Analiza morfologiczna i czynniki predykcyjne występowania polipów ząbkowanych jelita grubego u uczestników Programu Badań Przesiewowych w kierunku wczesnego wykrywania raka jelita grubego w latach 2000-2004
Rozprawa na stopień doktora habilitowanego nauk medycznych

Andrzej Mróz

Summary
Last decade has brought substantial development of knowledge concerning colonic serrated polyps. From the previously recognized hyperplastic polyps several subgroups have been extracted and described naming classical hyperplastic polyps, sessile serrated polyps and traditional serrated adenomas. In addition classical hyperplastic polyps have been subdivided in three types – microvesicular hyperplastic polyps, goblet cell hyperplastic polyps and mucin poor hyperplastic polyps. All of them are characterized by increased infoldings of the epithelium forming serration sometimes also depicted as saw-tooth pattern. Histopathological examination represents the base of serrated polyps diagnosis. Serrated polyps are believed to give rise to 15-20% of colon cancers developing via serrated neoplasia pathway. Sessile serrated polyps and traditional serrated adenomas are at the greatest risk of progressing to cancer. The diagnosis and differentiation from classical hyperplastic polyps are of great clinical importance since the follow up for SSP and TSA should be the same as for classical adenomas. History of the serrated polyps recognition and detailed histopathological diagnostic criteria of serrated polyps are presented in Introduction.
Aim
The aim of the study is to assess morphology of serrated polyps in subjects of the colon cancer screening programme from Warsaw region who underwent colonoscopy in Oncology Center-Institute in years 2000-2004. All subtypes of serrated polyps were analysed with regard to sex and age of patient, localization and the size of the polyp. Concurrence of serrated polyps with regard to mentioned factors was also studied as well as coincidence of serrated polyps and conventional adenomas. Predilection factors for serrated polyps ocurrence in the colon were also searched for. The risk of colon cancer development among patients with serrated polyps was assessed based on the interval cancer occurrence within analyzed group.
Materials and Methods
Database of colon cancer screening programme from the years 2000-2004 was used. 1597 subjects with 2970 serrated polyps were identified. All specimen were histologically reevaluated and ascribed with size and localization including rectum, sigmoideum, descending colon, transverse colon, ascending colon and cecum. Information about age and sex of patients was collected. Statistical analyses using all these factors were performed.
Results
Most of the polyps (> 95%) were of classical, small hyperplastic polyp type located in the left part of the colon. Most prevalent subtype in all locations was MVHP and the MVHP:GCHP:MPHP ratio amounted to 7:4:1.
The prevalence of SSP and TSA was 2% and 1% respectively. Half of them were smaller than 5 mm. SSP were located mainly in ascending and transverse colon and in sigmoideum. TSA were most prevalent in sigmoideum and rectum.
Multifactorial analyses displayed predilection of MVHP occurrence to women and distal part of the colon and GCHP occurrence to men. SSP were most likely to be found with proximal direction regardless the sex of the patient. Similarly, no significant impact of colonic adenomas on serrated polyps was shown with the exception of increased MPHP presence in subjects with adenomas.
Increased risk of colon cancer was not displayed in patients with serrated polyps as judged on interval cancer occurrence in comparison with the whole screening population in the analyzed period.
Conclusions
1. Morphology of serrated polyps of the colon in colon cancer screening program participants:
– The most prevalent type of serrated polyps are classical hyperplastic polyps.
– Classical hyperplastic polyps are mostly found in the left part of the colon (the sigmoid and rectum) and are smaller than 5 mm in diameter.
– The most common subtype of classical hyperplastic polyp is MVHP. It is also the most common type in each segment of the colon.
– Prevalence of SSP and TSA in screenees population amounts to 2% and 1%, respectively.
– Size of SSP is similar in the right and left parts of the colon.
– Different types of serrated polyps may coexist but are most commonly isolated lesions.
2. Predictive factors of serrated polyps ocurrence:
– Sessile serrated polyp is commonly bigger than hyperplastic polyp and is predilected to the right side of the colon (cecum, ascending and transverse colon). Half of SSP are however smaller than 5 mm. Size criterium cannot be decisive in SSP diagnosis.
– SSP ocurrence is not associated with sex and age of the patient.
– TSA are usually bigger than 5 mm in diameter.
3. Presence of serrated polyps including SSP and TSA is not connected with the higher risk of interval colon cancer development.

To jest tylko fragment artykułu. Aby przeczytać całość, przejdź do Czytelni medycznej.