KEYWORDS:
Adenomas
-
colon
-
colonoscopy
-
polyps
INTRODUCTION
Colonic polyps (CP) are often incidentally detected during colonoscopy. The significance
of these incidental polyps and the need for polypectomy is not known. CP are commonly
adenomatous, hyperplastic, or juvenile.[1] In the West, including the USA, the prevalence of adenomatous polyps parallels the
rate of colorectal malignancy.[2] Screening for polyps and colorectal cancers from 45 years of age is therefore considered
mandatory in these countries. There are few publications from India on the frequency
and spectrum of polyps by age.
Our retrospective study was done in patients undergoing lower gastrointestinal (LGI)
endoscopy for various routine indications at our center to identify the histological
type of CP and their characteristics by age, location, and size.
MATERIALS AND METHODS
Patients who underwent ileocolonoscopy or sigmoidoscopy between 2014 and 2016 were
considered for the analysis. Baseline patient information included age, gender, and
indication for LGI endoscopy. In addition, polyp characteristics (site/size/histology)
were collected from our endoscopy and histopathology databases.
Exclusion criteria
Fibroepithelial polyps, anal canal polyps and in those where biopsy tissue was inadequate
for interpretation were excluded from the study
Based on the histology, CP were classified as adenomatous (low- or high-grade dysplasia
[HGD], adenomatous malignancy), hyperplastic, inflammatory, others (including juvenile
polyps, benign space occupying lesions such as lipoma) and normal. The histopathology
reporting was done by a single pathologist (MV).
The characteristics of the three major histology groups (adenomatous, hyperplastic,
and inflammatory) were further stratified by age (<40, 40–60, and >60 years), location
(right colon: cecum, ascending colon and transverse colon, left colon: descending
and sigmoid colon and rectal when confined to the rectum) and by size (diminutive:
<0.5 cm, small: 0.5–1 cm and large: >1 cm).
Statistical analysis
The data were tabulated in Microsoft excel sheet and analyzed for age distribution
(median and range), sex distribution (percentages), and distribution in terms of size
and location of polyps (percentages). The size, site, and age comparison of the polyps
were done using Chi Square test 3 × 3 contingency tables.
Ethics Committee of the Institution approved the study. Ethical principles as dictated
by the Declaration of Helsinki, which provides guidance to physicians and other participants
in medical research involving human subjects was strictly followed.
RESULTS
LGI endoscopy was done in 2303 patients (sigmoidoscopy: 818; colonoscopy: 1485) during
the study for the following indications: irritable bowel syndrome constipation/diarrhea/evacuation
disorder (59%), hematochezia (38%), anemia (10%), perianal discomfort (7%), screening
for dysplasia/carcinoma in inflammatory bowel disease (1%), evaluation for liver metastasis
(4%), and family history of polyposis (4%).
Figure 1: (a) Sessile polyp in colon. (b) Pedunculated polyp in colon
Two hundred and ninety patients (12.7%) had CP which were single (274 patients) or
multiple (16 patients; 43 polyps). 45% of the polyps were pedunculated. The median
age of these patients was 61.1 years (range 5–99 years); 223 were men (76.9%). The
detailed algorithm of the study is shown in [Figure 1]. It highlights the patient and polyp characteristics noted in the study cohort.
The distribution of polyps as per the indication for LGI endoscopy is shown in [Table 1].
Most of the polyps in the study cohort (301/317; 95%) were classifiable by histology
into one of the following three groups: adenomatous 155 (48.9%), hyperplastic 75 (23.7%),
and inflammatory 71 (22.4%). The remaining 16 included juvenile polyps (5), lipoma,
and carcinoid (1 each). In 9, the histology was reported as normal colonic mucosa.
The median age for adenomatous, hyperplastic, and inflammatory polyps was 66 years
(range 34–99 years), 57 (range 24–85), and 59 (range 24–86), respectively.
As noted in [Table 2], adenomatous polyps were significantly more common above 60 years age (P < 0.0002),
located mostly in the left and right colon and were often large (54.2%). The majority
showed low-grade dysplasia (LGD) (139; 89.7%). Only 5 polyps had features of HGD (3.2%;
1–2 cm size). The remaining 11 polyps were malignant; 9 were >2 cm size. Hyperplastic
polyps were the most common type in the rectum (P < 0.00001), mostly <1 cm size (93.3%)
and seen in the middle age (40–60 years). While inflammatory polyps were distributed
between the right colon (39.4%), left colon (23.9%), and the rectum (36.6%), they
were the most common type seen in the young (<40 years age) and were mostly <1 cm
size (87.3%), similar to hyperplastic polyps.
DISCUSSION
CP are a frequent finding during colonoscopy for specific indications. However, scanty
data are available from India regarding the location and types of polyps detected
during routine LGI scopy. In the present study, polyps were 3.2 times more common
in men and were incidental findings in 12.7%. Bhargava and Chopra[3] reported a much lower prevalence of 2% as incidental CP. A study from Kerala in
Southern India[4] noted incidental polyps in 124 (5.1%) of 2412 colonoscopy studies. The higher prevalence
in our series is partly attributed to the fact that our patients were being evaluated
for symptoms and were not healthy subjects.
Polyps in our series were uncommon below 40 years. The median age of our cohort was
61.1 years (range 5–99 years). In Amarapurkar's series,[5] the mean age with colorectal polyps was 54.8 years. Kumar et al.[6] found polyps in relatively young patients.
Table 1:
Distribution of polyp detection as per indications of lower gastrointestinal endoscopy
|
Indication for lower gastrointestinal endoscopic study
|
Total number of cases
|
Number of cases with polyps
|
|
Irritable bowel syndrome
|
1360
|
217
|
|
Hematochezia
|
880
|
78*
|
|
Anemia
|
230
|
26*
|
|
Perianal discomfort
|
161
|
1
|
|
Screening in IBD
|
23
|
1
|
|
Liver metastases
|
91
|
4
|
|
Family history of polyposis
|
93
|
4
|
*Overlap of cases was present in these 2 groups. IBD=Inflammatory bowel disease
Table 2:
Differentiating adenomatous, hyperplastic, and inflammatory colonic polyps by age,
location, and size
|
Adenomatous (155)
|
Hyperplastic (75)
|
Inflammatory (71)
|
P
|
|
Age, years (%)
|
|
<40
|
6 (3.9)
|
7 (9.3)
|
10(14.1)
|
0.000249
|
|
40-<60
|
46 (29.7)
|
39 (52)
|
26 (36.6)
|
|
>60
|
103 (66.5)
|
29 (38.7)
|
35 (49.3)
|
|
Site (%)
|
|
Right
|
55 (35.5)
|
20 (26.7)
|
28 (39.4)
|
<0.00001
|
|
Left
|
66 (42.6)
|
8 (10.7)
|
17 (23.9)
|
|
Rectum
|
34 (21.9)
|
47 (62.7)
|
26 (36.6)
|
|
Size, cm (%)
|
|
<0.5
|
13 (8.4)
|
19 (25.3)
|
11 (15.5)
|
<0.00001
|
|
0.5-1
|
58 (37.4)
|
51 (68)
|
51 (71.8)
|
|
>1
|
84 (54.2)
|
5 (6.7)
|
9 (12.7)
|
Amarapurkar et al.[5] recently studied the histomorphological features of colorectal polyps and determined
risk stratification of adenomatous polyps in adults. Of 515 colorectal polyps, 270
(52.4%) were adenomatous, with equal distribution of inflammatory and hyperplastic
polyps (15% each). Fifteen (2.9%) cases had adenocarcinoma presenting as polyps. The
mean age for adenomatous polyps was 59.5 years with male-to-female ratio of 2:1. The
majority of adenomatous polyps (45.9%) were tubular adenomas and frequently found
in the rectosigmoid. Authors found a significant prevalence of high-grade dysplasia
of 14% in their series. Similar to this study, we also found a male preponderance
among adenomatous polyp; most patients were more than 60 years, and the polyps were
invariably greater than one cm in size. Further, our cancer incidence in polyps was
also similar (11/317; 3.5%). However, very few of our adenomatous polyps had HGD (3.4%).
Wickramasinghe et al. from Srilanka reported 158 patients (median age 56.5 years,
male:female 2:1) with CP. 76% of the polyps were left sided, and tubulovillous polyps
were the commonest.[7] The results from these studies highlight that the profile of CP differs from one
region to another. This could be due to multiple factors such as ethnicity, environmental
factors, and variations in pathology reporting.
The spectrum of polyps in Indian children and adolescents differs from adults. Poddar
et al.[8] studied 236 CP in children and reported that solitary polyps were seen in 76%, multiple
polyps in 16.5%, and juvenile polyposis in 7%. Nearly 93% of polyps in children were
juvenile and 85% were located in rectosigmoid region. Similar high prevalence of juvenile
polyps was also documented by Rathi et al. from Mumbai;[9] 97.2% of these polyps were located in the left colon. In our study of predominantly
adult patients, five patients had juvenile polyps, and their median age at presentation
was 14 (9–34) years.
Should all incidental polyps including adenomatous polyp be removed? Based on our
study, we propose that polypectomy is not indicated for polyps <1 cm size located
in the left colon despite being adenomatous, as majority have LGD (89.7%). Approximately,
69.8% of our diminutive polyps were nonadenomatous quite distinct from the West where
50% of diminutive polyps are adenomatous.[10] Polyps, especially adenomatous and those <1 cm, require histology and close surveillance
for progression from low to HGD. Advanced endoscopic imaging may improve dysplasia
detection. Several new technologies have been evaluated for the same. Dye based and
digital chromocolonoscopy[11],[12] is a robust way of identifying these polyp subtypes at endoscopy. Improvement in
visualization of the colon using cap-assisted colonoscopy,[13] endo ring,[14] and endocuff[15] may help in early polyp detection. Newer scopes such as third eye retroscopes and
extra wide angle view scopes have also been developed to improve polyp detection.[16],[17] Among all these modalities, narrow band imaging (NBI) seems to be the best modality
suited for day-to-day practice. However, the routine use of NBI requires upgrade of
equipment in all units, and both modalities require a steep learning curve before
an endoscopist can confidently classify the polyp type at endoscopy. Till such time,
we believe that polyp biopsy is mandatory to typify the lesion histologically enabling
decision-making for further surveillance.
CONCLUSION
This single-center, retrospective study on polyps in a patient population revealed
higher than previously reported polyp prevalence. Polyps were rare in young (<40 years).
Overall, adenomas were the most common type of polyps: they frequently occurred over
60 years, were larger in size and found mostly in the left and right colon with 90%
showing LGD. Hyperplastic polyps were the most commonly present in rectum and inflammatory
polyps were the most common type in young individuals.
Multicenter studies, especially longitudinal (a practically difficult proposition)
from various centers across the Indian subcontinent are required to understand the
natural history of adenomatous polyps in our population. Detailed assessment and follow-up
of adenomatous polyps with LGD would help to develop surveillance guidelines for Indian
patients.
Limitations
One-third of cohort had only sigmoidoscopy as per clinical indication preventing confident
statements on the overall distribution of polyps by site. Lack of clinical and endoscopic
follow-up data prevents postulating definitive guidelines from the analysis. Retrospective
nature of study and single-center experience is other obvious limitations. Single
histopathologist reporting is both a strength and weakness of the study.
Financial support and sponsorship
Nil.
