Gerson’s book [1] and articles in English [2-4] are primarily reports of the details of the Gerson regimen, supplemented with case reports of patients seen in his clinical practice. His book presents an extended discourse on the empirical and scientific foundation for his treatment regimen and an expansive description of the treatment and diet followed by 50 patients selected from 30 years of clinical practice. Gerson’s published cases encompass a variety of cancer types. The reports are extended case notes, with occasional x-rays of the patients over time. Although some attempt at follow-up is made, it is not systematic and consists chiefly of anecdotal reports and conversations with patients by mail or phone.

Few published studies evaluate the Gerson therapy. The one study that was conducted by the Gerson Institute that looked at patients treated in the Gerson clinic is retrospective; while showing some survival advantage, this study has never been duplicated or followed with a prospective study.[5]

A preliminary study conducted between 1983 and 1984 attempted to collect any available retrospective data on three nonallopathic treatments offered in clinics in Tijuana, Mexico: Gerson, Hoxsey, and Contreras.[6] In general, this study was extremely limited and provided no scientifically useful information. The authors did not have access to medical records and relied on patient interviews for all information. The self-reporting was incomplete and inconsistent, lacking precise information in areas such as how far the disease had advanced. In the Gerson segment, only 18 of the 38 patients stayed in the study for 5 years or until they died; their mean survival was 9 months from the beginning of the study. The other 20 patients were lost to follow-up. At 5 years, 17 of the 18 had died, and 1 patient with advanced non-Hodgkin lymphoma was alive but not disease-free.

A 1990 noncontrolled, self-selected, matched-pairs study conducted in Austria used a diet regimen based on the Gerson therapy to evaluate diet as an adjuvant to surgery. This diet was ovolactovegetarian.[7] The Gerson regimen is basically strictly vegetarian (no eggs or milk) and does not introduce food other than buttermilk until 6 or 8 weeks into the regimen, if at all, depending on the patient.

Two groups of patients who had undergone surgery—18 patients with colorectal cancer with metastases to the liver and 38 with breast cancer —were treated. Each of the two groups was divided into a diet group and a nondiet group. All patients continued with whatever prescribed conventional regimen was required after their surgery. Results in the matched pairs with colorectal cancer showed an increased survival time in three of the nine patients in the diet group (28.6 months) as compared to four of the nine patients (16.2 months) in the nondiet group. In the breast cancer matched pairs, side effects of chemotherapy as well as pain and pleural effusion were lower in the diet group. No statistically significant information was generated in this small number of patients; however, the authors stated that the diet regimen appeared to have beneficial effects that required further study.[7]

A 1995 report of a retrospective study of patients at the Gerson Institute with melanoma, colorectal cancer, and ovarian cancer reported slightly higher survival rates than those found in the published literature. Statistics to substantiate this finding were not provided. When asked to publish statistics on these findings, the authors published another retrospective study of survival rates among melanoma patients alone.[5]

The study looked at records of 153 patients with stage I–IV melanoma treated with the Gerson diet. Of the 14 stage I–II patients, all were disease-free at 17 years posttreatment; however, this number was too small for a statistical comparison with other cohorts. For stage III patients, the 5-year survival rate was 71% compared to rates of 27% to 42% reported in the literature. The stage IV patients had the largest survival advantage. The 5-year survival rate for these 18 patients was 39%, compared to 6% in the published literature. The analysis did not include 53 patients who were lost to follow-up, which could have influenced the survival comparisons.

A small best-case series published in [8] suggests that the evidence presented supports the development and conduct of a more definite clinical study on the Gerson regimen.

No conclusions about the effectiveness of the Gerson therapy, either as an adjuvant to other cancer therapies or as a cure, can be drawn from any of the studies reported above.

References

1. Gerson M: A Cancer Therapy: Results of Fifty Cases and The Cure of Advanced Cancer by Diet Therapy. San Diego, Calif: The Gerson Institute, 2002. 
   
   
2. Gerson M: Effects of a combined dietary regime on patients with malignant tumors. Exp Med Surg 7 (4): 299-317, illust, 1949.  [PUBMED Abstract]
   
   
3. Gerson M: Dietary considerations in malignant neoplastic disease: preliminary report. Rev Gastroenterol 12: 419-25, 1945. Also available online. ¹ Last accessed September 4, 2007. 
   
   
4. Gerson M: The cure of advanced cancer by diet therapy: a summary of 30 years of clinical experimentation. Physiol Chem Phys 10 (5): 449-64, 1978.  [PUBMED Abstract]
   
   
5. Hildenbrand GL, Hildenbrand LC, Bradford K, et al.: Five-year survival rates of melanoma patients treated by diet therapy after the manner of Gerson: a retrospective review. Altern Ther Health Med 1 (4): 29-37, 1995.  [PUBMED Abstract]
   
   
6. Austin S, Dale EB, DeKadt S: Long term follow-up of cancer patients using Contreras, Hoxsey and Gerson therapies. J Naturopathic Med 5 (1): 74-6, 1994. 
   
   
7. Lechner P, Kroneberger L Jr: Experiences with the use of diet therapy in surgical oncology. Aktuel Ernahrungsmed 2 (15): 72-8, 1990. 
   
   
8. Molassiotis A, Peat P: Surviving against all odds: analysis of 6 case studies of patients with cancer who followed the Gerson therapy. Integr Cancer Ther 6 (1): 80-8, 2007.  [PUBMED Abstract]
   
   

Glossary Terms

A process in which anything complex is separated into simple or less complex parts.

An incomplete description of the medical and treatment history of one or more patients. Anecdotal reports may be published in places other than peer-reviewed, scientific journals.

Glandular organ located on the chest. The breast is made up of connective tissue, fat, and breast tissue that contains the glands that can make milk. Also called mammary gland.

A term for diseases in which abnormal cells divide without control. Cancer cells can invade nearby tissues and can spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord.

A detailed report of the diagnosis, treatment, and follow-up of an individual patient. Case reports also contain some demographic information about the patient (for example, age, gender, ethnic origin).

Treatment with drugs that kill cancer cells.

Having to do with the examination and treatment of patients.

Cancer that develops in the colon (the longest part of the large intestine) and/or the rectum (the last several inches of the large intestine before the anus).

The things a person eats and drinks.

Monitoring a person's health over time after treatment. This includes keeping track of the health of people who participate in a clinical study or clinical trial for a period of time, both during the study and after the study ends.

A diet plan that has been claimed to be a treatment for cancer, migraine, tuberculosis, and other diseases. It is a vegetarian diet that includes eating organic fruits and vegetables and 13 glasses of fresh juice each day. It also includes supplements with iodine, vitamin B-12, potassium, thyroid hormone, liver extract, and pancreatic enzymes. No clinical trial to test Gerson therapy has been reported.

A large organ located in the upper abdomen. The liver cleanses the blood and aids in digestion by secreting bile.

A statistics term. The average value in a set of measurements. The mean is the sum of a set of numbers divided by how many numbers are in the set.

A form of cancer that begins in melanocytes (cells that make the pigment melanin). It may begin in a mole (skin melanoma), but can also begin in other pigmented tissues, such as in the eye or in the intestines.

The spread of cancer from one part of the body to another. A tumor formed by cells that have spread is called a “metastatic tumor” or a “metastasis.” The metastatic tumor contains cells that are like those in the original (primary) tumor. The plural form of metastasis is metastases (meh-TAS-tuh-SEEZ).

Any of a large group of cancers of the immune system. Non-Hodgkin lymphomas can occur at any age and are often marked by enlarged lymph nodes, fever, and weight loss. There are many different types of non-Hodgkin lymphoma, which can be divided into aggressive (fast-growing) and indolent (slow-growing) types and can be classified as either B-cell or T-cell non-Hodgkin lymphoma. B-cell non-Hodgkin lymphomas include Burkitt lymphoma, diffuse large B-cell lymphoma, follicular lymphoma, immunoblastic large cell lymphoma, precursor B-lymphoblastic lymphoma, and mantle cell lymphoma. T-cell non-Hodgkin lymphomas include mycosis fungoides, anaplastic large cell lymphoma, and precursor T-lymphoblastic lymphoma. Lymphomas related to lymphoproliferative disorders following bone marrow or stem cell transplantation are usually B-cell non-Hodgkin lymphomas. Prognosis and treatment depend on the stage and type of disease. Also called NHL.

Cancer that forms in tissues of the ovary (one of a pair of female reproductive glands in which the ova, or eggs, are formed). Most ovarian cancers are either ovarian epithelial carcinomas (cancer that begins in the cells on the surface of the ovary) or malignant germ cell tumors (cancer that begins in egg cells).

An abnormal collection of fluid between the thin layers of tissue (pleura) lining the lung and the wall of the chest cavity.

A doctor's order for medicine or another intervention.

In medicine, a study or clinical trial in which participants are identified and then followed forward in time.

A treatment plan that specifies the dosage, the schedule, and the duration of treatment.

Looking back at events that have already taken place.

A study that compares two groups of people: those with the disease or condition under study (cases) and a very similar group of people who do not have the disease or condition (controls). Researchers study the medical and lifestyle histories of the people in each group to learn what factors may be associated with the disease or condition. For example, one group may have been exposed to a particular substance that the other was not. Also called a case-control study.

A problem that occurs when treatment affects healthy tissues or organs. Some common side effects of cancer treatment are fatigue, pain, nausea, vomiting, decreased blood cell counts, hair loss, and mouth sores.

The extent of a cancer in the body. Staging is usually based on the size of the tumor, whether lymph nodes contain cancer, and whether the cancer has spread from the original site to other parts of the body.

Describes a mathematical measure of difference between groups. The difference is said to be statistically significant if it is greater than what might be expected to happen by chance alone. Also called significant.

A procedure to remove or repair a part of the body or to find out whether disease is present. An operation.

The percentage of people in a study or treatment group who are alive for a given period of time after diagnosis or treatment. This is often measured 5 years after diagnosis or treatment and called the 5-year survival rate. Also called overall survival rate.

A type of high-energy radiation. In low doses, x-rays are used to diagnose diseases by making pictures of the inside of the body. In high doses, x-rays are used to treat cancer.