Comparison between endoscopic and surgical treatment of screen-detected versus non-screen-detected colorectal cancers

Since 2005, the Italian National Health System (NHS) has implemented a screening program for colorectal cancer for all citizens over 50. Screening tests are free for the target population (so-called Minimal Care Level guaranteed for all Italian citizens). Invitees are asked to take an immunological test for Faecal Occult Blood (FOBT) every two years. Individuals with a positive FOBT test are invited to undergo a total colonoscopy in an SSN-accredited Endoscopy Department. 
 
 
Each Italian Region has a centre for the coordination of the screening programme, which employs a dedicated software that can trace the progress of each citizen within the programme: 
 
 
FOBT invitation (first round) compliance/non-compliance (reminder); 
 
 
FOBT positive cases: total colonoscopy, endoscopic or surgical treatment of screen-detected lesions plus follow-up; 
 
 
FOBT negative cases: FOBT invitation after two years (second round). 
 
 
 
 
The ‘Screening Centre’ has a database that can provide a detailed, real-time status of the programme: it is therefore possible to compare the characteristics of screen-detected and non-screen-detected cancers. 
 
The target population for the screening programme includes all citizens aged 50–70, except ‘high-risk’ subjects (family history; serious, persistent IBD; previous colorectal surgery; recent non-screen-related FOBT and/or colonoscopy; apparent digestive-tract symptoms (proctorrhagia, abdominal pain, bowel irregularities, etc)).


Introduction
Since 2005, the Italian National Health System (NHS) has implemented a screening program for colorectal cancer for all citizens over 50. Screening tests are free for the target population (so-called Minimal Care Level guaranteed for all Italian citizens). Invitees are asked to take an immunological test for Faecal Occult Blood (FOBT) every two years. Individuals with a positive FOBT test are invited to undergo a total colonoscopy in an SSN-accredited Endoscopy Department.
Each Italian Region has a centre for the coordination of the screening programme, which employs a dedicated software that can trace the progress of each citizen within the programme: • FOBT invitation (first round) compliance/noncompliance (reminder); • FOBT positive cases: total colonoscopy, endoscopic or surgical treatment of screen-detected lesions plus follow-up; • FOBT negative cases: FOBT invitation after two years (second round).
The 'Screening Centre' has a database that can provide a detailed, real-time status of the programme: it is therefore possible to compare the characteristics of screen-detected and non-screen-detected cancers.

Non-screen-detected lesions
Through the NHS archives, it was possible to analyse workload and results of colorectal-cancer treatment in clinical practice ('symptomatic' patients) over the same period of time as the NHS-activated screening. Surgical radicalization (resection plus lymphadenectomy) after 'complete' endoscopic polypectomy was performed in 39 patients (27 screen detected and 12 non-screen detected).

Discussion
Screen-detected tumours have a more favourable staging than non-screen-detected lesions, as demonstrated in Table 3, with a significantly lower incidence of pT 3-4 , pN+, M+ cases.  Cancerous polyps are 35.8% of screen-detected carcinomas and only 11.4% of non-screen detected tumours.
During the first screening round (2006-7), colorectal-cancer incidence increased both in Lombardy and in Milan, as reported in the corresponding Tumour Registry. This increase is due to the diagnosis of colorectal cancer in asymptomatic subjects. Through tumour registries it will be possible to evaluate whether there is a future incidence decrease (which is probable, considering that during the screening 'high-risk' polyps are diagnosed and removed, that is definitely pre-cancer lesions).
Because of the screening programme, it is more often possible to detect lesions that were rare during the pre-screening era. In particular, a large number of 'cancerous' and 'high-risk' polyps are detected and treated. This has led to better knowledge of these lesions. Figures 1-8 show histopathological characteristics of cancerous polyps at 'low' and 'high risks' for nodal metastases. Because of the everyday incidence of these 'early-stage' carcinomas, the screening programme led to an improvement in both endoscopic and pathological diagnoses, with a better evaluation   As for the already well-established screening programmes for breast and cervical cancers, Italian experts from different areas created the Italian Group for Colorectal Cancer Screening  (Gruppo Italiano Screening ColoRettale-GISCoR), which promotes and quality-controls screening programmes all over Italy.
Through the assessment of screen-detected lesions, it will be possible to understand whether screening only offers 'earlier diagnosis' or if there are real 'biological differences' between screen-and non-screen-detected tumours. Through the establishment of a tissue bank of carefully collected specimens from all the screening centres, any differences can be analysed by clinical and translational studies comparing screen-detected and non-screen-detected cancers.
As Italian screening programmes are still new, the follow-up of identified lesions is still too recent to allow a comparison on survival (either overall or disease free) and mortality (either disease related or non-disease related). Significant data regarding follow-up of both screen-detected and nonscreen-detected tumours will be available in a few years' time.