Evaluation of the growth pattern of carcinoma of colon and rectum by MDCT

Colorectal cancer is a leading cause of cancer morbidity and mortality worldwide. Knowledge of colorectal cancer tumor growth is of importance for basic understanding of tumor biology and for the clinical handling of the disease.

To conduct a retrospective evaluation of the growth pattern of colorectal cancer by multidetector computed tomography (MDCT).

Pathologically proven adenocarcinomas of the colon and rectum in 44 patients were examined by MDCT on at least two separate occasions with an interval of >1 month in patients not receiving therapy. Maximal longitudinal diameters, wall thicknesses, and volume changes, as determined by serial CT scans, were used in calculation of growth rates.

Mean longitudinal diameters of tumors at initial and follow-up investigations were 3.8 cm (1.0-9.1 cm) and 5.4 cm (2.5-12.2 cm), respectively. The mean growth rate of longitudinal tumor diameter was 3.4 cm/year (0-13.8 cm/year). Mean axial wall thicknesses at initial and follow-up investigations were 1.4 cm (0.6-6.6 cm) and 1.9 cm (0.8-6.8 cm), respectively. Mean growth rate of tumor axial wall thickness was 1.0 cm/year (0-3.1 cm/year). Mean tumor volumes at initial and follow-up investigations were 1975 cm(3) (172-9756 cm(3); median, 1490) and 3545 cm(3) (442-15211 cm(3); median, 2846), respectively. Mean growth rate of tumor volume was 2912 cm(3)/year (216-12548 cm(3)/year; median, 1698), and volume doubling times varied from 0.05 to 7.1 years (mean, 1.2; median, 0.7). Significant correlations were observed between initial wall thickness and volume growth rate (p = 0.004). No significant difference was observed between other initial tumor size and growth rate.

The tumor growth doubling time of colorectal cancer has a very broad aspect. The initial wall thickness of the tumor on MDCT appears to be the most powerful parameter showing correlation with the volume growth rate.