| 11. |
- Frisch, Morten, et al.
(author)
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Benign anal lesions, inflammatory bowel disease and risk for high-riskive and -negative anal carcinoma
- 1998
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In: British Journal of Cancer. - 0007-0920 .- 1532-1827. ; 78:11, s. 1534-1538
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Journal article (peer-reviewed)abstract
- A central role in anal carcinogenesis of high-risk types of human papillomaviruses (hrHPV) was recently established, but the possible role of benign anal lesions has not been addressed in hrHPV-positive and -negative anal cancers. As part of a population-based case-control study in Denmark and Sweden, we interviewed 417 case patients (93 men and 324 women) diagnosed during the period 1991-94 with invasive or in situ anal cancer, 534 patients with adenocarcinoma of the rectum and 554 population controls. Anal cancer specimens (n = 388) were tested for HPV by the polymerase chain reaction. Excluding the 5 years immediately before diagnosis, men, but not women, with anal cancer reported a history of haemorrhoids [multivariate odds ratio (OR) 1.8; 95% confidence interval (CI) 1.04-3.2] and unspecific anal irritation (OR 4.5; CI 2.3-8.7) significantly more often than controls. Women with anal cancer did not report a history of benign anal lesions other than anal abscess to any greater extent than controls, but they had used anal suppositories more often (OR 1.5; CI 1.1-2.0). Patients with hrHPV in anal cancer tissue (84%) and those without (16%) reported similar histories of most benign anal lesions, but anal fissure or fistula was more common among hrHPV-positive cases. Ulcerative colitis and Crohn's disease, reported by <1% of study participants, were not associated with anal cancer risk. The higher proportion of hrHPV-positive anal cancers among case patients with anal fissure or fistula suggests that such mucosal lesions may provide direct viral access to basal epithelial layers. Since risk associations with benign anal lesions in men may be confounded by unreported sexual behaviour, and since risk associations in women were generally negative, it seems unlikely that benign anal lesions act as promoters in hrHPV-associated anal carcinogenesis. Moreover, benign anal lesions appear not to be linked to an alternative, hrHPV-unassociated causal pathway to anal cancer. Ulcerative colitis and Crohn's disease were not supported as causal factors for anal cancer.
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| 12. |
- Frisch, Morten, et al.
(author)
-
[Sexually transmitted infection as a cause of anal cancer]
- 1998
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In: Ugeskrift for læger. - 0041-5782 .- 1603-6824. ; 160:49, s. 7109-7117
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Journal article (peer-reviewed)abstract
- Interviews were carried out with 423 women and 93 men with invasive or in situ anal cancer in Denmark and Sweden in a search for clues to the aetiology of this neoplasm. Patients with rectal adenocarcinoma (n = 534) and persons drawn from the background population (n = 554) served as controls. Multivariate logistic regression analyses confirmed previous observations of a strong association between either male homosexual experience or a history of anogenital warts and the risk for anal cancer. Moreover, hitherto unknown, but strong and consistent associations were observed between measures of high heterosexual activity and the risk for anal cancer among both sexes. Polymerase chain reaction analysis revealed human papilloma-virus DNA in the majority (88%) of anal cancer specimens but in none of 20 examined rectal adenocarcinomas. It is concluded that most anal cancers appear to be caused by sexually transmitted types of human papillomaviruses and, consequently, that anal cancer is a potentially preventable neoplasm.
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| 13. |
- Frisch, Morten, et al.
(author)
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Sexually transmitted infection as a cause of anal cancer
- 1997
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In: New England Journal of Medicine. - 0028-4793 .- 1533-4406. ; 337:19, s. 1350-1358
-
Journal article (peer-reviewed)abstract
- BACKGROUND: The incidence of anal cancer has increased in recent decades, particularly among women. To identify underlying risk factors, we conducted a population-based case-control study in Denmark and Sweden. METHODS: We conducted telephone interviews with 324 women and 93 men in whom invasive or in situ anal cancer was diagnosed between 1991 and 1994, 534 controls with adenocarcinoma of the rectum, and 554 population controls. The interviews covered a wide spectrum of possible risk factors for anal cancer. Odds ratios were calculated by logistic regression. Specimens of anal-cancer tissue and samples of rectal adenocarcinomas were tested for human papillomavirus (HPV) DNA with the polymerase chain reaction. RESULTS: Multivariate analysis revealed consistent and statistically significant associations between measures of sexual promiscuity and the risk of anal cancer in both men and women. There was a significant trend toward an association between higher numbers of partners of the opposite sex in women (P<0.001) and men (P<0.05) and strong associations with a variety of venereal diseases. In women, receptive anal intercourse, particularly before the age of 30 years, and venereal infections in the partner were also associated with an increased risk (odds ratios, 3.4 and 2.4, respectively). Fifteen percent of the men with anal cancer reported having had homosexual contact, as compared with none of the controls (P<0.001). High-risk types of HPV, notably HPV-16, were detected in 84 percent of the anal-cancer specimens examined, whereas all rectal-adenocarcinoma specimens tested were negative for HPV. CONCLUSIONS: Our study provides strong evidence that a sexually transmitted infection causes anal cancer. The presence of high-risk types of HPV, notably HPV-16 (which is known to cause cancer of the cervix), in the majority of anal-cancer tissue specimens suggests that most anal cancers are potentially preventable.
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| 14. |
- Frisch, Morten, et al.
(author)
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Tobacco smoking as a risk factor in anal carcinoma : an antiestrogenic mechanism?
- 1999
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In: Journal of the National Cancer Institute. - : Oxford University Press (OUP). - 0027-8874 .- 1460-2105. ; 91:8, s. 708-715
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Journal article (peer-reviewed)abstract
- BACKGROUND: Human papillomavirus-associated anogenital carcinogenesis depends on poorly defined cofactors. Smoking was recently suggested to increase the risk of anal cancer more in premenopausal women than in postmenopausal women. Thus, we used our population-based anal cancer case-control study in Denmark and Sweden to test this hypothesis. METHODS: Our study included 417 patients (324 women and 93 men) who were diagnosed with anal cancer (84% invasive cancer) from 1991 through 1994; it also included five patients diagnosed in 1995. Two control groups were used: 1) 554 population control subjects (349 women and 205 men) and 2) 534 patients with rectal adenocarcinoma (343 women and 191 men). Odds ratios (ORs), calculated from logistic regression analyses, were used as measures of relative risk. All P values are two-sided. RESULTS: Compared with the risk for lifelong nonsmokers, the risk of anal cancer was high among premenopausal women who currently smoked tobacco (multivariate OR = 5.6; 95% confidence interval [CI] = 2.4-12.7) and increased linearly by 6.7% per pack-year smoked (one pack-year is equivalent to one pack of cigarettes smoked per day for 1 year) (P for trend <.001). Smoking was not statistically significantly associated with anal cancer risk in postmenopausal women or men. Women whose menstrual periods started late were at high risk (multivariate OR = 3.6; 95% CI = 1.8-7.3, for > or = 17 years of age versus < or = 12 years of age; P for trend <.001), and body mass index (weight in kg/[height in m]2) was inversely associated with risk among women (P<.001). CONCLUSIONS: Because the risk of anal cancer associated with smoking was restricted to premenopausal women and because higher risk was associated with late menarche and lean body composition, female sex hormones may be a factor in anal cancer development in women. Since the anal mucosa is an estrogen-sensitive area, we hypothesize an antiestrogenic mechanism of action for smoking in anal carcinogenesis.
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| 15. |
- Frisch, Morten, et al.
(author)
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Variants of squamous cell carcinoma of the anal canal and perianal skin and their relation to human papillomaviruses
- 1999
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In: Cancer Research. - 0008-5472 .- 1538-7445. ; 59:3, s. 753-757
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Journal article (peer-reviewed)abstract
- High-risk types of human papillomaviruses (hrHPVs) may be a necessary cause in cervical cancer and in some subtype of anal, vulvar, and penile cancers. Large studies aimed at characterizing hrHPV-associated and non-hrHPV-associated subtypes of anal carcinomas are, however, lacking. We searched for human papillomavirus type 16 and 13 other hrHPVs in tumor tissue by PCR and performed a systematic histological evaluation of specimens from 386 patients with anal cancer (86% invasive; 302 women and 84 men). Cancers in women and homosexual men were more often hrHPV positive (P < 0.01) and located in the anal canal (P < or = 0.01) than were cancers in heterosexual men. In both women and men, anal canal cancers contained hrHPV clearly more often than did perianal skin cancers, and increasing hrHPV positivity was seen with higher localization in the anal canal. Indeed, 95 and 83% of cancers involving the anal canal in women and men, respectively, were hrHPV positive versus 80 and 28% of perianal skin cancers (P-trend < 0.001). Basaloid feature, adjacent anal intraepithelial neoplasia, poor or absent keratinization, and a predominance of small or medium neoplastic cells were all strongly positively associated with hrHPV status. Like cancer of the uterine cervix, the development of cancer of the anal canal may require infection with hrHPV, whereas a dual etiology of perianal skin cancers bears parallels to vulvar and penile cancers.
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| 16. |
- Gustafsson, L., et al.
(author)
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Efficency of organized and oppurtunistic cytological screening for cancer in situ of the cervix
- 1995
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In: British Journal of Cancer. - 0007-0920 .- 1532-1827. ; 72:2, s. 498-505
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Journal article (peer-reviewed)abstract
- Cervical cancer incidence and mortality can be reduced by removal of precursor lesions detected at cytological screening. Organised screening, i.e. regular invitation of defined target groups, is generally considered more effective than opportunistic screening. The latter method however, is predominant in most settings. There is no scientific basis for advocating one type of screening or the other. Our aim was to compare the two types and to analyse their efficiency. We analysed 466,275 smears taken in an open cohort of 118,890 women during 1969-88. A computerised database permitted standardised classification of all smears and complete ascertainment of cancer in situ through record linkage. The number of in situ cancers detected per 1000 smears, the detection ratio, was used as an outcome measure both in univariate analyses and in multivariate logistic regression models. Cancer in situ was detected in 1076 women in the study cohort, with a detection ratio of 3.0 at organised and 2.1 at opportunistic screening, yielding an unadjusted odds ratio of 0.69 (95% CI 0.61-0.79). After adjustment for age and time period, the probability of detecting cancer in situ was around 25% higher with opportunistic than with organised screening (OR = 1.26; 95% CI 1.09-1.46). This difference in favour of opportunistic screening was most pronounced in the first 10 year period and disappeared during the last decade. The difference in efficiency between organised and opportunistic screening in the detection of cancer in situ was slight, if any. The dogma that organised screening is significantly more efficient than the opportunistic type needs reconsideration.
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| 17. |
- Gustafsson, Leif, et al.
(author)
-
International incidence rates of invasive cervical cancer after introduction of cytological screening
- 1997
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In: Cancer Causes and Control. - 0957-5243 .- 1573-7225. ; 8:5, s. 755-763
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Journal article (peer-reviewed)abstract
- Because Pap-smear screening can detect pre-invasive cervical cancer, such screening can markedly reduce the occurrence of invasive cancer. However, its impact in different populations is uncertain. This study compares the changes in cervical cancer incidence at different ages after the introduction of screening in different populations, and addresses the impact of organized and opportunistic smear taking. We identified 17 cancer registries large enough and existing long enough to analyze screening effects. For each registry, we calculated the relative reduction in age-specific incidence rates and in incidence rates age-standardized to the world population after the introduction of cytologic screening. In 11 of the 17 populations, age-standardized incidence rates declined markedly from 27 percent in Norway and to 77 percent in Finland. Age-specific declines were confined to women aged 30 to 70 years old with a nadir around ages 40 to 55. In six other populations, age-standardized incidence rates declined less than 25 percent, an amount too small to provide unambiguous evidence of a screening effect. In several populations, cytologic screening had a more pronounced effect than is generally recognized. Because age-specific declines in cervical cancer incidence rates were strikingly similar in populations with widely different screening practices, organized screening may not be markedly superior to opportunistic screening. The reduction in reported cancer incidence because of screening is smaller in younger and older women.
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| 18. |
- Gustafsson, Leif, et al.
(author)
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International incidence rates of invasive cervical cancer before cytological screening
- 1997
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In: International Journal of Cancer. - 0020-7136 .- 1097-0215. ; 71:2, s. 159-165
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Journal article (peer-reviewed)abstract
- Huge differences in incidence rates of invasive cervical cancer occur among populations. These differences reflect the influences of both etiological environmental factors and removal of precursor lesions detected upon screening. The purposes of this article are (i) to describe similarities and differences in the shapes and magnitudes of age-specific incidence rates of invasive cervical cancer before screening had an effect, (ii) to provide baseline data for further global study of screening effects, and (iii) to provide baseline incidence data for the design of optimal screening programs. To eliminate the impact of screening effects, we have selected age-specific incidence rates from times when and from populations in which screening was insignificant. The selected rates were suitably scaled and compared regarding age at onset of increase in incidence, age at peak incidence, and rate of subsequent decline. Despite a 16-fold difference in incidence rates, all curves had the same basic structure, with an increase to a peak followed by a decline or a plateau. Although all populations but one had an onset around age 25, 7 European countries showed an earlier peak age (mean = 46 vs. 59) and a more rapid decline after the peak than most other populations. The common basic shape of the age-specific incidence curve, overall, suggests a relatively similar development of invasive cervical cancer in different populations. These results illustrate the underlying similarities in the markedly different age-specific incidence rates of invasive cervical cancer. They also provide a basis for studying screening effects and for optimizing screening programs in specific geographic areas.
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| 19. |
- Gustafsson, L., et al.
(author)
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Low efficiency of cytologic screening for cancer in situ of the cervix in older women
- 1995
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In: International Journal of Cancer. - 0020-7136 .- 1097-0215. ; 63:6, s. 804-809
-
Journal article (peer-reviewed)abstract
- Cytologic screening for cervical cancer has proven to be beneficial in many countries, although the value of this intervention in women older than 50 years remains controversial. The purpose of this study was to investigate the efficiency of detecting cancer in situ by means of a cytologic smear at different ages, with special emphasis on the benefit of screening in women above the age of 50. We analyzed 466,275 smears taken in an open cohort of 118,890 women in Sweden between 1969 and 1988. The number of cancers in situ detected per 1,000 smears, the detection ratio, was used as an outcome measure in univariate analyses and in multivariate regression models. Cancer in situ was detected in 1,076 women in the study cohort. The detection ratio peaked at ages 30 to 34 and decreased heavily during the next 15 years of age. The efficiency of taking smears at ages above 50 was only 20 per cent (OR, 0.19; 95% CI, 0.14-0.26) of that at ages 30 to 34. These results were not changed when adjusting for time period and time interval since the previous smear. In spite of a high incidence of invasive cervical cancer in older women, the benefit of cytologic screening to detect cancer in situ above the age of 50 is uncertain.
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| 20. |
- Helgesen, Fred, et al.
(author)
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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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In: Journal of the National Cancer Institute. - 0027-8874 .- 1460-2105. ; 88:17, s. 1216-1221
-
Journal article (peer-reviewed)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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