No abstract

Objective: transanal endoscopic microsurgery (TEM) allows locally complete excision of rectal neoplasms and provides an alternative to conventional surgery for benign tumours. However, its role in the curative treatment of invasive carcinoma is controversial. This paper examines the results of TEM compared with radical surgery (RS) for T1 rectal cancer. Methods: 51 patients with T1 rectal tumours treated by RS, or local excision by means of TEM were included. The following parameters were evaluated: operating time, blood loss, hospital stay and complications, as well as local recurrence rate and survival. Results: 17 patients were treated by RS and 34 by TEM. Operative time, blood loss, and duration of hospitalization were significantly lower in the TEM group compared with the RS group. In the RS group there were 4 patients with complications which required an operative revision (23.5%), compared to 1 reintervention (2.9%) in the TEM group. Local recurrence was 5.88% (n = 2) in the TEM group compared with none after RS (p = 0.547). The overall survival and disease-free survival showed not significant statistical differences between both groups (p = 0.59; p = 1.000, resp.). Conclusions: although local recurrence was only observed after local excision, patients treated with TEM showed no significant differences in terms of overall survival and disease-free survival compared with patients who underwent RS. Inasmuch as local excision represents a minimally invasive technique in terms of morbidity, mortality and functional outcome, TEM should be offered as a valid option for well selected patients with early rectal cancer.

To date, no effective method exists that predicts the response to preoperative chemoradiation (CRT) in locally advanced rectal cancer (LARC). Nevertheless, identification of patients who have a higher likelihood of responding to preoperative CRT could be crucial in decreasing treatment morbidity and avoiding expensive and time-consuming treatments. The aim of this study was to identify signatures or molecular markers related to response to pre-operative CRT in LARC. We analyzed the gene expression profiles of 26 pre-treatment biopsies of LARC (10 responders and 16 non-responders) without metastasis using Human WG CodeLink microarray platform. Two hundred and fifty seven genes were differentially over-expressed in the responder patient subgroup. Ingenuity Pathway Analysis revealed a significant ratio of differentially expressed genes related to cancer, cellular growth and proliferation pathways, and c-Myc network. We demonstrated that high Gng4, c-Myc, Pola1, and Rrm1 mRNA expression levels was a significant prognostic factor for response to treatment in LARC patients (p<0.05). Using this gene set, we were able to establish a new model for predicting the response to CRT in rectal cancer with a sensitivity of 60% and 100% specificity. Our results reflect the value of gene expression profiling to gain insight about the molecular pathways involved in the response to treatment of LARC patients. These findings could be clinically relevant and support the use of mRNA levels when aiming to identify patients who respond to CRT therapy.