Information is power—the power to make informed choices and to be an active participant in your own treatment experience.
Lise Alschuler, ND, FABNO, Professor of Clinical Medicine at the University of Arizona School of Medicine and Assistant Director of the the Integrative Medicine Fellowship at the Andrew Weil Center for Integrative Medicine
At a glance
For each complementary therapy, we search published medical studies to find evidence of these four medical benefits:
- Improving treatment outcomes: Does the therapy improve survival, reduce metastasesthe development of secondary malignant growths (tumors) at a separate location from a primary site of cancer; metastasis is an indication of advanced cancer, shrink tumors or reduce tumor markers? Does it enhance other treatments?
- Optimizing your body terrainthe internal conditions of your body, including nutritional status, fitness, blood sugar balance, hormone balance, inflammation and more: Does the therapy address factors known to support the growth or spread of cancer?
- Managing side effects and promoting wellness: Does the therapy prevent or reduce any of the common side effects of cancer treatments or symptoms of cancer?
- Reducing risks of cancer or recurrence
We assess whether study results are clinically relevant, the size of effects, and whether studies involve humans or only cells or animals. We evaluate whether studies are designed well enough to draw meaningful conclusions. We determine whether findings across studies are consistent or conflicting. We summarize and interpret each set of findings for you but also allow you to see details and sources if that interests you.
We rate therapies on a 0–5-point scale to assess how strong the evidence is regarding questions that most people with cancer want to know:
- Does this therapy improve treatment outcomes?
- Does it improve my general health and resilience (my body terrain)?
- Does it manage side effects and symptoms?
- Does it reduce my risk of cancer or recurrence?
- How do experts use this therapy?
- What safety concerns do I need to know about?
- What does it cost, and where can I find it?
Rating the strength of evidence is not the same as rating how effective a therapy is (the first four questions). A therapy may be very effective, but not much evidence has been published yet. For example, a rating of “2” for “preliminary evidence” means research shows medical benefit, but because only a few small studies have been published, we don’t have much confidence that we know the full scope and scale of the benefit.
For some therapies and some medical benefits, we may report studies that did not find an effect. Knowing that a therapy did not find any effect for a specific use and among a specific group of people is helpful information. Look carefully at how we describe the research, whether we report that we could not find any studies or that we found studies, but they found no evidence of an effect.
Reviews are updated frequently as new research comes to our attention. All therapy reviews are scheduled for a full update at least every three years.
Researching medical effects
For each complementary therapy, we search published medical studies to find evidence of four medical benefits.
Improving treatment outcomes
Does the therapy
- Improve survival?
- Reduce metastases?
- Reduce or reverse tumor growth?
- Reduce cancer markers, such as PSA in prostate cancer?
- Enhance conventional treatments such as chemotherapy or surgery in achieving any of these effects?
Optimizing your body terrain
Does the therapy address these factors and others which are known to support the growth or spread of cancer when out of balance?
- Bleeding and coagulation imbalance
- Body weight
- High blood sugar and insulin resistance
- Hormone imbalance
- Immune function
- Inflammation
- Oxidative stress
- Your microbiomethe collection of microbes living on and within your body
Managing side effects and promoting wellness
Does the therapy prevent or reduce any of the common side effects of cancer treatments or symptoms of cancer, such as these?
- Anxiety
- Blood-related symptoms
- Body composition or cachexiaweakness and wasting of the body due to severe chronic illness
- Breathlessness
- Changes in appetite
- Cognitive difficulties
- Depression
- Dehydration
- Fatigue
- Gastrointestinal symptoms
- Hot flashes
- Neuropathy and other neurological symptoms
- Oral symptoms
- Pain
- Sexual difficulties
- Sleep disruption
- Stress
Reducing risks of cancer
Does the therapy reduce risks?
- Cancer
- Recurrence
Assessing the strength of the evidence
After we gather all the evidence, we ask ourselves several further questions:
- Are these results useful in the “real world” (clinically relevant)? How big are the effects? Are these effects found in humans (clinical studies) or is all the evidence from cell and animal studies (preclinical)?
- How strong is the evidence? Are the studies large enough to assess effects? Are the studies designed well enough to draw meaningful conclusions?
- How consistent are the findings across studies? What might contribute to conflicting findings?
Study design and size
The strength of study evidence depends quite a lot on the study design and size. The design categories we use, from weakest to strongest:
- Case studies and other uncontrolled studies: people are given a therapy and changes are observed; this is a weak design because researchers don’t know if any changes would have happened even without the therapy, such as less pain or less nausea over time
- Observational studies: groups of people who use a therapy or practice a behavior are compared to others who do not use the therapy or practice the behavior; large studies finding trends and patterns can provide good evidence of a link but not that the therapy or practice caused any differences between groups
- Randomized controlled trials (RCTs): people are assigned to groups, with some given a therapy and others not given the therapy, and the differences in groups is recorded; the strongest designs randomly assign large numbers of people to each group, and both the people in the study and the researchers are not aware whether they are receiving an active therapy or a similar but inactive therapy (a control or placebo)
- Meta-analysis of RCTs or observational studies or an umbrella review: several studies are analyzed together as through they were one larger study; the combined analysis can be only as good as the studies being combined, and many meta-analyses rate the quality of the studies
Larger studies provide more confidence that a “fluke” error hasn’t been found. Larger studies are also able to find subtler effects than small studies. Study sizes we use:
| Small | Fewer than 100 participants |
| Mid-sized | 100 to 999 participants for observational studies or 100-499 participants for RCTs |
| Large | 1000 to 5000 participants for observational studies or 500 to 1000 participants for RCTs |
| Very large | More than 5000 participants for observational studies or more than 1000 participants for RCTs |
We mark meta-analyses as large if they include 10,000 to 100,000 subjects, and very large if they include more than that across all the studies in the combined analysis.
Because meta-analyses and umbrella reviews combine the results of several other studies—and typically report combined numbers of participants anywhere from several hundred to more than a million—they give greater confidence of an accurate assessment of effects. Of course, combining the results of several poorly designed studies still doesn’t provide good evidence. But typically it’s better evidence than each of the smaller studies alone.
We summarize all the strongest and most relevant studies we find, but we also interpret each set of findings for you so that you can read in a sentence or two what all the evidence may mean for you. We tell you how big the reported effects are and how strong the evidence is.
| Insufficient | Preclinical evidence only OR clinical studies with such poor or unclear methodology that no conclusion can be drawn OR conflicting findings across clinical studies with no preponderance of evidence in one direction; conflicting evidence occurs when studies find conflicting effects (an effect vs no evidence of an effect or evidence of worse outcomes) with the same treatment and the same general study population (same cancer type, for example) |
| Weak | One or more case studies, supported by animal evidence OR small treatment effects of limited clinical significance OR studies with no controls OR weak trends |
| Preliminary | Significant effects in one or more small or poorly designed controlled clinical studies OR conflicting results in adequate studies but a preponderance of evidence in one direction |
| Modest | Significant effects in at least three small but well-designed RCTs, or one or more well-designed, mid-sized clinical studies of reasonably good quality (RCTs or observational studies), or several small studies aggregated into a meta-analysis |
| Good | Significant effects in one large or several mid-sized and well-designed clinical studies (RCTs with an appropriate placebo or other strong comparison control or observational studies that control for confounds) |
| Strong | Consistent, significant effects in several large (or at least one very large) well designed clinical studies or at least two meta-analyses of clinical studies of moderate or better quality (or one large meta-analysis) finding similar results |
Clinical evidence for each effect is presented in the How can this therapy (or practice) help me? part of each review. Further evidence, including notable preclinical evidencetesting a drug, a procedure or another medical treatment in isolated cells or in animals; preclinical evidence is considered only an initial indication of possible effects in people and modes of action, is presented in the Are you a health professional? section of each review.
Rating therapies on the evidence
For improving treatment outcomes, optimizing your body terrainthe internal conditions of your body, including nutritional status, fitness, blood sugar balance, hormone balance, inflammation and more, managing side effects and promoting wellness, and reducing cancer risk, we use this general rating scheme.
On a 0–5-point scale:
| 0 | Ineffective in clinical studies (no evidence of an effectoverall, one or more studies did not demonstrate that a treatment or intervention led to an expected outcome; this does not always mean that there is no effect in clinical practice, but that the studies may have been underpowered (too few participants) or poorly designed. Larger, well-designed studies provide more confidence in making assessments. or insufficient evidence) OR not studied for this effect |
| 1 | Preclinical evidencetesting a drug, a procedure or another medical treatment in isolated cells or in animals; preclinical evidence is considered only an initial indication of possible effects in people only or weak clinical evidence (case studiesa descriptive and exploratory analysis of a person, group, or event regarding changes observed over time; because changes due to treatment are not compared to similar changes over time without treatment, a case study is considered a weak study design, uncontrolled trialsa study in which a therapy is used, but without a comparison group to judge outcomes against; an uncontrolled trial is considered a weak study design, or weak trendsan apparent change due to a therapy, close to but not achieving full statistical significance (this is the CancerChoices definition; other researchers and studies may define this differently)) of positive effects for one or more medical benefit |
| 2 | Preliminary clinical evidence (one or more studies totaling less than about 100 participants) of positive effects and/or slight/very small treatment effects and/or mixed results and/or weak study designs (serious confounds, for instance) for one or more medical benefit |
| 3 | Modest evidence for one or more medical benefit: several small or at least one mid-sized clinical trial(s) or meta-analysesa statistical analysis that combines the results of two or more research studies; the results of smaller research studies addressing the same or similar questions can be analyzed as though they are one bigger, more powerful study (totaling more than 100 to a few hundred participants) OR one or more smaller RCTsrandomized controlled trial, a study design in which people are randomly assigned to either an experimental group or a control group to compare the outcomes from different treatments; an RCT is considered a strong design for determining a therapy’s effects with adequate study design and modest to substantial treatment effects; both randomized and observational studies qualify |
| 4 | Good or strong clinical evidence of small to modest positive treatment effects for one or more medical benefit with at least several hundred people in well-designed studies with good control comparisons |
| 5 | Good or strong clinical evidence of moderate to substantial positive treatment effects for one or more medical benefit with at least several hundred people in well-designed studies with good control comparisons |
Because any therapy can show medical benefits across a wide range of cancers and symptoms, our ratings reflect the highest effect shown by that therapy for each of the medical benefits. Check individual summaries for each effect to see how a therapy performs and what the evidence for that performance is.
Example 1: Turkey tail mushroom shows a wide range of benefits for improving treatment outcomes. It has modest evidence or preliminary evidence of benefit for some types of cancer, but no evidence of benefit for others. Because turkey tail has modest evidence of benefit for at least one type of cancer, we rate it 3 for improving treatment outcomes, but this does not mean it rates 3 for every type of cancer.
Example 2: Acupuncture shows a wide range of benefits for side effects and symptoms. It has good evidence of benefit for fatigue and other symptoms, but no evidence of an effect on gastrointestinal symptoms and other symptoms. Many other symptoms fall in between these endpoints. Because acupuncture has good evidence of benefit for at least one symptom, we rate it 5 for managing side effects and promoting wellness, but this does not mean it rates 5 for every symptom or side effect.
How experts use therapies
When rating therapies, we look to integrative oncology experts for what they say and how they use each therapy. We summarize this separately in the How do experts use [therapy]? section of each review.
Medical research is very expensive to do properly. If no one has a financial incentive to conduct large studies, a therapy may not be well researched. How experts use a therapy can be a valuable source of information beyond what research shows. However, several of the expert sources we cite are several years old.
If published research that is more recent than the programs or protocolsa package of therapies combining and preferably integrating various therapies and practices into a cohesive design for care we reference is available, we encourage you to consider both published research and expert use.
Clinical practice guidelines
Medical groups and societies convene groups of experts to evaluate all the evidence related to a set of therapies and make professional recommendations about their use. We report conclusions and recommendations from practice guidelines from integrative oncology groups including the Society for Integrative Oncology and many others.
Integrative oncology experts
We look at published programs from experts, many of whom are among our advisors, and summarize if and how they use each therapy.
Use in traditional medicine
We report whether a therapy is used in traditional Chinese medicine, Ayurvedic medicine, or other traditional medical systems.
Rating expert use
We use this 0–5-point scale:
| 0 | No use in our program sources and/or recommendation against use in oncology clinical practice guidelines |
| 1 | Very limited use (only one of our program sources) and not mentioned in oncology clinical practice guidelines |
| 2 | Limited use by our program sources (fewer than four) and/or used only outside the US and not mentioned in cancer clinical practice guidelines and/or conflicts in use—conflicting recommendations across practice guidelines OR widely used by our program sources and mentioned in practice guidelines without recommendation for use due to insufficient evidence |
| 3 | Used in several (at least 4) of our program sources and recommended weakly or not mentioned in integrative cancer clinical practice guidelines OR used by several of our program sources and in traditional medicine but not mentioned or no consensus reached in oncology clinical practice guidelines OR mentioned with at least a weak recommendation in clinical practice guidelines |
| 4 | Widely used by integrative practitioners and recommended weakly in integrative cancer clinical practice guidelines OR used widely by integrative oncology experts but not yet evaluated in clinical practice guidelines OR recommended more than weakly in clinical practice guidelines |
| 5 | Widely used by integrative practitioners and recommended (more than weakly) in integrative cancer clinical practice guidelines |
Safety, affordability, and access
We evaluate and rate therapies on their safety, affordability and access.
Rating safety
| 0 | Dangerous for most or all people |
| 1 | Extreme caution is needed with use by most people, and supervision by a medical professional is essential |
| 2 | Extreme caution is needed with use by people with specific conditions, or those undergoing treatments which may cause significant, even life-threatening interactions; supervision by a medical professional is essential |
| 3 | Moderate caution is needed or may interact with other treatments, and supervision by a medical professional is highly recommended |
| 4 | Generally safe, although some serious side effects are possible; caution and supervision are needed for people with specific conditions |
| 5 | Generally safe, with only minor side effects |
Rating affordability and access
Ratings reflect the more restrictive aspect, whether access or affordability. A therapy that is widely available but expensive (between $5000 US and $10,000 US) would be rated 2 due to expense, even though its is readily available.
| 0 | Unavailable in most places (such as controlled substances) and/or extremely expensive (more than $50,000 US) |
| 1 | Unavailable in many places (perhaps only in a few countries) and/or very expensive (between $10,000 US and $50,000 US) |
| 2 | Available with some difficulty (needing travel, for example) and/or expensive (between $5000 US and $10,000 US) |
| 3 | Available with restrictions (such as a prescription) and/or moderately expensive (between $2000 and $5,000 US/year) |
| 4 | Widely available without restriction and somewhat expensive (between $500 US and $2000 US/year) |
| 5 | Widely available without restriction and generally inexpensive (less than $500 US/year) |