Tumor vascularity evaluated by transrectal color Doppler US in predicting therapy outcome for low-lying rectal cancer

To evaluate the impact on T downstaging of the vasculature supplying blood flow to rectal cancer evaluated by color Doppler ultrasound.

Color Doppler images were graded in 29 T3-staged rectal carcinoma patients sonographically just before chemoradiation. Any arterial vessels detected in rectal masses were assigned one of two grades: vascularity was considered as grade 1 for vessels feeding the periphery and as grade 2 for vessels coursing in all rectal masses within its peripheral and central portions. The pulsatility indices (PI = peak systolic velocity - end-diastolic velocity/time-averaged maximum velocity) were calculated in the central and peripheral portions.

The pathologic observations showed a change in stage in 15 of the 23 patients graded 2, positive predictive value 65.2% (p = 0.047), and in one of the six rectal cancers graded 1 (negative predictive value, 83.3%). The minimal peripheral PI values in rectal cancer graded 2 were higher in nonresponding (2.2 +/- 1.3) than in responding lesions (1.6 +/- 0.7) p = 0.01.

Vascularity graded 2 associated with low peripheral PI values are indicators of therapy outcome. Vascularity graded 1 and high peripheral PI values in graded 2 have negative predictive value.