Abstract
Background and aim
The impact of oral health related disease and treatment on the patient’s overall well-being and functioning is a topic of growing interest in clinical research and practice. Research shows that there is a significant reduction in the quality of life for the patients throughout the treatment of head and neck cancer. Therefore, the aim of the study is to assess the quality of life among treated head and neck cancer patients.
Materials and method
The cross sectional study was conducted among 225 head and neck cancer patients. The European Organization for Research and Treatment of Cancer (EORTC QLQ C-30), Quality Of Life Head and Neck35” (QLQ-HN35) instruments were used to assess their quality of life. The study population was divided into three groups based on the treatment done: Group I (Surgery), Group II (Surgery and Radiotherapy) and Group III (Surgery, Radiotherapy and Chemotherapy). Independent t-test and one way ANOVA test were done to analyze the data.
Results
Trouble with opening mouth (34.66 ± 30.58) was one of the highest rated symptoms among the study population. Salivary dysfunction leading to dry mouth (33.33 ± 34.06), sticky saliva (33.33 ± 26.72) were also found to be severe. Among the three groups, the Global Health Status, Symptom Scale mean scores were more high in Group I, Functional Scale and H&N35 symptoms mean scores was high in Group III however no statistical significance was observed (p > 0.05).
Conclusion
Head and neck cancer has severe effects on the quality of life. As observed from the findings of the current study, Global Health Status indicated a healthy level of living among patients who have undergone surgery alone; head and neck symptoms were more severe and problematic among patients who had surgery and radiotherapy. Therefore, assessing health related quality of life can be a factor that is weighed against treatment burden, toxicity, survival benefit. It can be more integral to treatment planning, refining treatment protocols and a better post-operative care and support.
Keywords: EORTC-QOL, Oncology, Tobacco, India, Oral cancer
1. Introduction
In India, head and neck cancer (HNC) constitutes to one third of all cancers affecting the oral cavity, tongue, tonsil, oropharynx, naso-pharynx, parotid, thyroid compared to 4–5% in the global world.1It affects one fourth of the male population and one tenth of female population. This is mainly attributed to tobacco usage, areca nut, alcohol etc. Standard therapy for HNC is surgery and radiotherapy, and up to two-third of patients in advanced stages undergo a combination of surgery, radiotherapy and chemotherapy and even after that the prognosis is unsatisfactory. The success rate is also not impressive in HNC treated patients, as studies suggest 60–70% of the patients develop a loco regional recurrence and develop distant metastasis.2 Studies showed occurrence of comorbidities in 80% of patients who have undergone treatment for HNC,3 hence they require coordinated management. Primary site surgery has been shown to affect speech, swallowing, and even radiotherapy predominantly affects swallowing, taste hence leading to poor nutrition. Oral complications like mucositis, oro-pharyngeal candidiasis, radiation induced neuropathies, from pain, dysphagia, airway obstruction are common to HNC patients after treatments,4 which makes it all the more important to devise better modalities to enhance quality of life among cancer patients post treatment.
Quality of life (QoL) is a multidimensional broad ranging concept which affects a person’s physical, psychological state of health, social relationships and their relationship to the environment.5 HNC patients undergo significant and persistent change in physical, functional, psychological aspects of life.6,7 The potential for an adverse effect on QOL is conceivably greater in cases of head and neck cancer as the key functions are disturbed, both by the disease and its treatment. In recent time, researches on quality of life have been starting to gain importance as it may help the clinician understand the patient’s perception on the disease, impacts of the effects of the treatment rendered, which in turn will enable the healthcare professionals to appropriately modify the treatment and facilitate rehabilitation services suited to the patient’s need.8,9 Though various assessment tools were used to assess QoL in HNC patients, European Organization for Research and Treatment of Cancer (EORTC) remains a valid and reliable tool in Indian context.10,11 Hence, the present study was contemplated to assess the quality of life among head and neck cancer treated patients using EORTC QoL and QLQ HN35.
2. Materials and method
This study is a cross-sectional study that included 225 patients who underwent treatment for HNC. Prior to the study, ethical clearance (IHEC/SDC-PHD-1801/19/172) was obtained from the Scientific Review Board of the author’s institution. The study was conducted among patients in public and private cancer institutes in Chennai. Prior permission to conduct the study was obtained from the cancer institutes. Also written informed consent was obtained from the patients included in the study after explaining the purpose of it. Confidentiality of the patient’s diagnosis and treatment was maintained throughout the study. The present cross-sectional study was conducted for a period of 10 months from March 2019–January 2020.
Patients with age greater than 18 years, diagnosed with carcinoma in Head and neck region probably with primary tumor sites in oral cavity, oropharynx, larynx, and hypo pharynx and also who underwent surgical and other adjuvant therapy such as chemotherapy and radiotherapy in the last 2 years were included. Newly diagnosed HNC patients and patients who had ongoing mental and cognitive impairment (assessed using a brief community screening instrument for dementia (CSI-D) and informant interview) that limits the ability to comprehend the questionnaires were excluded from the study.
The European Organization for Research and Treatment of Cancer (EORTC QLQ C-30), Quality Of Life Head and Neck35” (QLQ-HN35) instruments were used. The EORTC QLQ C-30 questionnaire is a reliable, validated cancer health related quality of life questionnaire which includes five functional domains (physical, emotional, social, role, cognitive), eight symptom domains (fatigue, pain, nausea/vomiting, constipation, diarrhea, insomnia, dyspnea, and appetite loss) and global health and financial impact. The items in the questionnaire use a “past week” recall period, and the responses are recorded in a four point scale from “not at all” to “very much”. Raw scores are linearly converted to a 0–100 scale with higher scores reflecting higher levels of function and higher levels of symptom burden.12
Score (S) was obtained by applying a linear transformation to 0–100:
| FSs: S = (1 – [(RS − 1)/range]) × 100 |
| SS: S = ([RS − 1]/range) × 100 |
| GHS/QOL: S = ([RS − 1]/range) × 100 |
Range is the difference between the maximum possible value of RS and the minimum possible value. Most items were scored 1–4, giving range 3. The GHS/QOL question was scored 1–7, giving range 6.
The QOL-HN35 10 is used for the head and neck core symptoms, including 35 items in total, out of which 7 multiple-item scales (Pain, Swallowing, Senses, Speech, Social eating, Social contact, and Sexuality), in addition to 11 single items (eg, Opening mouth, Sticky saliva, Dry mouth, etc) are present.
These instruments had high Cronbach’s alpha coefficient (>0.70) and Pearson’s correlation coefficient (>0.40) indicating a good reliable and construct valid tool. However these instruments were translated from the original English version into vernacular language (Tamil). The forward and backward translation of the questionnaire was executed using stalwarts in both the languages (English and Tamil). The agreement obtained among them was satisfactory with a kappa value (>0.70).
The patients were categorized into three different groups: Group I: Patients undergone Surgery (S), Group II: Patients undergone Surgery and Radiotherapy (SR), Group III: Patients undergone Surgery, Radiotherapy and Chemotherapy (SRC). The pre-validated, self-administered questionnaires were given to each patient irrespective of their years in treatment.
2.1. Statistical analysis
Statistical analysis was done using Statistical Package for Social Sciences (SPSS) Version 23.0. Descriptive statistics were used to report the demographic and clinical data variables and mean functional scores, symptom scores and global health status. Independent t-test and one way analysis of variance (one-way ANOVA) was done to report the comparison of the scores with clinical variables between the three groups.
3. Results
The mean age of the patients was 53.1 ± 12.51 years. About 72% were males and 28% were females thus showing a male predilection in the study population, majority of the males were in Group I (75.5%), followed by Group II (69.4%), however majority of the female population (43.8%) were found in Group III. According to the findings of the study, 27.3% were in the age group ≤50 years and 72.7% of the participants were in the age group >50 years age group, which shows the head and neck cancer has a higher prevalence among people above 50 years of age. Table 1 shows the mean distribution of scores of quality of life questionnaire C-30. The Global Health Status/QOL was 76.33 ± 18.24 among the study population. Cognitive functioning (98 ± 5.428), followed by social functioning (96.66 ± 8.183) and role functioning (95.33 ± 12.06) were mostly affected among the functional scales. Among the symptom scales, higher mean scores were seen with fatigue (16.44 ± 18.66), insomnia (12 ± 22.91) and pain (10.66 ± 16.95). Table 2 shows the mean distribution of quality of life questionnaire Head and Neck 35, among the study population. Weight loss (44.00 ± 49.74) and trouble with opening mouth (34.66 ± 30.58) was one of the highest rated symptoms among the study population. Salivary dysfunction leading to dry mouth (33.33 ± 34.06), sticky saliva (33.33 ± 26.72) were severe. Mean scores of symptoms with pain (14.33 ± 19.97), difficulty in swallowing (15.00 ± 18.14), and trouble with social eating (15.33 ± 18.24) were also high. Table 3 shows the comparison of quality of life scores with gender, age and the treatment groups. The FS (95.09 ± 6.47), SS (8.25 ± 8.74) and H&N 35 (13.88 ± 8.56) scores were higher among the males and the GHS (78.09 ± 17.48), scores were higher among the females; however no statistical significance was observed. Patients above 50 years of age suffered more according to the GHS, FS, SS and H&N 35 scores, as can be seen in the table below, with no statistical significance. Based on the laterality of the lesion, 36.4% had the lesion on the left side whereas 63.5% had on the right side and the GHS (77.06 ± 18.12), SS (8.70 ± 9.22), H&N35 (13.70 ± 8.89) was found to be higher among participants who had the lesion on the left side, but FS (95.13 ± 6.38) was higher in participants who had the lesion on the right side. Similar results were observed in relation to the anterior-posterior side of the lesion. Among the treatment groups, the GHS (77.20 ± 18.07), SS (8.31 ± 8.93) was higher among Group I, FS (95.16 ± 6.39), H&N35 (13.90 ± 8.39) was higher in Group III. Again, no statistical significance was observed among the three treatment groups.
Table 1.
Mean distribution of scores of quality of life questionnaire C-30.
| QLQ C-30 |
||
|---|---|---|
| Patients | Mean scales ±SD | |
| Global Health Status/QoL | 225 | 76.33 ± 18.24 |
| Functional Scales | ||
| Physical functioning | 225 | 88.80 ± 15.89 |
| Role functioning | 225 | 95.33 ± 12.06 |
| Emotional functioning | 225 | 95.33 ± 10.58 |
| Cognitive functioning | 225 | 98.00 ± 5.428 |
| Social functioning | 225 | 96.66 ± 8.183 |
| Symptom Scales | ||
| Fatigue | 225 | 16.44 ± 18.66 |
| Nausea And Vomiting | 225 | 3.333 ± 8.183 |
| Pain | 225 | 10.66 ± 16.95 |
| Dyspnea | 225 | 1.333 ± 6.546 |
| Insomnia | 225 | 12.00 ± 22.91 |
| Appetite Loss | 225 | 4.00 ± 10.85 |
| Constipation | 225 | 5.333 ± 12.24 |
| Diarrhea | 225 | 10.66 ± 18.22 |
| Financial Difficulties | 225 | 8.000 ± 17.11 |
Table 2.
Mean distribution of scores of quality of life questionnaire head and neck 35.
| Symptom scales | QLQ Head and Neck – 35 |
|
|---|---|---|
| Patients | Mean scales ±SD | |
| Pain | 225 | 14.33 ± 19.97 |
| Swallowing | 225 | 15.00 ± 18.14 |
| Senses problems | 225 | 13.33 ± 17.03 |
| Speech problems | 225 | 10.66 ± 13.16 |
| Trouble with social eating | 225 | 15.33 ± 18.24 |
| Trouble with social contacts | 225 | 6.93 ± 8.124 |
| Less sexuality | 225 | 5.33 ± 12.24 |
| Teeth | 225 | 20.0 ± 23.14 |
| Opening mouth | 225 | 34.66 ± 30.58 |
| Dry mouth | 225 | 33.33 ± 34.06 |
| Sticky saliva | 225 | 33.33 ± 26.72 |
| Coughing | 225 | 6.666 ± 13.36 |
| Felt ill | 225 | 5.333 ± 15.46 |
| Pain killers | 225 | 12.00 ± 32.56 |
| Nutritional supplements | 225 | 20.00 ± 40.08 |
| Feeding tube | 225 | 4.000 ± 19.63 |
| Weight loss | 225 | 44.00 ± 49.74 |
| Weight gain | 225 | 8.000 ± 27.18 |
Table 3.
Comparisons of Quality of life scores with Gender, Age, lesion laterality, site of the lesion.
| Variables | Groups | Total (n) | Mean ± SD |
|||||||
|---|---|---|---|---|---|---|---|---|---|---|
| GHS | p value | FS | p value | SS | p value | H & N 35 | p value | |||
| Gender | Male | 156 | 76.04 ± 18.15 | 0.528 | 95.09 ± 6.47 | 0.576 | 8.25 ± 8.74 | 0.631 | 13.88 ± 8.56 | 0.481 |
| Female | 69 | 78.09 ± 17.48 | 94.55 ± 6.70 | 7.63 ± 8.70 | 12.98 ± 8.77 | |||||
| Age | ≤50 years | 63 | 75.63 ± 18.97 | 0.518 | 94.42 ± 6.89 | 0.459 | 9.52 ± 9.66 | 0.123 | 14.46 ± 8.90 | 0.372 |
| >50 years | 162 | 77.36 ± 17.56 | 95.14 ± 6.38 | 7.52 ± 8.28 | 13.31 ± 8.50 | |||||
| Lesion Laterality | Left | 82 | 77.06 ± 18.12 | 0.723 | 94.60 ± 6.80 | 0.279 | 8.70 ± 9.22 | 0.467 | 13.70 ± 8.89 | 0.597 |
| Right | 143 | 76.77 ± 17.90 | 95.13 ± 6.38 | 7.72 ± 8.42 | 13.59 ± 8.47 | |||||
| Site of lesion | Anterior | 90 | 77.15 ± 18.47 | 0.524 | 94.80 ± 6.69 | 0.508 | 8.60 ± 9.07 | 0.582 | 13.51 ± 8.86 | 0.595 |
| Posterior | 135 | 76.69 ± 17.64 | 95.04 ± 6.43 | 7.74 ± 8.48 | 13.71 ± 8.47 | |||||
| Treatment | Group I (Surgery) | 99 | 77.20 ± 18.07 | 0.944 | 94.70 ± 6.70 | 0.887 | 8.31 ± 8.93 | 0.936 | 13.46 ± 8.85 | 0.947 |
| Group II (Surgery & Radiotherapy) | 54 | 77.07 ± 18.28 | 95.09 ± 6.47 | 8.00 ± 8.69 | 13.59 ± 8.60 | |||||
| Group III (Surgery, Chemotherapy & Radiotherapy) | 72 | 76.29 ± 17.94 | 95.16 ± 6.39 | 7.83 ± 8.53 | 13.90 ± 8.39 | |||||
4. Discussion
Quality of life is a multidimensional concept which provides a holistic view of human living as it considers a number of domains of people’s lives, the principle ones being subjective well-being, health, income, standard of living, social relations, quality of work and the association between these dimensions.13,14 The current study was conducted to assess the quality of life patients who have been treated for head and neck cancer. The current study showed a higher prevalence of H&N cancer among males, compared to females, similar to other studies15,16,17 which could be attributed mostly to higher incidence of tobacco use among males. The prevalence of H&N cancer was also higher among people 50 years and above, which is again a common finding in India,18 it correlates to the observation that prevalence of tobacco consumption increases up to the age of 50 years and then there is decline in Indian population.19 Patients in the current study population have reported a higher QoL, similar to other studies.20,21 The mean score of FS was 95.09 ± 6.47 in males and 78.09 ± 17.48 in females, showing the study participants had a good ability to perform daily activities, similar findings were observed in other studies as well.9,22 In the current study, symptoms like dyspnea, diarrhea, nausea and vomiting, constipation, financial difficulties were less troublesome as compared to fatigue, pain. Symptoms like opening of mouth, swallowing, speech, teeth were more difficult for the patients, and the findings coincided with various other studies as well,23,24 as dental rehabilitation though present, it accounts for heavy out of pocket expenditure among the population. Salivary gland dysfunction was also highly prevalent among the study population owing to radiation therapy. Weight loss was also a highly prevalent symptom seen among the study population, as their mastication, nutrition was compromised. The overall QoL (GHS) was more in the current study population, similar to other studies 25. The GHS, SS, were slightly higher in Group I (Surgery) suggesting a healthy level of functioning, however no statistical significant difference was found among the mean scores among the three study groups. The study had certain limitations as we were not able to gather data on the radiation dose, chemotherapy agents and techniques used to implement those therapies which play a major role affecting the quality of life of the patients. This could be a potential reason for finding no statistical difference in the mean scores of quality of life among the three groups. Further detailed research should be conducted among a larger patient population, in order to gather more evidence to make the quality of life better among cancer patients and promote more symptom directed therapies.
5. Conclusion
The treatment for Head and neck cancer play a great role in deteriorating the quality of life among the patients. There was no significant difference in the scores of quality of life among the patients who have undergone different modality of treatment. However the scores were found to be less in patients who have undergone surgery with radiotherapy and surgery with radiotherapy and chemotherapy. The post-operative symptoms were more aggressive in patients who have undergone surgery and radiotherapy, with no significant difference in the scores with other two treatment modalities. Therefore, psychological therapy along with surgery, chemotherapy and radiotherapy should be considered for improved treatment outcomes in Head and Neck cancer patients.
Contributor Information
Manali Deb Barma, Email: manali100492@gmail.com.
Meignana Arumugham Indiran, Email: drmei.sdc@saveetha.com.
Pradeep Kumar R, Email: drrpradeepkumar@gmail.com.
Arthi Balasubramaniam, Email: arthi.bds@gmail.com.
M.P Santhosh Kumar, Email: santhoshsurgeon@gmail.com.
References
- 1.Heroiu Cataloiu A.-D., Danciu C.E., Popescu C.R. Multiple cancers of the head and neck. Maedica. 2013;8(1):80–85. https://www.ncbi.nlm.nih.gov/pubmed/24023604 [PMC free article] [PubMed] [Google Scholar]
- 2.Marcial V.A., Pajak T.F. Radiation therapy alone or in combination with surgery in head and neck cancer. Cancer. 1985;55(9 Suppl):2259–2265. doi: 10.1002/1097-0142(19850501)55:9+<2259::aid-cncr2820551432>3.0.co;2–7. [DOI] [PubMed] [Google Scholar]
- 3.Aird D.W., Bihari J., Smith C. Clinical problems in the continuing care of head and neck cancer patients. Ear Nose Throat J. 1983;62(5):230–243. https://www.ncbi.nlm.nih.gov/pubmed/6190622 [PubMed] [Google Scholar]
- 4.Sroussi H.Y., Epstein J.B., Bensadoun R. Common oral complications of head and neck cancer radiation therapy: mucositis, infections, saliva change, fibrosis, sensory dysfunctions, dental caries, periodontal disease, and osteoradionecrosis. Cancer Med. 2017;6(12):2918–2931. doi: 10.1002/cam4.1221. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.The World Health Organization Quality of Life Assessment (WHOQOL) Development and general psychometric properties. Soc Sci Med. 1998;46(12):1569–1585. doi: 10.1016/s0277-9536(98)00009-4. [DOI] [PubMed] [Google Scholar]
- 6.List M.A., Ritter-Sterr C., Lansky S.B. A performance status scale for head and neck cancer patients. Cancer. 1990;66(3):564–569. doi: 10.1002/1097-0142(19900801)66:3<564::aid-cncr2820660326>3.0.co;2-d. [DOI] [PubMed] [Google Scholar]
- 7.Keefe F.J., Wilkins R.H., Cook W.A., Jr., Crisson J.E., Muhlbaier L.H. Depression, pain, and pain behavior. J Consult Clin Psychol. 1986;54(5):665–669. https://www.ncbi.nlm.nih.gov/pubmed/2945848 [PubMed] [Google Scholar]
- 8.Karimi A.M., Gairola M., Ahlawat P. Health-related quality of life assessment for head-and-neck cancer patients during and at 3 months after radiotherapy - a prospective, analytical questionnaire-based study. Natl J Maxillofac Surg. 2019;10(2):134–140. doi: 10.4103/njms.NJMS_92_18. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9.Khandelwal A., Neeli A., Gadiyar A., Khandelwal A. Assessment of quality of life of patients 1–5 years after treatment for oral cancer. Indian J Dent Res. 2017;28(5):538. doi: 10.4103/ijdr.IJDR_97_17. [DOI] [PubMed] [Google Scholar]
- 10.Aaronson N.K., Ahmedzai S., Bergman B. The European Organization for Research and Treatment of Cancer QLQ-C30: a quality-of-life instrument for use in international clinical trials in oncology. J Natl Cancer Inst. 1993;85(5):365–376. doi: 10.1093/jnci/85.5.365. [DOI] [PubMed] [Google Scholar]
- 11.McLachlan S.-A., Devins G.M., Goodwin P.J. Validation of the european organization for research and treatment of cancer quality of life questionnaire (QLQ-C30) as a measure of psychosocial function in breast cancer patients. Eur J Canc. 1998;34(4):510–517. doi: 10.1016/S0959-8049(97)10076-4. [DOI] [PubMed] [Google Scholar]
- 12.Fayers P., Aaronson N., Bjordal K., Groenvold M., Curran D., Bottomley A. third ed. 2001. EORTC QLQ-C30 Scoring Manual. Brussels, Belgium. Published online. [Google Scholar]
- 13.Ficko S.L., Pejsa V., Zadnik V. Health-related quality of life in Croatian general population and multiple myeloma patients assessed by the EORTC QLQ-C30 and EORTC QLQ-MY20 questionnaires. Radiol Oncol. 2019;53(3):337–347. doi: 10.2478/raon-2019-0047. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Sherman A.C., Simonton S., Adams D.C., Vural E., Owens B., Hanna E. Assessing quality of life in patients with head and neck cancer: cross-validation of the European organization for research and treatment of cancer (EORTC) quality of life head and neck module (QLQ-H&N35) Arch Otolaryngol Head Neck Surg. 2000;126(4):459–467. doi: 10.1001/archotol.126.4.459. [DOI] [PubMed] [Google Scholar]
- 15.Das R., Kataki A.C., Sharma J.D., Baishya N., Kalita M., Krishnatreya M. A study of head and neck cancer patients with special reference to tobacco use and educational level. Clinical Cancer Investigation Journal. 2017;6(1):21. https://www.ccij-online.org/article.asp?issn=2278-0513;year=2017;volume=6;issue=1;spage=21;epage=25;aulast=Das [Google Scholar]
- 16.Bhattacharjee A., Chakraborty A., Purkaystha P. Prevalence of head and neck cancers in the north east-An institutional study. Indian J Otolaryngol Head Neck Surg. 2006;58(1):15–19. doi: 10.1007/BF02907731. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 17.Alam M.S., Siddiqui S.A., Perween R. Epidemiological profile of head and neck cancer patients in Western Uttar Pradesh and analysis of distributions of risk factors in relation to site of tumor. J Canc Res Therapeut. 2017;13(3):430–435. doi: 10.4103/0973-1482.180687. [DOI] [PubMed] [Google Scholar]
- 18.Kulkarni M.R. Head and neck cancer burden in India. Int J Head Neck Surg. 2013;4(1):29–35. [Google Scholar]
- 19.Rani M., Bonu S., Jha P., Nguyen S.N., Jamjoum L. Tobacco use in India: prevalence and predictors of smoking and chewing in a national cross sectional household survey. Tobac Contr. 2003;12(4):e4. doi: 10.1136/tc.12.4.e4. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 20.Gomes EPA de A., Aranha A.M.F., Borges A.H., Volpato L.E.R. Head and neck cancer patients’ quality of life: analysis of three instruments. J Dent. 2020;21(1):31–41. doi: 10.30476/DENTJODS.2019.77677.0. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 21.Martino R., Ringash J. Evaluation of quality of life and organ function in head and neck squamous cell carcinoma. Hematol Oncol Clin N Am. 2008;22(6):1239–1256. doi: 10.1016/j.hoc.2008.08.011. [DOI] [PubMed] [Google Scholar]
- 22.Pierre C.S., Dassonville O., Chamorey E. Long-term quality of life and its predictive factors after oncologic surgery and microvascular reconstruction in patients with oral or oropharyngeal cancer. Eur Arch Oto-Rhino-Laryngol. 2014;271(4):801–807. doi: 10.1007/s00405-013-2592-z. [DOI] [PubMed] [Google Scholar]
- 23.Rogers S.N., Hannah L., Lowe D., Magennis P. Quality of life 5–10 years after primary surgery for oral and oro-pharyngeal cancer. J Cranio-Maxillofacial Surg. 1999;27(3):187–191. doi: 10.1016/S1010-5182(99)80049-3. [DOI] [PubMed] [Google Scholar]
- 24.Konstantinović V.S. Quality of life after surgical excision followed by radiotherapy for cancer of the tongue and floor of the mouth: evaluation of 78 patients. J Cranio-Maxillo-Fac Surg. 1999;27(3):192–197. doi: 10.1016/s1010-5182(99)80050-x. [DOI] [PubMed] [Google Scholar]
- 25.Klug C., Neuburg J., Glaser C., Schwarz B., Kermer C., Millesi W. Quality of life 2–10 years after combined treatment for advanced oral and oropharyngeal cancer. Int J Oral Maxillofac Surg. 2002;31(6):664–669. doi: 10.1054/ijom.2002.0301. [DOI] [PubMed] [Google Scholar]