Excerpted from April 2011's newsletter:
If you have cancer, you have probably already read that asparagus will cure your cancer. A letter making this claim has gone viral on the internet. I doubt that there are more than a handful of people with cancer who have not received a copy forwarded to them by some well meaning friend or relative.
Let me start by saying there is little reason to believe the claim that asparagus will cure cancer. Instead it may actually make a few specific cancers worse.
Let me summarize what we do know about these claims in the hope that information may antidote this long, standing urban myth.
The “Asparagus Cure for Cancer” first appeared in print in the February 1974 issue of Prevention magazine. This article was followed by a similar article in the December 1979 issue of Cancer News Journal, a magazine once distributed in health food stores. Both articles claim that a dentist named Richard R. Vensal discovered that eating asparagus could cure cancer.
According to the letter, a cure can be achieved by consuming 4 tablespoons of pureed cooked asparagus twice a day. Improvement is supposedly seen in two to four weeks.
Unfortunately there is little reason why we should believe this information. The dentist Richard Vensal never published anything in either a scientific journal or book that can be found.
It is certainly possible that some chemical found in asparagus might be beneficial against cancer.
There is a single study suggesting this that was published in 2009. Chinese researchers report that a chemical, which they named asparanen A, showed an anticancer effect when tested on liver cancer cells. 
There are no studies that describe the results of feeding asparagus to animals with cancer. Nor are there any published clinical trials on giving asparagus to human cancer patients. Nor are is there any epidemiological data that hints that asparagus farmers have less cancer.
While there is a wealth of research that diets high in vegetables are anti-cancer, there is no evidence that singles out asparagus in particular suggesting it has an anti-cancer effect. So while there may be some health benefits from eating asparagus because it is a vegetable, at this point, there is little reason to think that asparagus are exceptional.
In contrast there is substantial published data on the anticancer effect of other specific vegetables. For example, a current search of the National Institute of Health’s National Library of Medicine, lists 597 published articles in the medical and scientific literature related to the anticancer effect of broccoli.  A search for published papers on garlic and cancer yields 648 references. 
There are only two clinical trials involving asparagus in humans. One paper published in 2009, describes a study in which patients with high blood pressure were given a combination of parsley and asparagus extracts in the hope that their blood pressure would improve. Unfortunately, no benefit was seen.  An earlier study published in 2008, reported that a combination of asparagus and elderberry extracts helped patients lose weight. 
Losing weight is not the same as curing cancer.
Thus at this point there is little reason to think that asparagus will cure cancer.
Ironically though there is a long established link between asparagus and a particular form of cancer. Unfortunately, asparagus may, instead of curing this cancer, make it worse. Let me explain:
In 1953 a pathologist named John G. Kidd discovered that blood serum taken from healthy guinea pigs, when injected into mice, killed leukemia cancer cells.  Ten years later John D. Broome MD explained why this happened. Guinea pig blood contains an enzyme called l-asparaginase that breaks down an amino acid called l-asparagine. Healthy cells make l-asparagine, but certain types of leukemia cells are not able to. These leukemia cells rely on nearby healthy cells to supply them with l-asparagine. The enzyme in the guinea pig blood breaks down the needed l-asparagine and so deprives the nearby cancer cells of this amino acid they require for their growth. 
L-asparaginase enzyme is now available as a drug (Elspar) and is part of the standard treatment for acute lymphoblastic leukemia (ALL). The drug, by decreasing l-asparagine, starves the cancer cells. Most types of cancer do make l-asparagine, so Elspar is useful in treating only a few specific types of cancer.
As the names hints, asparagus contain large quantities of l-asparagine. Eating asparagus would seem ill-advised for people who have cancers treated with Elspar or l-asparaginase. Eating asparagus may stimulate growth in these cancers, most especially in ALL. Eating a lot of asparagus may have an undesirable impact on other types of leukemia and possibly lymphomas as well.
People diagnosed with cancer are often desperate to do everything in their power to fight the disease. They grasp onto every story and rumor about anything that might possibly help them. The myth that asparagus cures cancer is a good example of this.
Broiling asparagus is so simple that one hardly needs a recipe. This is how I do it.
Line a cookie sheet with foil. Wash the asparagus, break off the bottoms. Oil them lightly with olive oil. Sprinkle them lightly with Kosher or sea salt. Broil them until they taste done. Serve either warm of cold.
1. Liu W, Huang XF, Qi Q, Dai QS, Yang L, Nie FF, Lu N, Gong DD, Kong LY, Guo QL. Asparanin A induces G(2)/M cell cycle arrest and apoptosis in human hepatocellular carcinoma HepG2 cells. Biochem Biophys Res Commun. 2009 Apr 17;381(4):700-5. Epub 2009 Feb 28.
2. To search yourself, go to: http://www.ncbi.nlm.nih.gov/
4. Chrubasik S, Droste C, Black A. Asparagus P(R) cannot compete with first-line diuretics in lowering the blood pressure in treatment-requiring antihypertensives. Phytother Res. 2009 Sep;23(9):1345-6.
5. Chrubasik C, Maier T, Dawid C, Torda T, Schieber A, Hofmann T, Chrubasik S. An observational study and quantification of the actives in a supplement with Sambucus nigra and Asparagus officinalis used for weight reduction. Phytother Res. 2008 Jul;22(7):913-8.
6. H. D. Moon Presentation of the Gold Headed Cane to John G. Kidd. February 24, 1973. Am J Pathol. 1973 October; 73(1): 1–6. PMCID: PMC1904051
7. BROOME JD. Evidence that the L-asparaginase of guinea pig serum is responsible for its antilymphoma effects. I. Properties of the L-asparaginase of guinea pig serum in relation to those of the antilymphoma substance.
J Exp Med. 1963 Jul;118:99-120.