Population-based colorectal cancer screening: Interval cancers and relationship with the quantitative faecal immunological for hemoglobin

INTRODUCTION AND OBJECTIVE

The sensitivity of colorectal cancer screening programmes determines their effectiveness and is directly related to the interval cancer (IC). This study describes the frequency and characteristics of the IC of the Programme of Barcelona, Spain, and analyses its relationship with the quantitative value of the screening test (FIT).

MATERIAL AND METHODS

ICs after negative FIT of the first two rounds of the Programme (2010-2013) were included, observation period until July 2017. The information source of the ICs was their notification by professionals and patients, hospital databases and CMBD (Spanish Minimum Basic Data Set).

RESULTS

The sensitivity of the Programme is 82%. ICs are diagnosed more in proximal and rectal colon and in advanced stages than screening cancers, and have higher FIT values than overall people with negative FIT.

CONCLUSIONS

The sensitivity is acceptable and comparable to that of other programmes. The quantitative value of FIT in people with negative test should be included in the personalisation strategies of screening to reduce the risk of IC.

[Colonoscopy in the screening, follow-up and treatment of colorectal cancer and precursor lesions]

Endoscopic polypectomy reduces the incidence of colorectal cancer and mortality due to this disease. Interval cancer is the marker par excellence of the effectiveness and quality of screening and surveillance programs. Interval cancer is defined as colorectal cancer appearing after a negative screening or surveillance test (whether colonoscopy or another type of test) for colorectal cancer and before the recommended date of the following screening test. It has been estimated that up to 75% of interval colorectal cancers may be due to poor endoscopic technique. Therefore, to reduce mortality from this disease, diagnostic and therapeutic colonoscopy must be carried out with high quality standards. In the latest congress of the American Gastroenterological Association, presentations were given on studies designed to analyse interval cancer and its possible causes, as well as to evaluate endoscopic techniques that could improve detection of polyps or optimize their complete resection. Likewise, strategies have begun to be evaluated that would allow rationalization of efforts and resources to achieve screening of the maximum number of individuals, with high quality standards, but without completely overloading the healthcare system. Finally, the congress also devoted substantial space to presentations on the management of post-polypectomy complications and large polyps.

[Colorectal cancer screening]

Colorectal cancer is one of malignancies showing the greatest benefit from preventive measures, especially screening or secondary prevention. Several screening strategies are available with demonstrated efficacy and efficiency. The most widely used are the faecal occult blood test in countries with population-based screening programmes, and colonoscopy in those conducting opportunistic screening. The present article reviews the most important presentations on colorectal cancer screening at the annual congress of the American Gastroenterological Association held in Washington in 2015, with special emphasis on the medium-term results of faecal occult blood testing strategies and determining factors and on strategies to reduce the development of interval cancer after colonoscopy.

[Interval cancers and episode sensitivity in population-based screening programmes for colorectal cancer: a systematic review]

OBJECTIVE

To describe interval cancers (IC) and the sensitivity of colorectal cancer (CRC) screening programmes.

METHODS

A systematic review of the literature was conducted through a MEDLINE (PubMed) search. The search strategy combined the terms 'interval cancer', 'false negative', 'mass screening', 'screening' 'early detection of cancer', 'colorectal cancer' and 'bowel cancer'. Inclusion criteria consisted of population-based screening programmes, original articles written in English or Spanish and publication dates between 1999/01/01 and 2015/02/28. A narrative synthesis of the included articles was performed detailing the characteristics of the screening programmes, the IC rate, and the information sources used in each study.

RESULTS

Thirteen articles were included. The episode sensitivity of CRC screening programmes ranged from 42.2% to 65.3% in programmes using the guaiac test and between 59.1% and 87.0% with the immunochemical test. We found a higher proportion of women who were diagnosed with IC and these lesions were mainly located in the proximal colon.

CONCLUSION

There is wide variability in the IC rate in CRC programmes. To ensure comparability between programmes, there is a need for consensus on the working definition of IC and the methods used for their identification and quantification.

[Colonoscopies for colorectal cancer screening]

Colonoscopies play a vital role in population screening programs, either for initial examinations or as a test carried out after a positive result from a fecal occult blood test or sigmoidoscopy. Colonoscopies, and ancillary techniques such as polipectomies, must comply with basic quality criteria that must be reflected in the quality standards of screening programs. A quality colonoscopy is absolutely vital to avoid the occurrence of interval cancers. It is extremely important to detect any proximal lesions during a colonoscopy, especially those which are serrated, because they are difficult to identify and due to the increased risk of colorectal cancer. Regarding follow-up programs for resected colorectal polyps, current evidence of the relationship between the risk of neoplasia and certain variables (age, sex, smoker, BMI, diabetes, etc.) must allow for individualized risk and algorithms for screening and follow-up frequency to be developed for these patients. However, initial endoscopic exploration in a screening colonoscopy is essential to establishing the optimum interval and ensuring follow-up. Despite poor adherence to follow-up programs, mostly due to their overuse, follow-up colonoscopies 3 years after resection of all polypoid lesions detect clinically significant lesions as effectively as colonoscopies at one year.

[Proportion of breast cancer in women aged 50 to 69 years from Girona, Spain, according to detection method]

BACKGROUND AND OBJECTIVE

The aim of this study was to determine the tumor stage, the proportion of cases and the age specific rate of breast cancer (BC) cases according to detection method.

MATERIAL AND METHOD

Cases of women aged 50 to 69 years diagnosed with BC in the Girona province during 1999-2006 were extracted from the population-based Girona Cancer Registry (n=1,254). BC was classified by detection method: screen-detected cancer, interval cancer and others. Proportion of cases and age-specific incidence were calculated according to detection method.

RESULTS

During the period 2002-2006, the proportion of screen-detected cancers, interval cancers and other cancers were 42.2%, 5.8% and 52.2%, respectively. After implementation of the early detection of breast cancer program (PDPCM), the incidence of screen-detected cases raised; thereafter, interval cancers also increased and the rate of other cancers decreased.

CONCLUSIONS

In the Girona province during the fully implemented PDPCM period (2002-2006), interval cancers represented a low proportion (5.8%) of women diagnosed with BC at 50 to 69 years old.

[Surveillance colonoscopy: risk of colorectal tumors]

Colonoscopy is currently the technique of choice for the diagnosis of colorectal cancer (CRC), as well as for the identification and resection of precursor lesions. However, its efficacy has been questioned due to evidence that some patients receive a diagnosis of CRC after a recent "negative" colonoscopy. These post-colonoscopy cancers are also known as interval cancers and, in the last few years, there has been interest in identifying their possible causes. The studies presented this year in the congress of the American Gastroenterological Association (AGA), described in the present article, provide important information for identification of the potential causes of neoplasms detected after a recent colonoscopy and propose methods to reduce this risk. Notable among such studies are those on the prevalence of interval colorectal cancer, those aiming to improve the quality of colonoscopy with a view to increasing the detection of neoplastic lesions, such as assessments of bowel cleansing and of the adenoma detection rate, and studies that propose new alternatives in endoscopy and in colon visualization, such as the colon capsule.

[Classification and characteristics of interval cancers in the Principality of Asturias's Breast Cancer Screening Program]

OBJECTIVE

To review and classify the interval cancers found in the Principality of Asturias's Breast Cancer Screening Program (PDPCM). A secondary objective was to determine the histological characteristics, size, and stage of the interval cancers at the time of diagnosis.

MATERIAL AND METHODS

We included the interval cancers in the PDPCM in the period 2003-2007. Interval cancers were classified according to the breast cancer screening program protocol, with double reading without consensus, without blinding, with arbitration. Mammograms were interpreted by 10 radiologists in the PDPCM.

RESULTS

A total of 33.7% of the interval cancers could not be classified; of the interval cancers that could be classified, 40.67% were labeled true interval cancers, 31.4% were labeled false negatives on screening, 23.7% had minimal signs, and 4.23% were considered occult. A total of 70% of the interval cancers were diagnosed in the year of the period between screening examinations and 71.7% were diagnosed after subsequent screening. A total of 76.9% were invasive ductal carcinomas, 61.1% were stage II when detected, and 78.7% were larger than 10mm when detected.

CONCLUSIONS

The rate of interval cancers and the rate of false negatives in the PDPCM are higher than those recommended in the European guidelines. Interval cancers are diagnosed later than the tumors detected at screening. Studying interval cancers provides significant training for the radiologists in the PDPCM.