Colorectal cancer (CRC) incidence and mortality rates have been decreasing over the past several decades.1 2 polyps , which when removed, prevent the development of CRC.3,4 5 2 6 7–9 10
The evidence supporting initiating CRC screening at a younger age has been accumulating for some time. However, it is not known whether the application of existing surveillance protocols for average-risk patients younger than 50 in whom polyps are found is appropriate. Given that screening colonoscopies were previously recommended to start at age 50, polyps discovered in younger patients are often found incidentally on diagnostic colonoscopies for other indications such as abdominal symptoms or bleeding. Indeed, the most recent guidelines published by the US Multi-Society Task Force (USMSTF) of Colorectal Cancer is based on data for adults 50 and above and provides no clear guidelines on colonic polyp surveillance for younger patients, identifying the topic as an area for more needed research.11 polyps discovered, and therefore further study is warranted regarding how to appropriately surveil these younger patients. Thus, the aim of this study was to determine whether existing colonic polyp surveillance guidelines are appropriate to use in younger patients who have polyps resected during an index colonoscopy.
MATERIALS AND METHODS
We performed a retrospective cohort study assessing the patient populations of 2 medical centers, which included a tertiary academic medical center and a Veterans Affair Medical Center. Patients included in the study were between the ages of 20 and 75 and had undergone at least 2 colonoscopies in a 10-year period, with their index colonoscopy occurring between January 1, 2008, and December 31, 2017, at least 6 months before their surveillance colonoscopy. Patients were split into 3 separate age groups—those below 45 years of age, those 45 to 49 years of age, and those 50 and above. Each subject also had at least 1 polyp removed which was submitted for pathologic analysis on either the index or surveillance colonoscopy. Exclusion criteria included having a diagnosis of inflammatory bowel disease, having a familial CRC syndrome, or having CRC diagnosed on the index colonoscopy—all of which have their own distinct surveillance guidelines.12–14
Demographic variables were assessed including age, gender, race, ethnicity, presence of obesity [defined as body mass index (BMI) >30], a diagnosis of former tobacco use or tobacco use disorder, diabetes, family history of CRC, and use of aspirin during or within 1 year of their index colonoscopy (as aspirin is a well-studied chemopreventative medication for CRC15 polyps found, the size of the largest polyp found, and the histopathology of the polyp(s). The location of the polyp(s) found were recorded as well; proximal polyps entailed those found in the cecum, ascending colon, or transverse colon, while distal polyps comprised of polyps found in the descending colon, sigmoid colon, or rectum. In addition, we quantified the duration of time between the index and surveillance colonoscopies.
Updated guidelines for follow-up after polypectomy were recently published by the USMSTF.11 polyps found. For our study, we grouped patients into 1 of 5 distinct Risk Stratification Groups (RSG) (Table 1 ) based on the recommended surveillance intervals put forth by the USMSTF. RSGs 1, 2, 3, and 4 included patients whose burden of colonic polyps warranted an interval colonoscopy of 10 years, 5 to 10 years, 3 to 5 years, or 1 year, respectively. RSG 2 was created by combining 2 categories from the USMSTF guidelines with overlapping surveillance intervals (ie, 1 to 2 adenomas <10 mm with a recommendation of 7 to 10 y to surveillance colonoscopy and 1 to 2 sessile serrated polyps with a recommendation of 5 to 10 y to surveillance colonoscopy). RSG 5 was reserved for patients who were found to have CRC on surveillance colonoscopy.
TABLE 1 -
Risk Stratification of Patients Based on Surveillance Colonoscopy Time Recommendations
11
Findings on Index Colonoscopy
Surveillance Colonoscopy Time (y)
Risk Stratification Group
Normal colonoscopy
10
1
<20 hyperplastic polyps <10 mm
1-2 adenomas <10 mm
5-10
2
1-2 sessile serrated polyps <10 mm
3-10 adenomas
3-10 sessile serrated polyps
Hyperplastic polyp >10 mm
Any adenoma or sessile serrated polyp >10 mm
3-5
3
Adenoma with villous or tubulovillous histology and/or high-grade dysplasia
Sessile serrated polyps with dysplasia
Traditional serrated adenoma
>10 adenomas
1
4
Colorectal cancer
5
After stratifying patients into these distinct groups, we measured RSG changes for each patient from their index to surveillance colonoscopy. “Improved RSG” signified that a less advanced adenoma was found on the surveillance colonoscopy compared with the index colonoscopy, prompting a longer surveillance interval to the next (third) colonoscopy. “Unchanged RSG” indicated that the polyp found on both the index and surveillance colonoscopy necessitated the same surveillance interval. “Worsened RSG” delineated a more advanced adenoma found on the surveillance colonoscopy compared with the index colonoscopy, prompting a shorter surveillance interval to next (third) colonoscopy. Further analysis was performed for this cohort of patients since having more advanced polyps on surveillance colonoscopy compared with index colonoscopy may signify an inappropriate surveillance interval. We defined an “appropriate surveillance interval” as a surveillance colonoscopy finding lower or equal grade polyps (“Improved RSG” or “Unchanged RSG”) compared with the findings on the index colonoscopy.
Statistical analysis was conducted in SAS, v9.4 (SAS Institute Inc., Cary, NC). All continuous variables are reported as means (SD). The Welch t tests were used to compare the unadjusted marginal differences in continuous variables by age group or by RSG change group. All categorical variables are reported as counts (percentages or frequencies). The association between categorical variables and age group, as well as between categorical variables and RSG change group, were examined using χ2 test with exact P -value from Monte Carlo simulation. Multivariable logistic regression was conducted to analyze the association between RSG worsening and age group while controlling for other risk factors. A P -value <0.05 was considered to be statistically significant.
Institutional review board approval was obtained from both institutions before the commencement of the research. All authors had access to the study data and reviewed and approved the final manuscript.
RESULTS
A total of 4517 patients were initially screened, with 1895 patients meeting all inclusion and exclusion criteria (Fig. 1 ). Demographics for each age group are shown in Table 2 . Overall, there were 167 patients in the less than 45 years age group (8.81%), 204 patients in the 45 to 49 years age group (10.77%), and 1524 patients (80.42%) in the 50 and above age group. Older cohorts of patients tended to be male, have diabetes, and be on aspirin within 1 year of their index colonoscopy compared with younger cohorts of patients. Younger patients were more likely to have a family history of CRC compared with the older cohorts of patients. Variables not found to be statistically different between age groups were race, BMI, and smoking history.
FIGURE 1: Decision tree. CRC indicates colorectal cancer.
TABLE 2 -
Demographics and Polyp Characteristics by Age Group
n (%)
Variables
Level
Total (N=1895)
<45 [n=167 (8.81%)]
45-49 [n=204 (10.77%)]
≥50 [n=1524 (80.42%)
P
Gender
Female
810 (42.74)
108 (64.67)
93 (45.59)
609 (39.96)
<0.0001
Male
1085 (57.26)
59 (35.33)
111 (54.41)
915 (60.04)
Age at index colonoscopy (mean±SD)
Unit=year
56.61±9.21
39.52±4.55
47.43±1.42
59.71±7.08
<0.0001
Race
Asian
28 (1.48)
0 (0.00)
4 (1.96)
24 (1.57)
0.0713
Black
146 (7.70)
5 (2.99)
12 (5.88)
129 (8.46)
Other
96 (5.07)
8 (4.79)
13 (6.37)
75 (4.92)
White
1625 (85.75)
154 (92.22)
175 (85.78)
1296 (85.04)
Ethnicity
Hispanic
107 (5.74)
13 (7.88)
18 (8.87)
76 (5.08)
0.0420
Non-Hispanic
1756 (94.26)
152 (92.12)
185 (91.13)
1419 (94.92)
BMI
<30
1131 (59.68)
111 (66.47)
124 (60.78)
896 (58.79)
0.1496
≥30
764 (40.32)
56 (33.53)
80 (39.22)
628 (41.21)
Smoking history
No
1484 (78.31)
134 (80.24)
163 (79.90)
1187 (77.89)
0.6600
Yes
411 (21.69)
33 (19.76)
41 (20.10)
337 (22.11)
Diabetes
No
1631 (86.07)
161 (96.41)
189 (92.65)
1281 (84.06)
<0.0001
Yes
264 (13.93)
6 (3.59)
15 (7.35)
243 (15.94)
Family history of CRC
No
1562 (82.43)
99 (59.28)
150 (73.53)
1313 (86.15)
<0.0001
Yes
333 (17.57)
68 (40.72)
54 (26.47)
211 (13.85)
Aspirin use within 1 y of first colonoscopy
No
1632 (86.12)
162 (97.01)
194 (95.10)
1276 (83.73)
<0.0001
Yes
263 (13.88)
5 (2.99)
10 (4.90)
248 (16.27)
Worsened RSG
Yes
508 (26.81)
43 (25.75)
74 (36.27)
391 (25.66)
0.0054
No
1387 (73.19)
124 (74.25)
130 (63.73)
1133 (74.34)
Polyp type at index colonoscopy
Sessile serrated adenoma
148 (7.81)
20 (11.98)
16 (7.84)
112 (7.35)
<0.0001
Advanced neoplasia
390 (20.58)
11 (6.59)
27 (13.24)
352 (23.10)
Low-risk adenoma
578 (30.50)
42 (25.15)
49 (24.02)
487 (31.96)
Normal
779 (41.11)
94 (56.29)
112 (54.90)
573 (37.60)
Polyp type at surveillance colonoscopy
Sessile serrated adenoma
103 (5.44)
12 (7.19)
9 (4.41)
82 (5.38)
0.0003
Advanced neoplasia
250 (13.19)
9 (5.39)
18 (8.82)
223 (14.63)
Low-risk adenoma
599 (31.61)
41 (24.55)
67 (32.84)
491 (32.22)
Normal
943 (49.76)
105 (62.87)
110 (53.92)
728 (47.77)
Location of adenoma/s at index colonoscopy
No polyp
483 (25.49)
58 (34.73)
75 (36.76)
350 (22.97)
<0.0001
Proximal
487 (25.70)
30 (17.96)
32 (15.69)
425 (27.89)
Distal
608 (32.08)
71 (42.51)
68 (33.33)
469 (30.77)
Both
317 (16.73)
8 (4.79)
29 (14.22)
280 (18.37)
Location of adenoma/s at surveillance colonoscopy
No polyp
621 (32.77)
66 (39.52)
68 (33.33)
487 (31.96)
0.0002
Proximal
451 (23.80)
25 (14.97)
46 (22.55)
380 (24.93)
Distal
547 (28.87)
64 (38.32)
67 (32.84)
416 (27.30)
Both
276 (14.56)
12 (7.19)
23 (11.27)
241 (15.81)
Indication for procedure at first colonoscopy
Bleeding
184 (9.76)
38 (22.75)
43 (21.08)
103 (6.80)
<0.0001
Other
532 (28.21)
75 (44.91)
73 (35.78)
384 (25.35)
Screening
1170 (62.04)
54 (32.34)
88 (43.14)
1028 (67.85)
Indication for procedure at second colonoscopy
Bleeding
133 (7.07)
17 (10.18)
15 (7.39)
101 (6.69)
0.0008
Other
536 (28.51)
69 (41.32))
58 (28.57)
409 (27.09)
Screening
1211 (64.41)
81 (48.50)
130 (64.04)
1000 (66.23)
Interval (mo) between index and surveillance colonoscopies (mean±SD)
Unit=month
48.04±26.06
51.01±26.39
52.37±25.80
47.14±25.99
0.0086
BMI indicates body mass index; CRC, colorectal cancer; RSG, Risk Stratification Groups.
Demographic data, patient characteristics, and colonoscopy results compared between age groups are also recorded in Table 2 . At index colonoscopy, younger patients had higher rates of normal colonoscopies compared with older patients (below 45: 56.29%, 45 to 49: 54.9%, above 50: 37.60%, P <0.01). For those with adenomas, older patients had higher proportions of low-risk adenomas (above 50: 31.96%, 45 to 49: 24.02%, below 45: 25.15%, P <0.01) and advanced neoplasia (above 50: 23.10%, 45 to 49: 13.24%, below 45: 6.59%, P <0.01) compared with younger patients. Younger patients had more distal polyps compared with older patients (below 45: 42.51%, 45 to 49: 33.33%, above 50: 30.77%, P <0.01). When comparing the indication for the index colonoscopy across the 3 age groups, younger cohorts of patients had higher rates of colonoscopies for bleeding and other indications compared with those above 50 who were more likely to undergo colonoscopy for screening purposes.
At surveillance colonoscopy, younger patients were still more likely to have normal colonoscopies compared with older patients (below 45: 62.87%, 45 to 49: 53.92%, above 50: 47.77%, P <0.01). Those in the below 45 age group had a lower rate of low-risk adenomas (24.55%) compared with older cohorts (45 to 49: 32.84%, above 50: 32.22%, P <0.01), as well as lower rates of advanced neoplasia (below 45: 5.39%, 45 to 49: 8.82%, above 50: 14.63%, P <0.01). In terms of location of polyps , distal polyps more still more prevalent in younger patients (below 45: 38.32%, 45 to 49: 32.84%, above 50: 27.30%, P <0.01). The above 50 age group had the highest rate of screening colonoscopies compared with the younger age groups, though the difference was smaller compared with the index colonoscopy (above 50: 66.23%, 45 to 49: 64.04%, below 45: 48.50%). Younger age groups were still more likely to undergo their surveillance colonoscopy for specific symptoms (bleeding and other) rather than for screening purposes. The average time between colonoscopies was 51.01±26.39 months for patients below 45, 52.37±25.80 months for patients 45 to 49, and 47.14±25.99 months for patients above 50 years old (P <0.01).
After stratifying patients into RSG based on colonoscopy results, changes in RSG were tracked for each patient from their index to surveillance colonoscopy, shown in Table 3 . In the below 45 age group, 74.25% of patients had unchanged RSG or improved RSG (41.92% and 32.33%, respectively), while 25.75% of patients had worsened RSG. The largest cohort of patients in this age group had normal colonoscopies or small hyperplastic polyps (both RSG 1) on both their index and surveillance colonoscopy (32.34%). Patients in the 45 to 49 age group had 63.73% of patients have unchanged or improved RSG (27.45% and 36.28%, respectively), with 36.27% of patients having worsened RSG. The high percentage of worsened RSG was driven by 26.47% of patients going from RSG 1 to RSG 2 (1 to 2 small tubular adenomas). The above 50 age group consisted of 74.34% of patients with unchanged or improved RSG (34.45% and 39.89%, respectively) and 25.66% of patients with worsened RSG. In this age group, the largest cohort consisted of patients who went from RSG 2 on their index colonoscopy to RSG 1 on their surveillance colonoscopy (18.24%).
TABLE 3: Changes in Risk Stratification Group (RSG) From Index to Surveillance Colonoscopy for Less Than 45, 45 to 49, and More Than 50 Age Groups
A subgroup analysis was performed to compare patients with unchanged or improved RSG to patients with worsened RSG (Table 4 ). In the entire studied population, 508 patients had worsened RSG (26.81%), while 1387 patients had unchanged or improved RSG (73.19%). Patients with worsened RSG were statistically more likely to be male compared with those with unchanged or improved RSG (61.05% vs. 55.88%, P =0.04). Otherwise, age, race, ethnicity, BMI, smoking history, diabetes, family history of CRC, or aspirin use was not statistically different between both groups. Patients with worsened RSG were more likely to have normal index colonoscopies (83.86% vs. 25.45%, P <0.01) and more likely to undergo their index colonoscopy for nonscreening indications (47.44% vs. 34.47%, P <0.01) compared with those with unchanged or improved RSG. Advanced neoplasia (31.5% vs. 6.49%, P <0.01) and low-risk adenomas (57.28% vs. 22.21%, P <0.01) were more commonly found on surveillance colonoscopies in patients with worsened RSG compared to patients with unchanged or improved RSG. Patients that had worsened RSG had longer intervals between their colonoscopies compared with those with unchanged or improved RSG (55.44±27.75 vs. 45.33 ±24.87 mo, P <0.01).
TABLE 4 -
Demographics and Polyp Characteristics of Patients in Whom Risk Stratification Groups Worsened Compared With Patients in Whom Risk Stratification Groups Improved or Stayed the Same
n (%)
Variables
Level
Total (N=1895)
Worsen [n=508 (26.81%)]
No [n=1387 (73.19%)]
P
Gender
Female
810 (42.74)
198 (38.98)
612 (44.12)
0.0448
Male
1085 (57.26)
310 (61.02)
775 (55.88)
Age at index colonoscopy (mean±SD)
Unit=year
56.61±9.21
56.45±9.07
56.66±9.27
0.6585
Race
Asian
28 (1.48)
5 (0.98)
23 (1.66)
0.4763
Black
146 (7.70)
45 (8.86)
101 (7.28)
Other
96 (5.07)
27 (5.31)
69 (4.97)
White
1625 (85.75)
431 (84.84)
1194 (86.09)
Ethnicity
Hispanic
107 (5.74)
32 (6.37)
75 (5.51)
0.4771
Non-Hispanic
1756 (94.26)
470 (93.63)
1286 (94.49)
BMI
<30
1131 (59.68)
288 (56.69)
843 (60.78)
0.1083
≥30
764 (40.32)
220 (43.31)
544 (39.22)
Smoking history
No
1484 (78.31)
407 (80.12)
1077 (77.65)
0.2481
Yes
411 (21.69)
101 (19.88)
310 (22.35)
Diabetes
No
1631 (86.07)
427 (84.06)
1204 (86.81)
0.1256
Yes
264 (13.93)
81 (15.94)
183 (13.19)
Family history of CRC
No
1562 (82.43)
409 (80.51)
1153 (83.13)
0.1848
Yes
333 (17.57)
99 (19.49)
234 (16.87)
Aspirin use within 1 y of first colonoscopy
No
1632 (86.12)
440 (86.61)
1192 (85.94)
0.7073
Yes
263 (13.88)
68 (13.39)
195 (14.06)
Polyp type at first colonoscopy
Sessile serrated adenoma
148 (7.81)
10 (1.97)
138 (9.95)
<0.0001
Advanced neoplasia
390 (20.58)
1 (0.20)
389 (28.05)
Low-risk adenoma
578 (30.50)
71 (13.98)
507 (36.55)
Normal
779 (41.11)
426 (83.86)
353 (25.45)
Polyp type at second colonoscopy
Sessile serrated adenoma
103 (5.44)
57 (11.22)
46 (3.32)
<0.0001
Advanced neoplasia
250 (13.19)
160 (31.50)
90 (6.49)
Low-risk adenoma
599 (31.61)
291 (57.28)
308 (22.21)
Normal
943 (49.76)
0 (0.00)
943 (67.99)
Indication for procedure at first colonoscopy
Bleeding
184 (9.76)
61 (12.01)
123 (8.93)
<0.0001
Other
532 (28.21)
180 (35.43)
352 (25.54)
Screening
1170 (62.04)
267 (52.56)
903 (65.53)
Indication for procedure at second colonoscopy
Bleeding
133 (7.07)
49 (9.74)
84 (6.10)
0.0086
Other
536 (28.51)
127 (25.25)
409 (29.70)
Screening
1211 (64.41)
327 (65.01)
884 (64.20)
Interval (mo) between index and surveillance colonoscopies (mean±SD)
Unit=month
48.04±26.06
55.44±27.75
45.33±24.87
<0.0001
BMI indicates body mass index; CRC, colorectal cancer.
A multivariable logistic regression model was performed to assess if worsened RSG was associated with age group after controlling for BMI, gender, race, smoking history, diabetes, indication for the procedure, and location of adenoma at index and surveillance colonoscopy (Table 5 ). Worsened RSG from index to surveillance colonoscopy was not significantly associated with age group, both when comparing below 45 to those above 50 [odds ratio (OR)=0.840, 95% confidence interval (CI): 0.504-1.399, P =0.50] and when comparing those 45 to 49 to those above 50 (OR=1.416, 95% CI: 0.905-2.216, P =0.13). Only gender was found to be statistically associated with worsened RSG after controlling for other variables, with females being less likely to have worsened RSG compared with males (OR=0.652, 95% CI: 0.486-0.875, P <0.01).
TABLE 5 -
Estimated ORs and 95% CI of Explanatory Variables for Risk Stratification Groups Comparison From Index to Surveillance Colonoscopy
Variables
Level
OR With 95% CI
Pairwise P
P
Age group
<45 vs. ≥50
0.840 (0.504-1.399)
0.5023
0.2004
45-49 vs. ≥50
1.416 (0.905-2.216)
0.1282
BMI
≥30 vs. <30
1.090 (0.818-1.452)
0.5564
0.5564
Gender
Female vs. male
0.652 (0.486-0.875)
0.0043
0.0043
Race
Asian vs. white
0.363 (0.106-1.243)
0.1065
0.3723
Black vs. white
0.833 (0.500-1.388)
0.4836
Other vs. white
1.076 (0.576-2.008)
0.8187
Smoking history
Yes vs. no
0.909 (0.647-1.278)
0.5839
0.5839
Diabetes
Yes vs. no
0.943 (0.630-1.414)
0.7778
0.7778
Indication for procedure at the first colonoscopy
Other vs. bleeding
0.942 (0.569-1.559)
0.8149
0.7809
Screening vs. bleeding
0.865 (0.537-1.395)
0.5523
BMI indicates body mass index; CI, confidence interval; OR, odds ratio.
In addition, 3 separate multivariate analyses were also performed—one with adjustment of the interaction term between age group and severity at index colonoscopy (“not severe” being RSG 1, 2 to denote a nonadvanced adenoma and “severe” being RSG 3, 4, 5 to denote an advanced adenoma), one comparing patients below 50 to 50 and above, and another comparing patients below 50 to 60 and above, all to further assess whether worsened RSG was not associated with any relevant age group cutoff or grade of the polyp. None of these analyses showed a significant association between age group and worsened RSG.
DISCUSSION
Our study found that younger cohorts of patients, both less than 45 years old and those between 45 and 49 years old, are not statistically more likely to develop more advanced polyps necessitating a shorter time to surveillance colonoscopy than their index colonoscopy, compared with patients 50 and above years old. This finding supports using existing colonic polyp surveillance colonoscopy guidelines that were developed for patients 50 and above in both patients 45 to 49 and those younger than 45.
While there have been several papers looking at whether existing colonic polyp surveillance guidelines are appropriate to use in patients younger than 50 years old, their conclusions were based largely on comparing the rates of metachronous adenoma development in younger patients compared with older patients. A case-control study by Nagpal et al16 17 18 19
The largest study in the literature to date looking at this question used the New Hampshire Colonoscopy Registry to examine the risk for metachronous advanced adenomas and large serrated polyps in 12,380 patients divided into several age groups. Anderson et al20 21
Our study took a different and novel approach to this research question. For surveillance guidelines to be effective, the duration between colonoscopies should allow for early detection of lesser grade polyps before they potentially develop into more advanced polyps , and ultimately CRC. If a surveillance colonoscopy detects a more advanced polyp than the index colonoscopy, necessitating a shorter time to their next (third) colonoscopy (worsened RSG), one may argue that the interval between the first and second colonoscopy was too long and the surveillance colonoscopy should have been performed sooner. With this in mind, instead of solely measuring and comparing the rates of metachronous adenoma development on surveillance colonoscopy between age groups like previous studies, we also tracked changes in RSG between colonoscopies to assess whether different age groups developed adenomas at different rates that led to shorter times to their next colonoscopy. The question endoscopists face regarding how to surveil younger patients with colonic polyps should also be assessed with existing data comparing the differences in follow-up colonoscopy intervals between young and older patients, in addition to measuring rates of metachronous adenoma development in young versus older patients.
Consistent with other studies, our data did indeed show that younger patients had lower rates of both low-risk adenomas and advanced neoplasia on their surveillance colonoscopy compared with older patients. When looking specifically at RSG changes between age groups, there were similar rates of worsened RSG between those below 45 years old (25.75%) and those 50 years and above (25.66%). Interestingly, patients in the 45 to 49 age group had a higher rate of worsened RSG (36.27%) compared with the other age groups. One possible explanation is the slightly longer time between colonoscopies compared with the other 2 age groups (52.37 mo, compared with 51.01 mo in patients below 45 y and 47.14 mo in patients 50 and above). However, after controlling for other variables in a multivariate analysis, both patients below 45 and patients 45 to 49 were not statistically more likely to have RSG worsening compared with those 50 years and above. In addition, this was also true when comparing patients below 50 to 50 and above, as well as comparing patients below 50 to 60 and above.
Gender was the only variable found to be statistically related to RSG worsening after controlling for other variables, with female patients 35% less likely to have a worsened RSG at their surveillance colonoscopy compared with male patients. Age group, BMI, race, smoking history, diabetes, and indication for the index colonoscopy all were not associated with RSG worsening. This finding may suggest that younger male patients in whom colonic polyps are discovered should be surveilled more closely, as per our study, they are more likely to progress to a higher RSG on their surveillance colonoscopy.
In addition, it is important to note that the majority of RSG worsening in all age groups occurred in patients with an index colonoscopy that was normal or that only had small hyperplastic polyps (RSG 1), with the surveillance colonoscopy revealing 1 to 2 <10 mm tubular adenomas or 1 to 2 <10 mm sessile serrated polyps (RSG 2). This could represent missed adenomas on index colonoscopy given their small size rather than the development of new polyps .22 polyps can be surveilled anywhere between 5 and 10 years. There were no instances of CRC found on surveillance colonoscopy in both the below 45 and the 45 to 49 age groups, and 4 cases of CRC found in the above 50 age group. Interestingly, these cases were found in patients who fell into RSG 1 (3 patients) and RSG 2 (1 patient) on their index colonoscopy.
There are several limitations to our study. This was a retrospective cohort study that relied on chart review data for clinical, endoscopic, and histopathology findings, inherently introducing bias into the results. Demographically, our patient population was largely white and non-Hispanic, limiting the overall scope of the results and the generalizability of our findings. Many patients did not undergo their surveillance colonoscopy at appropriate interval times (most completed their surveillance colonoscopy earlier than guidelines recommend), thus limiting the ability to truly evaluate if surveillance guidelines are appropriate. Adenoma detection rates were not available for all the endoscopists during the years of our study, which could affect the detection of polyps in our patient population. We were limited by the data available in our electronic medical record. If a patient underwent a colonoscopy at a different institution earlier than the index colonoscopy that was recorded in our electronic medical record, they may have been unknowingly included in our dataset. Finally, an inherent limitation with studying younger patients with colonic polyps is the fact that this specific cohort of patients underwent their colonoscopies largely due to symptoms or a family history significant for CRC and not for average-risk CRC screening purposes, thus introducing bias into any comparison of younger and older patients. We accounted for this bias by performing a multivariate regression model and controlled for the indication of the procedure, subsequently finding that RSG changes were not statistically associated with this variable.
That being said, there are numerous strengths to our study. This was a multicenter study that was comprised of a suburban civilian patient population as well as a veteran patient population, increasing the diversity of our study subjects. We included patients over a 10-year period, further adding to the generalizability of the results. We also took a novel approach to assessing whether interval surveillance colonoscopy times were appropriate, creating a more practical and clinically relevant method of assessing surveillance guideline appropriateness. In addition, given the recent lowering of the screening age for CRC screening to 45 by numerous organizations, our study is one of the first to look specifically at the age group (45 to 49) that will be undergoing colonoscopies at much higher rates going forward, providing much needed research on surveilling this specific patient population that stands to undergo far more colonoscopies with more polyps discovered.
CONCLUSIONS
As greater numbers of patients younger than 50, specifically between the ages of 45 and 49, undergo screening colonoscopies based on the most recent guideline changes, more polyps will be discovered in this age group and the question of how to surveil them will arise more often. Our study shows that existing colonic polyp surveillance guidelines, despite being created based on data for patients 50 and above, should be appropriate to use in patients younger than 50 given that worsened RSG is not statistically different between age groups. Prospective studies are needed to definitively determine whether patients in the 45 to 49 age group should indeed undergo surveillance colonoscopies at similar intervals than patients 50 and above.
ACKNOWLEDGMENTS
The authors acknowledge the biostatistical consultation and support provided by Xiaoyue Zhang, MS, and the Biostatistical Consulting Core at the School of Medicine, Stony Brook University.
REFERENCES
1. Henley SJ, Ward EM, Scott S, et al. Annual report to the nation on the status of cancer, part I: National cancer statistics. Cancer. 2020;126:2225–2249.
2. Siegel RL, Miller KD, Goding Sauer A, et al. Colorectal cancer statistics, 2020. CA Cancer J Clin. 2020;70:145–164.
3. Leslie A, Carey FA, Pratt NR, et al. The colorectal adenoma-carcinoma sequence. Br J Surg. 2002;89:845–860.
4. Vogelstein B, Fearon ER, Hamilton SR, et al. Genetic alterations during colorectal-tumor development. N Engl J Med. 1988;319:525–532.
5. US Preventive Services Task Force, Bibbins-Domingo K, Grossman DC, et al. Screening for colorectal cancer: US Preventive Services Task Force Recommendation Statement. JAMA. 2016;315:2564–2575.
6. Siegel RL, Fedewa SA, Anderson WF, et al. Colorectal cancer incidence patterns in the United States, 1974-2013. J Natl Cancer Inst. 2017;109:djw322.
7. Peterse EFP, Meester R, Siegel R, et al. The impact of the rising colorectal cancer incidence in young adults on the optimal age to start screening: Microsimulation analysis I to inform the American Cancer Society Colorectal Cancer Screening Guideline. Cancer. 2018;124:2964–2973.
8. Wolf AMD, Fontham ETH, Church TR, et al. Colorectal cancer screening for average-risk adults: 2018 guideline update from the American Cancer Society. CA Cancer J Clin. 2018;68:250–281.
9. Shaukat A, Kahi CJ, Burke CA, et al. ACG Clinical Guidelines: colorectal cancer screening 2021. Am J Gastroenterol. 2021;116:458–479.
10. US Preventive Services Task Force, Davidson KW, Barry MJ, Mangione CM, et al. Screening for colorectal cancer: US Preventive Services Task Force Recommendation Statement. JAMA. 2021;325:1965–1977.
11. Gupta S, Lieberman D, Anderson JC, et al. Recommendations for follow-up after colonoscopy and polypectomy: a consensus update by the US Multi-Society Task Force on Colorectal Cancer. Gastroenterology. 2020;158:1131.e5–1153.e5.
12. Kahi CJ, Boland CR, Dominitz JA, et al. Colonoscopy surveillance after colorectal cancer resection: recommendations of the US Multi-Society Task Force on Colorectal Cancer. Gastroenterology. 2016;150:758.e11–768.e11.
13. Laine L, Kaltenbach T, Barkun A, et al. SCENIC international consensus statement on surveillance and management of dysplasia in inflammatory bowel disease. Gastroenterology. 2015;148:639.e28–651.e28.
14. Syngal S, Brand RE, Church JM, et al. ACG clinical guideline: Genetic testing and management of hereditary gastrointestinal cancer syndromes. Am J Gastroenterol. 2015;110:223–263.
15. Katona BW, Weiss JM. Chemoprevention of colorectal cancer. Gastroenterology. 2020;158:368–388.
16. Nagpal SJS, Mukhija D, Sanaka M, et al. Metachronous colon
polyps in younger versus older adults: a case-control study. Gastrointest Endosc. 2018;87:657–665.
17. Kim HG, Cho Y-S, Cha JM, et al. Risk of metachronous neoplasia on surveillance colonoscopy in young patients with colorectal neoplasia. Gastrointest Endosc. 2018;87:666–673.
18. Laish I, Katz L, Ben-Horin S, et al. Risk of metachronous neoplasia on surveillance colonoscopy among young and older patients after polypectomy. Dig Liver Dis. 2020;52:427–433.
19. Bushyhead D, Lin OST, Kozarek RA. A review of the management of sporadic colorectal adenomas in young people: is surveillance wasted on the young? Dig Dis Sci. 2019;64:2107–2112.
20. Anderson JC, Robinson CM, Butterly LF. Young adults and metachronous neoplasia: risks for future advanced adenomas and large serrated
polyps compared with older adults. Gastrointest Endosc. 2020;91:669–675.
21. Jung YS, Park JH, Park CH. Comparison of risk of metachronous advanced colorectal neoplasia in patients with sporadic adenomas aged <50 versus ≥50 years: a systematic review and meta-analysis. J Pers Med. 2021;11:120.
22. Rex DK. Colonoscopic withdrawal technique is associated with adenoma miss rates. Gastrointest Endosc. 2000;51:33–36.
