Complementary and alternative medicine (CAM) generally refers to a set of medical interventions which are not taught widely in medical schools, and are not generally available in hospitals¹⁾. In more detail, complementary medicine is an unconventional medical technique accompanying conventional medical treatment, and alternative medicine refers to an unconventional medical technique pursued in place of conventional treatment²⁾. There is some controversy as to the increasing popularity of CAM among cancer patients, as different studies report vastly different numbers with respect to its prevalence (16–83%)^3–6). The increasing interest in CAM among cancer patients may be due to the limitations of conventional treatment, the increasing advertisements for CAM, or the desire for holistic or natural treatments. Although clinicians care for many cancer patients using CAM in everyday clinics, little information is available regarding CAM, and there are, as yet, no available and definitive practical guidelines for CAM usage in Korea.

The present study was undertaken in order to assess various parameters of CAM usage among Korean cancer patients, using a sample group from a single cancer center. These parameters included the prevalence, types, cost, subjective effects, and side effects associated with CAM use. Other parameters included the patients’ reasons for using CAM, the clinical characteristics of CAM users compared to those of nonusers, and the patients’ expectations of doctors regarding CAM usage.

The present survey revealed that the use of CAM was fairly widespread, with 78.5% of patients using at least one type of CAM, in addition to conventional treatment. This prevalence seems slightly higher what might be found in Western countries^{7, 8)}. We were able to interview only 186 patients among 1,670 total patients admitted during the study period, as the majority of hospitalized patients were unwilling to enroll in this study, due to the grave status of their cancer. Therefore, our results might not reflect the true prevalence. Furthermore, most of the subjects were in advanced stages of cancer, which might be related to the high prevalence of CAM use in our results.

In our study, younger and more educated patients were significantly associated with the use of CAM (Table 1). However, logistic regression analysis showed that only higher education was a significant predictor for CAM use. Gender and diagnosis of cancer were not significantly associated with CAM use. The majority of patients were unwilling to answer questions regarding their income, therefore we were unable to assess statistical differences with respect to income. In outpatient³⁾, inpatient⁷⁾, and telephone survey⁹⁾ studies from various cancer centers, gender (women)^{3, 7, 9)}, younger³⁾, more educated^{3, 7, 9)}, and higher income⁹⁾ patients with advanced metastasis³⁾, breast cancer³⁾, or central nervous system tumors⁹⁾ have been found to be associated with CAM use. However, in other studies^{4, 5, 10, 11)}, gender^{4, 5, 10)}, age^{5, 10)}, education^{4, 5, 10, 11)}, income or profession^{10, 11)}, cancer diagnosis^{5, 11)} and severity of disease severity⁵⁾ were not significantly associated with CAM use. Therefore, the pattern of CAM usage appears to be more closely related to the cultural and socioeconomic status of the subjects.

The patients’ main source of information regarding CAM was, largely, family members (52.1%)^{4, 5)}, followed by books or magazines (17.8%), or other cancer patients (8.2%)^{4, 5)}, and infrequently, doctors of Oriental medicine (1.4%). In a Taiwanese study, 30% of patients were found to have obtained the prescriptions for the CAM products from Chinese medical clinics⁴⁾. This indicates that a large section of the Korean population believes in CAM and its purported effects.

In our study, the most commonly-used types of CAM in our study were extract of Korean red ginseng (35.6%), Phellinus linteus-a medicinal mushroom (33.5%), vegetable green juice (18.4%) and Ulmus davidiana-a medicinal tree (18.4%). In the United States of America, the most commonly-used types of CAM include dietary treatments and megavitamins^{4, 9)}. Therefore, the types and patterns of CAM usage appear to be closely related to the patients’ cultural and socioeconomic background.

The reasons for CAM use include nutritional support, physical strengthening, and improvement of immunity, which are all complementary, rather than alternative, therapies. Many studies have shown that CAM users expected the CAM to improve their quality of life^{3, 4, 8, 10)}, augment their immune systems^{3, 8, 10)}, relieve symptoms³⁾, cure their illnesses^{3, 4, 8)}, or give them feelings of hope^{3, 5)}. Rari et al.⁶⁾ reported that many of the psychological side effects of cancer, such as fear, anxiety, and hopelessness, become the major reasons for patients to turn to CAM^{6, 12)}. Most patients initially approached CAM with the expectation of direct anti-cancer effects. However, even though the expected anti-cancer effects did not materialize, these patients continued CAM therapies, mostly due to psychological benefits⁸⁾.

We compared the mean monthly expense for CAM use with the monthly cost of standard chemotherapy for various cancers. If we assume that an adult patient with a body surface area of 1.7 m² carried governmental health insurance, the patient usually has to pay 6,176 Won (about $5.80) for chemotherapeutic agents of 5-fluorouracil plus cisplatin for the treatment of metastatic stomach cancer per month, and 386,545 Won (about $315) for one-cycle paclitaxel plus cisplatin for non-small cell lung cancer, because the patient pays only 20% of the total price of these drugs under the coverage of national health insurance. The mean monthly cost of CAM use in our study was 1,380,000 Won, which was much higher than the cost of conventional medicine covered by health insurance. The total national cost of CAM use, if calculated, would amount to an enormous sum. Therefore, nationwide reasonable guidelines for the usage of CAM would be greatly appreciated.

4.8% of our patients experienced adverse effects from CAM, including hepatotoxicity and renal toxicity. This rate of frequency, however, might have been underestimated, as it depended only on the patients’ perceptions and memory. Moreover, potential harmful interactions definitely exist between conventional medicine and CAM.

In two hospitals in England, 6 patients of 66 CAM users with diet therapy reported dissatisfaction, due to such criteria as severe weight loss and the unpalatable nature of the diet, and 1 patient described feeling physically unwell after being treated with an herbalist regimen⁸⁾. In the United States of America, 6% of cancer patients who have used CAM reported side effects, while 53% of 91 physicians attending their patients noted adverse effects, including the delay of conventional treatment (46%). 35% of these cases involved the direct toxicity of the treatment: these discrepancies may be an unfortunate product of the way patients and physicians perceive communications⁹⁾.

Two-thirds of CAM users wanted to discuss their interest in CAM with their doctors. If patients are combining these agents with conventional treatment, the doctors should discourage these agents, as this combined therapy often results in the delay of conventional treatments of proven efficacy. Physicians should also always monitor patients for possible drug-herb-vitamin interactions^{3, 11)}.

Doctors should discourage any treatment by unlicensed professionals, and the injection of substances not approved by the Food and Drug Administration, particularly during periods of active chemotherapy or radiation therapy^12–14), even though current evidence remains inadequate to actually make predictions regarding which supplements may increase or decrease the effects of chemotherapy or radiation therapy^{13, 15)}.

In order to facilitate patient-doctor communication, appropriate databases and information regarding CAM products are essential. Expanded research is required in order to determine the safety and efficacy of a variety of drug and herb interactions³⁾. Only proper scientific and chemical trials will clarify the issue of whether CAM really plays any role whatsoever in cancer treatment or improvement of quality of life. If, indeed, this is the case, we should find reasonable ways of incorporating CAM into conventional treatments¹⁶⁾.

Our present study showed that more than two-thirds of Korean cancer patients used various kinds of CAM, at considerable costs and risks of side effects. Therefore, medical society should be open to communication with patients, in order to assist patients in making informed choices. Not only scientific, but also economic aspects of CAM usage should be studied further, in order to ensure proper distribution of medical resources.