Does cassava help to control prostate cancer

Article · January 2012with33 Reads
Case report Open Access
Does cassava help to control prostate cancer? A case
Anuruddha M Abeygunasekera
1† *
and Kalana H Palliyaguruge
These authors contributed equally to this work.
Urology Department, Colombo South Teaching Hospital, Kalubowila, Dehiwela, Sri Lanka.
Natural products are getting popular among patients as therapy for many diseases. However these remedies should be
proven scientically as some may be hazardous with no proven benets. Cassava root, used as a carbohydrate rich food
in many countries is promoted as a cure for prostate and bladder cancer. Serum prostate specic antigen is a sensitive
tumour marker which corresponds to the activity of malignant cells in patients with acinar adenocarcinoma of prostate.
We report a patient with hormone-resistant prostate cancer whose serum PSA level continued to rise despite
consumption of large quantities of boiled roots of cassava indicating its ineectiveness in controlling the prostate cancer.
ough this is a single case, it provides guidance to health care workers who look aer patients with castration-resistant
prostate cancer in the absence of more comprehensive research on cassava and its eectiveness on prostate cancer.
Keywords: Tapioca, manioc, herbal medicine, prostatic carcinoma, treatment
© 2013 Abeygunasekera et al;
licensee Herbert Publicaons Ltd. This is an open access arcle distributed under the terms of Creave Commons Aribuon License
(hp://crea,This permits unrestricted use, distribuon, and reproducon in any medium, provided the original work is properly cited.
Medicinal plants play a vital role in the development of
new drugs. There is an increasing interest in remedies
for illnesses based on natural products. However these
remedies should be proven scientifically as some tend
to make unsubstantiated claims of efficacy based on
emotions related to illnesses which do not have effective
therapy based on established medical practice. Cassava,
also known as tapioca or manioc is promoted widely as
a cure for cancer in the electronic and printed media
especially for bladder and prostate cancer [1,2]. Excess
consumption of cassava based on unscrupulous reports
can be hazardous [
]. We describe the outcome of a patient
with hormone-resistant prostate cancer who tried cassava
to control his malignancy.
Case report
A 65 year old man was diagnosed of having adenocarcinoma
of prostate with a Gleason score of 3+3 in 2002. The CT and
isotope bone scans did not show evidence of metastases
stage). The serum prostate specific antigen (PSA)
was 11.5 µg/l. He underwent external beam radiotherapy
(70 Gy) and bilateral orchidectomy. The PSA decreased to a
nadir of 0.02 µg/l and remained around that level till 2008
when it started rising slowly suggesting local recurrence
(Figure 1). When PSA was 3.4 µg/l, he had a repeat biopsy
which showed an adenocarcinoma of Gleason score 3+5.
Flutamide 250mg three times a day brought down the
PSA to 0.75 µg/l. After 2 years it started rising gradually
and discontinuation of the anti-androgen (flutamide),
caused a drop in the PSA suggestive of anti-androgen
withdrawal response. Six months later when the PSA
started rising again and reached 9.5 µg/l, oral fosfestrol
(‘Honvan’) 240 mg/ day was started. His serum testosterone
level was below 50 ng/dl, which is the cut-off level to
diagnose hormone-resistant (castration-resistant) prostate
cancer. With oral fosfestrol, the PSA fell to 1.86 µg/l and
the therapeutic response lasted for one year. When the
PSA rose to 10.4 µg/l in March 2012, he responded to a
combination of ketoconazole (200mg three times a day)
and hydrocortisone (20mg in the morning and 10mg in
the evening). The PSA fell to 0.13 µg/l in six weeks.
At this time the patient came to know through the
media about consuming cassava in the diet to control
cancers and started consuming 150 g of boiled cassava
root (sweet variety) three times a day [
]. He stopped
all the medications and consumed boiled cassava root
diligently in measured amounts for three weeks. At the
end of the three weeks PSA rose to 4.05 µg/l. A week
later it increased further and reached 4.95 µg/l despite
continuing to consume cassava. He restarted ketoconazole
and hydrocortisone and the PSA level dropped to 3.24
µg/l after one week. All PSA levels were done in the same
laboratory and there was no clinical or microbiological
evidence of urinary infection during the period when the
patient consumed cassava.
Cassava also known as manioc and tapioca (Manihot
esculenta Crantz), has been used as a food for centuries. It
Journal of
Pharmaceutical Technology
Drug Research
Page 1
Abeygunasekera et al. Journal of Pharmaceutical Technology & Drug Research 2013,
doi: 10.7243/2050-120X-2-3
originated in South America and was introduced to Africa by
the Portugese in the sixteenth century [4]. It is a rich source
of carbohydrates and grows in dry conditions with little
water. Today it is consumed by millions of people around
the world [
]. There are two types of cassava – sweet and
bitter varieties. Sweet variety is preferred by consumers as
it is more palatable while the bitter variety is preferred by
farmers as it is more resistant to pests. Both cassava root
(tuber) and leaves are used as herbal medicine especially
in Africa and South America [6]. Although it has not been
used in the past by native physicians of India and Sri Lanka
in their traditional medical therapies like ‘Ayurveda’ [
], in
recent times boiled roots of cassava is being promoted
as a potential cure for prostate and bladder cancer in Sri
Lanka [1,2].
Linamarin, the main cyanogenic glucoside in manioc
has been shown to cause toxicity to malignant cell lines [
A nested case control study conducted in India to identify
the effect of dietary factors on causation of breast cancer
using food frequency questionnaires has shown that
consumption of tapioca is associated with a decreased
risk of developing breast cancer [9]. The cyanogenic
glucosides (linamarin and lotaustralin) in cassava leads
to the production of amygdaline or vitamin B-17 which is
claimed to kill cancer cells by those who promote cassava
as an anti-cancer agent [
]. However two case-control
studies from India have shown that cassava consumption
is associated with a higher risk of colorectal and pancreatic
carcinoma [
]. In addition cassava may cause ataxic
polyneuropathy, amblyopia and tropical pancreatitis as
reported in several case reports from India and Nigeria
[11,12]. Therefore it is prudent that we determine both the
safety and efficacy of cassava in treating prostate cancer
before it is promoted as a treatment.
Despite clinical and analytical limitations, PSA is an
effective surrogate marker of cancer activity of already
diagnosed cases of acinar adenocarcinoma of prostate
]. This patient’s cancer was treated with accepted and
proven forms of treatment in a stepwise manner and as
expected, PSA levels varied accordingly with each form
of treatment. This predictable response was confirmatory
of its applicability as an efficient marker of malignant cell
activity of this patient. However the PSA level rose while
on cassava indicating its ineffectiveness in controlling
the cancer. It appears that consumption of cassava in
large quantities in the diet has no biochemically evident
therapeutic benefit in castration-resistant prostate cancer.
Anti-androgen withdrawal is a potential therapeutic
manoeuvre for patients with progressive prostate carcinoma.
About 19% of patients with prostate cancer experience a
progression-free period of over one year after cessation
of anti-androgens [14]. Some patients who discontinue all
medications including anti-androgens andstart consuming
cassava may experience a reduction in PSA due to this
phenomenon but may attribute it to the consumption
of cassava.
A single case may not be adequate to test a hypothesis.
However in the absence of scientific publications about
the effects of cassava on prostate cancer, this scientifically
tested case would act as a basis of evidence that can be
used by health care workers who look after patients with
castration-resistant prostate cancer as well as by patients
with the disease until further research is done and better
evidence is available.
Competing interests
The authors have no financial or other interests related to this
Authors contributions
AMA conceived the idea, performed the literature search,
wrote the manuscript and managed the patient. KHP
helped with the literature search and management of the
patient. Both read and approved the final manuscript.
We thank the patient for agreeing to share his
clinical details with the scientific community.
Publication history
Received: 27-Nov-2012 Revised: 16-Dec-2012
Accepted: 22-Dec-2012 Published: 10-Jan-2013
Figure 1. Prostate-specic antigen levels and events
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