BackgroundThe routine application of neoadjuvant chemoradiotherapy for T3N0 rectal cancer remains controversial. The aim of this study was to use clinical, Magnetic resonance imaging, and pathological parameters to identify a subgroup of patients with low risk of local recurrence who might be precluded from neoadjuvant chemoradiotherapy.MethodsWe retrospectively reviewed a prospectively maintained database of consecutive rectal cancer patients who underwent curative resection. 166 pathologic confirmed T3N0 rectal cancer patients with tumor located 5–12cm above the anal verge and preoperative circumferential resection margin>1mm were included in analysis. The primary outcomes measured were3- and 5-year local recurrence rates.ResultsLocal recurrence was demonstrated during follow-up in 5 patients; the actuarial overall 3- and 5-year local recurrence rates were 2.5% and 3.4%, respectively. Inadequate sampling of lymph nodes (≤12) was associated with higher local recurrence (P = 0.03) in this group of patients.ConclusionFor upper and middle T3N0 rectal cancer with preoperative circumferential resection margin>1mm, local recurrence rate after total mesorectal excision is low and surgery alone may be enough for this group of patients.

Diels-Alder reaction between furan and maleic anhydride resulted in 5,6-dehydro norcantharidin, then norcantharidin was obtained by reduction. The substituted-carboxylic acid was condensed with N-aminothiourea in presence of phosphorus oxychloride, yielding 2-amino-1,3,4-thiadiazole derivatives. Novel norcantharidin derivatives were synthesized with acylation, then intramolecular condensation using norcantharidin (or 5,6-dehydro norcantharidin) and 2-amino- 1,3,4-thiadiazole derivatives. All the target compounds were confirmed by IR, (1)HNMR, ESI-MS and were reported for the first time. Norcantharidin derivatives antiproliferative assay was tested by MTT method against A549 and PC-3 cell lines. The results showed that all the norcantharidin derivatives displayed moderate inhibitory activities.