Connect
MJA
MJA

The short to medium term benefits of the Australian colorectal cancer screening program

Sasha Taylor, Farhad Salimi, Arul Earnest, Alexander G Heriot, John R Zalcberg and Susannah Ahern
Med J Aust 2021; 214 (2): 90-92. || doi: 10.5694/mja2.50859
Published online: 7 December 2020

In Australia, colorectal cancer is the second most frequently diagnosed cancer and one of the most common causes of cancer‐related death.1 Evidence that bowel cancer screening reduces mortality through early detection and treatment2 led to the introduction in 2006 of the Australian National Bowel Cancer Screening Program (NBCSP), offering faecal occult blood testing. The NBCSP has been progressively rolled out, from covering those aged 55 or 65 years in 2006 to screening every two years for all Australians aged 50–74 years by 2020.3 During 2016–17, 41% of people invited to participate in screening did so.4 A recent review of the NBCSP found that the risk of death from colorectal cancer was lower for invitees, and that those who had cancer were diagnosed at an earlier stage of disease.5

In Australia, jurisdictional cancer registries do not collect data on surgery‐related morbidity. However, the Binational Colorectal Cancer Audit (BCCA) (https://www.bowel​cance​raudit.com) has collected information since 2007 on the diagnosis, management, and outcomes of surgically managed Australian and New Zealand patients with colorectal cancer, as well as whether patients were identified by the NBCSP. BCCA data are voluntarily collected by 435 registered surgeons at 138 participating hospitals across Australia and New Zealand, covering about 24% of newly diagnosed cases of colorectal cancer in 2019.6 We sought to determine whether patients with surgically managed colorectal cancer diagnosed through the NBCSP have better post‐operative outcomes than those diagnosed in other pathways.

We undertook a cross‐sectional analysis of de‐identified BCCA data for patients aged 18 years or over who underwent surgery in Australia for colorectal cancer during January 2007 – December 2018. Outcome measures were inpatient and 30‐day mortality; surgical complications; medical complications; return to theatre; and hospital length of stay. We undertook binary logistic regression to assess associations between screening and binary outcomes. The association with length of stay was assessed in ordinary least squares linear regression models. The Monash University Human Research Ethics Committee (project, 19327) and the BCCA Operations Committee provided ethics approval for our study.

Of 23 310 cases of colorectal cancer in the database, we could include 15 630 cases with data on cancer type and screening status in our comparison of demographic and clinical characteristics. A larger proportion of patients identified by the NBSCP than of otherwise identified patients were men (58% v 54%); their mean age (64 years, standard deviation [SD], 7 years v 69 years; SD, 14 years) was lower, and larger proportions had American Society of Anesthesiologists (ASA) scores in the low risk range (77% v 59%), were from lower socio‐economic status areas, had presented for elective surgery (96% v 85%), had less advanced cancer stage disease (stages 0–II: 69% v 63%), and underwent minimally invasive surgery (80% v 66%) (Box 1).

Data on adjusting variables and outcomes were available for the 11 366 cases included in our logistic regression models. NBSCP‐detected patients were less likely to have post‐operative surgical (adjusted odds ratio [aOR], 0.83; 95% confidence interval [CI], 0.69–0.99) or medical complications (aOR, 0.75; 95% CI, 0.59–0.94); their length of stay was also briefer (adjusted mean difference, –1.56 days; 95% CI, –2.06 to –1.06 days). Post‐operative mortality and return to theatre rates were similar for screened and other patients (Box 2).

Our analysis of BCCA data indicates that, in addition to the lower long term mortality associated with the NBCSP,5 short term post‐operative benefits are also evident that should be taken into account when promoting the program. Our study reinforces calls to improve participation rates in the national screening program by eligible participants to optimise the value of this critically important initiative.

Box 1 – Demographic and clinical features of 15 730 patients who underwent surgery for colorectal cancer in Australia, 2007–2018, by diagnostic pathway

 


 


Identification of patients


 


Characteristic

Total

NBSCP

Other

P


Number of patients

15 730

1357

14 373

 

Age at surgery (years)

 

 

 

 

 Mean (SD)

69 (13)

64 (7)

69 (14)

< 0.001

 Range

18–100

50–75

18–100

 

 50 or under*

1556 (10%)

77 (6%)

1479 (10%)

 

 51–60

2433 (15%)

385 (28%)

2048 (14%)

 

 61–70

4192 (27%)

651 (48%)

3541 (25%)

 

 71–80

4473 (28%)

244 (18%)

4229 (29%)

 

 over 80

3073 (20%)

0

3073 (21%)

 

 Missing data

3

0

3

 

Sex

 

 

 

0.003

 Women

7142 (45%)

563 (42%)

6579 (46%)

 

 Men

8586 (55%)

792 (58%)

7794 (54%)

 

 Missing data

2

2

0

 

American Society of Anesthesiologists score

 

 

 

< 0.001

 1–2 (low risk)

9205 (60%)

1000 (77%)

8205 (59%)

 

 3–5 (high risk)

6033 (40%)

294 (23%)

5739 (41%)

 

 Missing data

492

63

429

 

Socio‐economic status (IRSD quintile)

 

 

 

< 0.001

 1 (most disadvantaged)

2470 (16%)

224 (17%)

2246 (16%)

 

 2

2385 (16%)

221 (17%)

2164 (16%)

 

 3

2957 (20%)

278 (22%)

2679 (19%)

 

 4

3107 (21%)

288 (22%)

2819 (20%)

 

 5 (least disadvantaged)

4153 (28%)

282 (22%)

3871 (28%)

 

 Missing data

658

64

594

 

Cancer type

 

 

 

0.50

 Colon

11 287 (72%)

963 (71%)

10 324 (72%)

 

 Rectal

4443 (28%)

394 (29%)

4049 (28%)

 

Operative urgency

 

 

 

< 0.001

 Elective

13 457 (86%)

1310 (96%)

12 147 (85%)

 

 Emergency

999 (6%)

11 (1%)

988 (7%)

 

 Urgent

1248 (8%)

36 (2%)

1212 (8%)

 

 Missing data

26

0

26

 

Cancer stage

 

 

 

< 0.001

 0 (cancer in situ)

699 (5%)

92 (7%)

607 (4%)

 

 I (local disease)

3728 (24%)

535 (41%)

3193 (23%)

 

 II (local disease)

4689 (31%)

278 (21%)

4411 (32%)

 

 III (nodal spread)

4437 (29%)

347 (26%)

4090 (29%)

 

 IV (metastatic disease)

1625 (11%)

42 (3%)

1583 (11%)

 

 X (not identifiable)

121 (1%)

16 (1%)

105 (1%)

 

 Missing data

431

47

384

 

Operative approach

 

 

 

< 0.001

 Minimally invasive surgery

10 498 (67%)

1082 (80%)

9416 (66%)

 

 Open

5140 (33%)

269 (20%)

4871 (34%)

 

 Missing data

92

6

86

 


IRSD = Index of Relative Socioeconomic Disadvantage (Australian Bureau of Statistics); NBSCP = National Bowel Cancer Screening Program; SD = standard deviation. * National screening program participants are aged 50 years or more. † Laparoscopic, hybrid, conversion of laparoscopic, robotic and transanal total mesorectal excision.

Box 2 – Logistic and linear regression analysis of the association between screening and outcomes for 11 366 patients with colorectal cancer, Australia, 2007–2018

 


Identification of patients


NBSCP v other


Outcome

NBSCP

Other

Univariate regression:
OR (95% CI)

Multivariate regression:
aOR* (95% CI)


Number of patients

843

10 523

 

 

30‐day mortality

2

175

0.14 (0.02–0.44)

0.31 (0.05–1.01)

Surgical complications

171

2494

0.82 (0.69–0.97)

0.83 (0.69–0.99)

Medical complications§

89

1889

0.54 (0.43–0.67)

0.75 (0.59–0.94)

Returned to theatre

52

658

0.99 (0.73–1.31)

1.02 (0.75–1.37)

 

 

 

Mean difference (95% CI)

Adjusted mean difference* (95% CI)

Length of stay (days), mean (SD)

7.27 (6.17)

9.62 (8.02)

–2.34 (–2.90 to –1.79)

–1.56 (–2.06 to –1.06)


aOR = adjusted odds ratio; CI = confidence interval; NBSCP = National Bowel Cancer Screening Program; OR = odds ratio; SD = standard deviation. * Adjusted for age, sex, socio‐economic status, screen category, cancer type, American Society of Anesthesiologists score. † Within 30 days of surgery. ‡ Abdominal/pelvic collection, anastomotic leak, entero‐cutaneous fistula, wound dehiscence, wound infection, sepsis, ileus, small bowel obstruction, urinary retention, ureteric injury, splenectomy, post‐operative haemorrhage. § Including chest infection, cardiac complications, deep vein thrombosis, pulmonary embolus.

Received 13 January 2020, accepted 22 July 2020

  • Sasha Taylor1
  • Farhad Salimi1
  • Arul Earnest1
  • Alexander G Heriot2,3
  • John R Zalcberg1
  • Susannah Ahern1,4

  • 1 School of Public Health and Preventive Medicine, Monash University, Melbourne, VIC
  • 2 Epworth HealthCare, Melbourne, VIC
  • 3 Peter MacCallum Cancer Institute, Melbourne, VIC
  • 4 University of Melbourne, Melbourne, VIC

Correspondence: susannah.ahern@monash.edu

Acknowledgements: 

The Binational Colorectal Cancer Audit is supported by the Colorectal Surgical Society of Australia and New Zealand (CSSANZ).

Competing interests:

No relevant disclosures.

Author

remove_circle_outline Delete Author
add_circle_outline Add Author

Comment
Do you have any competing interests to declare? *

I/we agree to assign copyright to the Medical Journal of Australia and agree to the Conditions of publication *
I/we agree to the Terms of use of the Medical Journal of Australia *
Email me when people comment on this article

Online responses are no longer available. Please refer to our instructions for authors page for more information.