10; and (c) 4.22 (1.43-12.43) for a daily duration >6h of chewing qat, also a traditional habit in Yemen. Likewise, decreased OR were (a) 0.39 (0.18-0.85) for rinsing the mouth after the shammah application; (b) 0.36 (0.17-0.78) for successful attempts to stop the use in the past; and (c) 0.26 (0.09-0.72) for existing knowledge about the carcinogenicity of shammah that was present in only 19% overall. In conclusion, evidence was shown for a significant association between the prevalence of OL and the daily duration of shammah application in a dose-dependent manner. An appropriate public health program might help to reduce this potential OSCC burden in shammah users.

Traditional healers' perceptions of smokeless tobacco use and health in the Limpopo Province of South Africa

Traditional healers (THs) exert a significant influence in indigenous South African communities, where smokeless tobacco (SLT) use and dependence is common among women. This study was conducted during 2002. It sought to explore THs' beliefs about SLT use and its health effects. In-depth interviews were conducted with 28--mostly female (68%)--registered THs, with a mean age of 55 years and with an average of 17 years of practice experience. These listed THs were randomly selected from two culturally diverse regions of the (largely rural) Limpopo Province in South Africa. The THs perceive the ritual (external) use of SLT as an absolute necessity in divination, but 32% have also prescribed its 'internal' use to their clients, usually following a "directive from the ancestors." Almost all the THs who themselves regularly consume SLT condemned the recreational use of SLT and believe that SLT is addictive. However, 39% of them claimed to be able to treat addiction resulting from tobacco use not sanctioned by the ancestors. This study has identified opportunities for enlisting THs' collaboration in future community-based tobacco dependence interventions.

Intra-oral carcinomas in Maiduguri, north-eastern Nigeria

OBJECTIVE

To document the pattern of intra-oral carcinomas diagnosed in north-eastern Nigeria.

DESIGN AND SETTING

A retrospective clinical and histopathological review seen in a tertiary care hospital (January 1987-December 2002).

MATERIALS AND METHODS

Information on socio-demographic characteristics of patients and details of cancer management were retrieved from the files and histopathology records of cases diagnosed at the hospital.

RESULTS

A total of 378 biopsies, 317 primary cancers including 279 carcinomas of the head and neck were diagnosed during the study period. Intra-oral carcinomas constitute 43 (15.4%) of all head and neck carcinomas reported, with no occurrence in children. The overall mean age of occurrence was 51.2 +/- 15.6 years (male = 56.2 +/- 13.7 years; females = 47.5 +/- 16.2 years) and an overall male-female ratio of 3:4. Carcinomas were commonly reported in the palate 19 (44.2%) and lip six (13.9%) and floor of mouth four (9.3%). Squamous cell carcinoma 28 (65.1%), adenoidcystic carcinoma seven (16.3%) and mucoepidermoid carcinoma five (11.6%) were the commonly reported carcinomas. Squamous cell carcinoma was the most common carcinoma in all sites, in the sixth decade of life, of equal gender distribution and commonly reported in users of kola nuts and tobacco. The occupation of patients diagnosed with oral carcinoma and squamous cell carcinoma was farming (50%, 61.5%). All the staged cancers patients (n = 7) reported in the late stages (III/IV) of the disease. The mean interval between symptoms and presentation for the different carcinomas ranged between 9 and 25 months, with the least interval reported for mucoepidermoid carcinoma.

CONCLUSIONS

Squamous cell carcinoma was the most common oral carcinoma, commonly reported in the palate, among farmers and in the sixth decade of life. Its occurrence in under 40 year olds is three to six times greater than reported for the USA and Europe and may be associated with poor diet and the habitual use of kola nuts and tobacco. The survival rates of patients diagnosed with intra-oral carcinomas, although not available, would be expectedly low in view of the prognostic indicators recorded in this series. The routine oral cancer screening of each patient, and counselling of patients with high-risk habits, by dentists is recommended to improve the prognosis of the disease.

Oral malignant neoplasia: a survey of 428 cases in two Zimbabwean hospitals

A review of oral malignant neoplasms biopsies accessioned in the pathology services of Harare Central Hospital and Parirenyatwa Hospital, Harare, Zimbabwe, during the 10year period January 1982 to December 1991 was carried out. Clinical records of 428 patients with histologically diagnosed oral malignant neoplasms by ICD-O type and site (COO.O-CO6.9) were retrieved and analyzed for gender, age, history of tobacco and alcohol usage, neoplastic type and histologic differentiation of squamous cell carcinoma (8000/3). Oral malignant neoplasms constituted 24.8% (n = 428) of the 1723 biopsies accessioned in the department during this period. There was a male to female ratio of 1.9:1, with lesions being most common in the 41-60 year age group. Squamous cell carcinoma, (8070/3) 73.1%, was the predominant oral malignancy most common in the 61-70 year age group with 21.1% on the mandibular gingivae (CO3.1), 20.5% on the tongue (CO1.9-CO2.9), 18.5% on the floor of the mouth (CO4.9) and 10.5% each on the maxillary gingivae (CO3.O) and buccal mucosa (CO6.O). The hard palate (CO5.9) had 9% of the lesions. Lip malignancy (COO-COO.9 and C44.0), inclusive of mucosa of lip, vermilion and skin, constituted 3.3% and minor salivary gland (CO6.9) malignancy (M-8940/3) 4.9%. The remaining oral malignancies, 11%, included Burkitt's lymphoma (M-9687/3) 4.7%; Kaposi's sarcoma (M-9140/3) 3.7%; osteosarcoma (M-9180/3) 2.6% and malignant melanoma (M-8720/3) 1.9%. Fourty five percent of the patients admitted tobacco and alcohol consumption, of whom 95% were males. Oral malignant neoplasms were more common in males than females and occurred in a relatively young age group. Well-differentiated squamous cell carcinoma (M-8070/31) was the most common oral malignant neoplasm and was most frequently found on the mandibular gingivae (CO3.1), tongue (CO1.9-CO2.9) and floor of the mouth (CO4.9). The lip (COO-COO.9) was least affected with a high palatal (CO5.9) involvement.

Smokeless tobacco use and risk of cancer of the pancreas and other organs

Limited data are available on the carcinogenicity of smokeless tobacco products in organs other than the mouth. Snus is a smokeless tobacco product widely used in Norway. We studied 10,136 Norwegian men enrolled since 1966 in a prospective cohort study, 31.7% of whom were exposed to snus. The relative risk of pancreatic cancer for snus use was 1.67 (95% confidence interval [CI] = 1.12, 2.50); that of oral and pharyngeal cancer was 1.10 (95% CI = 0.50, 2.41), that of esophageal cancer was 1.40 (95% CI = 0.61, 3.24), and that of stomach cancer was 1.11 (95% CI = 0.83, 1.48). The relative risks of cancers of the lung (either all histological types or adenocarcinoma), urinary bladder and kidney were not increased among snus users. The increase in the relative risk of pancreatic cancer was similar in former and current snus users and was restricted to current tobacco smokers. Our study suggests that smokeless tobacco products may be carcinogenic on the pancreas. Tobacco-specific N-nitrosamines are plausible candidates for the carcinogenicity of smokeless tobacco products in the pancreas.

Habitual risk factors for head and neck cancer

Chronic tobacco smoking and alcohol consumption are well-established risk factors for the development of squamous cell carcinoma (SCC) of the head and neck. There are, however, a variety of other habitual and culturally based activities that are less commonly seen in the Western world and that are also risks factors for the development of this type of cancer. In this era of globalization, many of these habits have now crossed borders and appear in various areas throughout the world. This article reviews habitual and social risk factors for cancer of the head and neck, excluding smoking and alcohol consumption. These factors include chewing tobacco and snuff, areca nut in its various forms, Khat leaves, and the drinking of Mate.

EBM RATING

D.

The Swedish snus and the Sudanese toombak: are they different?

In Sweden, snuff (locally known as snus), was introduced since the year 1637. Presently, Sweden has the highest per capita consumption and sale figures of snuff in the world, and the habit is becoming increasingly popular. Snus is manufactured into a dry form used in the nasal cavity and a moist form used in the oral cavity. Snus manufactured for oral use is a moist ground tobacco of Dark Kentucky or Virginia species mixed with an aqueous solution of water and other blending ingredients. This form of snuff is found in two types: (1) loose and (2) portion-bag-packed. These are the most widely used. The loose moist form (1-2 g a quid) is the most popular type consumed by 73% of the males, followed by the portion-bag-packed form (0.5-1 g a quid), consumed by 13% of the males, while 14% of the males are mixed users. The majority of snus users place the quid in the vestibular area of the upper lip, and the prevalence among persons 15 years of age or older in 15.9% among males and 0.2% among females. The pH of snus has declined from a previous range of 8-9 to a range of 7.8-8.5, moisture content ranges 35-60% and nicotine content is in the order of 5-11 mg/g dry wt tobacco-specific N-nitrosamines (TSNAs) in micrograms (N'-nitrosonornicotine: NNN 5-9; 4-(methyl-nitrosamino)-1-(3-pyridyl)-1-butanone: NNK 1-2; N'-nitrosoanatabine: NAT 2-5). In the Sudan, snuff, locally known as toombak, was introduced approximately 400 years ago. It is always processed into a loose moist form, and its use is widespread in the country. Tobacco used for manufacture of toombak is of the species Nicotiana rustica, and the fermented ground powder is mixed with an aqueous solution of sodium bicarbonate. The resultant product is moist, with a strong aroma, highly addictive and its use is widespread particularly among males. Its pH range is 8-11, moisture content ranges 6-60% and nicotine content is from 8 to 102 mg/g dry wt, and TSNAs contents in micrograms (NNN 420-1 550; NNK 620-7 870; NAT 20-290). Snus and toombak dippers develop a clinically and histologically characteristic lesion at the site of dipping. Probably due to control of the TSNAs in snus, this type of snuff is associated with a lower risk of cancer of the oral cavity (relative risk: RR 5-6-fold), whereas the risk for cancer of the oral cavity among toombak users was high (RR 7.3-73.0-fold). In conclusion, the two snuff products significantly differ in many aspects. Most notable differences are tobacco species, fermentation and ageing, nicotine and TSNAs content, pH, expression of the p53 tumour suppressor gene, and keratin types 13, 14, and 19. It was, therefore, the object of the present study to highlight the oral health hazards of toombak, and to compare it with snus regarding the aforementioned differences.

Toombak use and cigarette smoking in the Sudan: estimates of prevalence in the Nile state

BACKGROUND

Survey data on the prevalence of use of oral snuff (toombak) and cigarette consumption according to various demographic factors are needed in the Sudan.

METHODS

A house to house cross-sectional survey of a random population sample of 4,535 households was performed. Of the 23,367 household members identified, 21,648 (92.6%) eligible individuals were questioned about tobacco use.

RESULTS

Among children and adolescents (4-17 years) prevalence of tobacco use was quite low (2%, range 1-2%), but there was an abrupt increase up to 25% in late adolescence. Among the adult population aged 18 years and older the prevalences of toombak use (34%) and cigarette smoking (12%) among males were significantly higher than among females (2.5 and 0.9%, respectively). The prevalence of toombak use among the male population aged 18 years and older was significantly higher in the rural than in the urban areas (35% vs 24%), while cigarette smoking had a higher prevalence in urban areas (18% vs 12%). The highest rates of toombak use were found in rural areas among the male population ages 30 years and older (mean 46.6%, range 45-47%).

CONCLUSIONS

In view of the high prevalence of tobacco use, especially of toombak, among the population surveyed, there is an urgent need to educate the public on the health consequences of these habits.

Immunohistochemical detection of p53 in non-malignant and malignant oral lesions associated with snuff dipping in the Sudan and Sweden

Immunohistochemistry was used to examine the expression of p53 in pre-malignant oral lesions and oral squamous-cell carcinomas (SCCs) from Swedish and Sudanese snuff-dippers, as well as in pre-malignant oral lesions and oral SCCs from non-snuff-dippers from the Sudan, Sweden and Norway. Of the 14 SCCs from Sudanese snuff-dippers, 21% (3/14) expressed p53. Of the 14, 60 and 41 SCCs from non-snuff-dippers from the Sudan, Sweden and Norway, 64% (9/14), 65% (39/60) and 68% (28/41) expressed p53, respectively. A statistically significant difference in expression of p53 was found in SCCs from Sudanese snuff-dippers compared to those from non-snuff-dippers from all/or any of the 3 countries. None of the suspected pre-malignant oral lesions from Sudanese snuff dippers or non-snuff-dippers expressed p53. Only 2 out of the 15 oral fibro-epithelial hyperplastic lesions from Swedish snuff-dippers expressed p53. Some of the oral epithelial dysplastic lesions, as well as the carcinoma in situ lesions from Norwegian non-snuff-dippers, expressed p53, while the oral fibro-epithelial hyperplastic lesions did not. The low relative frequency of p53 expression found in oral SCCs from snuff-dippers compared to those from non-snuff-dippers might suggest differences in mechanisms of oncogenic action induced by snuff. Alternatively, the pathogenesis of malignant oral lesions from snuff-dippers may follow a p53-independent pathway. In view of the unusually high levels of the tobacco-specific nitrosamines (TSNA) found in the type of snuff used in the Sudan, investigations of p53 mutations or oncogenes are needed.

Toombak-associated oral mucosal lesions in Sudanese show a low prevalence of epithelial dysplasia

Clinical (n = 281) and histopathological (n = 141) characteristics of toombak-associated oral mucosal lesions detected in an epidemiological study in northern Sudan in 1992/93 are described. The lesional site in the majority of toombak users was the anterior lower labial groove and the lower labial mucosa. 4 degrees (1-4) of clinical severity of lesions, similar to those used to characterise Swedish snuff-dipper's lesion, were applied. An association between the severity of mucosal lesions and a longer lifetime duration (> 10 years) of toombak use was found, but the severity was not related to the daily frequency of the habit. Parakeratosis, pale surface staining of the epithelium and basal cell hyperplasia were commonly observed, but epithelial dysplasia was infrequent (10/141). The most significant observation was a PAS-positive amorphous deposit between the lamina propria and the submucosa, found in 25/141 biopsies. The clinical and histopathological features of toombak lesions are closely similar to Swedish moist snuff-dipper's lesions and this may reflect the high alkalinity of these products, resulting in an alkaline burn on the oral mucosa following chronic exposure. The low prevalence of epithelial dysplasia implies a low risk of malignant transformation. Nevertheless, the high concentrations of tobacco-specific nitrosamines present in toombak, and the high prevalence of oral cancer in Sudan, mandate biopsy and careful histopathological analysis of any such lesions detected in habitues.

Formation and analysis of tobacco-specific N-nitrosamines

Chemical-analytical studies during the past 4 years led to several new observations on the formation of tobacco-specific N-nitrosamines (TSNA) and their occurrence in smokeless tobacco, mainstream smoke (MS), and sidestream smoke (SS) of American and foreign cigarettes. When snuff was extracted by means of supercritical fluid extraction with carbon dioxide containing 10% methanol, analysis of this material confirmed that the extraction with organic solvents had been partially incomplete. Epidemiological studies in the northern Sudan showed a high risk for oral cancer for users of toombak, a home-made oral snuff. Toombak contains 100-fold higher levels of TSNA than commercial snuff in the U.S. and Sweden. The TSNA content in the saliva of toombak dippers is at least ten times higher than that reported in the saliva of dippers of commercial snuff. Biomarker studies have shown corresponding high levels of hemoglobin adducts with metabolites of NNN and NNK as well as for urinary metabolites of NNK. These data supported the epidemiological findings. The analyses of MS of U.S. and foreign cigarettes smoked under FTC conditions revealed comparable data for the smoke of nonfilter cigarettes and filter cigarettes except in the case of low- and ultralow-yield cigarettes, which showed reduced TSNA yields. The MS of cigarettes made from Burley or dark tobacco is exceptionally high in TSNA, primarily because of the high nitrate content of those tobacco types. Taking puffs of larger volume and drawing puffs more frequently, practices observed among most smokers of cigarettes with low nicotine yield, results in high TSNA values in the MS. The formation of the lung carcinogen NNK is favored during the smoldering of cigarettes, between puffs, when SS is generated. Consequently, in most samples from indoor air polluted with environmental tobacco smoke (ETS), the highest concentration of an individual TSNA is that of NNK. When nonsmokers had remained for up to 2 h in a test laboratory with high ETS pollution, they excreted measurable amounts of NNK metabolites in the urine, indicative of the uptake of TSNA.

Toombak dipping and cancer of the oral cavity in the Sudan: a case-control study

To investigate the possible causal association between squamous-cell carcinomas of the oral cavity and use of toombak, we retrospectively compared the history of use of this substance in 375 patients with squamous-cell carcinomas of the lip, buccal cavity and floor of mouth, and 271 patients with squamous carcinomas of the tongue, palate and maxillary sinus, with 204 patients exhibiting non-squamous oral and non-oral malignant neoplasms and 2,820 individuals who had no malignancy, selected from the general population. The study revealed that the high prevalence of oral cancer in the Sudan is largely due to chronic use of toombak. The adjusted ORs associated with toombak dipping for the first case group, cancer of the lip, buccal cavity and floor of mouth in comparison with the hospital and population control groups, were 7.3 and 3.9 (95% confidence limits, 4.3-12.4 and 2.9-5.3) respectively and among long-term users the adjusted ORs were 11.0 and 4.3 (95% confidence limits, 4.8-25.1 and 2.9-6.3) respectively. The elevated risk found when investigating intra-oral cancers of sites in direct contact with toombak quid compared to those with little or no contact, confirms the hypothesis that direct contact with tissues is an important factor in tobacco carcinogenesis in the mouth. The increased risk associated with the use of toombak is of particular concern in view of its wide consumption in the Sudan.

Descriptive epidemiology of oral neoplasms in Sudan 1970-1985 and the role of toombak

Data from 1,916 cases of oral neoplasms occurring in the Sudan in a 16-year period, from January 1970 to December 1985, were retrieved and analysed. The study revealed a relatively high frequency of oral neoplasms in comparison with neighbouring countries. In this study, squamous-cell carcinoma was the most common oral malignancy (66.5%), followed by tumours of the salivary gland (14.7%), neoplasms of nonodontogenic and non-epithelial origin (9.6%) and odontogenic neoplasms (8.6%). Men had a higher frequency than women. The older age group of both genders showed a relatively high frequency of squamous-cell carcinoma. Among northern Sudanese there was a high rate of squamous-cell carcinoma, while southern Sudanese showed a high rate of odontogenic and salivary-gland neoplasms. The use of toombak has been stated to play a major role in the aetiology of oral squamous-cell carcinoma in the Sudan, and is suspected to be associated with neoplasms of the salivary glands.