Validation of a diagnostic prediction tool for colorectal cancer: a case–control replication study

Abstract

Background Early detection of colorectal cancer (CRC) is crucial for survival. Primary care, the first point of contact in most cases, needs supportive risk assessment tools. We aimed to replicate the Swedish Colorectal Cancer Risk Assessment Tool (SCCRAT) for non-metastatic CRC in primary care and examine if risk factor patterns depend on sex and age. Methods 2,920 adults diagnosed with non-metastatic CRC during the years 2015–2019 after having visited a general practitioner the year before the diagnosis were selected from the Swedish Cancer Register and matched with 11,628 controls, using the same inclusion criteria except for the CRC diagnosis. Diagnostic codes from primary care consultations were collected from a regional health care database. Positive predictive values (PPVs) were estimated for the same 5 symptoms and combinations thereof as in the baseline study. Results The results for patients aged ≥50 years old in the present study were consistent with the results of the SCCRAT study. All symptoms and combinations thereof with a PPV >5% in the present study had a PPV >5% in the baseline study. The combination of bleeding with abdominal pain (PPV 9.9%) and bleeding with change in bowel habit (PPV 7.8%) were the highest observed PPVs in both studies. Similar risk patterns were seen for all ages and when men and women were studied separately. Conclusion This external validation of the SCCRAT for non-metastatic CRC in primary care replicated the baseline study successfully and identified patients at high risk for CRC.

The performance of FIT-based and other risk prediction models for colorectal neoplasia in symptomatic patients: a systematic review

“… 80 All of these studies were rated as high risk of bias, due to analysis concerns and issues of predictor selection 80 , 83 and outcome definitions. 35 , 77 , 83 Nemlander and colleagues 2023b 84 validated the symptom combinations used by Ewing and colleagues, 83 in a separate Swedish population with a focus on non-metastatic CRC and found similar PPVs, for example CIBH and rectal bleeding PPVs were 7.8% and 13.7%, rectal bleeding and abdominal pain were 10.7% and 12.2%, respectively.…”

“…81 Databases or registries were used in 17 studies. 30 , 47 , 48 , 50 , 51 , 52 , 53 , 54 , 56 , 60 , 77 , 78 , 79 , 80 , 82 , 83 , 84 …”

“…One study examined patients from two different countries: Scotland and Spain. 18 A further 24 studies assessed patients from the UK, 30 , 31 , 38 , 41 , 43 , 44 , 45 , 46 , 47 , 51 , 56 , 57 , 59 , 60 , 61 , 62 , 66 , 70 , 71 , 77 , 80 , 81 eight from Denmark, 35 , 39 , 48 , 69 , 74 , 76 , 79 , 82 seven from Spain, 19 , 30 , 34 , 40 , 49 , 63 , 65 five from the Netherlands, 50 , 52 , 53 , 54 , 64 five from Sweden, 67 , 68 , 78 , 83 , 84 four from Australia, 27 , 28 , 37 , 72 two from China, 32 , 55 one from the USA, 73 one from Canada, 42 one from New Zealand, 58 one from Egypt, 75 one from Italy, 36 one from Malaysia 33 and one from Nigeria. 29 For further...…”

“…(Oct 2013–March 2014) Median (IQR) = 64 (52–73) Range = 16–90 Analysed: Male = 342 Female = 413 NR Colonoscopy CRC = 28 HRA = 41 Nemlander 2023a 78 (Sweden) Case-control Primary Overall = 2681 Development = 2013 Validation = 668 Swedish cancer register and the VEGA regional administrative healthcare database. Dates NR Age at diagnosis date Mean (SD) Cases = 71.2 (11.7) Controls = 71.2 (11.7) Male Cases = 272/542 Controls = 1074/2139 I = 118 II = 278 III = 130 Registry Non-metastatic CRC Development = 407 Validation = 135 Nemlander 2023b 84 (Sweden) Case-control Primary Overall = 14,548 Stockholm regional health care administration database (VAL) 2015–2019 Age at diagnosis date Mean (SD) Cases = 70.7 (12.6) Controls = 70.6 (12.5) Male Cases = 1483/2920 Controls = 5901/11,628 I = 731 II = 846 III = 1343 Registry Non-metastatic CRC cases = 2920 Norrelund 1996 35 (Denmark) Cross-sectional Primary Study 1 = 208 Study 2 = 209 (analysis = 156) Study 1 Every fourth GP registered in the directory of the Danish medical associaton (n = 750) were to participate in the study. The GPs were to include a maximum of three consecutive patients, 40 years and older, who presented with a first episode of overt rectal bleeding within the previous six months.…”