Combined analysis of VEGF and EGFR predicts complete tumour response in rectal cancer treated with preoperative radiotherapy

High Ki67, Bax, and thymidylate synthase expression well correlates with response to chemoradiation therapy in locally advanced rectal cancers: proposal of a logistic model for prediction

Background:

Recently, preoperative chemoradiation therapy (CRT) for rectal cancer has been increasingly used as a neoadjuvant treatment. In the present study, the relation between histological response to CRT and immunohistochemical markers in biopsy specimens was investigated.

Methods:

Biopsy specimens from a total of 60 patients were collected before preoperative CRT with S-1 and irinotecan, and liniac 45 Gy. Immunohistochemical staining for Ki67, Mcm3, Bax, Bcl-2, ssDNA, Grp78, thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), CD34, vascular endothelial growth factor, nestin, and L-type amino-acid transporter 1 was performed to allow comparison of the Ki67 labelling index (LI), Bax score, TS score, DPD score, microvessel density by CD34, and Grp78 score with cancer regression.

Results:

When the cases were divided into responders (Dworak grades 3 and 4) and non-responders (grades 1 and 2) groups, good correlations were evident with Ki67 LI, Bax, Grp78, and TS expression. On multiple logistic regression analysis, Ki67 LI, Bax, and TS scores were found to be independent factors. With their use in a logistic model, P-values could predict responder cases with a sensitivity of 82.8% and a specificity of 83.9%.

Conclusion

Using this system, treatment strategy for locally advanced rectal cancers can be determined before chemoradiation.

Factors influencing histological response after neoadjuvant chemoradiation therapy for rectal carcinoma

Neoadjuvant chemoradiation therapy is one of the standard therapeutic regimens for rectal carcinoma. Nevertheless, chemoradiation therapy is not completely devoid of adverse effects, and it would be interesting to try to predict which patient will respond to neoadjuvancy. This study aimed at analyzing factors influencing pathological response after therapy. We reviewed the clinical and morphological data of 39 patients after neoadjuvant chemoradiation therapy. We performed immunohistochemistry for p53, cyclin D1, MIB-1 (Ki67), and bcl-2 protein in paraffin-embedded tissue. In our series, 12 patients did not respond to neoadjuvant therapy, 12 showed a complete response, and 15 a partial response. There was a statistically significant association between response and cardiomyopathy (p=0.02) and tenesmus (p=0.02) and a trend towards significance for age (p=0.08), preoperative TNM (p=0.08), peritumoral inflammatory response (p=0.07), and preoperative CEA (p=0.08). As for immunohistochemistry, we only found a trend towards significance for cyclin D1 (p=0.08). In our series of patients with rectal carcinoma receiving preoperative chemoradiation therapy, few factors were predictive of a histological response. The histological response seems to improve survival and reduce relapses.