Screening or symptoms? Colorectal cancer diagnosis in Uruguay.

Abstract

71 Background: Colorectal cancer (CRC) remains a major health burden worldwide. Screening is employed due to its proven efficacy in reducing CRC incidence and mortality. In Uruguay, there is a longstanding National CRC screening program using fecal occult blood test (FOBT) as the preferred method. It is to be expected that patients with screen-detected CRC have better prognosis than those with symptoms due to earlier diagnosis and other favorable tumor/host characteristics. Beyond the well described earlier stage at diagnosis, other aspects have not been widely studied and data is sparse. An increasing proportion of CRC patients are diagnosed by screening rather than symptoms. Aim: We sought to establish and evaluate the correlation between clinicopathological features and TNM stage at diagnosis and diagnostic modality. Methods: A retrospective review of all newly diagnosed CRC patients from January 2008 to December 2021 was conducted by the authors. A total of 934 patients aged 50-80 years at diagnosis were included. Clinical, histological, diagnostic and treatment data was collected and findings were stratified and correlated according to screening detection vs symptomatic patients. Results: On one hand, 15% of patients had a positive FOBT leading up to their diagnosis. FOBT detected tumors presented a less advanced locoregional T-N staging (p = 0.001). Tumors were preferentially located in the proximal colon (33.1 vs 19.9%); p<0.001. Stage I CRC was more frequently detected in subjects with positive FOBT (14.2%) than in individuals with symptoms (5.9%); p = 0.002. Conversely, detection rates for stage IV CRC were 17.7% and 26.7% respectively; p = 0.002. A higher percentage of stage III screened patients underwent adjuvant chemotherapy when compared to their symptomatic counterparts (97.7 vs. 85.0 %, p = 0.016). On the other hand, 793 patients (85 %) were diagnosed after onset of signs or symptoms. There was a preponderance of advanced-stage disease (stages III–IV 36-27% respectively). The most common symptoms reported were change in bowel habits (52%), abdominal pain (47 %) and bleeding (45%). The most common overall sign was anemia. One hundred eighty-two patients (22.5%) required an emergency surgery mainly for obstructive colon cancer. Conclusions: Despite equal access to colorectal cancer screening, in Uruguay diagnosis after development of symptomatic cancer remains more common. FOBT detected cancers presented less advanced clinicopathological characteristics and differing management that potentially could be driving a more favorable outcome. Mode of detection is therefore an important indicator that should be taken into account when defining risk assessment in treatment decisions. These findings also support the need for continued improvement and recruitment of patients into screening programs. It must be the focus for future initiatives.