Patients with cancer using complementary medicine (CM) were more likely to decline potentially curative conventional cancer treatment, which in turn increased their risk for death, concludes a new study.
The patients in this study, drawn from the National Cancer Database, had a variety of nonmetastatic cancers (breast, prostate, lung, or colorectal) and were receiving at least one type of conventional cancer treatment.
Patients who chose CM did not delay initiating standard treatment but had higher rates of refusing subsequent modalities, such as surgery, chemotherapy, and radiation therapy.
The use of CM was associated with worse 5-year overall survival than seen in patients who didn't use CM (82.2% vs 86.6%; P = .001) and was independently associated with a greater risk for death (hazard ratio [HR], 2.08; 95% CI, 1.50 - 2.90).
However, the association with increased mortality was largely based on treatment delay or refusal.
Once those factors were removed from the analysis, CM was no longer associated with an increased risk for death.
"The survival limitation of CM is associated with treatment refusal, and we did not find that CM by itself decreases survival," said study coauthor James B. Yu, MD, associate professor of therapeutic radiology at Yale Cancer Center, New Haven, Connecticut.
"Patients need further education about the use of CM and its limitations, and it needs to be done in an integrated manner — rather than in an adversarial one," he told Medscape Medical News. "Patients need to understand that CM is not going to help them cure their cancer."
The study was published online July 19 in JAMA Oncology.
Building on Previous Data
Last year, these authors conducted a similar study that also used the National Cancer Database to examine mortality and the use of alternative cancer treatments. As reported by Medscape Medical News at that time, they found that choosing alternative therapy over conventional medicine was associated with a 2.5-fold higher risk for death.
They evaluated the same four cancer types, and only for prostate cancer was alternative therapy not associated with a significantly increased risk for death compared with standard care. In that group of patients, the 5-year survival rates were similar (86.2% vs 91.5%; P = .36).
In their previous study, the team investigated alternative medicine, which is therapy used instead of standard care, but they did not investigate CM, which is used alongside conventional cancer treatment. However, they note that there is limited information on the association between the use of CM, adherence to conventional cancer treatment, and overall survival of patients with cancer who receive CM vs those who do not.
CM Linked to Treatment Refusal
This latest study is a retrospective analysis of data from the National Cancer Database. It identified patients diagnosed with nonmetastatic breast, prostate, lung, or colorectal cancer between January 1, 2004, and December 31, 2013.
Patients were defined as using CM if they received "other-unproven: cancer treatments administered by nonmedical personnel" in addition to at least one conventional modality, defined as surgery, radiotherapy, chemotherapy, and/or hormone therapy.
Of the 1,901,815 patients in the database, 258 were identified (0.01%) as using CM.
Those in the CM cohort were more likely than nonusers to be younger, be female, have breast cancer or colorectal cancer, have higher socioeconomic status, a higher level of education, reside in the Intermountain West and Pacific West regions, have private insurance, have stage I and lll disease, and have a Charlson-Deyo comorbidity score of 0.
The patients receiving CM were then matched with 1032 patients who had received conventional therapy.
Median delay to treatment from time of diagnosis did not significantly differ between the two groups (median, 29 days for patients who used CM vs 28 days for those who did not; P = .41).
But patients using CM had higher rates of refusing surgery (7.0% [18 of 258] vs 0.1% [1 of 1031]; P < .001), chemotherapy (34.1% [88 of 258] vs 3.2% [33 of 1032]; P < .001), radiotherapy (53.0% [106 of 200] vs 2.3% [16 of 711]; P < .001), and hormone therapy (33.7% [87 of 258] vs 2.8% [29 of 1032]; P < .001).
On univariate survival analysis, CM use was associated with worse 5-year survival and remained independently associated with a higher mortality risk compared with no CM use after adjustment for confounders such as cancer site, age, sex, income, clinical stage, and education level (HR, 2.08).
However, after adjustment for treatment refusal and delay from diagnosis to treatment, CM was no longer statistically significantly associated with the risk for death (HR, 1.39).
The greater risk for death associated with CM, the authors note, is therefore linked to its association with treatment refusal.
Limitations and Missing Data
Because this is a retrospective database study, it is not clear whether patients declined a component of care initially and then decided to use CM or whether they decided to use CM and then forgo additional conventional therapy. Skyler Johnson, MD, first author of the paper and chief resident in radiation oncology at Yale School of Medicine, noted that these patients are unlikely to be receiving CM for improving symptoms or quality of life but rather are doing so for "cancer treatment." As such, the association with refusal of other aspects of multidisciplinary care is not surprising.
"Although we can't know which came first, the association with treatment refusal is still interesting," he said. "For example, do they feel more comfortable refusing because they are doing an unproven treatment that they think is just as good or better, or are they likely to refuse because they have a propensity to pursue complementary medicines? Fascinating stuff and worthy of further research."
Approached for comment on the study, Donald Abrams, MD, professor of clinical medicine at the University of California San Francisco and a general oncologist at Zuckerberg San Francisco General Hospital, noted that because this is a retrospective study, it is not the "highest level of evidence" and has many limitations related to its design.
Controlling for delayed or refusal of treatment eliminated survival disparities between the groups, he pointed out. "But there is no information available on why patients refused therapy, and no information on what complementary therapies were used by the patients, or how many types of therapies they may have used."
The authors indicate that CM use is likely underestimated in their study, given the hesitancy of patients to report its use to clinicians and for database registrars to code this use reliably.
Abrams agreed that this topic is not often discussed. "Doctors don't ask about it as they don't want to open a can of worms," he told Medscape Medical News. "Unless you have training in integrative medicine, it is difficult to have these discussions with your patient. And patients hesitate to bring it up, so the end result is that it isn't discussed."
The authors are planning to continue their research into complementary and alternative medicines. "We'll be digging deeper into other clinical situations for which they may or may not benefit patients," said Yu.
Yu reported receiving research funding from 21st Century Oncology and serving as a consultant for Augmenix. Johnson has disclosed no relevant financial relationships.. Several coauthors report relationships with industry.
JAMA Oncol. Published online July 19, 2018. Abstract
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Cite this: Complementary Medicine and Refusal of Conventional Cancer Tx - Medscape - Jul 19, 2018.