Upsala Journal of Medical Sciences. 2009; 114: 160 164 ORIGINAL ARTICLE Serum vitamin B12 and folate status among patients with chemotherapy treatment for advanced colorectal cancer PER BYSTR O¨M1, KARIN BJO¨ RKEGREN2, ANDERS LARSSON3, LINDA JOHANSSON3 & A˚ KE BERGLUND4 1Department of Oncology and Pathology, Karolinska University Hospital, Stockholm, Sweden, 2Flogsta Va˚ rdcentral, Uppsala, Sweden, 3Department of Medical Sciences, Akademiska Sjukhuset, Uppsala, Sweden, and 4Department of Oncology, Radiology and Clinical Immunology, Akademiska Sjukhuset, Uppsala, Sweden Abstract Background. There are conflicting results on the role of cobalamin and folate for epidemiology and carcinogenesis in colorectal cancer patients and the need of supplementation for prevention of chemotherapy toxicity. Patients and methods. Serum cobalamin, folate, and homocysteine were analysed before and during the treatment of 93 patients with advanced colorectal cancer (ACRC) with first-line chemotherapy treatment. This cohort was compared with a healthy control group of 224 individuals. Results. Patients with ACRC had similar cobalamin, folate, and homocysteine values as the healthy control group. There were no correlations between serum cobalamin, folate, and homocysteine values and objective response. There were no correlations to anaemia or other severe toxicity for cobalamin and homocysteine. A total of 12 patients had folate deficiency, and 10 of those suffered from severe toxicity (grade 3 or more). All patients had markedly increased folate values after 2 months of treatment. Folate and homocysteine did not predict patient outcome; however, patients with subclinically low cobalamin values (B300 pmol/L) had significant better overall survival and time to progression than patients with normal or high cobalamin values. Conclusion. Patients with ACRC seem to have fairly adequate cobalamin and folate status before and during chemotherapy treatment. This study indicates that ACRC patients receiving chemotherapy do not need supplementation with vitamin B12 and folate. A minor portion of the patients had folate deficiency, and most of those patients had severe toxicity. Patients with subclinically low cobalamin values had surprisingly better survival. Key words: Chemotherapy, cobalamin, colorectal cancer, folate, homocysteine Introduction Vitamin B12 deficiency may cause genetic instability, and folate is essential for regenerating methionine, the methyl donor for DNA methylation, and for producing the metabolites for DNA synthesis. Inade- quate availability of folate may contribute to abnorm- alities in DNA synthesis or repair, either of which may influence colon carcinogenesis. There are several studies which indicate that people with deficiency of vitamin B12 and folate have an increased risk for developing colorectal cancer (1 4). There are also cohort studies indicating decreased risk for colorectal cancer among patients with high intake of folate, dietary or as supplementation (5). Other authors do not find these correlations, and there might be a theoretical risk of potentiating the progression of an already established early neoplastic clone (e.g. color- ectal adenoma) (6). Pemetrexed (Alimta†) is a novel multi-target antifolate that inhibits several enzymes involved in DNA synthesis such as thymidylate synthase (TS), dihydrofolate reductase (DHFR), and glycinamide ribonucleotide formyltransferase (GARFT). Early studies showed a severe toxicity profile, but further Correspondence: A˚ ke Berglund MD, PhD, Department of Oncology, Radiology and Clinical Immunology, Akademiska Sjukhuset, SE-751 85 Uppsala, Sweden. Fax: 46 18 611 10 27. E-mail: ake.berglund@onkologi.uu.se (Received 23 February 2009; accepted 8 April 2009) ISSN 0300-9734 print/ISSN 1502-4725 online # 2009 Informa UK Ltd. (Informa Healthcare, Taylor & Francis AS) DOI: 10.1080/03009730903027172