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Database Searching

How to Create and Conduct a Search Strategy

Whether you are searching for literature for an evidence-based (PICO) project, or a research question, the steps to create a search are essentially the same. The main differences are the breadth and focus of the topic, as well as how much complexity or detail needs to be included.

 

Steps to Creating a Search Strategy
  • Step 1: What are the major concepts?
  • Step 2: What terms or phrases should be searched?
  • Step 3: How do you combine terms together?

Step 1: What are the Major Concepts?

Once you have chosen your search topic, the next step is to identify what the major concepts are. These major concepts are going to become the terms you search for in the database.

PICO Question
In breast cancer patients, does scalp cooling decrease the amount of hair loss, during active cancer treatment?
Patients
  • Breast cancer
  • Cancer patients
Intervention
  • Scalp cooling
Outcome
  • Hair loss
Time Frame
  • Cancer treatment

Research Question

How do CAR-T toxicities present in critically ill cancer patients and what are the best practices to treat these patients?

  • Critically ill patients
  • Cancer patients
  • CAR-T therapy
  • Drug toxicities

Step 2: What Terms/Phrases should be Searched?

The search terms you will be using may not always be the concepts you identify from your topic, they may include those terms, but almost always there will be multiple search terms for each concept identified. Here are some ways to assist you in building those search terms for each concept.

 
Controlled Vocabulary

It's important to see if there are any controlled vocabulary terms that are related to your concepts, there may even be multiple controlled terms for each concept, or no controlled terms!

The easiest way to go about finding controlled vocabulary is to go to PubMed's MeSH Database. I suggest using PubMed/MeSH since it's easily available and is often the first place to search. It's much easier to take terms identified in PubMed/MeSH and check other databases when needed.

Once in the MeSH Database, simply search for your concept and it will return potentially relevant terms. Sometimes this requires a bit of trial and error, as sometimes a concept may not have an exact term, but by searching for other similar terms you may be able to identify one or more terms that would include your concept.

 

Synonyms

Identifying synonymous terms for each of your concepts is important, as is making sure that any spelling differences. This is because authors may use different ways to describe the same thing, and it's important to account for all of those different ways. Also, not all results can be captured using controlled vocabulary, so it is still very important to include keywords.

As easy way to find synonyms is if there is a relevant controlled vocabulary term, within the database there will be a list of "entry terms" or synonyms that redirect to that controlled vocabulary term.

 
Truncation

Sometimes identifying these terms is as easy as using truncation to include a variety of words based off a single root word. This allows for searching many different words with the same root word, but only using a single term in the actual search strategy. While it may end up including words that you don't necessarily want, the hope is that the rest of the search strategy will be able to eliminate anything irrelevant.

In most databases, truncation is accomplished by adding an astrerik (*) at the end of a root word.

Example

child* would retrieve results with keywords including child, children, childhood, etc

PICO Question
In breast cancer patients, does scalp cooling decrease the amount of hair loss, during active cancer treatment?
 
Keywords
Patients
  • "breast cancer*"
  • "cancer patient*"
Intervention
  • "scalp cool*"
  • "cryotherap*"
  • "induced hypotherm*"
Outcome
  • "hair*"
  • "alopecia"
  • "side effect*"
  • "adverse effect*"
  • "adverse event*"
Time Frame
  • "cancer treatment*"
  • "cancer therap*"
  • Chemotherap*
  • Radiotherap*
  • Chemoradiotherap*
 
Relevant Controlled Vocabulary
  • Breast Neoplasms
  • Cancer Patients
  • Scalp
  • Hair
  • Cryotherapy
  • Induced Hypothermia
  • Drug-Related Side Effects and Adverse Reactions
  • Drug Therapy
  • Antineoplastic Agents
  • Radiotherapy
  • Chemoradiotherapy

Research Question

How do CAR-T toxicities present in critically ill cancer patients and what are the best practices to treat these patients?

 
Keywords
  • "CAR-T cell therap*"
  • "CAR T-cell therap*"
  • "CAR-T therap*"
  • "chimeric antigen receptor*"
  • "chimeric antigen receptor therap*"
  • "toxic*"
  • "side effect*"
  • "adverse react*"
  • "cytokine release syndrome*"
  • "cytokine storm*"
  • "immune effector cell-associated neurotoxicit*"
  • "CRS"
  • "ICANS"
  • "critical illness*"
  • "critically ill"
  • "critical care"
  • "intensive care"
  • "cancer*"
 
Relevant Controlled Vocabulary
  • Adoptive Immunotherapy
  • Chimeric Antigen Receptors
  • Drug-Related Side Effects and Adverse Reactions
  • Cytokine Release Syndrome
  • Neurotoxicity Syndromes
  • cell-associated neurotoxicity
  • Critical Illness
  • Critical Care
  • Intensive Care Units
  • Neoplasms

Step 3: How do you Combine Terms?

Terms are combined using Boolean Operators (AND, OR, and NOT).

The simplest way to think about using Boolean Operators is to combine similar terms (same concept) with OR, and dissimilar terms (different concepts) with AND. The operator NOT should be used with extreme caution.

PICO Question
In breast cancer patients, does scalp cooling decrease the amount of hair loss, during active cancer treatment?
First combine similar terms together using the Boolean Operator OR. Use parentheses if a concept requires multiple groups of terms, to combine them.
Patients

("Breast Neoplasms"[MeSH] OR "breast cancer*"[tiab]) AND ("cancer patient*"[tiab])

Intervention

(("Cryotherapy"[MeSH] OR "Hypothermia, Induced"[MeSH] OR "hypotherm*"[tiab] OR "cryotherap*"[tiab]) AND ("Scalp"[MeSH] OR "scalp*"[tiab] OR "head*"[tiab])) OR "scalp cool*"[tiab]

Outcome

("Alopecia"[MeSH] OR "Hair"[MeSH] OR "hair*"[tiab] OR "alopecia"[tiab]) AND ("Drug-Related Side Effects and Adverse Reactions"[MeSH] OR "adverse react*"[tiab] OR "side effect*"[tiab] OR "adverse event*")

Time Frame

"Drug Therapy"[MeSH] OR "Antineoplastic Agents"[MeSH] OR "Radiotherapy"[MeSH] OR "Chemoradiotherapy"[MeSH] OR "chemo*"[tiab] OR "radiotherap*"[tiab] OR "chemoradiotherap*"[tiab] OR "cancer treatment*"[tiab] OR "cancer therap*"[tiab]

 

Now combine concepts with AND to create search strategy. Be sure to nest each concept together with parentheses (this may include additional parentheses on top of ones already included).

(("Breast Neoplasms"[MeSH] OR "breast cancer*"[tiab]) AND "cancer patient*"[tiab]) AND ((("Cryotherapy"[MeSH] OR "Hypothermia, Induced"[MeSH] OR "hypotherm*"[tiab] OR "cryotherap*"[tiab]) AND ("Scalp"[MeSH] OR "scalp*"[tiab] OR "head*"[tiab])) OR "scalp cool*"[tiab]) AND (("Alopecia"[MeSH] OR "Hair"[MeSH] OR "hair*"[tiab] OR "alopecia"[tiab]) AND ("Drug-Related Side Effects and Adverse Reactions"[MeSH] OR "adverse react*"[tiab] OR "side effect*"[tiab] OR "adverse event*")) AND ("Drug Therapy"[MeSH] OR "Antineoplastic Agents"[MeSH] OR "Radiotherapy"[MeSH] OR "Chemoradiotherapy"[MeSH] OR "chemo*"[tiab] OR "radiotherap*"[tiab] OR "chemoradiotherap*"[tiab] OR "cancer treatment*"[tiab] OR "cancer therap*"[tiab])

Research Question
How do CAR-T toxicities present in critically ill cancer patients and what are the best practices to treat these patients?

First combine similar terms together using the Boolean Operator OR. Use parentheses if a concept requires multiple groups of terms, to combine them.

CAR-T Therapy

"Immunotherapy, Adoptive"[MeSH] OR "Receptors, Chimeric Antigen"[MeSH] OR "CAR-T cell therap*"[tiab] OR "CAR T-cell therap*"[tiab] OR "CAR-T therap*"[tiab] OR "chimeric antigen receptor*"[tiab]

Toxicities

"Drug-Related Side Effects and Adverse Reactions"[MeSH] OR "Cytokine Release Syndrome"[MeSH] OR "Neurotoxicity Syndromes"[MeSH] OR "cell-associated neurotoxicity"[Supplementary Concept] OR "toxic*"[tiab] OR "side effect*"[tiab] OR "adverse react*"[tiab] OR "adverse event*"[tiab] OR "cytokine release syndrome*"[tiab] OR "cytokine storm*"[tiab] OR "CRS"[tiab] OR "immune effector cell-associated neurotoxicit*"[tiab] OR "ICANS"[tiab]

Critically ill cancer patients

"Critical Illness"[MeSH] OR "Critical Care"[MeSH] OR "Intensive Care Units"[MeSH] OR "critical illness*"[tiab] OR "critically ill"[tiab] OR "critical care"[tiab] OR "intensive care"[tiab]) AND ("Neoplasms"[MeSH] OR "cancer*"[tiab]

 

Now combine concepts with AND to create search strategy. Be sure to nest each concept together with parentheses (this may include additional parentheses if you already have included parentheses within a specific concept).

("Immunotherapy, Adoptive"[MeSH] OR "Receptors, Chimeric Antigen"[MeSH] OR "CAR-T cell therap*"[tiab] OR "CAR T-cell therap*"[tiab] OR "CAR-T therap*"[tiab] OR "chimeric antigen receptor*"[tiab]) AND ("Drug-Related Side Effects and Adverse Reactions"[MeSH] OR "Cytokine Release Syndrome"[MeSH] OR "Neurotoxicity Syndromes"[MeSH] OR "cell-associated neurotoxicity"[Supplementary Concept] OR "toxic*"[tiab] OR "side effect*"[tiab] OR "adverse react*"[tiab] OR "adverse event*"[tiab] OR "cytokine release syndrome*"[tiab] OR "cytokine storm*"[tiab] OR "CRS"[tiab] OR "immune effector cell-associated neurotoxicit*"[tiab] OR "ICANS"[tiab]) AND ("Critical Illness"[MeSH] OR "Critical Care"[MeSH] OR "Intensive Care Units"[MeSH] OR "critical illness*"[tiab] OR "critically ill"[tiab] OR "critical care"[tiab] OR "intensive care"[tiab]) AND ("Neoplasms"[MeSH] OR "cancer*"[tiab])