Coexistence of pernicious anemia and prostate cancer - 'an experiment of nature' involving vitamin B₁₂ modulation of prostate cancer growth and metabolism: a case report

This report presents the clinical and laboratory course of a patient with prostate cancer and severe vitamin B₁₂ deficiency undergoing watchful waiting for prostate cancer. The possible interaction between therapy for B₁₂ deficiency and the natural course of prostate cancer is presented.

We present the case of a 75-year-old Chinese man with prostate cancer and pernicious anemia. His serum vitamin B₁₂ level was 32 pg/ml (300-900 pg/ml) and holotranscobalamin was 0 pg/ml (>70 pg/ml). There was an unexpected rapid progression of Gleason's score during 10 months of watchful waiting. After the diagnosis of pernicious anemia was made, therapeutic injections of vitamin B₁₂ were started. We observed a significant acceleration in prostate-specific antigen and prostatic acid phosphatase and a shortening of prostate-specific antigen doubling time after initiation of B₁₂ therapy.

We propose that the relatively short period of watchful waiting before histological progression of Gleason's score (GS [3+2] = 5 to GS [3+4] = 7 over 10 months) may have been a result of depleted holotranscobalamin 'active' B₁₂. Replacement of B₁₂ was associated with an initial rapid increase in serum prostate-specific antigen and prostatic acid phosphatase followed by stabilization. The patient represents an 'experiment of nature' involving vitamin B₁₂ metabolism and raises the question as to whether rapid histological progression of Gleason's score was related to absence of serum holotranscobalamin while prostate-specific antigen and prostatic acid phosphatase, markers of cell growth, were accelerated by vitamin B₁₂ replacement. To our knowledge, this is the first report of a possible cellular kinetic interaction between an epithelial malignancy and vitamin B₁₂ metabolism.