Towards a psychobiological model of cancer: biological considerations

Disadvantage and male cancer incidence and mortality in New South Wales 1985-1993

Male premature mortality variations from cancers by socioeconomic status and marital status were analysed for the period 1986-1989 and 1990-1993 for New South Wales. Cancer incidence and mortality were also surveyed by statistical local areas within metropolitan Sydney between 1985-1991 and correlation and regression analyses were undertaken with socioeconomic indicators and the modified Jarman 8 disadvantage indicator. Martial status variations were found with most major cancers, with not currently married men being more at risk. Cancers of the oesophagus, oral cavity, pancreas, bladder, kidney, liver and trachea, bronchus and lung were more associated with manual occupations and the disadvantage indicator, while cancer of the colon and melanoma were more associated spatially and occupationally with higher socioeconomic status. An unexpected finding with mortality was an occupational status bipolarity with several cancers, notably with managerial and manual workers. There are implications for the more precise targeting of populations at risk.

Mortality from respiratory system cancer in New South Wales and Sydney

Differential and spatial analyses of respiratory system cancer were undertaken for New South Wales and Sydney for the period 1980-1986. The source of data was death certificate information on the unit list mortality file tapes provided by the Australian Bureau of Statistics. Characteristics of persons dying included age, sex, birthplace, occupational status and cause of death (ICD9 classification). The aim was to identify populations at risk from respiratory system cancer, and where they were located. Deaths were disaggregated for the abovementioned categories by cross-tabulation at the state level and for geographical areas having populations with higher levels of respiratory cancer mortality. Never-married males of lower occupational status had higher rates of respiratory cancer, mainly lung cancer. Divorced men also had higher mortality as did widowers who were in lower occupational status work, while married men in managerial work also had significantly high mortality. The marital status variation was mostly not found with females, although significantly high female mortality was found in several low socioeconomic status areas of Sydney. Mortality of both sexes was significantly higher in metropolitan Sydney than in the rest of New South Wales and associations between older age mortality and some industrial areas were found in Sydney.

Mortality from selected cancers in NSW and Sydney, Australia

This study utilizes unit list mortality data for New South Wales, Australia in differential mortality analysis, at state and local levels, and examines geographic patterns of stomach, colo-rectum, respiratory system, female breast cancer and total cancer mortality in Sydney. Associations between manual occupations, low socioeconomic status and male stomach and respiratory cancer mortality were found, as were higher mortality from stomach and respiratory cancer among European-born immigrants in manual occupations. However, unexpected associations were also found between high mortality from stomach and respiratory cancers and managerial occupations. There were also more acute associations between colo-rectum and female breast cancer and higher status areas. Further, mortality variations between specific occupational groups occurred when martial status was controlled for, and the strongest variations were between married and never married males where the social isolation risk factors were presumed to be operative. The highest mortality at the local level in Sydney occurred where more than one at risk population resided and where other influences may have been operative.

Cancer rates after the Three Mile Island nuclear accident and proximity of residence to the plant

BACKGROUND

In the light of a possible link between stress and cancer promotion or progression, and of previously reported distress in residents near the Three Mile Island (TMI) nuclear power plant, we attempted to evaluate the impact of the March 1979 accident on community cancer rates.

METHODS

Proximity of residence to the plant, which related to distress in previous studies, was taken as a possible indicator of accident stress; the postaccident pattern in cancer rates was examined in 69 "study tracts" within a 10-mile radius of TMI, in relation to residential proximity.

RESULTS

A modest association was found between postaccident cancer rates and proximity (OR = 1.4; 95% CI = 1.3, 1.6). After adjusting for a gradient in cancer risk prior to the accident, the odds ratio contrasting those closest to the plant with those living farther out was 1.2 (95% CI = 1.0, 1.4). A postaccident increase in cancer rates near the Three Mile Island plant was notable in 1982, persisted for another year, and then declined. Radiation emissions, as modeled mathematically, did not account for the observed increase.

CONCLUSION

Interpretation in terms of accident stress is limited by the lack of an individual measure of stress and by uncertainty about whether stress has a biological effect on cancer in humans. An alternative mechanism for the cancer increase near the plant is through changes in care-seeking and diagnostic practice arising from postaccident concern.

Emotional expression in cancer onset and progression

Despite the intensive biomedical research in oncology since World War II, recent studies show a steady increase in age-adjusted mortality for all kinds of cancer. This findings gives impetus to the efforts of researchers who have adopted the biopsychosocial model. Systematic research using such a model has shown several psychosocial factors to be associated with cancer onset and progression, and Temoshok has recently suggested a theoretical model which unifies these findings. In this paper, I consider the evidence that one of these psychosocial factors, emotional expression, may be directly involved in cancer onset and progression. I review 18 relevant studies, discuss how one might operationalize the term 'emotional expression', and make 12 suggestions for future research.

Current perspectives on immunology and psychiatry

We selectively review recent research findings in the field of psychoimmunology which test the hypotheses that immunological dysfunction may be aetiologically related to mental illnesses such as schizophrenia, and that certain morbid affective states such as depression and other forms of psychosocial distress may be the cause of immunosuppression and through this mechanism affect the outcome of illnesses such as cancer. Our examination of research implicating immunological or infective mechanisms in the aetiology of schizophrenia indicates that most studies have been unable to control for major methodological difficulties but the compatibility of these theories with the dopamine hypothesis suggests that further research attention is warranted. More clearly, there is growing evidence demonstrating a link between depression, other states of psychological distress and immunosuppression, but the clinical significance of these findings remains uncertain. The complex relationship between stress and the outcome of illnesses such as cancer is discussed and the possible implications of these findings for clinical psychiatry are suggested.

The psychological aspects of the doctor-patient interaction in the healing process. General practitioners' attitudes and beliefs

The present study had three main objectives. To survey: 1) General practitioners' views on the possibility of influencing different diseases by psychological means. 2) GPs' views on the doctor/patient relationship. 3) GPs' general interest in psychosomatic issues. Altogether 180 GPs completed the questionnaire. GPs found chronic disorders to be more easily influenced by psychological means that acute disorders, and they prefer the counsellor aspects of the doctor role to the caretaker aspects. They think psychosomatic issues are very relevant to their daily work.

Aspects of the psychological management of breast cancer

Psychological factors influence the survival of patients with breast cancer through the early detection of the cancer and through compliance with the treatment. There is now evidence that psychological factors also influence the immune factors which control micrometastases. In particular, stoical acceptance of cancer is associated with a shorter survival of the patient, while the expression of hostility towards the cancer is associated with a longer survival of the patient. Unrecognized psychological morbidity can impair the quality of a patient's life for years. Such psychological morbidity may be reduced by more open communication with the patient, by encouragement of the expression of feelings (especially anger), by preoperative diagnosis of the cancer by biopsy and by a greater time allowance before a mastectomy is performed. Morbidity may also be reduced by the encouragement of patients to take an active part in their treatment decisions, by the avoidance of a mastectomy, by immediate breast-reconstruction surgery, and by appropriate psychological support which includes self-help techniques, such as meditation. Breast cancer can be a positive turning-point in a person's life.

Towards a psychobiological model of cancer: psychological considerations

To date, the evidence relating to the role of stress and psychological variables in cancer aetiology and promotion is contradictory. We have attempted to clarify the issues by presenting an hypothetical psychobiological model. Two components of this model are described: (1) a characteristic behaviour pattern (Type C) which may mediate stress reactions and (2) the biological concomitants of this behaviour pattern. The mechanisms of cancer initiation and promotion are described in a companion paper (Pettingale). The main hypothesis advanced by this model is that the psychological factors described may promote cancer development; the model is offered for investigation.