A total of 27 relevant published articles on head and neck cancers from 1968 to 2008 were reviewed. Ten of them were on the pattern of head and neck cancers from different regions [6–10, 12, 14–18] (Additional file 1), while others were on specific sites namely nasopharynx, sino-nasal, larynx, oral cavity and salivary glands from different regions[13, 19–34] (Additional file 2).
Epidemiology
A review of the published literature from Nigeria showed that the age of patients ranged between nine months to over 80 years [6–10, 12, 13, 19–35]. It is known generally that cancers are diseases of the elderly. But reports from Jos and Maiduguri in Northern Nigeria [6, 8, 14] show a peak incidence in the 3rd and 4th decades, those from Lagos (South west) and Ilorin (North central) [10, 16] reported a peak incidence in the 4th to 5th decades while reports from Ibadan (South west) Nigeria [12, 18] showed a peak incidence in the 6th decade of life. The peak age of incidence of Nasopharyngeal malignancies in most reports from Nigeria was found in the 4th decade of life [9, 10, 15, 21, 16–23]. However, a bimodal curve was reported from Jos (North central) and Lagos (South west) with the first peak in the 2nd decade and the second peak in the 4th and 5th decade [21–23]. Laryngeal cancers had a peak incidence in the 5th decade in South-western cities of Lagos and Ibadan [10, 28], while in northern city of Jos [26] the mean age was 46.5 years with peak incidence in the 4th decade. The peak age occurrence of maxillary cancer was in the 4th decade in Jos [24] and in the 5th decade and the 6th to 7th decades in two different reports from Lagos [10, 25]. A recent study from Lagos showed that the peak age of incidence of oral cancer in Lagos was in the 5th decade of life [29]. In this study the age of patients ranged from 2.5 to 85 years, and 25% of the cases were found in patients below the age of 40 years [29]. A review of squamous cell carcinoma of the oral cavity in Lagos found the peak incidence in the 20 to 29-year and 40 to 49-year age groups, with 40% cases occurring in patients under age of 40 years [30]. The mean age of occurrence of salivary gland tumours in Enugu and in Lagos was 40 years [32–34].
In most studies from Nigeria, HNC affected more males than females [6, 8, 10, 12, 14, 15, 17, 35, 36], except a study from Ilorin (North central) [16], where females were affected more than males. The male to female ratio ranged from 1:1 to 2.3:1 [6, 8, 10, 12, 14–16, 29, 30, 36].
Aetiological Factors
Identified risks factors among the reviewed articles included: kola nuts, tobacco, farming, viral infections, alcohol and smoking [7, 9, 12, 13, 23, 26, 35]. In a report from Maiduguri [7] northern region of the country, tobacco smoking, tobacco chewing and chewing of kola nuts were associated with carcinoma of oral cavity. Kola nuts (Cola acuminate) has been reported to promote palatal mucosa keratinization of cigarette smokers and is considered a co-carcinogen. Laryngeal cancer was commoner in patients who consumed alcohol than smokers in the report from Jos [26], while in reports from Enugu [35], Lagos [13] and Ile Ife [9] most patients with laryngeal carcinoma were non-smokers. Virus is thought to be responsible for some HNC in sero-positive patients by viral oncogenesis. Nwaorgu et al [12] reported that salivary gland malignancy was the commonest tumour in patients with HIV sero-positivity in Ibadan (South-west) while Otoh et al [7] reported Kaposi sarcoma as the most common tumours in these patients in North-eastern Nigeria.
Tumour Sites
Reports on the overall pattern of Head and neck cancers from different regions of the country cited nasopharynx as the commonest site [7, 8, 10, 12, 14, 15] (Additional file 3). The nose and paranasal sinuses were the second most common reported sites [7, 10, 12, 14] while larynx, was the third commonly affected site [8, 10, 14, 17]. In contrast, Amusa et al [9] and Otoh et al [7] reported differently that malignancy of the oral cavity was the commonest in Ile-Ife (South-west) and Maiduguri (North central) Nigeria. Ologe et al [16] and Otoh et al [7] reported that thyroid is not an uncommon site of HNC. A review on commonest sites of oro-facial malignancy from Lagos, noted the mandible, maxilla, palate, tongue, cheek, lip and floor of the mouth [29, 30] as the most commonly affected sites. Tumours of the oropharynx, hypopharynx, skin and eye were also seen but in low in prevalence in some reports [7, 8, 10, 12, 14–17]. A recent study [18] from Ibadan (South-west) reported that oral cavity and oropharyx were the most commonly affected sites accounting for 31.1% of cases, followed by nasopharynx (16.4%) and nose/paranasal sinuses (15%). Cancers of the ear was notably few [7–9, 14, 17]. Unknown metastatic neck nodes was reported in some of the series [7, 9, 10, 12, 15, 16].
Tumour Type
The majority of HNC was epithelial in origin and was mostly squamous cell carcinoma (SCC) [7–10, 14–16, 18]. SCC constituted 66.7% of all epithelial tumours in a recent study from Ibadan (South-west), Nigeria. Lymphomas were the second most frequent cell type seen in many centres [6, 7, 9, 14, 15]. Nwawolo et al in Lagos, Lilly-Tariah in Jos and Okoye et al in Port-harcourt found sarcomas to be the second most occurring histologic type [8, 10, 17]. The two most common head and neck cancers in Ibadan were SCC, which accounted for 47.8% of all cases, followed by lymphomas which accounted for 19.3% [18]. By contrast, Amusa et al [9] found that lymphoma was the most frequently diagnosed head and neck cancer, accounting for 40.3%, whereas SCC only accounted for 25% of cases. Ajayi et al [29] from Lagos reported epithelial malignant tumours (69%), mostly SCC as the most common orofacial malignant tumours followed by sarcomas (18%) and lymphomas (13%).
Presentation, Diagnosing and Staging
Few studies reported on the clinical presentations and staging of head and neck tumours [7, 13, 23, 25, 26]. Late presentation of the advanced disease was a common feature in most reports from different parts of Nigeria. [7, 13, 19, 20, 22, 23, 25, 26]. By the TNM classification of tumours, only 1 study reported stage 1 tumours among all the studied reports [13]. Stage II cancers were few and the reported sites were larynx and nasopharynx [7, 13, 22, 27]. Most reports were on stages III and IV and the reported sites were larynx, nasopharynx and maxillary antrum [7, 13, 19, 20, 25, 27].
Treatment and Outcome
There are few reports on the treatment and outcome of HNC in Nigeria [7, 13, 15, 19, 20, 22, 23, 25, 27]. Otoh et al [7] in North central Nigeria reported that radiotherapy, surgery and chemotherapy were the main therapeutic modalities for carcinoma, sarcoma and lymphoma respectively. In their study, radiotherapy was used in 41.7%, surgery 39.6%, combination of radiotherapy/surgery in 11.4% and chemotherapy in 7.3% [7], however, treatment outcome was not reported. Iseh and Malami [15] reported that surgery and chemotherapy were the main treatment modalities in Sokoto (North-west, Nigeria), and adduced non availability of radiotherapy in the region and the logistics of assessing the radiotherapy facility as the reasons for the treatment modalities in the report. Report on laryngeal carcinoma treatment in South western Nigeria [13] showed 86.1% of patients had radiotherapy, 2.7% had laryngectomy and 8.3% received a combination of surgery and radiotherapy. Of these cases [13] 47.3% of the patients were lost to follow up less than two years, 16.7% after two years, 22.2% were dead after two years of treatment of which 5.6% were unrelated to the carcinoma. Recurrence rate after 2 years was 16.7%. Alive and disease free 4 years post-treatment was 5.6%. Treatment modality for laryngeal carcinoma from North central Nigeria [27], showed that 31.5% had total laryngectomy, 20.4% were inoperable and were referred for radiotherapy and 48% refused surgery. Almost all the patients were lost to follow up after 1 year [27]. Radiotherapy is the mainstay of nasopharyngeal carcinoma [21] except where such is not available [15, 19, 20, 23]. Lilly-Tariah et al [24] on report on treatment of naso-antral carcinoma from north western Nigeria: 33.3% had surgery (hemimaxillectomy/frontoethmoidectomy), 41.7% had chemotherapy alone, and 5.6% received a combination of radiotherapy and chemotherapy. Management of maxillary antral carcinomas as reported by Ogunlewe et al [25] in Lagos (South west, Nigeria) included hemi-maxillectomy and radiotherapy in 68.2% of cases, hemi-maxillectomy/orbital exenteration and radiotherapy in 10.53% of patients, and radiotherapy and chemotherapy in 13.6% of cases. After 2 years, recurrence rate was 5.3%, death due to the disease occurred in 10.5% of cases and 84.2% was lost to follow up during the period.