This complementary and alternative medicine (CAM) information summary provides an overview of the use of laetrile as a treatment for people with cancer. The summary includes a history of laetrile research, a review of laboratory studies, the results of clinical trials, and possible side effects of laetrile use.
This summary contains the following key information:
Laetrile is another name for the chemical amygdalin, which is found in the pits of many fruits and in numerous plants.
Infection with the human papillomavirus (HPV), especially HPV type16, also known as HPV-16.[5,6,7]
Similar to other cancers of the head and neck, tobacco and alcohol abuse represent significant risk factors for the development of oropharyngeal cancer.[3,8] (Refer to the PDQ summaries on Hypopharyngeal Cancer Treatment and Lip and Oral Cavity Cancer Treatment for more information.)
Because of the decreased incidence of smoking in the United States, HPV-negative, smoking-related oropharyngeal cancer is decreasing and HPV-associated oropharyngeal cancer is increasing in incidence. The prevalence of HPV in oropharyngeal cancers has increased by 225% from 1988 to 2004, and the HPV-negative cancers have declined by 50% according to the Surveillance, Epidemiology, and End Results (SEER) tissue repository data.[Level of Evidence: 3iii]
HPV-positive oropharyngeal cancers may represent a distinct disease entity that is causally associated with HPV infection and is also associated with an improved prognosis. Several studies indicate that individuals with HPV-positive tumors have significantly improved survivals.[6,10,11,12] In a prospective study involving 253 patients with newly diagnosed or recurrent head and neck SCC, HPV was detected in 25% of the cases. Poor tumor grade and an oropharyngeal site independently increased the probability of the presence of HPV.
The prognosis of oropharyngeal carcinoma is based on HPV status, smoking history (pack-year smoking history of 10 or more years), tumor stage, and nodal stage. The following criteria are used to determine whether patients have low-, intermediate-, or high-risk oropharyngeal carcinoma and have been defined using recursive partitioning analysis in a retrospective analysis of a randomized trial of stage III and IV oropharyngeal SCC patients treated with chemoradiation:
Low-risk patients include those with HPV-positive tumors, a smoking history of 10 or fewer pack years, and N0 to N2a nodal disease.
Intermediate-risk patients include those with HPV-positive tumors, a smoking history of more than 10 pack years, and N2b-N3 disease; or, for those with HPV-negative tumors, a smoking history of 10 or fewer pack years, N2b or N3 disease, or T2-3 tumors.
High-risk patients include those with HPV-negative tumors and a smoking history of more than 10 pack years; or, for those with HPV-negative tumors, a smoking history of 10 or fewer pack years, and T4 disease.