Cancer Alarm Signals

Summarized by Robert W. Griffith, MD
July 18, 2007

Summary

A study shows that four so-called alarm symptoms, if promptly reported, carry a good likelihood of helping in the early diagnosis of four matching types of cancer. They are: blood in the urine, blood in the sputum, difficulty in swallowing, and blood in the stool.

Introduction

Unfortunately, many people with symptoms of cancer are not referred for appropriate treatment early enough. This can be because they ignore or suppress their symptoms, or their primary care physician doesn't recognize the potential importance of their symptoms. A group of scientists and physicians working in the Public Health System in UK have tried to evaluate the relevance of so-called "alarm symptoms" for their usefulness in the timely management of possible cancer. Their findings are published in the British Medical Journal, and we summarize them here.

What was done

The UK General Practice Research Database was used for this analysis. Those general practitioners (family doctors) who provided good-quantity information - there were 128 of them - were selected. Data from almost one million of their patients were screened, and those whose first occurrence of hematuria (blood in the urine), hemoptysis (coughing up blood), dysphagia (difficulty in swallowing), or rectal bleeding were identified. Each of these patients had their records searched for the occurrence of related cancers: urinary tract cancer (kidney, bladder), respiratory tract cancer (bronchus, lungs), esophageal cancer, and colorectal cancer.

For each alarm symptom, its frequency in patients who developed one of the specified cancers was calculated, as well as the proportion of those with symptoms who developed the corresponding cancer or cancers within the next 3 years (the Positive Predictive Value). As a test of Sensitivity, the proportion of cancer patients who had previous alarm symptoms in defined preceding periods was calculated. To test for the Likelihood of correct diagnosis following an alarm symptom, the time of first diagnosis was determined for successive quarter up to 5 years.

What was found

Out of almost one million eligible patients, 37,000 presented with one or other of the alarm symptoms between 1995 and 2000 (blood in urine, sputum, urine, stool, or difficulty in swallowing). Their average ages ranged between 53 and 61. According to statistical tables of the frequencies of cancer, there should have been 4,800 cases of the corresponding cancers in this number of patients. So it was clear that first reports of alarm symptoms were generally 10 times more frequent than the expected cancers, except for reports of blood in the sputum, which was only 3 times more frequent than respiratory cancer cases.

The positive predictive values for each symptom, whether they occurred in the 6 months before a cancer or within 3 years, are shown in the table:

Symptom	Sex	Positive Predictive Value (%)	Positive Predictive Value (%)
		Cancer within 6 months	Cancer within 3 years
Hematuria	male	5.5	7.4
	female	2.5	3.4
Hemoptysis	male	5.8	7.5
	female	3.3	4.3
Dysphagia	male	5.3	5.7
	female	2.1	2.4
Rectal Bleed	male	1.8	2.4
	female	1.5	2.0

It can be seen that prediction rates were low, albeit better in men than in women. They increased, however, with age, and were highest in men with hemoptysis and dysphagia (17% and 9%, respectively).

The sensitivity of the symptoms - i.e. the proportion of cancer sufferers who had had alarm symptoms in the previous 3 years - was fairly high, as shown below:

Cancer type/symptom	Sensitivity (% cancer patients with alarm symptoms)	Sensitivity (% cancer patients with alarm symptoms)
	Men	Women
Urinary tract/hematuria	59%	52%
Respiratory/hemoptysis	22%	14%
Esophageal/dysphagia	58%	54%
Colorectal/bleeding	33%	25%

The likelihood of a correct diagnosis based on an alarm symptom was relative high in the first 3 months (especially for dysphagia/esophageal cancer), but fell quite quickly over subsequent quarters.

What the findings mean

This study confirms the usefulness of the so-called alarm symptoms - hematuria, hemoptysis, dysphagia, and rectal bleeding - in the early detection of specific cancers. Actual predictive values vary according to age, sex, and the alarm symptom, and they rise with age. The likelihood for the diagnosis of a specific tumor after its alarm symptom has been reported are high in the first 3-6 months, but fall off rapidly after the first year. As an example, the presence of dysphagia makes it 300 times more likely that the patient has cancer than someone without this symptom, so it should be taken seriously and investigated.

Most physicians are aware of the possible relevance of the 4 alarm symptoms evaluated in the study. However, many patients may not be as well informed; it's probable that they may ignore symptoms, dismiss them as irrelevant, or even choose to delay a visit to their doctor out of fear of the diagnosis. It's important that everyone - patient and health care professional - is alert to such symptoms, especially in younger patients where there is no other simple explanation for the symptoms. The earlier cancer is detected, the greater the chance of complete cure.

Source

• Alarm signal in early diagnosis of cancer in primary care: cohort study using General Practice Research Database. R. Jones, R. Latinovic, J. Charlton, MC. Gulliford, BMJ, 2007, vol. 334, pp. 1040--1044

Related Links
NIH's NKUDIC: Hematuria
MedlinePlus: Coughing Up Blood
MedlinePlus: Swallowing Disorders
MedicineNet Rectal Bleeding

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