Cannabis has been found to help cancer patients with pain and nausea, and recent research indicates it has tumor-reducing and anti-carcinogenic properties as well. It has proven highly effective at controlling the nausea associated with chemotherapy, and its appetite-stimulation properties help combat wasting. Cannabis can also help control the pain associated with some cancers, as well as that resulting from radiation and chemotherapy treatment.
Cannabis and chemotherapy side effects

One of the most widely studied therapeutic applications for cannabis and the pharmaceutical drugs derived from cannabinoids is in the treatment of nausea and vomiting associated with cancer chemotherapy. Numerous clinical studies have reported that the use of cannabis reduces nausea and vomiting and stimulates appetite, thereby reducing the severity of cachexia, or wasting syndrome, in patients receiving chemotherapy treatment.

The 1999 Institutes of Medicine report concluded: “In patients already experiencing severe nausea or vomiting, pills are generally ineffective, because of the difficulty in swallowing or keeping a pill down, and slow onset of the drug effect. Thus an inhalation (but, preferably not smoking) cannabinoid drug delivery system would be advantageous for treating chemotherapy-induced nausea.”[58]

A 1997 inquiry by the British Medical Association found cannabis more effective than Marinol, and a 1998 review by the House of Lords Science & Technology Select Committee concluded that “cannabinoids are undoubtedly effective as anti-emetic agents in vomiting induced by anti-cancer drugs. Some users of both find cannabis itself more effective.”[59, 60]

In the last three years, there have been major advances in both cannabinoid pharmacology and in understanding of the cancer disease process. In particular, research has demonstrated the presence of numerous cannabinoid receptors in the nucleus of the solitary tract, a brain center important in control of vomiting.

Although other recently developed anti-emetics are as effective or more effective than oral THC, nabilone or smoked cannabis, for certain individuals unresponsive to conventional anti-emetic drugs, the use of smoked cannabis can provide relief more effectively than oral preparations which may be difficult to swallow or be vomited before taking effect, as the IOM report notes.

The psychoactive euphoriant effects of THC or inhaled cannabis may also provide an improvement in mood. By contrast, several conventional medications commonly prescribed for cancer patients, e.g. phenothiazines such as haloperidol (known as “major tranquillizers”), may produce unwanted side effects such as excessive sedation, flattening of mood, and/or distressing physical “extrapyramidal” symptoms such as uncontrolled or compulsive movements.

While clinical research on using cannabis medicinally has been severely limited by federal prohibition, the accumulated data speaks strongly in favor of considering it as an option for most cancer patients, and many oncologists do. Survey data from a Harvard Medical School study in 1990, before any states had approved medical use, shows that 44% of oncologists were then recommending cannabis to at least some of their patients. Nearly half said they would do so if the laws were changed. According the American Cancer Society’s 2003 data, more than 1,300,000 Americans are diagnosed with cancer each year.[61] At least 300,000 of them will undergo chemotherapy, meaning as many as 132,000 patients annually may have cannabis recommended to them to help fight the side effects of conventional treatments.

As the Institutes of Medicine report concluded, “nausea, appetite loss, pain and anxiety … all can be mitigated by marijuana.”
Research on cannabis and chemotherapy

Cannabis is used to combat pain caused by various cancers and nausea induced by chemotherapy agents. Over 30 human clinical trials have examined the effects of cannabis or synthetic cannabinoids on nausea, not including several U.S. state trials that took place between 1978 and 1986.[62] In reviewing this literature, Hall et al. concluded that “. . . THC [delta-9-tetrahydrocannabinol] is superior to placebo, and equivalent in effectiveness to other widely-used anti-emetic drugs, in its capacity to reduce the nausea and vomiting caused by some chemotherapy regimens in some cancer patients.”[63] A 2003 study found “Cannabinoids—the active components of Cannabis sativa and their derivatives—exert palliative effects in cancer patients by preventing nausea, vomiting and pain and by stimulating appetite. In addition, these compounds have been shown to inhibit the growth of tumor cells in culture and animal models by modulating key cell-signaling pathways. Cannabinoids are usually well tolerated, and do not produce the generalized toxic effects of conventional chemotherapies.”[64] Authors of the Institute of Medicine report, “Marijuana and Medicine: Assessing the Science Base,” found that there are many cancer patients for whom cannabis should be a valid medical option.[65]

A random-sample anonymous survey conducted in the spring of 1990 measured the attitudes and experiences of oncologists concerning the antiemetic use of cannabis in cancer chemotherapy patients. Of the respondents expressing an opinion, a majority (54%) thought cannabis should be available by prescription.[66]
Cancer-fighting properties of cannabis

Recent scientific advances in the study of cannabinoid receptors and endocannabinoids have produced exciting new leads in the search for anti-cancer treatments. More than twenty major studies published between 2001 and 2006 have shown that the chemicals in cannabis known as cannabinoids have a significant effect fighting cancer cells. We now know cannabinoids arrest many kinds of cancer growths (brain, breast, leukemic, melanoma, phaeochromocytoma, etc.) through promotion of apoptosis (programmed cell death) that is lost in tumors, and by arresting angiogenesis (increased blood vessel production).

There is growing evidence of direct anti-tumor activity of cannabinoids, specifically CB1 and CB2 agonists, in a range of cancer types including brain (gliomas), skin, pituitary, prostate and bowel. The anti-tumor activity has led in laboratory animals and in-vitro human tissues to regression of tumors, reductions in vascularisation (blood supply) and metastases (secondary tumors), as well as the direct destruction of cancer cells (apoptosis). Indeed, research on the complex interactions of endogenous cannabinoids and receptors is leading to greater scientific understanding of the basic mechanisms by which cancers develop.

The findings of these studies are borne out by the anecdotal reports of such patients as Steve Kubby, whose cannabis use is credited with keeping rare, terminal cancers in a state of remission for decades beyond conventional expectations.
Research on Tumor Reduction

Although cannabis smoke has been shown to have precancerous-causing effects in animal tissue, epidemiological studies have failed to link cannabis smoking with cancer.[67-68] If smoke inhalation is a concern, cannabis can be used with a vaporizer, orally in baked goods, and topically as a tincture or a suppository.

Cannabinoids, the active components of cannabis, have been shown to exhibit anti-tumor properties. Multiple studies published between 2001 and 2003 found that cannabinoids inhibit tumor growth in laboratory animals.[69-73] In another study, injections of synthetic THC eradicated malignant brain tumors in one-third of treated rats, and prolonged life in another third by as much as six weeks.[74] Other journals have also reported on cannabinoids’ antitumoral potential.[75-81] Italian research teams reported in 1998 and 2001 that the endocannabinoid anandamide, which binds to the same brain receptors as cannabis, “potently and selectively inhibits the proliferation of human breast cancer cells in vitro” by interfering with their DNA production cycle.[82-84] Cannabis has been shown in recent studies to inhibit the growth of thyroid, prostate and colorectal cancer cells.[85-87] THC has been found to cause the death of glioma cells.[88-89] And research on pituitary cancers shows cannabinoids are key to regulating human pituitary hormone secretion.[90-93]

In 2004 an Italian research team demonstrated that the administration of the non-psychoactive cannabinoid cannabidiol (CBD) to nude mice significantly inhibited the growth of subcutaneously implanted U87 human glioma cells. The authors of the study concluded that “… CBD was able to produce a significant antitumor activity both in vitro and in vivo, thus suggesting a possible application of CBD as an antineoplastic agent (an agent that inhibits the growth of malignant cells.)”[94]

More recently, investigators at the California Pacific Medical Center Research Institute reported that the administration of THC on human glioblastoma multiforme cell lines decreased the proliferation of malignant cells and induced apoptosis (programmed cell death) more rapidly than did the administration of an alternative synthetic cannabis receptor agonist.[95]
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