Page 39 - SRPSKO DRUŠTVO ISTRAŽIVAČA RAKA

SDIRSACR Oncology Insights

determinants (6). Since these analyses are rather expensive, they are still mostly used for research and development
of novel therapies. Therefore, the input of the pathologist remains crucial for diagnosis, risk stratification and choice of
treatment in routine clinical practice (7).
The aim of this study was to describe trends in tumor pathology in Serbian patients with colorectal cancer in the period
2003-2016. Additionally, the study aimed to provide insight into the pathological features of early-onset CRC and
response to standard nCRT.

Material and methods
The study was conducted in a tertiary care unit. Data on all patients who underwent operative CRC resection between
2003 and 2016 were included in the electronic database. Collected data included demographic data, surgical information
and pathology findings. The following data on the tumor pathology were included in the analysis: tumor position,
tumor dimensions, type of macroscopic tumor growth, histopathological type of tumor according to the 2019 WHO
release (8), stage of TNM tumor disease according to the 9th edition of American Joint Committee on Cancer (9), the
degree of tumor differentiation, and the classification of residual status. Stages of tumor disease were analyzed using
systems according to the Dukes and Aster Coller classification.
The tumor pathological features of the subgroup of patients under 50 years of age were compared with the rest of the
cohort.
Pathological response to the standard nCRT regimen (45 Gy delivered in 25 daily fractions over 5 weeks with concurrent
425 mg/m of 5-fluorouracil and 20 mg/m2 of leucovorin) was assessed based on histological examination of the
resected specimens according to the Mandard tumor regression grade (TRG) classification system (10).
Statistical analysis was performed by the Statistical Package for Social Sciences 20.0 (SPSS Inc., Chicago, Illinois, USA).
Continuous variables are presented as mean ± standard deviation (SD), while categorical variables are presented as
frequencies. The differences between categorical variables were analyzed by Fisher’s exact test and Pearson χ2 test. A
p value less than 0.05 was considered statistically significant.

Results
The observed 14-year period (2003-2016) encompassed 2462 surgical resections of CRC. The annual number of
resections varied between 88 and 286, with an average of 175 per year. The resections were conducted in 1465 men
(60%) and 997 women (40%) with an average age at diagnosis of 62±12 years (Figure 1).

Figure 1. Frequency of surgical CRC resection cases according to sex and age

Characteristics of patients with early-onset and late-onset disease are given in Table 1. Differences in demographic
and pathologic characteristics were tested between young adults and older individuals. Among early-onset patients,
women were significantly overrepresented (P=0.013), patients were diagnosed at significantly later stages (P=0.033),
tumors were significantly less differentiated (P=0.001) and tumors of the right colon were overrepresented (P<0.001).
Patients with early-onset disease represented between 11% and 22% of all cases per year, with an average of 15.6%
(Figure 2). In 2014 and 2016, a significant reduction in the number of CRC cases was observed among patients aged
over 50. Specifically, the incidence of CRC in this age group showed a noticeable decline during these years compared
to previous years (Figure 2). This reduction may reflect broader trends in CRC detection and management, particularly
related to the introduction of the national screening program in 2013.

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