Second primary cancers after cancers of the colon and rectum in New South Wales, Australia, 1972-1991

Data from the New South Wales Central Cancer Registry for the period 1972-1991 were examined to determine the risk of second primary cancers after an initial invasive cancer of the colon (ICD-9 153) or rectum (ICD-9 154). The expected numbers of cancers were obtained by assuming that subjects experienced the same cancer incidence as prevailed in the corresponding general population and by applying sex-, age-, and calendar-specific rates to the appropriate person-years at risk. The relative risk (RR) of a second primary cancer was taken to be the ratio of observed:expected numbers of second cancers. After colon cancer, there was an excess of cancers of the small intestine in both sexes (RRs of 4.5 and 4.4); prostate (RR = 1.4) and kidney (RR = 1.8) in men; and breast (RR = 1.3), body of uterus (RR = 1.9), ovary (RR = 2.8), and thyroid (RR = 2.7) in women. Lung cancer occurred less frequently in men than expected (RR = 0.7). After rectal cancer, men had increased risks of cancers of the colon (RR = 1.5) and prostate (RR = 1.3) and a reduced risk of pancreatic cancer (RR = 0.3). A reciprocal relationship of increased risk was seen between cancers of the proximal (but not the distal) colon and rectum. Shared luminal risk factors for proximal colon cancer and rectal cancer and three syndromes of hereditary predisposition to colon cancer seem to be the major contributors to second primary cancers in patients with an initial colon cancer. Sources of bias have been considered.

Trends in colorectal cancer incidence and mortality in New South Wales, 1973-1992

OBJECTIVE

To assess changes in incidence and mortality rates of colorectal cancer in different age groups in New South Wales (NSW) between 1973 and 1992.

DESIGN

Descriptive analysis of data on incidence and mortality from the population-based NSW Central Cancer Registry and on colorectal cancer diagnostic tests from the Health Insurance Commission.

MAIN OUTCOME MEASURES

Age-standardised incidence and mortality rates for colon and rectal cancer (defined by codes 153 and 154 in the International classification of diseases, 9th revision) by sex and age group (15-44, 45-59, 60-74 or > or = 75 years) and incidence by cancer spread at diagnosis; age-standardised rates for faecal occult blood tests, sigmoidoscopy and colonoscopy.

RESULTS

From 1973 to 1992, colorectal cancer incidence increased significantly in NSW by an average of 2.0% per year in males (95% confidence interval [CI], 1.8 to 2.3) and 0.9% in females (95% CI, 0.7 to 1.1). Mortality rates remained nearly constant in males, but fell significantly in females by an average of -1.0% per year (95% CI, -1.3 to -0.7). In the youngest age group (15-44 years) both incidence and mortality rates fell significantly, while rates were stable or rose in older age groups, except for a significant fall in mortality in women aged > or = 75 years. Use of colonoscopy (an early detection method) increased, but a corresponding shift to detection of earlier-stage cancers was not seen.

CONCLUSIONS

A reduction in risk factors and better treatment leading to longer survival may have contributed to the falls in incidence in younger people and in mortality in females.

Differences in patterns of care of prostate cancer, New South Wales, 1991

BACKGROUND

In this time of uncertainty about the benefits of earlier diagnosis for prostate cancer and the optimal choice of treatment in various clinical scenarios, we addressed the hypothesis that two groups in the population, namely country dwellers and migrants from non-English-speaking countries, were less likely to be offered new methods of diagnosis and treatment for prostate cancer.

METHODS

Incident cases of prostate cancer in 1991 were identified through the population-based New South Wales Central Cancer Registry. For 73% of eligible cases information relating to diagnosis, staging and treatment was abstracted onto a checklist from clinical records in urologists' consulting rooms and in public hospitals.

RESULTS

Transrectal ultrasound and prostatic biopsy were used for diagnosis significantly more often in urban than in rural cases while the reverse was true for transurethral resection of the prostate. Intravenous pyelography, ultrasound (other than transrectal) and bone scans were performed for staging more frequently in urban than rural cases. Rural cases were more likely to be treated with anti-androgens than urban cases and less likely to be given luteinizing-hormone releasing hormone (LH-RH) agonists. The pattern of use of various diagnostic and staging procedures for 1991 rural cases resembled that for urban men diagnosed with prostate cancer in 1986 rather than that for 1991 urban cases.

CONCLUSIONS

At least in part, these urban-rural differences could be explained by the fact that some patients in the country would have been treated by general surgeons rather than urologists. The patterns of care for non-English-speaking migrants resembled those for the Australian-born and for English-speaking migrants.

Occurrence of melanomas on the upper and lower limbs in eastern Australia

In view of the changing trends in the incidence of melanoma at different body sites and in particular on the limbs, the detailed distributions of over 10,000 invasive melanomas diagnosed on the upper and lower limbs in residents of mainland eastern Australia between 1987 and 1993 were examined. Cancer notifications and histopathology reports from the cancer registries of Queensland, New South Wales and Victoria were searched manually, and subsites when specified were recorded as shoulder, upper arm, forearm, elbow, wrist or hand, and thigh, leg, knee, ankle or foot. On the upper limbs relative tumour densities were highest on the shoulder, approximately equal on the upper arm and forearm and least on the hand in both men and women; on the lower limbs melanomas occurred more than twice as often on the leg than on the thigh or the foot, taking account of surface area. There was a clear inverse gradient of incidence of melanoma with latitude in the three eastern Australian states studied, but little difference between the states or between sexes in distribution of histological type: the majority specified being specified as superficial spreading melanomas. In contrast to predictions based on apparent frequency of sun exposure at subsites on the upper limbs, the relative concentration of melanomas on the shoulder suggests that wearing sleeveless garments outdoors in the sun should be avoided whenever possible. Also, the similar densities of leg and forearm melanomas seems inconsistent with the relative degree of exposure of each and further suggests that women's adoption of ankle-length skirts or trousers, in preference to knee-length skirts would be a worthwhile modern control measure.

International renal-cell-cancer study. VI. the role of medical and family history

A number of medical conditions have been linked with renal-cell cancer, although the evidence is not consistent in every case. In a large international case-control study of renal-cell cancer, we examined, among other hypotheses, associations with a personal history of certain medical conditions and a family history of cancer of the kidney or thyroid. Relative risks (RR), adjusted for the effects of age, gender, body-mass index, tobacco smoking and study centre, were significantly increased by a history of kidney stones or thyroid or kidney disease. The RR were not altered by additional adjustment for hypertension, or when diagnoses were restricted to those made at least 5 or 10 years before 1987 (the usual "cut-off" date). The link with kidney injury is particularly likely to be affected by recall bias. Increased RR of borderline significance were found for kidney infection (RR, 1.2) and diabetes (RR, 1.4). Having one first-degree relative with kidney cancer was associated with a significantly increased risk of renal-cell cancer (RR, 1.6; 95% Cl, 1.1-2.4). Seven cases reported 2 first-degree relatives with kidney cancer. No controls had first-degree relatives with kidney cancer. None of our participants reported having von Hippel-Lindau disease. The data suggests that a few conditions of the kidney are strongly associated with renal-cell cancer and that heredity plays a role in a small proportion of cases.

International renal-cell-cancer study. VI. the role of medical and family history

A number of medical conditions have been linked with renal-cell cancer, although the evidence is not consistent in every case. In a large international case-control study of renal-cell cancer, we examined, among other hypotheses, associations with a personal history of certain medical conditions and a family history of cancer of the kidney or thyroid. Relative risks (RR), adjusted for the effects of age, gender, body-mass index, tobacco smoking and study centre, were significantly increased by a history of kidney stones or thyroid or kidney disease. The RR were not altered by additional adjustment for hypertension, or when diagnoses were restricted to those made at least 5 or 10 years before 1987 (the usual "cut-off" date). The link with kidney injury is particularly likely to be affected by recall bias. Increased RR of borderline significance were found for kidney infection (RR, 1.2) and diabetes (RR, 1.4). Having one first-degree relative with kidney cancer was associated with a significantly increased risk of renal-cell cancer (RR, 1.6; 95% Cl, 1.1-2.4). Seven cases reported 2 first-degree relatives with kidney cancer. No controls had first-degree relatives with kidney cancer. None of our participants reported having von Hippel-Lindau disease. The data suggests that a few conditions of the kidney are strongly associated with renal-cell cancer and that heredity plays a role in a small proportion of cases.

Second primary cancers following cancers of the kidney and prostate in New South Wales (Australia), 1972-91

Data from the New South Wales (NSW) (Australia) Central Cancer Registry for the period 1972-91 were examined to determine the risk of second primary cancers following an initial invasive cancer of the renal parenchyma (ICD-9 code 189.0), renal pelvis (code 189.1), or prostate (code 185). Eligible cases were restricted to those who had survived for at least two months after diagnosis of the first primary cancer. Expected numbers of cancers were obtained by assuming that subjects experienced the same cancer incidence as prevailed in the corresponding general population and applying gender-, age-, and calendar-specific rates to the appropriate person-years at risk. The relative risk (RR) of a second primary cancer was taken to be the ratio of observed to expected numbers of second cancers. Following prostatic cancer, there was an overall deficit of cancers at all sites combined (RR = 0.79, 95 percent confidence interval [CI] = 0.75-0.84), and no site had a significantly raised RR. Taking this into consideration, there appeared to be a reciprocal relationship of increased risk of prostatic cancer (RR = 1.7, CI = 1.2-2.3) following an initial cancer of the renal parenchyma and of renal parenchymal cancer (RR = 1.2, CI = 0.8-1.7) after cancer of the prostate. An increased risk of bladder cancer occurred following renal parenchymal (RR = 3.4, CI = 1.1-8.0, for women only) as well as after renal pelvic cancer (men: RR = 8.7, CI = 5.4-13; women: RR = 39, CI = 26-56). A tobacco-related pattern of excess risk was seen after renal pelvic cancer but not after cancer of the renal parenchyma. These data illustrate that an excess of second primary cancers may reflect shared etiologic factors or increased medical surveillance.

Activated clotting time differential is a superior method of monitoring anticoagulation following coronary angioplasty

The standard high-range activated clotting time (sHR ACT) is used to monitor anticoagulation postangioplasty (PTCA), but may be unreliable. We assessed the accuracy of a new method we termed the ACT differential (ACT Diff), obtained by measuring the difference between an sHR ACT and a heparinase ACT from the same sample. Heparinase removes heparin from its sample and provides a current heparin-free baseline. For phase 1 of the study, the sHR ACT, ACT Diff, and laboratory APTT were measured in 250 samples from 75 PTCA patients. In 125 samples with an APTT prolonged but within measurement range, linear regression against the APTT was performed. The correlation coefficient was 0.74 for the ACT Diff and 0.24 for the sHR ACT. An ACT Diff of 15-25 sec was found to equal an APTT of 2.5-3.5 x control. In 50 samples with a normal activated partial thromboplastin time (APT), there was good differentiation by the ACT Diff of results from those adequately heparinized, with a value of 0.9 +/- 4.4 sec. The sHR ACT was 114 +/- 15.5 sec, and could not reliably distinguish between anticoagulated and nonanticoagulated samples. In 75 samples obtained with a high APTT (above measurement range), the ACT Diff was > 30 sec in 95% of samples, and again this allowed differentiation from therapeutic samples. The equivalent sHR ACT was 148 sec, and could not reliably distinguish between anticoagulated and overanticoagulated samples as the ACT Diff could. In phase 2, to examine the clinical usefulness of the ACT Diff, 286 patients were managed post-PTCA by starting heparin when ACT Diff fell to < 50 sec, maintaining ACT Diff at 15-25 sec during heparin infusions, and following cessation of heparin, by removing sheaths when the ACT Diff was < 7 sec. These patients were compared to a control group of 250 patients. Major bleeding (5% vs. 0.5%, P < 0.005) and minor bleeding (30% vs. 13%, P < 0.001) were significantly reduced in the group managed using the ACT Diff. The reduction in bleeding was thought to be due to the rapid availability of reliable results. Abrupt closure was low in both groups (0% with ACT Diff vs. 0.8%). No other thrombotic events occurred. Following phases 1 and 2, the ACT Diff replaced the APTT in all PTCA patients at this institution. In the 18 mo from July 1993, 1,104 patients were managed this way. Incidence of major bleeding (0.2%), transfusion requirement (0.1%), false anneurysm (0.6%), and abrupt closure during heparin infusion (0.1%) remained low. In conclusion, the ACT Diff is more accurate than an sHR ACT, and its clinical use in PTCA patients is associated with a very low incidence of complications from anticoagulation. Its routine use should be considered by units unable to obtain rapid APTT results.

International renal cell cancer study. VII. Role of diet

We investigated the role of diet in the etiology of renal cell cancer (RCC) in a multi-center, population-based case-control study conducted in Australia, Denmark, Sweden and the United States, using a shared protocol. A total of 1,185 incident histopathologically confirmed cases (698 men, 487 women) and 1,526 controls (915 men, 611 women) frequency-matched to cases by sex and age were included in the analyses. The association between RCC and diet was estimated by relative risks (RR) and 95% confidence intervals (CI) adjusted for age, sex, study center, body mass index and smoking. A statistically significant positive association was observed for total energy intake (RR = 1.7, 95% CI = 1.4-2.2 for the highest vs. lowest quartile, p value for trend < 0.00001), while the hypothesis that protein and fat are risk factors independent of energy was not supported. Fried meats were associated with increased RCC risk, while vegetables and fruits were protective, with the strongest effect observed for the highest quartile of consumption of orange/dark green vegetables but not vitamin C or beta carotene. Increased risk was associated with low intake (lowest decile) of vitamin E and magnesium. We observed an apparent protective effect of alcohol confined to women and probably due to chance. Our findings indicate an important role of nutrition in the development of RCC. The apparent positive association of energy intake with risk of RCC needs further investigation in a prospective cohort study to exclude the possible impact of differences in recall between cases and controls.

Multiple primary melanomas: an analysis of cancer registry data from Victoria and New South Wales

All primary invasive cutaneous malignant melanomas (CMM) diagnosed in Victoria and New South Wales from 1985 to 1989 were obtained from the population-based cancer registries. Altogether 14,590 people with first CMMs were followed for at least 2 years, during which time 496 multiple primary CMMs were identified. Of the study population, 3.4% developed a second primary CMM and 0.3% developed three or more. It was estimated that 4.5% of people would develop a second CMM within 5 years of the first and that the risk was higher in males, particularly in men aged over 70 years. With regard to metachronous primaries, only age and thickness of the first primary were significant predictors of the thickness of the second: older people tended to have thicker CMMs and second CMMs were generally thinner than the first. Body site concordance was higher than expected by chance, particularly for synchronous diagnoses. The high degree of site concordance of metachronous primaries lent support to the hypothesis that skin adjacent to the first CMM might have undergone a 'field effect', rendering it at increased susceptibility to malignancy.

Changes in cancer incidence and mortality in New South Wales

OBJECTIVE

To assess changes in cancer incidence and mortality in New South Wales (NSW) between 1973-1977 and 1988-1992.

DESIGN

Descriptive analysis of statutory cancer notifications to the NSW Central Cancer Registry.

OUTCOME MEASURES

Age-standardised incidence and mortality rates calculated with the "world" standard population.

RESULTS

Overall cancer incidence rose markedly, from 251 to 318 per 100,000 in men and from 202 to 241 per 100,000 in women. The rise was greatest in the 60-and-over age group. Cancer mortality fell marginally in men (from 166 to 162 per 100,000) and did not change in women (100 per 100,000 in both periods). It fell in the under-60 age group, and remained stable or rose in older people. Prostate and breast cancers and melanoma of the skin accounted for about half the increase in incidence. Both incidence and mortality increased significantly (P < 0.01) for melanoma and non-Hodgkin's lymphomas in men and lung cancer in women, and fell substantially for stomach cancer in both sexes, lung cancer in men and cervical cancer in women. Despite increasing incidence, mortality, also fell for testicular cancer in men and rectal cancer in women and for leukaemias in children.

CONCLUSIONS

The major factor causing the increased incidence of overall cancer was earlier detection. Altered exposure to risk factors could be identified for only a minority of the changes.

Risk factors and preventive strategies for breast cancer

Several risk factors for breast cancer are readily identifiable, but most are not preventable. Hence the importance of screening, as early diagnosis and treatment offer the best hope of saving lives.

International renal-cell cancer study. VIII. Role of diuretics, other anti-hypertensive medications and hypertension

Risk of renal-cell cancer in relation to use of diuretics, other anti-hypertensive medications and hypertension was assessed in a multi-center, population-based, case-control study conducted in Australia, Denmark, Germany, Sweden and the United States, using a shared protocol and questionnaire. A total of 1,732 histologically confirmed cases and 2,309 controls, frequency-matched to cases by age and sex, were interviewed. The association between renal-cell cancer and the drugs was estimated by relative risks (RRs) and 95% confidence intervals (CIs). Risks were increased among users of diuretics and other anti-hypertensive medications. After adjustment for hypertension, risk for diuretics was reduced to unity, except among long-term (15+ years) users. Risk for use of non-diuretic anti-hypertensive drugs remained significantly elevated and increased further with duration of use. Overall risk was not enhanced when both classes of medications were used. Excess risk was not restricted to any specific type of diuretic or anti-hypertensive drug and no trend was observed with estimated lifetime consumption of any particular type of product. The RR for hypertension after adjustment for diuretics and other anti-hypertensive medications was 1.4 (95% CI = 1.2-1.7), although among non-users of any anti-hypertensive medications, there was little excess risk associated with a history of hypertension. Exclusion of drug use that first occurred within 5 years of cancer diagnosis or interview did not alter the associations. Our findings suggest small effects on renal-cell cancer risk associated with hypertension and use of diuretics and other anti-hypertensive medications. However, because of potential misclassifications of these highly correlated variables, it is difficult to distinguish the effect of treatment from its indication, hypertension.

Adequacy of histopathology reports for breast cancer in New South Wales

To assess the adequacy of diagnostic histopathology reports for breast cancer in New South Wales (NSW) and the Australian Capital Territory (ACT), a cross-sectional survey of diagnostic histopathology reports was carried out on a random sample (n = 1000) of NSW and ACT women diagnosed with breast cancer in 1992 and notified to the NSW Central Cancer Registry. A single pathologist with expertise in breast cancer reviewed the reports, from laboratories in public and private sectors, against a checklist enumerating basic features considered useful for decision making by surgeons and/or medical and radiation oncologists. While information was provided by almost all reports on histological classification (94%), size of tumor (93%) and involvement of lymph nodes (99.8%), this was not so for tumor resection/biopsy margin (77%), histological grade (69%), nuclear grade (23%), mitotic rate (11%) and the presence or absence of lymphatic (34%) or vascular (24%) invasion. Pathologists from teaching hospitals and those who reported on more than 10 cases in the sample were more likely to provide relevant information. Many diagnostic histopathology reports for breast cancer did not fulfil the requirements for a satisfactory report, established prognostic and predictive features frequently being omitted. The uniform use by pathologists of a carefully designed checklist could ensure that standard information is provided for every breast cancer, thereby facilitating choice of therapy for all patients.

Second cancers occurring after cancers of the mouth and pharynx: data from three population-based registries in Australia, Scotland and Slovenia

Data over at least 20 years from three large population-based registries in Europe and Australasia have been used to assess the risk of second primary tumours occurring after a cancer of the mouth or pharynx. These patients have previously been shown in clinical series to be at a particularly high risk of subsequent tumours, while data from cancer registries have shown conflicting results on the magnitude of the risk. In this study, patients were found to have between a 2-fold (Scotland and New South Wales) and 4-fold (Slovenia) increase in risk of a subsequent tumour over that in the population, although the actual risk in each centre was similar (between 2.8 and 3.1 per 100 person years). The risk remained for 10 years after diagnosis of the original tumour and was primarily in the upper aerodigestive tract. The most elevated risks (approximately 10-fold) were for tumours in the oral cavity and oesophagus. These data provide higher estimates of risk than previously reported from European cancer registries for second primary tumours and emphasize the need for close follow-up of patients who may represent an appropriate population in which to assess possible new chemopreventive agents.

Breast cancer in NSW women: a shift in tumour size

OBJECTIVE

To determine whether there has been an increase in the proportion of small (< 1 cm in size) and localised breast cancers in women aged 50-69 (the group actively recruited to mammographic screening) compared with women aged 40-49.

DESIGN

Cases of invasive breast cancer in women aged 40-69 notified to the NSW Central Cancer Registry in 1986, 1989 and 1992 were included. Tumour sizes were determined from histopathology reports.

RESULTS

A higher percentage of breast cancers were under 1 cm in size in 1992 (10%) than in 1986 and 1989 (7%). The increase in the percentage of small breast cancers was statistically significant in women aged 50-69 (chi 2 for linear trend, 7.9; P = 0.005) but not in those aged 40-49 (chi 2 for linear trend, 2.5; P = 0.12). Slightly more than half the breast cancers (53%) in 1992 were localised to the breast, representing an increase from 49% in both 1986 and 1989. This increase was also statistically significant in women aged 50-69 (chi 2 for linear trend, 3.9; P = 0.05) but not in those aged 40-49 (chi 2 for linear trend, 1.4; P = 0.24).

CONCLUSIONS

Breast cancers in 1986, 1989 and 1992 showed a moderately strong shift to smaller tumours and localised disease in women aged 50-69. As women of this age group were targeted by mammographic screening, the widespread availability of mammography may explain this shift.

International renal-cell cancer study. IV. Occupation

The relationship between renal-cell cancer (RCC) and occupation was investigated in an international multicenter population-based case-control study. Study centers in Australia, Denmark, Germany, Sweden and the United States interviewed 1732 incident RCC cases and 2309 controls. Significant associations were found with employment in the blast-furnace or the coke-oven industry [relative risk (RR), 1.7; 95% confidence interval (CI), 1.1-2.7], the iron and steel industry (RR, 1.6; 95% CI, 1.2-2.2) and exposure to asbestos (RR, 1.4; 95% CI, 1.1-1.8), cadmium (RR, 2.0; 95% CI, 1.0-3.9), dry-cleaning solvents (RR, 1.4; 95% CI, 1.1-1.7), gasoline (RR, 1.6; 95% CI, 1.2-2.0) and other petroleum products (RR, 1.6; 95% CI, 1.3-2.1). Asbestos, petroleum products and dry-cleaning solvents appear to merit further investigation, in view of the relationship between risk and duration of employment or exposure and after adjustment for confounding. There was a negative association between RCC and education, but it was not consistent across all centers. Overall, the results of our multicenter case-control study suggest that occupation may be more important in the etiology of RCC than indicated by earlier studies.

International renal-cell cancer study. V. Reproductive factors, gynecologic operations and exogenous hormones

The relationships between reproductive factors, exogenous hormones and renal-cell cancer were examined in an international, multicenter, population-based, case-control study undertaken in 1989-1991. Data from 5 centers situated in Australia, Denmark, Germany, Sweden and the United States included for analysis 608 women with renal-cell cancer and 766 female controls. A significant trend in risk (p = 0.002) was associated with number of births, with an 80% excess risk for 6 or more births [RR = 1.8, 95% confidence interval (CI) = 1.1 to 2.9] compared with one birth. A decreasing risk was seen for increasing age at first birth, although this was confounded by body-mass index and number of births. A suggestive reduction of risk was also seen for increasing age at menarche. Age at menopause was unrelated to risk of renal-cell cancer. An increased risk was observed for women having had both a hysterectomy and an oophorectomy. Use of oral contraceptives in non-smoking women reduced the risk of renal-cell cancer (RR = 0.5, 95% CI = 0.4 to 0.8); this reduction increased with longer duration of use. No association was observed for estrogen replacement therapy. Our results indicate that certain hormonal and reproductive variables may be related to risk of renal-cell cancer and deserve further investigation, both epidemiologically and experimentally.

Cancer incidence in Asian migrants to New South Wales, Australia

Cancer incidence during 1972-90 in Asian migrants to New South Wales, Australia, is described. Overall cancer incidence was lower than in the Australia born in most migrant groups, and this reached significance in migrants born in China/Taiwan, the Philippines, Vietnam and India/Sri Lanka, and in male migrants born in Indonesia. For the majority of cancers, rates were more similar to those in the Australia born than to those in the countries of birth. For cancers of the breast, colorectum and prostate, rates were relatively low in the countries of birth, but migrants generally exhibited rates nearer those of the Australia born. For cancers of the liver and cervix and, in India/Sri Lanka-born migrants, of the oral cavity, incidence was relatively high in the countries of birth but tended to be lower, nearer Australia-born rates, in the migrants. For these cancers, environmental factors related to the migrant's adopted country, and migrant selection, appeared to have a major effect on the risk of cancer. For certain other cancers, incidence was more similar to that in the countries of birth. Nasopharyngeal cancer, and lung cancer in females, had high rates in both the countries of birth and in migrants to Australia. Nasopharyngeal cancer rates were highest in China/Taiwan and Hong Kong-born migrants, and were also significantly high in migrants from Malaysia/Singapore, Vietnam and the Philippines. Rates of lung cancer were significantly high in women born in China/Taiwan, and the excess was greater for adenocarcinoma than for squamous cell carcinoma. Melanoma had low rates in both the migrants and in the countries of birth. For these cancers, it was probable that genetic factors, or environmental factors acting prior to migration, were important in causation.

Incidence of cancer among New South Wales adolescents: which classification scheme describes adolescent cancers better?

This report has the dual purpose of describing patterns of cancer incidence among adolescents in New South Wales (NSW), Australia, and comparing adult and childhood cancer classification schemes. All cases of cancer incident between 1972 and 1991 in NSW residents aged 10-19 years were obtained from the population-based NSW Central Cancer Registry and coded according to Birch and Marsden (1987) in addition to routine coding by the Ninth Revision of the International Classification of Diseases. The average incidence rate for all cancers combined was 158 and 140 per million in males and females respectively. The Birch and Marsden category of "carcinomas and other epithelial neoplasms" comprised 22% of all cancers in male adolescents and 37% in females. Melanoma alone accounted for 16% of all cancers in males and 26% in females. Rates of leukaemias and central nervous system tumours were similar in the age groups 10-14 years and 15-19 years. By contrast, lymphomas, bone tumours (males only), soft tissue (males only), "germ-cell, trophoblastic and other gonadal tumours" and "carcinomas and other epithelial neoplasms" were more common in the older age group. The Birch and Marsden classification with its emphasis on morphology provided a clearer picture of some types of cancer which occurred frequently among teenagers. Cancers common in adults did occur in older adolescents but were less well described by the childhood scheme. Cancers of colon and lung were often of unusual histological type compared to adult tumours. It would appear appropriate to use the childhood classification scheme to describe cancer incidence in adolescent age groups, perhaps with minor modification.

International renal-cell cancer study. II. Analgesics

There has been concern about the role of analgesics in the development of renal-cell cancer, although a few studies have reported moderately elevated risks with regular or long-term use. In a large international case-control study of renal-cell cancer we examined, among other hypotheses, the effect of phenacetin-containing and of other types of analgesics: paracetamol (acetaminophen), salicylates (mainly aspirin) and pyrazolones (e.g., antipyrine or phenazone). Relative risks, adjusted for the effects of age, sex, body-mass index, tobacco smoking and study centre, were not significantly increased with intake of phenacetin, either when lifetime consumption was categorized at the level of > or = 0.1 kg or when subjects were subdivided further by amount. Nor were paracetamol, salicylates or pyrazolones linked with renal-cell cancer. No consistently increasing risks with consumption level was found. The lack of association was not altered by restricting analgesic use to that which occurred 5 or 10 years before the defined "cut-off" date or when analysis was restricted to exclusive users of a particular type of analgesic. Neither was the risk influenced by the rate of consumption or whether the consumption had occurred at a young age. Our study provides clear evidence that aspirin is unrelated to renal-cell cancer risk, and our findings do not support the hypothesis that analgesics containing phenacetin or paracetamol increase the risk, although the number of "regular" users and the amount of these types of analgesic consumed were too small to confidently rule out a minor carcinogenic effect of phenacetin and paracetamol.

International renal-cell cancer study. III. Role of weight, height, physical activity, and use of amphetamines

Although numerous studies have identified obesity or high relative weight as a risk factor for renal-cell cancer in women, the degree to which this effect is present in men remains unclear. A multicenter population-based case-control study concerning incident cases of histologically verified renal-cell cancer (n = 1,732) and age- and sex-matched controls (n = 2,309) was conducted in Australia, Denmark, Germany (2 centers), Sweden and the United States. Relative weight was estimated by the body mass index, and the association between this factor and other factors, such as height, physical activity and use of amphetamines, was measured by the relative risk estimated in logistic regression models. Body mass index was found to be a risk factor among women and, to a lesser extent, among men. A 3-fold increased risk (RR = 3.6, 95% CI = 2.3-5.7) was observed for women with a relative weight in the top 5% compared with those in the lowest quartile. Rate of weight change (estimated as weight change per annum in kilograms) appeared to be an independent risk factor among women but not among men. Physical activity and height were unrelated to risk of renal-cell cancer regardless of level of BMI, while use of amphetamines was associated with an increased risk among men, although no dose or duration effect was seen. Our findings verify the link between high relative weight and risk of renal-cell cancer, particularly among women. The mechanism that underlies this association is, however, still unclear, although the rate of weight change may play a role.

International renal-cell cancer study. I. Tobacco use

The relationship between renal-cell cancer (RCC) and tobacco use was investigated in an international, multicenter, population-based case-control study. Coordinated studies were conducted in Australia, Denmark, Germany, Sweden and the United States using a shared protocol and questionnaire. A total of 1,732 cases (1,050 men, 682 women) and 2,309 controls (1,429 men, 880 women) were interviewed for the study. No association was observed between risk and use of cigars, pipes or smokeless tobacco. A statistically significant association was observed for cigarette smoking, with current smokers having a 40% increase in risk [relative risk (RR) = 1.4, 95% confidence interval (CI) 1.2-1.7]. Risk increased with intensity (number of cigarettes) and duration (years smoked). Among current smokers the RR for pack-years rose from 1.1 (95% CI 0.8-1.5) for < 15.9 pack years to 2.0 (95% CI 1.6-2.7) for > 42 pack years (p for trend < 0.001). Long-term quitters (> 15 years) experienced a reduction in risk of about 15-25% relative to current smokers. Those who started smoking late (> 24 years of age) had about two-thirds the risk of those who started young (< or = 12 years of age). Overall, the findings of this pooled analysis confirm that cigarette smoking is a causal factor in the etiology of RCC.

Modifying fluoroscopic views reduces operator radiation exposure during coronary angioplasty

OBJECTIVES

This three-part study examined the feasibility of reducing operator radiation exposure during coronary angioplasty.

BACKGROUND

As case loads and complexity increase, some cardiologists are receiving increasing radiation scatter doses. Techniques to reduce this are therefore becoming more important.

METHODS

First, the determinants of the operator dose were assessed by measuring the differences in scatter dose with different camera views. The relative contribution of fluoroscopy as opposed to cine was then quantified. Finally, operators were provided with these data, and subsequent changes in technique were evaluated.

RESULTS

Left anterior oblique views resulted in 2.6 to 6.1 times the operator dose of equivalently angled right anterior oblique views. Increasing steepness of the left anterior oblique view also resulted in a progressive increase in operator dose, with left anterior oblique 90 degrees causing eight times the dose of left anterior oblique 30 degrees and three times that of left anterior oblique 60 degrees. In the 45 coronary angioplasty cases prospectively analyzed, fluoroscopy was found to be a greater source of total radiation than cine by a 6.3:1 ratio (range 1.1 to 15.8). Once operators were made aware of the importance of left anterior oblique fluoroscopy, there was a marked reduction in its use. When this was not feasible, there was a reduction in the steepness of the angulation. Left anterior oblique fluoroscopy during angioplasty of the left anterior descending and circumflex coronary arteries was reduced from 40% of total screening time to approximately 5%, and left anterior oblique angulation for fluoroscopy during angioplasty of the right coronary artery decreased from 43.6 degrees (+/- 9.1 degrees) to 29.4 degrees (+/- 2.2 degrees). Success rates (90% vs. 89%) and screening times (19.5 vs. 20.7 min) remained unchanged in 200 coronary angioplasties performed after the study. Average operator radiation dose (measured by radiation badges worn under lead at waist level) was reduced from 32.6 to 14.3 microSv/operator per week despite a slight increase in case load.

CONCLUSIONS

Fluoroscopy is the major source of total radiation exposure during coronary angioplasty, with left anterior oblique views providing the highest dose. Modification of views is feasible and will result in significant reduction of operator radiation dose.