towards earlier cancer diagnosis hamish whitaker gp tutor guildford
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Towards Earlier Cancer Diagnosis
Hamish Whitaker GP Tutor Guildford
Context
• 25% deaths in developed world from cancer
• Most present to primary care with symptoms, even if a screening test exists
• Early symptoms shared with benign disease
• Average full time UK GP will have a new cancer diagnosed in one of their patients each month
Context
• UK cancer mortality record poor compared to other countries
• Current estimate 7500-10000 lives lost annually due to late diagnosis
• Two week rule and easier access to investigations has made little difference
Why the delay?
• Patient delay – eg only 41% patients report rectal bleeding to GP
• Positive predictive value of colorectal cancer with bleeding is 0.1%- but 2-3% by the time presented to GP (and 5-7% by time get to 2ary care)
• Do UK GPs have too high a threshold for selecting patients for referral?
• Pressure from PCT and 2ary care not to refer, criticism of inappropriate use of guidelines
Breast cancer
• 75% breast cancers identified following presentation of symptoms
• Screening much less impact• Little evidence to guide referral exists• Breast pain and lumps commonest
symptoms• 8% women with breast lump reported to
primary care are cancer- but depends on age (0.5% if < 25 yrs)
Breast cancer
• Breast pain cancer risk 0.9% overall
• Younger women higher risk of inflammatory breast cancer
• Present with swelling redness and warmth, may appear rapidly and therefore be mistaken for infection
• Poor prognosis
Lung cancer
• Prognosis generally poor – does early diagnosis make a difference?
• Usually spread by the time symptoms presented
• Only 20% UK patients eligible for surgical resection
• Screening little impact – current study on annual cytology and CT in COPD smokers, and spiral CT
Lung cancer
• Italian spiral CT trial- can detect nodules of 0.5cm (CXR smallest 3cm)
• High false positive rate
• Encouraging symptom awareness
• Study in Doncaster to encourage reporting cough and early CXR increased rate of cancers diagnosed in stage 1 or 2 from 11% to 19% after campaign
Lung cancer
• 25% lung cancers have normal CXR• But CXR cheap and easy to obtain• Estimate if CXR all smokers over 60 with
cough would speed the time to diagnosis by 9 months in 25% of cancer cases
• Haemoptysis is relatively uncommon in lung cancer- only 40% report it
• Haemoptysis risk is 2.4-7.5% depending on age
Lung cancer
• Cough , dyspnoea , weight loss, fatigue , chest pain, loss of appetite commoner symptoms than haemoptysis
• But even more common in benign conditions- positive predictive value 1%
• UK delay in diagnosis 51 days; Sweden 26 days
• Low threshold for CXR good strategy
Colorectal cancer
• Current UK guidelines 6 weeks of bleeding or bleeding with diarrhoea for TWR
• Over 60 risk of cancer > 2% for any bleeding so are current guidelines correct?
• Iron deficient anaemia- men <11 women <10 – risk of cancer 7.7% and 13.3% respectively
• Abdominal pain , constipation and diarrhoea much lower predictive value (<1%)
• Problem is colonoscopy more expensive , some risk, uncomfortable
Colorectal cancer
• CT colonography misses 1 in 10 lesions larger than 1cm – which colonoscopy picks up
• Biomarkers may help in future- matrix metalloproteinase-9, free DNA in rectum possibilities for future
• Risk scores – CAPER and SELVA- but both lead to too many false positives and excessive interventional investigation
Colorectal cancer
• GPs often do get it right• “change in bowel habit” means diarrhoea
or constipation and reasonable chance of bowel cancer
• Has 4% predictive value for cancer in 80yr old , whereas constipation or diarrhoea has 0.7% and 1.2%
• Unclear what these soft features are that GP uses to label as change in bowel habit
Prostate cancer
• Debate re importance of early diagnosis• Screening trials show little benefit to
mortality• Treating small cancers gives small mortality
gain , but possible complications ; incontinence/ impotence
• Treatment of larger cancers or spread less controversial- and these usually cause symptoms
Prostate cancer
• Suggests definitely appropriate to search for cancer if LUTS
• But positive predictive value only 3% for cancer
• Impotence can be an early symptom of cancer – rare
• Remember PSA in back pain in men
Ovarian cancer
• Symptoms are common and early- and often missed
• Fatigue, bloating, abdominal pain, urinary frequency
• Combination of Ca125 and TV ultrasound probably best initial investigation
Other cancers
• Oesophageal cancer 5.7% risk in men with dysphagia
• Urinary tract cancer 7.4% risk in men with haematuria (women 3.4%)
• <2% lymphadenopathy presented in 1ary care malignant
• Brain tumour risk with headache 0.1%
Tumour markers
• Over 50% tumour markers requested in primary and secondary care inappropriate – and requests for PSA in women and CA125 in men not unusual!
• Key points 1/measuring more than one not helpful (except germ cell HCG and AFP)
• 2/ not helpful in non specific symptoms – often raised in benign disease also
Tumour markers
• Main uses in monitoring cancers- response to treatment or detecting recurrence
• Not helpful in screening asymptomatic individuals
• Except AFP for hepatocellular ca in cirrhosis from Hep B or C
• Ca125 for ovarian cancer (with TVUS) and PSA debatable
Tumour markers
• PSA - prostate ; also elevated in BPH , prostatitis , UTI , cycling! PR doesnt raise . Finasteride reduces PSA
• C125- ovary . Also raised in endometriosis, menstruation, colitis, laparoscopy, SLE. In conjunction with TVUS. Can be negative despite cancer – refer if suspicious
Tumour markers
• CEA colon cancer – only useful for monitoring
• CA153 breast cancer – monitoring
• CA19-9 pancreatic cancer – can aid diagnosis
• HCG and AFP germ cell tumours – can aid diagnosis and AFP in hepatocellular ca
Tumour markers
• Calcitonin ; medullary thyroid cancer- can aid diagnosis
• Thyroglobulin ; follicular /papillary thyroid cancer -can aid diagnosis
• Paraproteins eg Bence Jones – myeloma; useful in diagnosis
• Ref BMJ 2009 ; 339:b3527
Conclusions
• GPs may have too high a threshold for investigation
• Gatekeeper role may inhibit early diagnosis, and financial pressures may be increasing this
• Two week rule does not appear to have made a significant impact on speeding cancer diagnosis
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