Table 1.

Model inputs: test characteristics, participation assumptions, utility losses, and costs associated with colorectal cancer screening and treatment.

Test characteristics
Specificity and sensitivity of FITa
 Specificity (per person)95.0%
 Sensitivity adenoma 1–5 mm0.0%
 Sensitivity adenoma 6–9 mm9.0%
 Sensitivity adenoma 10+ mm32.0%
 Sensitivity cancer long before clinical diagnosisb36.5%
 Sensitivity cancer shortly before clinical diagnosisb72.8%
Specificity and sensitivity of colonoscopyc,d
 Specificity86%
 Sensitivity adenoma 1–5 mm75%
 Sensitivity adenoma 6–9 mm85%
 Sensitivity adenoma 10+ mm95%
 Sensitivity preclinical cancer95%
Complication of colonoscopye
 Fatal complicationf0.040%
 General complicationg
  50–540.096%
  55–590.080%
  60–640.054%
  65–690.127%
  70–740.073%
Participation
Uptake of initial screening offerh
 50–5428.5%
 55–5936.8%
 60–6443.2%
 65–6943.5%
 70–7452.5%
Uptake of rescreeningh
 Previously attended76.0%
 Previously not attended19.7%
Attendance at general practitioneri90.0%
Uptake of diagnostic testh
 50–5472.3%
 55–5971.6%
 60–6471.4%
 65–6970.6%
 70–7468.2%
Adherence to surveillancej80.0%
Utility loss (QALYs)k
Per FIT0
Per colonoscopyl0.00274
Per complication of colonoscopym0.01918
Per LY with CRC caren,oInitial careContinuing careTerminal care (death CRC)Terminal care (death OC)
Stage I0.120.050.700.05
Stage II0.180.050.700.05
Stage III0.240.240.700.24
Stage IV0.700.700.700.70
Costs (2016 $AUD)p
 Per FIT invitationq17.35
 Per returned FITr22.60
 Per GP visits37.05
 Per colonoscopy (same day)t1,627
 Polygenic testu200
 Per complication of colonoscopyv9,027
 Treatment by stage and locationw,x,y
  Stage I CC (without bevacizumab)31,107
  Stage I RC (without bevacizumab)41,619
  Stage II CC (without bevacizumab)43,776
  Stage III CC (without bevacizumab)79,375
  Stage II/III RC (without bevacizumab)86,317
  Stage IV CRC without bevacizumab71,156
  Stage IV CRC with bevacizumab81,403
  • Abbreviations: CC, colon cancer; CRC, colorectal cancer; FIT, fecal immunochemical test; GP, general practitioner; OC, other cause; QALY, quality-adjusted life years; RC, rectal cancer; LY, life year.

  • aSpecificity and sensitivity of FIT derived from results of the Queensland Health Report (31).

  • bWe assume that FIT screening is more sensitive in cancers as they progress toward becoming symptomatic (visible bleeding) and clinically detectable. For preclinical cancers that will become symptomatic within the same stage, assumed test sensitivity is higher.

  • cThe lack of specificity with endoscopy reflects the detection of non-adenomatous lesions, where the non-adenomatous lesions are removed and therefore induce polypectomy and biopsy or lead to (unnecessary) referral with sigmoidoscopy. The evidence synthesis reported no specificity for endoscopy for any adenoma. Specificity for colonoscopy is therefore based on Schroy and colleagues (62).

  • dSensitivity of colonoscopy for the detection of adenomas and colorectal cancer within the reach of the endoscope was obtained from a systematic review on miss rates observed in tandem colonoscopy studies (63).

  • eComplications are conditional on polypectomy, and we assume that polypectomy is performed only if colonoscopy is positive.

  • fFatal perforation taken from Viiala and colleagues (64) and includes only deaths from colonoscopies performed in outpatients within 30 days of, and attributed to, colonoscopy.

  • gAge-specific rate of complication taken from National Bowel Cancer Screening Monitoring report (33). A complication is considered as an unplanned hospital admission within 30 days of a diagnostic colonoscopy.

  • hUptake of screening, rescreening, and participation in diagnostic follow-up taken from the National Bowel Cancer Screening Monitoring report (33).

  • iAttendance at general practitioner for referral to colonoscopy taken from Tran and colleagues (26).

  • jAttendance at surveillance colonoscopies assumed to be 80% based on Colquhoun and colleagues (34).

  • kThe loss of quality of life associated with a particular event.

  • lEqual to 2 days per colonoscopy at a utility of 0.5.

  • mComplications associated with hospitalization with 30 days of colonoscopy were assumed to be equal to 14 days at a utility of 0.5.

  • nCare for colorectal cancer was divided in three clinically relevant phases: the initial, continuing, and terminal care phases. The initial care phase was defined as the first 12 months after diagnosis; the terminal care phase was defined as the final 12 months of life; the continuing care phase was defined as all months in between. In the terminal care phase, we distinguished between colorectal cancer patients dying from colorectal cancer and colorectal cancer patients dying from another cause. For patients surviving less than 24 months, the final 12 months were allocated to the terminal care phase and the remaining months were allocated to the initial care phase.

  • oUtility losses for LYs with initial care were derived from a study by Ness and colleagues (42). For LYs with continuing care for stage I and II colorectal cancer, we assumed a utility loss of 0.05 QALYs; for LYs with continuing care for stage III and IV colorectal cancer, we assumed the corresponding utility losses for LYs with initial care. For LYs with terminal care for colorectal cancer, we assumed the utility loss for LYs with initial care for stage IV colorectal cancer. For LYs with terminal care for another cause, we assumed the corresponding utility losses for LYs with continuing care.

  • pCosts are from a health system's perspective and do not include patient time costs. All costs are presented in Australian dollars and are indexed to 2016 prices.

  • qFIT price based on the pricing of a commercially available alternative (35).

  • rThe cost to analyze a specimen based in Australian Medicare Benefits Schedule (36).

  • sCost to visit GP taken from Australian Medicare Benefits Schedule (37).

  • tCosts for colonoscopy are calculated based on information available from Independent Hospital Pricing Authority (38).

  • uCost of polygenic test based on a commercially available polygenic test for breast cancer (41).

  • vCosts for complications of colonoscopy are calculated based on information available from Independent Hospital Pricing Authority (38).

  • wCost of treatment taken from Ananda and colleagues (39).

  • xProportion of rectal cancer assumed to be 30.81% (27).

  • yProportion of stage IV cancers treated with bevacizumab assumed to be 50% (39).