Efficacy in standard clinical practice of colonoscopic polypectomy in reducing colorectal cancer incidence

BACKGROUND

Colorectal cancer is one of the leading causes of death from cancer in Western countries. Removal of adenomas is based on the assumption that it could lead to a reduction in the incidence of colorectal cancer, as demonstrated by the National Polyp Study in the USA. A critical issue is whether the benefit observed in clinical trials can also be observed in standard clinical practice. To address the issue, a multicentre Italian collaborative study was organised.

METHODS

The study cohort comprised 1693 subjects of both sexes, aged 40-69 years, enrolled between 1980 and 1987 following a total colon examination (TCE) (that is, total colonoscopy or colonoscopy and double contrast barium enema), with removal of at least one adenoma larger than 5 mm in diameter. Exclusion criteria were genetic syndromes, previous adenomas or colorectal cancer, previous colonic resection, inflammatory bowel disease, or sessile adenomas more than 3 cm in diameter. Follow up ended in December 1996 by TCE or telephone interview, and review of the medical records, clinical files, or death certificates. Incidence ratios for colorectal cancer were compared with expected age and sex specific incidences in the Italian general population.

RESULTS

Follow up data were obtained for 97.3% of cases for a total of 14 211 person/years. Mean follow up was 10.5 years. Six colorectal cancer cases (four in males, two in females) at various stages were ascertained (one at 29 months, two at five years, one at seven years, one at eight years, and one at 10 years from the index examination). The number of cancers expected in the reference population was 17.7 for an incidence ratio of 0.34 (confidence interval 0.23-0.63; p<0.01).

CONCLUSIONS

Colonoscopic polypectomy substantially reduced the incidence of colorectal cancer in the cohort compared with that expected in the general population. These results are of particular relevance considering that those with adenomas are at increased risk of colorectal cancer and that this retrospective study was performed on data obtained in standard clinical practice. This observation strengthens the concept of effective population screening in view of the fact that adenomatous polyps are the most frequent neoplastic outcome of screening and their removal is associated with a decrease in the incidence of colorectal cancer.

Reconstruction of human immunodeficiency virus (HIV) sub-epidemics in Italian regions

BACKGROUND

The spread of human immunodeficiency virus (HIV) infections is likely to consist of sub-epidemics in local areas and/or risk groups. Small-area risk group specific analyses may thus be a suitable means of better understanding and controlling the epidemic course.

METHODS

An age, period, and cohort back-calculation method was used to reconstruct region-specific epidemics of HIV infection. The HIV infection incidence rates were estimated for individual Italian regions by using as denominator the specific risk category population (i.e. intravenous drug user population [IDU], homosexual/ bisexual population [MSWM], and Italian general population for heterosexual contacts [HST]). Incidence rates obtained in this way represent the risk of HIV infection conditional to belonging to the specific sub-group of the population.

RESULTS

The HIV epidemic is heterogeneous in terms of gender, risk category and region. The highest risk of HIV infection has been estimated in the Lombardia region (North-West area) among men belonging to the IDU category in 1985. In recent years, a trend of decrease in HIV has been estimated, especially among IDU and MSWM. For the HST category, some regions have shown trends of great increase, particularly on the island of Sardegna and the regions of Puglia and Sicilia (Southern Italy). In 1987, most HIV infections were observed among IDU (39-90%), while in 1992 the MSWM and HST categories made the greatest contribution to the HIV epidemic.

CONCLUSIONS

The results stress the idea of sub-epidemics rather than a single epidemic affecting the entire country. Some Southern regions emerge as areas in which the spread of HIV infections, although still at a rather low level, should cause considerable concern, particularly the trend of new infections by heterosexual transmission involving the general population. Detailed information on levels and trends of HIV infection epidemics at the local level are essential for surveillance purposes and for planning health care facilities, and can highlight areas in which preventive measures can be effective.

Effect of sex, age and transmission category on the progression to AIDS and survival of zidovudine-treated symptomatic patients

OBJECTIVE

To evaluate the effect of transmission category and demographic, clinical and immunological characteristics on the progression to AIDS and survival of zidovudine-treated patients.

DESIGN

Prospective multicentre cohort study of symptomatic non-AIDS patients.

SETTING

Eighty-three clinical centres reporting data to the National Zidovudine Registry.

PATIENTS

A total of 1468 patients enrolled between July 1987 and January 1991 were analysed.

MAIN OUTCOME MEASURES

Three-year AIDS-free survival probability estimates since therapy start. Cox proportional hazards regression analysis was used to identify independent predictors of progression to AIDS and survival.

RESULTS

Faster progression was associated with increasing age (8% risk increase for a 5-year increase), low baseline CD4+ count (39% risk increase for 100 x 10(6)/l cells decrease), and zidovudine > 1000 mg/day (20% risk increase compared with < or = 1000 mg/day). Homosexual men had a 33% risk increase compared with other risk groups. The presence of fever and oral candidiasis at enrolment were also independently associated with a higher risk of progression. Differences in the risk of progression were not significant between men and women. Older age, baseline CD4+ count, homosexual behaviour, fever and oral candidiasis were independently associated with a shorter survival.

CONCLUSIONS

Our results confirm that age and baseline CD4+ count are independent predictors of progression, but do not provide evidence for differences in clinical outcome between the sexes. The higher risk of progression to AIDS and shorter survival for homosexual men appears to be correlated with the higher risk of developing Kaposi's sarcoma.