For healthcare providers who treat cancer patients, no area will bring more concerns or raise more reaction from the oncology community than the subject area on whether to combine natural health products (NHPs) / dietary supplements together during chemotherapy and/ radiation.

Following the eye-opening article published in the journal Oncology in 1999 by a naturopathic physician & medical oncologist who exposed the probable concerns of combining chemotherapy with dietary antioxidant supplements, the words "antioxidants" and "vitamins" have literally become associated as "bad-words" in many cancer treatment circles. Moreover, virtually the entire field of NHPs has also been grouped together under the shadows of this debate. Is the, more common than not, recommendation to not take any kind of NHP, whatsoever, during cancer treatment (i.e. with the exception of a multivitamin) the most prudent course of action when considering the best interest of a patient with cancer? Some would argue that this approach might be quite extreme especially when you consider the powerful negative effects of some well-known cancer treatments. Some insights can be learned from a recent June 2004 observational study in children with acute lymphoblastic leukemia (ALL) performed at Columbia University in New York. Lower intakes of antioxidant vitamins in the children were associated with increases in adverse side effects of chemotherapy. Conversely, higher vitamin intakes were associated with fewer therapy delays, fewer days spent in hospital, less toxicity, and lower incidence of infection.

A recent review published in the February 2004 issue in the Journal of Clinical Oncology examined 52 studies on the general subject of dietary antioxidants and cancer. Herbal or other nutritional supplements with antioxidant activity that were not defined in the dietary reference intakes as being required from the diet were not included in the review. Twelve trials looked into the subject of combining supplements to reduce chemotherapy toxicities and 6 studies on the subject of survival and recurrence of cancer. The researchers could not conclude a definitive effect on the issue of combination approaches and chemotherapy, in part, because of the variability of doses, timing, and duration of the supplementation in the studies reviewed. However, the article did suggest that total antioxidant status declined during cancer treatment.

Perhaps a simple approach to gain further insights into the potential impact dietary ingredients / NHPs may have with the antioxidant confusion is to examine some more aggressive combinations that have been published in the medical journals. The well known antioxidant glutathione, for example, has been studied in combination with chemotherapy. In fact, the popular chemotherapy drug Oxaliplatin along with glutathione (given by injection) has been studied in advanced colorectal cancer in a randomized, double-blind, placebo-controlled fashion published in the Journal of Clinical Oncology. Glutathione protected against the toxic nervous system effects of Oxaliplatin without adversely affecting the effectiveness of Oxaliplatin. Six independent studies in patients with gastric cancers have also failed to demonstrate a negative interaction with intravenous glutathione along side several chemotherapy regimens. Four additional studies in patients with advanced ovarian cancer have revealed similar findings with combination treatment. Overall, better patient outcomes have shared the common theme from the aggressive use of this intravenous "antioxidant" along with chemotherapy. At the University of Kansas Medical Centre, the intravenous application of vitamin C plus oral antioxidants is actively being studied for newly diagnosed ovarian cancer (stage III or IV) in combination with chemotherapy. Two related published case reports published last year have not demonstrated negative outcomes with chemotherapy effectiveness and high dose vitamin C (60,000 mg) administered twice weekly in stage III ovarian cancer.

Now where does this leave the non-vitamin based NHPs in the debate? Melatonin, for example, has been studied for many types of cancers in medical science. A recent 2003 study in 100 patients with metastatic lung cancer treated with chemotherapy alone or in combination with melatonin showed that the overall tumor regression rate and the 5-year survival results were higher in patients treated with melatonin. In fact, no patient treated with chemotherapy alone was alive after 2 years. Melatonin is also known to possess antioxidant properties. PSK, a medical mushroom extract from Coriolus versicolor, has a significant track record in adjunctive cancer care for several decades. All papers that I have read have incorporated PSK together with standard conventional treatments. In a recent study published in the March 2004 issue of the British Journal of Cancer, PSK along with chemotherapy (UFT) reduced recurrence in stage II and III in patients with colorectal cancer, and increased survival in stage III patients. PSK has also been shown to support the "antioxidant" system in the body.

As you can see, the above information tends to paint a much different picture on the use of select NHPs in cancer management. These are just a few examples from the vast information that has been published in the medical literature. Unfortunately, it is not typical for patients and concerned family and friends to be presented with such information by government cancer agencies in a well-rounded format. Popular cancer review articles often fail to comment on such "antioxidant" agents in the debate.

On a more positive thought, the antioxidant potential and phytochemical ingredients from whole foods do not seem to be of major concern under this debate of whether to combine or not to combine. Foods appear to be OK. Ironically, some would suggest that the antioxidant and cancer fighting potential of fruits & vegetables might possess greater biological activity than from vitamins and other NHPs.

It is important to stress that it is not the intention of this paper to give a complete green light to all NHPs in cancer care since there are definite areas that need exploration and validation. After all, some natural health products (i.e. St John's Wort) have been shown to decrease the blood levels of some numerous medications. For myself being a primary care physician, I have sworn to respect the principle of "first do no harm" and proper research helps support this fundamental principle.

So where does this leave the patient diagnosed with cancer who is actively seeking supplement treatment options. In private practice, instead of placing patients in the middle of this debate, I have found it valuable to provide balanced medical information and to allow the patient to make an informed choice in their healthcare treatment program. Empowerment along with proper guidance is an important cornerstone in all aspects of healthcare. Supporting a patient's choice may have invaluable health promoting benefits especially when you consider the mind-body perspective. Moreover, since a high number of patients choose to use NHPs without the knowledge of treating medical oncologists, it becomes important for patients to find appropriate healthcare providers to help guide them away from possible harm and towards a path of balanced health.

So while the debate continues to evolve in the field of cancer, it is important for people to understand that not all NHPs / dietary supplements are created equally. Some NHPs may have a positive track record along side cancer treatment. Not all NHPs are used because of their "antioxidant" properties. Even the aggressive use of antioxidant agents may have a place along side conventional cancer treatment. Overall, it is worthwhile for concerned patients to seek the advice of healthcare providers that have a well-rounded understanding of this subject area: since a naturopathic doctor first popularized this debate, a naturopathic doctor may be the most logical choice in seeking proper supplement advice.

References

1. Labriola D, Livingston R. Possible interactions between dietary antioxidants and chemotherapy. Oncology (Huntingt) 1999 Jul; 13(7): 1003-8
2. Kennedy DD et al. Low antioxidant vitamin intakes are associated with increases in adverse effects of chemotherapy in children with acute lymphoblastic leukemia. Am J Clin Nutr 2004 Jun; 79(6):1029-36
3. Ladas EJ et al. Antioxidants and cancer therapy: a systematic review. J Clin Oncol 2004. Feb 1; 22(3): 517-28
4. Cascinu S et al. Neuroprotective effect of reduced glutathione on oxaliplatin-based chemotherapy in advanced colorectal cancer: a randomized, double-blind, placebo-controlled trial. J Clin Oncol. 2002 Aug 15; 20(16):3478-83
5. Cascinu S et al. High curative resection rate with weekly cisplatin, 5-fluorouracil, epidoxorubicin, 6S-leucovorin, glutathione and filgastrim in patients with locally advanced, unresectable gastric cancer: a report from the Italian Group Study of Digestive Tract Cancer. Br J Cancer. 2004 April 19;90(8): 1521-5
6. Bohm S et al. Dose intensification of platinum compounds with glutathione protection as induction chemotherapy for advanced ovarian carcinoma. Oncology. 1999; 57(2): 115-20
7. Smyth JF et al. Glutathione reduces the toxicity and improves quality of life of women diagnosed with ovarian cancer: results of a double-blind randomized trial. Ann Oncol. 1997 Jun; 8(6): 569-73
8. Drisko JA, Chapman J, Hunter VJ. The use of antioxidants with first-line chemotherapy in two cases of ovarian cancer. J Am Coll Nutr. 2003 Apr; 22(2):118-23.
9. Lissoni P et al. Five years survival in metastatic non-small cell lung cancer patients treated with chemotherapy alone or chemotherapy and melatonin: a randomized trial. J Pineal Res 2003 Aug; 35(1):12-5
10. Ohwada S et al. Adjuvant immunotherapy with oral Tegafur/Uracil plus PSK in patients with stage II or III colorectal cancer: a randomized controlled study. Br J Cancer. 2004 Mar 8; 90(5): 1003-10