CT in the assessment of early response to neoadjuvant therapy of colon

Purpose: Neoadjuvant drug therapy is presumed to improve outcome in colon
cancer. Using multi-detector computed tomography (MDCT) we aimed to assess
the early response of neoadjuvant drug therapy for locally advanced colon cancer.
Material and Methods: MDCT with i.v. contrast were acquired from consecutive
67 patients before and after preoperative drug therapy. All patients had at
baseline histologically confirmed colon cancer with ctT4 or ctT3 tumour with
extramural invasion ≥5mm and without distant metastases or peritoneal nodules.
The tumour diameter in 2 different planes, extension of extramural tumour
invasion and number and size of enlarged lymph nodes were measured
before and after the therapy.
Results: Mean tumour length was 7.8 cm (95% CI: 5.3–10.4) at baseline and
4.34 cm (95%, CI: 4.0–4.9) after therapy. Mean extramural tumour invasion
was 10.6 mm (95% CI: 9.5–11.8) at baseline and 5.7 mm (95% CI: 4.7–6.7)
after therapy. Mean number of enlarged lymph nodes was 4.1 (95% CI: 3.4–
4.9) at baseline and 2.1 (95% CI: 1.4–2.7) after therapy. According to the RECIST
criteria 45% (95% CI: 34–57) of the patients had response and 55%
(95% CI: 43–67) had stable disease. No one showed progressive disease.
Conclusion: Using MDCT we demonstrate a significant reduction in tumour
size, extramural tumour invasion, number and size of enlarged lymph nodes
following neoadjuvant therapy for colon cancer. Using the RESIST criteria 45%
had a response.