The 2015 Guideline, Suspected cancer: recognition and referral [This link is to the shorter version of the guideline], is for United Kingdom primary care physicians. The U.S. approach to the primary care recognition and referral for suspected cancer is different from that of the United Kingdom. In the United States the recommendations for evaluation tend to be more resource intensive (more expensive) for a number of reasons.
But the NICE guideline is a good summary of the signs and symptoms that would lead a primary care physician to consider evaluation or/and referral for suspected cancer given our present knowledge base.
But as the full guideline notes [p26] there is often little data on the performance characteristics of tests performed by primary care physicians. And there is often little data data for the positive predictive value of symptoms for specific cancers.
Diagnostic accuracy studies should be carried out of tests accessible to primary care for a given cancer in symptomatic people. . . . Outcomes of interest are the performance characteristics of the test, particularly sensitivity, specificity and positive and negative predictive values.
There is very little information currently available on the diagnostic accuracy of tests available in primary care for people with suspected cancer. [Emphasis Added}
Observational studies should be used of symptomatic primary care patients to estimate the positive predictive value and other performance metrics of different symptoms for specific
cancers. Priority areas for research are those where the evidence base is currently insufficient and should include prostate cancer, pancreatic cancer, cancer in childhood and
young people and other rare cancers. Outcomes of interest are positive predictive values and likelihood ratios for cancer.
For several cancer sites, the primary care evidence base on the predictive value of symptoms is thin or non-existent. Filling this gap should improve future clinical guidance. [Emphasis Added]
The question is when should a patient symptom or symptoms lead to an evaluation for possible cancer. This is what the guideline suggests:
The identification of people with possible cancer usually happens in primary care, because the large majority of people first present to a primary care clinician. Therefore, evidence from primary care should inform the identification process and was used as the basis for this guideline.
The recommendations were developed using a ‘risk threshold’, whereby if the risk of symptoms being caused by cancer is above a certain level then action (investigation or referral) is warranted. The positive predictive value (PPV) was used to determine the threshold. In the previous guideline, a disparate range of percentage risks of cancer was used to form the recommendations. Few corresponded with a PPV of lower than 5%. The Guideline Development Group (GDG) felt that, in order to improve diagnosis of cancer, a PPV threshold lower than 5% was preferable. Taking into account the financial and clinical costs of broadening the recommendations, the GDG agreed to use a 3% PPV threshold value to underpin the recommendations for suspected cancer pathway referrals and urgent direct access investigations, such as brain scanning or endoscopy. Certain exceptions to a 3% PPV threshold were agreed. Recommendations were made for children and young people at below the 3% PPV threshold, although no explicit threshold value was set. The threshold was not applied to recommendations relating to tests routinely available in primary care (including blood tests such as prostate‑specific antigen and imaging such as chest X‑ray), primary care tests that could be used in place of specialist referral, non‑urgent direct access tests and routine referrals for specialist opinion. Further information about the methods used to underpin the recommendations can be found in the full version.
Here is the link to the pdf of the full guideline Suspected cancer: recognition and referral (378 pages).
Here is the link to the Terms used in this guideline (the sense in which the terms are used throughout the guidelines).
Here is the link to Appendix f: Evidence review. This appendix has lists of all of the evidence reviewed for the evidence recommendations of each cancer. For example, the evidence reviewed for the lung cancer recommendations runs from pages 39 to 123.
And so in upcoming posts on primary care evaluation for suspected cancer, I have reviewed the NICE guidelines possible warning symptoms and signs which are relevant to north american primary care physicians.
Suspected cancer: recognition and referral, NICE guideline [NG12] Published date: June 2015.
This guideline covers the identifying children, young people and adults with symptoms that could be caused by cancer. It outlines appropriate investigations in primary care, and selection of people to refer for a specialist opinion. It aims to help people understand what to expect if they have symptoms that may suggest cancer.
This guideline includes recommendations on the symptoms and signs that warrant investigation and referral for suspected cancer.
The recommendations are organised by:
- the site of the suspected cancer
- the symptom, alphabetically then in order of urgency of the action needed
- the findings of primary care investigations
The guideline includes recommendations on: