162 P. Bystro¨m et al. also received anti-emetic treatment with metoclopra- mide and selective serotonin antagonists (5-HT3) blockers. Response and toxicity evaluation Tumour response was assessed according to RE- CIST criteria (11). Toxicity was evaluated according to the National Cancer Institute common toxicity criteria, version 2 (16). The information prospec- tively recorded in the case record forms was used. Serum sampling and measurements Serum for cobalamin, folate, and homocysteine analyses was taken at base-line and prior to the fourth cycle, i.e. at 2 months of treatment. Immediately after sampling, aliquots were frozen at 208C for later analyses. The results of the analyses were unknown for the treating physicians. Serum cobalamin (re- agent: 6C09), folate (reagent: 7K60-32), and homo- cysteine (reagent: FHER100) were analysed on an Architect Ci8200 (Abbott Laboratories, Abbott Park, IL, USA) and reported using SI units. The total coefficients of variation were 7.0% at 480 pmol/L for cobalamin, 2.6% at 28 nmol/L for folate, and 2.7% at 29.3 mmol/L for homocysteine. The same measure- ment procedure was performed for the historical control of the healthy population. Statistical analyses Comparisons of proportion between groups were performed by chi-square analyses. Correlations were studied with Spearman’s rank correlation test. Sur- vival curves were drawn according to Kaplan-Meier. Results Patient homocysteine values did not correlate to patient outcomes, i.e. objective response (OR), time to progression (TTP), overall survival (OS), anae- mia, or chemotherapy toxicity (data not shown). There were only two patients with cobalamin values lower than reference. Those 2 patients and 33 patients with subclinically low values (B300 pmol/ L) did not have more toxicity than patients with higher values (approximately 50% of the patients suffered from at least one reported grade 3 or more toxicity). There was no correlation between cobala- min values and objective response; however, patients with values B300 pmol/L at base-line had better OS (P 0.0002) (Figure 1) and TTP (P 0.03) than patients with higher values. There were only modest changes of the patients’ cobalamin values after 2 months of treatment. A total of 12 patients (13%) had folate deficiency before the start of the chemotherapy treatment, and, of those, 10 patients (83%) suffered from grade 3 toxicity or more. Those 10 patients had the same toxic profile as other patients with severe toxicity. All patients had markedly increased folate values after 2 months of chemotherapy treatment. There were no correlations with patients’ folate status and OR, TTP, or OS. None of these markers correlated to haemoglo- bin value or performance status. The patients’ cobalamin, folate, and homocys- teine values were almost equal to a previously performed study with a healthy control group of 224 individuals from the same county (Table III), although the control group was slightly older (median 77 years). Discussion In the current study, we examined serum levels of cobalamin, folate, and homocysteine in patients with ACRC, before and after 2 months of treatment. There are, going through the literature, conflict- ing results on how to interpret the importance of the endogenous levels of B12, folate, and homocysteine in association with ACRC development, as discussed in the introduction, but also whether or not these levels should be taken into account when it comes to treatment. Table II. The results of the analyses. S-Cobalamin base-line, pmol/L S-Cobalamin after 2 months, pmol/L S-Folate at base-line, nmol/L S-Folate after 2 months, nmol/L S-Homocysteine at base-line, mmol/L S-Homocysteine after 2 months, mmol/L CI confidence intervals. n 81 67 93 71 93 73 Mean 421 409 10.0 28.4 19.3 16.6 Median 368 354 7.6 28.8 17.8 13.5 Range 37 1476 13 1480 1.0 45.3 10.2 45.5 6.6 43.5 0.6 230.0 95% CI 134 853 39 1123 3.0 30.4 16.8 38.6 9.6 36.2 8.2 21.4