Laetrile, also known as amygdalin, is a substance promoted as an alternative cancer treatment since the 1970s. It is derived from apricot pits and produces cyanide when metabolized. While some claim it selectively kills cancer cells, evidence shows it is toxic and there are no well-designed studies proving its effectiveness as a treatment. Reports of benefits are unreliable and risks include cyanide poisoning and unknown purity of sources being used. Many health authorities have banned its use due to lack of evidence and risks of toxicity.

1. Laetrile

2. Laetrile Alternative cancer treatment since 1970s Laetrile  benzaldehyde, glucose and cyanide

3. Also known as… Laetrile (trade name) = purified amygdalin Amygdalin a cyanogenetic (ie produces cyanide) glycoside pits of Rosaceae family e.g. peach, apricot, almond Vitamin B17 bitter almond apricot kernels laevo-mandelonitrile-beta-glucuronoside mandelonitrile beta-glucoronide mendelonitrile Xing Ren Amygdaloside Prunus armeniaca Nitriloside Prunasin … .etc…

4. History 1837 – amygdalin isolated 1845 – Russia – cancer treatment 1950s – IV amygdalin was named as Laetrile – Dr Ernst Krebs 1971 – “World Without Cancer” 1978 – National Cancer Institute – retrospective analysis 1979 – laetrile banned in USA, UK Today – use as anti-cancer therapy primarily in Mexico Contreras Hospital (www.oasisofhope.com) Advertised/sold mainly on Internet No government controls on these internet products Claims – has been made illegal to protect profits of the drug companies authorities only allow its opponents to test laetrile, hence the negative results. "The butchers of surgery, chemotherapy and radiation have grown rich on the mutilated bodies of millions of innocent victims while public health officials sold their souls.“ Barry Lynes, The Healing of Cancer, The Cures - the Cover-ups and the Solution Now! - page 68 (quoted at http:// www.cancertutor.com/WarBetween/War_Fda.html )

5. How is it used? Laetrile alone, Or combined with a metabolic therapy program diet, pancreatic enzymes and vitamins. Orally – tablet, injection (IM or IV). No uniform recommendations about treatment lengths/courses

6. Use in Australia TGA permit (for import) Doctor agrees to administer Special Access Scheme – approval Order from web/other source Exceptions – Queensland, Victoria Clinic Nuera Health – ( http:// www.nueracarecentre.com / ) Port Melbourne – natural therapies for cancer

7. Theories Rhodanese enzyme Present in healthy cells  they can breakdown cyanide Cancer cells are deficient  cyanide gathers and has cytotoxic effects Beta-Glucoronidase (breakdown Laetrile), Beta-glucosidase (breakdown amygdalin) High levels in cancer cells BUT no experimental evidence to show a difference in rhodanese enzymes nor betaglucosidase in tumour tissue compared to healthy Cyanide  increases acid content of cancer cells  disrupt lysosomes  enzyme release  death of cancer cells BUT cytotoxic activity could also affect healthy cells

8. Cancer is a metabolic disorder – develops due to a deficiency of ‘Vitamin B17’ Hunza tribe, Himalayas BUT no evidence that laetrile is a vitamin, that cancer is a metabolic disease, or lack of laetrile is involved in carcinogenesis

9. Evidence? 2006 - Cochrane Review – no RCTs or non-RCTs found Systematic review 2006 (Milazzo, Lejeune, Ernst, 2006) case series/ reports. “ the claim that laetrile has beneficial effect for cancer patients is not supported by sound data.” ‘ Evidence’ is weak, most, if not all reports showing benefits of therapy are not reliable Total cases = 352: 3.1% complete response, 9.4% partial response, 6.8% stable disease, 36.4% tumour progression. 22.9% symptomatic benefits. BUT denominator (number of cases treated overall) not given in reports cyanide poisoning risk seems high. Could increase with concomitant intake of fruit seeds, Vitamin C doses

10. Side Effects Oral Laetrile (vs injected) – higher incidence of cyanide poisoning some intestinal bacteria and commonly eaten plants (e.g. celery, peaches, bean sprouts, carrots) contain beta-glucosidases Other substances that may increase side effects – raw almonds, crushed fruit pits, high dose Vitamin C Increased S/Es in people with a genetic tendency to poorly detoxify cyanide. CYANIDE: Neurotoxin N+V, headache, dizziness, cyanosis, liver damage, hypotension, ptosis, ataxic neuropathies, fever, mental confusion, coma, death

11. Conclusion Many substances are marketed as ‘laetrile’ but may be different compounds. Uncertain whether laetrile works as an anti-cancer treatment Risks side effects from cyanide poisoning questionable purity of sources

12. References Contreras Hospital http://www.oasisofhope.com Ellison NM, Byar DP, Newell GR. Laetrile. N Engl J Med 1978 Sep 7; 299 (10): 549-52 Milazzo, S. Lejeune, S. Ernst, E. (2006) Laetrile for cancer a systematic review of the clinical evidence. Support Care Cancer . Milazzo, S. Ernst, E. Lejeune, S. Schmidt, K. Laetrile treatment for cancer. Cochrane Database of Systematic Reviews 2006, Issue 2. National Cancer Institute (2006) Laetrile/ Amygdalin. http://www.cancernet.nci.nih.gov/cancertopics/pdq/cam/laetrile/healthprofessional/all World Without Cancer Org (2000) The Ultimate Guide to Vitamin B-17 Metabolic Therapy , available online from www.worldwithoutcancer.org.uk http://worldwithoutcancer.org.uk http://www.laetrile.com.au http://www.quackwatch.org/01QuackeryRelatedTopics/Cancer/laetrile.html