1H NMR spectroscopy of colon tumors and normal mucosal biopsies; elevated taurine levels and reduced polyethyleneglycol absorption in tumors may have diagnostic significance.

Twenty-three pairs of normal mucosa and colonic adenocarcinoma biopsy specimens have been examined in this pilot study by 1H NMR spectroscopy at 9.4 T to determine whether it was possible to find spectral malignancy markers. The 3.2 ppm (trimethylamine-containing compounds)/0.9 ppm (methyl of fatty acids) resonance intensity ratio in water suppressed spectra, proposed by other authors as a malignancy marker, results in our hands, using resonance areas, in partial overlap between tumor and mucosa values, which reduces its diagnostic value. Furthermore, we have found that submucosa contamination could mask the normal mucosa pattern and artifactually decrease the 3.2/0.9 ppm, ratio value by increasing the 0.9 ppm resonance due to the known triglyceride content of normal submucosa. On the other hand, we have observed in the Hahn spin-echo spectra of intact biopsies resonances arising from taurine and exogenous polyethyleneglycol (PEG). Their assignment and quantification has been carried out in perchloric acid extracts of the tissue biopsies. The taurine (3.4 ppm)/creatine (3.0 ppm) area ratio produced an excellent discrimination between normal mucosa and tumour groups while the PEG (3.7 ppm)/creatine (3.0 ppm) area ratio presented a large overlap, although it was clearly higher in the mucosae than in the tumors for paired samples. These two NMR observable parameters are in our hands highly discriminating and are accordingly proposed as malignancy markers in tissue biopsies although their possible utility for in vivo studies remains to be demonstrated.

Intraoperative colonoscopy in patients with colorectal cancer.

Sixty-seven patients underwent intraoperative colonoscopy during elective surgery for colorectal cancer. Complete examination of the colon was achieved in 65 patients (97 per cent), albeit with insertion through a colotomy in three (4 per cent). A synchronous carcinoma was found in six patients (9 per cent), which necessitated a change of planned surgical procedure. Synchronous polyps were detected and removed in 24 patients (36 per cent); two had polyps with carcinoma in situ. The mean age of patients with synchronous carcinoma was significantly higher than that of those without (74.1 versus 61.2 years, P = 0.02). Intraoperative colonoscopy took a mean of 15 min surgical time and only two minor complications (serosal lacerations) were encountered. In patients with colorectal cancer, intraoperative colonoscopy allows complete assessment of the colon and identifies synchronous lesions.