| 1. |
- Liljegren, Göran, et al.
(författare)
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10-year Results After Sector Resection With or Without Postoperative Radiotherapy for Stage I Breast Cancer : a Randomized Trial
- 1999
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Ingår i: Journal of Clinical Oncology. - 0732-183X .- 1527-7755. ; 17:8, s. 2326-2333
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To study the long-term effectiveness of postoperative radiotherapy after sector resection for breast cancer in a randomized trial in which mammography is a major pathway to diagnosis. PATIENTS AND METHODS: Three hundred eighty-one women with a unifocal breast cancer < or = 20 mm in diameter on the preoperative mammogram and without histopathologic signs of axillary metastases were treated by sector resection plus axillary dissection. Of these patients, 184 women were randomized to receive postoperative radiotherapy to the breast (XRT group), and 197 women received no further treatment (non-XRT group). RESULTS: The local recurrence rate was 8.5% (95% confidence interval [CI], 3.9% to 13.1%) in the XRT group and 24.0% (95% CI, 17.6% to 30.4%) in the non-XRT group (P =.0001). Survival free from regional and distant recurrence was 83. 3% in the XRT group (95% CI, 77.5% to 89.1%) and 80.0% in the non-XRT group (95% CI, 73.9% to 86.1%) (P =.23). Overall survival was 77.5% in the XRT group (95% CI, 70.9% to 84.1%) and 78% in the non-XRT group (95% CI, 71.7% to 84.3%) (P =.99). A subgroup analysis suggested that women older than 55 years of age without comedo or lobular carcinomas had a low risk of local recurrence of 6.1% (95% CI, 0.1% to 9.1%) in the XRT-group and 11.0% (4.0% to 18.0%) in the non-XRT group (P =.16). CONCLUSION: Sector resection plus radiotherapy resulted in an absolute reduction in local recurrence of 16% at 10 years compared with surgery alone. Women older than 55 years of age without comedo or lobular carcinomas may have a low risk of local recurrence. Postoperative radiotherapy was not shown to reduce distant recurrences or improve overall survival.
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| 2. |
- Helgesen, Fred, et al.
(författare)
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Trends in prostate cancer survival in Sweden, 1960 through 1988 : Evidence of increasing diagnosis of nonlethal tumors
- 1996
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Ingår i: Journal of the National Cancer Institute. - 0027-8874 .- 1460-2105. ; 88:17, s. 1216-1221
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The incidence of prostate cancer has increased during the past 30 years but has been paralleled by increases in survival rates from this disease, despite the absence of documented major improvement in curative treatment. Since a high prevalence of microscopic prostate cancer has been observed in autopsied men and because many prostate cancers may never surface clinically, increased diagnostic activities might have led to increased detection of less aggressive tumors. PURPOSE: This study was conducted to elucidate whether the trends in prostate cancer incidence and patient survival may be due to increasing diagnoses of nonlethal tumors. METHODS: We analyzed a population-based cohort comprising all cases of prostate cancer (n = 80,901) detected in Sweden during the period of 1960 through 1988. Five hundred eighteen patients (0.64% of the total number) who could not be followed because of emigration or an incomplete national registration number were excluded. Observed and relative survival rates were calculated for the entire cohort of 80,383 assessable patients per 5-year age group in 5-year periods of diagnosis and according to diagnostic method and were compared between geographic areas with differences in incidence rates. To estimate the independent effects of these determinants, multivariate analyses were performed. RESULTS: For the 80,383 patients with complete follow-up, the 10- and 20-year observed survival rates were 17.5% (95% confidence interval [CI] = 17.2%-17.9%) and 3.5% (95% CI = 3.2%-3.7%), and the relative survival rates were 41.1% (95% CI = 40.3%-41.9%) and 28.6% (95% CI = 26.5%-30.1%), respectively. Relative survival rates improved markedly over time; 10-year relative survival rates increased from 29% (95% CI = 27%-31%) among case patients diagnosed in 1960 through 1964 to 45% (95% CI = 43%-46%) among those diagnosed in 1975 through 1979. Relative survival rates leveled off after about 18 years at 18% (95% CI = 15%-20%) among patients diagnosed in 1960 through 1964 and at 31% (95% CI = 28%-34%) among those diagnosed in 1970 through 1974. An even more favorable outlook was observed in those case patients diagnosed later. In areas with a high or low incidence of prostate cancer, the 10-year relative survival rates were 45% (95% CI = 44%-47%) and 36% (95% CI = 34%-38%), respectively. In the early 1960s, the calculated loss of life expectancy after diagnosis varied from about 68% (95% CI = 61%-75%) of the expected length of life in the youngest age group to about 48% (95% CI = 46%-50%) in the oldest age group. From 1960 through 1964 to 1985 through 1988, the loss of life expectancy decreased by more than 50% in all age groups. The differences in relative survival rates between age groups were small, with a gradual decrease in age groups more than 60-64 years of age. CONCLUSIONS: Most of the great temporal improvement and geographic variation in survival rates are quantitatively consistent, with likely increases in the rate of detection of nonlethal tumors. IMPLICATIONS: The increase in relative survival rates must be taken into consideration when evaluating the outcome of treatment of prostate cancer, since nonrandomized comparisons may be confounded by time trends. Diagnosis of nonlethal tumors raises concerns because the individual would suffer from the psychologic burden of a cancer diagnosis without any therapeutic benefit.
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| 3. |
- Holmberg, Lars, et al.
(författare)
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A search for recall bias in a case-control study of diet and breast cancer
- 1996
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Ingår i: International Journal of Epidemiology. - 0300-5771 .- 1464-3685. ; 25:2, s. 235-244
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND. In retrospective studies of dietary habits and breast cancer risk, recall bias is a concern since diet has been publicized as a cause of breast cancer. METHODS. In a case-control study of diet and breast cancer risk nested within a cohort of women screened with mammography, we contrasted answers to a retrospective dietary interview with answers to a dietary questionnaire which was filled out before any diagnostic procedures for breast cancer were undertaken. The source population was all women aged 40-74 in two counties in Sweden invited to mammographic screening and asked to fill out a questionnaire before the screening. Cases and controls were subsequently defined -- matched on age, county of residence, and time of mammography -- and approached for an interview. RESULTS. In all, 265 cases and 431 controls participated in the study. Means of frequencies differed between the agreement in the questionnaire's and the interview's classifications of study subjects into quartiles of monthly intake varied between 31 percent and 57 percent. Kappa statistics in all food groups were below 0.41. In a regression analysis, case subjects with low responses on the questionnaire about intake of meat, snacks, and coffee and tea gave higher responses on interview than did controls who had low questionnaire responses for these food groups. The reverse was also true: cases' responses that were high on the questionnaire were lower on interview for these food groups than were controls' responses. CONCLUSIONS. We found few signs of recall bias, and the few indications of a differential misclassification that we found were not in food groups that have been publicly discussed as causes of breast cancer.
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| 4. |
- Holmberg, Lars, et al.
(författare)
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Alcohol intake and breast cancer risk : effect of exposure from 15 years of age
- 1995
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Ingår i: Cancer Epidemiology, Biomarkers and Prevention. - 1055-9965 .- 1538-7755. ; 4:8, s. 843-847
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Tidskriftsartikel (refereegranskat)abstract
- Research regarding the relationship between alcohol intake and breast cancer risk has suggested an association between the two, although the data are inconsistent regarding dose effects and susceptible populations. To clarify these issues, we investigated the association of breast cancer risk with alcohol intake at various ages in a population-based case-control study nested within a screening cohort in Sweden. Subjects were women 40-75 years old who participated in a screening program in central Sweden. Information about personal characteristics, diet, and alcohol intake was obtained by a questionnaire sent out at the invitation to the screening interview and at a supplementary interview conducted among a sample of women who did and did not develop breast cancer. Alcohol intake did not affect breast cancer risk among women under 50 years old. However, among those over 50 years of age, ever-drinking conferred a relative risk of 1.8 (95% confidence interval = 1.2-2.6). Current and former drinkers had similar increases in risk. No particular latent period of alcohol effect was identified, but drinking later in life to have a bigger effect than did drinking earlier in life.
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| 5. |
- Holmberg, Lars, et al.
(författare)
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On the scientific inference from clinical trials
- 1999
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Ingår i: Journal of Evaluation In Clinical Practice. - : Wiley. - 1356-1294 .- 1365-2753. ; 5:2, s. 157-162
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Tidskriftsartikel (refereegranskat)abstract
- We have not been able to describe clearly how we generalize findings from a study to our own 'everyday patients'. This difficulty is not surprising, since generalization deals with how empirical observations are related to the growth of scientific knowledge, which is a major philosophical problem. An argument, sometimes used to discard evidence from a trial, is that the patient sample was too selected and therefore not 'representative' enough for the results to be meaningful for generalization. In this paper, we discuss issues of representativeness and generalizability. Other authors have shown that generalization cannot only depend on statistical inference. Then, how do randomized clinical trials contribute to the growth of knowledge? We discuss three aspects of the randomized clinical trial (Mant 1999), First, the trial is an empirical experiment set up to study the intervention on the question as specifically and as much in isolation from other -- biasing and confounding -- factors as possible (Rothman & Greenland 1998). Second, the trial is set up to challenge our prevailing hypotheses (or prejudices) and the trial is above all a help in error elimination (Popper 1992). Third, we need to learn to see new, unexpected and thought-provoking patterns in the data from a trial. Point one -- and partly point two -- refers to the paradigm of the controlled experiment in scientific method. How much a study contributes to our knowledge, with respect to points two and three, relates to its originality. In none of these respects is the representativeness of the patients, or the clinical situations, crucial for judging the study and its possible inferences. However, we also discuss that the biological domain of disease that was studied in a particular trial has to be taken into account. Thus, the inference drawn from a clinical study is not only a question of statistical generalization, but must include a jump from the world of experiences into the world of reason, assessment and theoretical judgement.
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| 6. |
- Johansson, Jan-Erik, et al.
(författare)
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Fifteen-year survival in prostate cancer : a prospective, population-based study in Sweden
- 1997
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Ingår i: Journal of the American Medical Association (JAMA). - : American Medical Association (AMA). - 0098-7484 .- 1538-3598. ; 277:6, s. 467-471
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To describe the natural history of initially untreated early-stage prostate cancer. A key secondary objective was to calculate long-term survival rates by stage, grade, and age at diagnosis. DESIGN: Prospective cohort study. SETTING: Population-based in 1 county of Sweden, without screening for prostate cancer. PATIENTS: A group of 642 patients with prostate cancer of any stage, consecutively diagnosed between 1977 and 1984 at a mean age of 72 years with complete follow-up to 1994. MAIN OUTCOME MEASURES: Proportion of patients who died from prostate cancer, and 15-year survival (with 95% confidence interval [CI]), corrected for causes of death other than prostate cancer. RESULTS: In the entire cohort, prostate cancer accounted for 201 (37%) of all 541 deaths. Among 300 patients with a diagnosis of localized disease (T0-T2), 33 (11%) died of prostate cancer. In this group, the corrected 15-year survival rate was similar in 223 patients with deferred treatment (81%; 95% CI, 72%-89%) and in 77 who received initial treatment (81%; 95% CI, 67%-95%). The corrected 15-year survival was 57% (95% CI, 45%-68%) in 183 patients with locally advanced cancer (T3-T4) and 6% (95% CI, 0%-12%) in those 159 who had distant metastases at the time of diagnosis. CONCLUSION: Patients with localized prostate cancer have a favorable outlook following watchful waiting, and the number of deaths potentially avoidable by radical initial treatment is limited. Without reliable prognostic indicators, an aggressive approach to all patients with early disease would entail substantial overtreatment. In contrast, patients with locally advanced or metastatic disease need trials of aggressive therapy to improve their poor prognosis.
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| 7. |
- Ljungman, Christer, et al.
(författare)
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Amputation risk and survival after embolectomy for acute arterial ischaemia : Time trends in a defined Swedish population
- 1996
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Ingår i: European Journal of Vascular and Endovascular Surgery. - 1078-5884 .- 1532-2165. ; 11:2, s. 176-182
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To assess the outcome of embolectomy over an 19 year period. METHODS: Time trends in the outcome of acute arterial thrombo-embolectomy of the extremities were analysed in a population-based cohort of 1190 patients operated on between 1965-83. RESULTS: A total of 262 (22%) initial amputations were performed. The limb salvage rates at 5 years postoperatively were lower between 1975-79 (61%) than between 1965-69 (81%). A proportional hazards model revealed a relative hazard (RH) of amputation of 2.2 (95% confidence interval (CI) 1.3-3.3) for 1975-79 compared with 1965-69. Operation at any district hospital entailed a 70% higher risk of amputation (RH 1.7; 95% CI 1.3-2.5) compared with the University hospital. The relative survival rate at 5 years postoperatively decreased towards the end of the study period (33% between 1975-79 compared with 43% between 1965-69). Younger age-groups had a considerably lower risk of death in the University hospital compared with the county and district hospitals. CONCLUSIONS: Contrary to the results in other hospital based reports no improvement in amputation or survival rates since 1965 could be demonstrated in this large series with no patient selection.
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| 8. |
- Wolk, Alicja, et al.
(författare)
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A prospective study of association of monounsaturated and other types of fat with risk of breast cancer
- 1998
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Ingår i: Archives of Internal Medicine. - : American Medical Association (AMA). - 0003-9926 .- 1538-3679. ; 158:1, s. 41-45
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Animal studies suggest that monounsaturated and polyunsaturated fat may have opposite effects on the risk of breast cancer. METHODS: We performed a population-based prospective cohort study, including 61,471 women aged 40 to 76 years from 2 counties in central Sweden who did not have any previous diagnosis of cancer; 674 cases of invasive breast cancer occurred during an average follow-up of 4.2 years. All subjects answered a validated 67-item food frequency questionnaire at baseline. Cox proportional hazards models were used to obtain adjusted rate ratio (RR) estimates with 95% confidence intervals (CIs). RESULTS: After mutual adjustment of different types of fat, an inverse association with monounsaturated fat and a positive association with polyunsaturated fat were found. The RR for each 10-g increment in daily intake of monounsaturated fat was 0.45 (95% CI, 0.22-0.95), whereas the RR for a 5-g increment of polyunsaturated fat was 1.69 (95% CI, 1.02-2.78); the increments correspond to approximately 2 SDs of intake in the population. Comparing the highest quartile of intake with the lowest, we found an RR of 0.8 (95% CI, 0.5-1.2) for monounsaturated fat and 1.2 (95% CI, 0.9-1.6) for polyunsaturated fat. Saturated fat was not associated with the risk of breast cancer. CONCLUSIONS: Our results indicate that various types of fat may have specific opposite effects on the risk of breast cancer that closely resemble the corresponding effects in experimental animals. Research investigations and health policy considerations should take into account the emerging evidence that monounsaturated fat might be protective for risk of breast cancer.
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