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Diagnostic Delay, Symptoms, and Stage of Colorectal Cancer: Population-based Studies in Denmark

Marianne Korsgaard  

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Accepted by: Faculty of Health Sciences University of Aarhus
Defended on: September 30, 2005
Official opponents: Ole Thorlacius-Ussing , Niels Qvist , Lars Påhlman
Tutors: Søren Laurberg , Henrik Toft Sørensen

Published in the PhD Database: August 20, 2007

English abstract
The aim of this Ph.D. thesis was to examine the association between diagnostic delay and stage for colorectal cancer, to determine the extent to which this diagnostic delay for colon cancer patients and/or for rectal cancer patients was caused by patients, general practitioners, or hospitals. We examined the adherence to the Danish Health Authorities guidelines recommending that patients with suspected colorectal cancer be further examined within 14 days, and those with the confirmed diagnosis, be treated within 14 days of diagnosis. Further, we examined the association between symptoms and diagnostic delay and between symptoms and stage. Finally, we sent questionnaires to 20% of the patients¿ general practitioner to estimate, if the patients and the general practitioners gave the same information about diagnostic delay.

The thesis was based on a populationbased observational study from three counties in Denmark, representative of the Danish population. Data of diagnostic delay and symptoms were based on interviews with the patients. 951 patients had primary colorectal cancer, histologically verified as adenocarcinoma. 743 (78.1%) were interviewed, 61 (6.4%) gave no concent, and 147 (15.5%) were excluced because of death, dementia/unable to cooperate, HNPCC, FAP, AFAP, chronic inflammatory bowel disease, or inability to understand Danish.

We calculated the relative risk of having an advanced stage (Dukes¿ C or D) for median delay (61-150 days), and long delay (>150 days) with short delay (£ 60 days) as our reference group, and found an about doubled relative risk of having an advanced rectal cancer if diagnostic delay was more than 60 days. This association could not be shown for colon cancer.

For both colon cancer and rectal cancer the total median diagnostic delay was long (116 vs. 135 days). Diagnostic delay was primarily caused by the patients for as well colon cancer as rectal cancer (patients¿ delay: 18 vs. 44 days). The adherence to the guidelines was poorly met. For colon cancer patients especially the delay of diagnosis exceeded 14 days, and for rectal cancer patients especially the delay of treatment exceeded 14 days.

Vague debut symptoms were more frequent for colon cancer patients than for rectal cancer patients, and vague debut symptoms were associated with advanced cancer, whereas more well-defined symptoms ¿ primary rectal bleeding ¿ were the most frequent debut symptoms of rectal cancer. Rectal bleeding as the debut symptom was associated with a non-advanced stage (Dukes¿ A or B).

The correlation between the patients' and the general practitioners' information of diagnostic delay was not perfect (Spearman¿s Rho 0.27-0.60) ¿ best correlation was found for patients with a short delay.

To improve the prognosis of rectal cancer it is important to decrease diagnostic delay.

Danish abstract
Formålet med denne Ph.D afhandling, som er en prospektiv interviewbaseret befolkningsundersøgelse foretaget i Århus Amt, Ringkøbing Amt og Ribe Amt, var at undersøge sammenhængen mellem diagnostisk delay og stadie for colorectal cancer, kortlægge hvor i sygdomsforløbet diagnostisk delay primært ligger, samt undersøge om 14-dages garantien på undersøgelse og behandling bliver overholdt. Derudover undersøgte vi sammenhængen mellem symptomer og diagnostisk delay og stadie. Slutteligt vurderede vi, om patienter og egen læge giver samme oplysninger om diagnostisk delay.

I alt 951 patienter. 743 (78,1%) kunne interviewes, 61 (6,4%) ønskede ikke at deltage og 147 (15,5%) måtte ekskluderes.

Vi beregnede relativ risiko for avanceret stadie (Dukes¿ C og D) for middel delay (61-150 dg) og langt delay (< 150 dg) med kort delay (£ 60 dg) som reference gruppe, og fandt for rectum cancer en ca. fordoblet relativ risiko, hvis delay var > 60 dage, mens der for colon cancer ikke var sammenhæng mellem diagnostisk delay og stadie.

Median diagnostisk delay var langt for både rectum cancer og colon cancer (135 vs. 116 dage), og årsagen ligger primært hos patienterne (44 vs. 18 dage). 14-dages garantien overholdes dårligt.

Vage debut symptomer var hyppigere hos colon cancer end hos rectum cancer patienter og var associeret med avanceret stadie, mens mere konkrete symptomer ¿ blødning pr. rectum ¿ var hyppigste debut symptomer hos rectum cancer patienter og associeret med ikke-avanceret stadie (Dukes¿ A og B).

Korrelationen mellem patienternes og egen læges oplysninger om diagnostisk delay var ikke perfekt (Spearman¿s Rho 0,27-0,60), bedst for kort delay.

Væsentligt at afkorte diagnostisk delay for at bedre prognosen for danske rectum cancer patienter.