About Herbs

Bottom Line: Clinical trials show that the injected form of lentinan can extend the survival of patients with advanced stomach and prostate cancers when used with chemotherapy. There is no proof that lentinan can prevent or treat cancer when taken by mouth.

Lentinan is a type of polysaccharide (sugar molecule) called a 1,3 beta glucan. In laboratory tests, lentinan does not kill cancer cells directly, instead enhances a number of aspects of the immune system, which may aid in slowing the growth of tumors. Lentinan also kills viruses and microbes directly in laboratory studies.

Over 300 case reports and studies have been published by foreign researchers who used lentinan alone or in combination with chemotherapy and/or radiation. In most of these studies, lentinan was given intravenously or by injection.

Stomach cancer:
Patients with cancers of the digestive tract were treated with 2 mg of intravenous lentinan three times a week. Specific aspects of their immune systems, often impaired in late stage cancer patients, were followed. Researchers think that these immune impairments are caused by an imbalance in types of T helper cell responses called the Th1 and Th2 response. After treatment with lentinan, patients showed a decrease in Th2-dominance and an improvement in the balance between Th1 and Th2 responses. However, this study did not show whether this immune change actually helped the patients fight their cancer better or live longer.

The effect of lentinan in combination with conventional cancer treatment was studied in 45 patients with advanced stomach cancer. All patients received treatment with tegafur and cisplatin; half received no other treatment, and the other half were given 2 mg of intravenous lentinan per week. After 12 weeks, the quality-of-life scores of the patients given lentinan were greatly improved compared to the control group. Survival after one year and maintenance of body weight also were better for the patients receiving lentinan, although studies with this few patients cannot give as reliable results as larger studies.

The effectiveness of lentinan injections combined with chemotherapy was examined in a study involving 89 patients with inoperable or recurrent gastric cancer. At the trial's end, it was found that chemotherapy combined with lentinan prolonged the survival of patients when compared to chemotherapy alone. These results further support the use of lentinan injections in gastric cancer treatment.

A clinical trial looked at the use of lentinan plus chemotherapy in patients with stomach cancer. In the control group, 68 patients were given 600 mg/day of Tegafur. In the treatment group, 96 patients in the treated group were given the same dose of Tegafur along with 2 mg of lentinan intravenously every week. At the end of the clinical trial and at the end of the followup survey (3 years later), survival was prolonged in the group receiving lentinan. This suggests that lentinan should be effective in combination with Tegafur for patients with stomach cancer.

Prostate cancer:
A clinical trial studied the effectiveness of lentinan in 69 patients with metastatic prostate cancer. All patients received hormonal therapy and chemotherapy. For three months, 33 patients received intramuscular injections of lentinan, while the other 36 did not. Patients treated with lentinan had significantly longer survival times overall and at five years, suggesting that lentinan helps prolong survival in metastatic prostate cancer when incorporated into hormono-chemotherapy.

Shitake, hua gu, snake butter, forest mushroom and pasania fungus

The polysaccharide, lentinan, is derived from the mycelium of the shiitake mushroom body. It is considered a biological response modifier. In other countries, parenteral lentinan is classified as an antineoplastic polysaccharide and is available for clinical use. Only oral formulations and extracts, which are considered dietary supplements, are available for use in the United States. Data on efficacy and safety are limited regarding oral administration of lentinan.

Lentinan's active polysaccharide 1,3 beta glucan is not cytotoxic but seems to enhance T-helper cell function, increase stimulation of interleukin, interferon, and normal killer cells ^{(2) (3)}. In addition to antitumor activity, it also possesses immune-regulatory effects, anti-viral activity, antimicrobial properties and cholesterol-lowering effects ⁽⁴⁾.

Case Report: Single case report of chest tightness when injected parenterally.
⁽⁷⁾

Zidovudine (AZT): Lentinan may enhance activity when used in combination ⁽⁵⁾.
Didanosine (ddi, Videx): Lentinan may increasing CD4 levels in HIV patients when used in combination ⁽⁶⁾.

CD4 counts may be altered.

A Med-Line search displayed over 300 case reports and foreign studies using lentinan as a single agent or in combination against many tumor types. Lentinan was administered intravenously or intramuscularly in a majority of these reports.

Yoshino S, et al. Immunoregulatory effects of the antitumor polysaccharide lentinan onTh1/Th2 balances in patients with digestive cancers. Anticancer Res 2000;20:4707-11.
Studies have demonstrated that patients with advanced cancer may have impaired cell-mediated immunity caused by an imbalance between Th1 and Th2 responses. The study evaluated the ability of lentinan to modulate Th1 and Th2 responses in patients with digestive cancers. After lentinan treatment, CD4+ IFN-gamma+ T-cell percentages increased significantly (p<0.05%), whereas Cd4+ IL-4+ T-cell and Cd4+ IL-6 T-cell percentages decreased significantly (p<0.02). Lentinan apparently can cancel Th2-dominant condition in patients with digestive cancers and may improve the balance between Th1 and Th2.

Nakano H, et al. A multi-institutional prospective study of lentinan in advanced gastric cancer patients with unresectable and recurrent diseases: effect on prolongation of survival and improvement of quality of life. Hepatogastroenterology 1999;46:2662-8.
A randomized, prospective evaluation of 45 patients who received treatment consisting of tegafur 600 mg/day plus 20 mg/m² and cisplatin IV weekly with or without 2 mg/week IV lentinan with quality of life (QOL) and survival as the primary outcomes. Twenty-two patients were in the control group (18 unresectable and 4 recurrent disease), and 23 patients received lentinan (17 unresectable and 6 recurrent disease). Total QOL scores after 12 weeks of treatment were significantly improved in all patients receiving lentinan as compared to the control group. One-year survival for patients with either unresectable or recurrent disease receiving lentinan was statistically better as compared to control, although the sample size may have been inadequate to detect actual difference. No difference in performance status was documented, but patients who received lentinan appeared to maintain body weight as compared to controls. Intravenous lentinan appears to improve QOL and possibly survival, but additional studies are needed.

Tari K, et al. Effect of lentinan for advanced prostate carcinoma. Hinyokika kiyo 1994;40:119-23.
A prospective, randomized, multi-center study assessing the clinical effectiveness of lentinan in 69 metastatic prostate cancer patients. All patients received hormonal therapy and chemotherapy using oral Tegafur at a dose of 400-800 mg/day. While 33 patients received lentinan IM for at least 3 months, the other 36 did not. The dose of lentinan was 2 mg weekly for inpatients and 4 mg every other week for outpatients. The median survival of treated and control patients were 48 and 35 months, respectively. The five-year survival rate of treated patients was 43% according to the Kaplan Meier method, while that of control patients was 29% (p<0.05). The authors conclude that lentinan is effective in metastatic prostate cancer when incorporated into hormonochemotherapy.

Ochiai T, et al. Effect of immunotherapy with lentinan on patients survival and immunological parameters in patients with advanced gastric cancer: results of a multicenter randomized controlled study. Int J Immunother 1992;8:161-9.
The clinical effectiveness of immunotherapy with lentinan was assessed in a study involving 89 patients with inoperable or recurrent gastric cancer. Patients were randomly assigned to two treatment groups receiving chemotherapy alone or lentinan plus chemotherapy. Among the 64 completely evaluable patients, a statistically significant difference in the survival curve was observed between the two treatment groups. Chemotherapy with lentinan prolonged the life span when compared with chemotherapy alone. The results emphasized the effectiveness of lentinan as an immunotherapeutic agent in advanced gastric cancer.

Taguchi T. Clinical efficacy of lentinan on patients with stomach cancer: end point results of a four-year follow-up survey. Cancer Detect Prev Suppl 1987;1:333-49.
Sixty-eight eligible patients in control groups were administered Tegafur 600 mg/day, and 96 eligible patients in the treated group were administered lentinan in combination with Tegafur. Lentinan was injected intravenously 2 mg weekly. Lifespan prolongation effects of lentinan were observed both at the end of the control trial and at the end of the followup survey. Survival at 1,2 and 3 years was observed in the treated group using lifetable analysis. The author suggests that lentinan should be effective in combination with Tegafur for patients with stomach cancer.