AbstractIntroduction: Research suggests that patients with head and neck cancer from poorer backgrounds are more likely to have recurrences or die earlier than similar patients from affluent backgrounds. Survival is influenced by tumour characteristics on presentation and a range of individual factors such as socioeconomic status and comorbidity. Deprived patients of more advanced age have a higher likelihood of having comorbidity; this may be due to high-risk lifestyle behaviours such as smoking and drinking. Therefore, it seems reasonable to assume that survival will be lower in these deprived patients which can be attributed to comorbidity compared to index diseases such as the head and neck cancer itself.
Survival rates for head and neck cancer patients are approximately 50% in the first five years in Scotland. This is dependent on a range of individual and tumour-related factors such as head and neck cancer sub-type and stage at diagnosis. The risk of head and neck cancer developing in deprived patients has been likened to that of developing head and neck cancer in heavy smokers. While the relationship between deprivation and comorbidity in head and neck cancer has been established, how both factors affect survival is yet to be explored. Reviewing these two factors individually has demonstrated the need to assess how both interact with each other in determining clinical presentation and survival.
Aim: The aims of this thesis are:-
1.To investigate the roles and interrelationship between comorbidity and deprivation on the survival of HNC patients.
2. To investigate whether there are differences in HNC presentation based on comorbidity and deprivation.
3.To ascertain whether patients from deprived backgrounds with comorbidity present with more advanced cancers.
Methods: In order to answer the research questions, this project began by describing the index disease, HNC and how comorbidity and deprivation are placed within the epidemiology of this disease using systematic review methods. The rationale for embarking upon this study was highlighted.
Data linkage of administrative datasets: We used anonymised patient data that was accessed through an encrypted repository held by the Health Informatics Centre. The data that was used in the retrospective cohort analysis was obtained from a prospective dataset collected by the Fife Head and Neck cancer Specialist Nurse (Fife data) and a retrospective case note review from the Tayside oncology records held by the Ear Nose and Throat Department and the Oral and Maxillofacial Surgery team. Thereafter we matched the patient data with that from routine medical datasets such the Scottish Morbidity Records, SMR01- inpatient discharges and SMR06 – Cancer Registry data. We conducted survival analysis methods with the intent of assessing the impact of both comorbidity and deprivation in determining survival.
Results: The systematic review found that worsening levels of comorbidity were linked to reduced survival whereas patients with low incomes and poor educational attainment also had poor survival outcomes. Being young and having severe comorbidity appeared to also be associated with poorer survival. In the retrospective cohort analysis, the level of association between risk of death with comorbidity and deprivation could not be clearly ascertained in the patients from Fife. The Tayside data to a larger extent supported the systematic review findings particularly for the comorbidity measures with clearly defined measures of association for the Scottish Index of Multiple Deprivation income and education domains.
Conclusions: This thesis was able to use evidence triangulation by way of a systematic review of the literature followed by a retrospective cohort analysis to investigate what influence on prognosis both comorbidity and deprivation posed in patients with head and neck cancer. There was substantiation of both factors interacting with head and neck cancer to cause a significantly reduced impact on survival. The inherent difficulties of measuring socioeconomic status and comorbidity encountered in this thesis may go some way towards illustrating the complexity and multifaceted nature of both comorbidity and socioeconomic status; particularly the quite complex interplay between socioeconomic status, comorbidity, stage at diagnosis, and access to care in head and neck cancer, and these factors’ ultimate impact on survival.
We found that socioeconomic status i.e. deprivation, comorbidity, stage at diagnosis, access to care, and survival are all potentially causally related. Future work directed at using administrative data linked to medical records would not be sufficient; there is need for epidemiological and clinical studies to unravel the survival disadvantage. To this end clinical cohorts could be nested within larger registry based studies which would allow for uniform interventions based on clinical practice guidelines, uniform SES measurement and ascertainment of comorbidity using a head and neck cancer comorbidity index, i.e. the Washington University Head and Neck Cancer Index.
|Date of Award||2015|
|Sponsors||Medical Research Council|
|Supervisor||Simon Ogston (Supervisor), Frank Sullivan (Supervisor), Fiona Williams (Supervisor) & Colin McCowan (Supervisor)|
- Head and neck cancer
- Additional morbidity
- Social class