Prevention of colorectal cancer by colonoscopic surveillance in individuals with a family history of colorectal cancer: 16 year, prospective, follow-up study

Abstract

Objective To determine to what extent individuals with various family histories of colorectal cancer (from one to three or more affected first degree relatives) benefit from colonoscopic surveillance. Design Prospective, observational study of high risk families, followed up over 16 years. Setting Tertiary referral family cancer clinic in London. Participants 1678 individuals from families registered with the clinic. Individuals were classified according to the strength of their family history: hereditary non-polyposis colorectal cancer (if they fulfilled the Amsterdam criteria), and one, two, or three affected first degree relatives (moderate risk). Interventions Colonoscopy was initially offered at five year intervals or three year intervals if an adenoma was detected. Main outcome measures The incidence of adenomas with high risk pathological features or cancer. This was analysed by age, the extent of the family history, and findings on previous colonoscopies. The cohort was flagged for cancer and death. Incidence of colorectal cancer and mortality during over 15 000 person years of follow-up were compared with those expected in the absence of surveillance. Results High risk adenomas and cancer were most common in families with hereditary non-polyposis colorectal cancer (on initial colonoscopy 5.7% and 0.9%, respectively). In the families with moderate risk, these findings were particularly uncommon under age 45 (1.1% and 0%) and on follow-up colonoscopy if advanced neoplasia was absent initially (1.7% and 0.1%). The incidence of colorectal cancer was substantially lower-80% in families with moderate risk (P = 0.00004), and 43% in families with hereditary non-polyposis colorectal cancer (P = 0.06)-than the expected incidence in the absence of surveillance when the family history was taken into account. Conclusions Colonoscopic surveillance reduces the risk of colorectal cancer in people with a strong family history. This study confirms that members of families with hereditary non-polyposis colorectal cancer require surveillance with short intervals. Individuals with a lesser family history may not require surveillance under age 45, and if advanced neoplasia is absent on initial colonoscopy, surveillance intervals may be lengthened. This would reduce the demand for colonoscopic surveillance.

Câncer ano-reto-cólico: aspectos atuais IV - câncer de cólon - fatores clínicos, epidemiológicos e preventivos

“…Por outro lado, na PAF, se a mutação não puder ser identificada, a doença pode ser descoberta pelo exame endoscópico, que deve ser iniciado na puberdade precoce 7 . Nos casos de HNPCC, seja para os portadores do gene e nos que a mutação não foi identificada, a recomendação é fazer o exame coloscópico a cada 2 anos, a partir dos 25 anos ou 5 anos antes da idade mais precoce em que houve o aparecimento do câncer na família [37][38][39][40][41][42] , incluindo, para as mulheres, o exame ginecológico sistemático com a citologia (aspirativa ou esfregaço) e ultra-som endovaginal, depois dos 25 anos de idade, apesar de algumas controversas 43,44 .…”

“…A pessoa que tem dois ou mais parentes de primeiro grau ou parente com câncer antes dos 60 anos de idade deve ser examinado, a cada 5 anos por meio de coloscopia, inicialmente aos 45 anos ou na idade menos 5 anos do parente mais jovem com cân-cer 39,42,45,46 .…”

Colonoscopic surveillance – a cost-effective method to prevent hereditary and familial colorectal cancer

“…The relative risks for HCRC/FCRC in our cohort are based on a study from 2005 by Dowe-Edwin et al [7]. The estimations correspond to an average lifetime risk for CRC in about 40% in the best estimate for HCRC families.…”

“…First, we performed a cohort analysis based on age, sex and calendar year matched CRC incidence rates for the general population in Sweden [9]. Then, as proposed by Dowe-Edwin et al [7], we applied three sets of relative risk estimations (lowest, best and highest) for individuals with inherited risk for CRC. To compare observed vs. expected cases of CRC, two-tailed standard incidence ratios (SIR) with 95% confidence intervals were calculated according to Byar's formula.…”

“…There are different opinions and guidelines on how extensive a familial clustering of CRC must be to justify surveillance, at what age to start surveillance, and the length of examination intervals [5][6][7][8][9][10].…”