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P1 An analysis of 8,503 cases of mesothelioma from the National Lung Cancer Audit

Background The National Lung Cancer Audit records outcomes in lung cancer and mesothelioma on a population scale, in order to explain the wide variations seen within the UK and between the UK and other countries and ultimately improving outcomes. Methods All cases of mesothelioma submitted to the audit by English Trusts 2006–2011 were analysed. A hierarchy of diagnosis from surgical histology to non-surgical histology to clinical diagnosis was used to exclude patients with potentially conflicting diagnoses. These records were further analysed to extract data on age/sex distribution, referral source, histological subtype, treatment regime and survival rates. Results There were 8,503 patients with mean age 72yrs (83% male), representing around 65% of expected incident cases (a substantial number diagnosed at autopsy and not included in the audit). 45% have right-sided disease, 28% left-sided, and 1% bilateral (data missing in 26%). The majority of patients (47%) were referred by their primary care physician, but at least 20% present to secondary care as emergencies. Overall, 89% were histo-cytologically confirmed with that figure appearing to rise slowly over the audit period from 81% (2006) to 92% (2011). Survival data is shown in the table. 37% of patients received no anti-cancer treatment, but 28%, 26% and 30% of patients received “surgery”, chemotherapy or radiotherapy at any time. Most surgical operations (60%) were pleurodesis. Median survival varied by first treatment modality: surgery 378 days, chemotherapy 399 days, radiotherapy 308 days, no anti-cancer treatment 140 days. Survival was highest in patients having “surgery” and chemotherapy (491 days). Use of chemotherapy varied across cancer networks from 14% to 41% of patients, but overall increased over the audit period from 13% to 34%. Conclusion Mesothelioma is predominantly a cancer of elderly males, with a striking tendency for right-sided disease. Only 11% have no histological confirmation, but where this is obtained, the epithelioid subtype has best prognosis. Low rates of anti-cancer treatment may reflect therapeutic nihilism as well as patient fitness, but there is an encouraging trend towards wider use of chemotherapy which was associated with a greater than doubling in survival compared with no treatment. Abstract P1 Table 1. n (%) Median survival (days) 1 year survival (%) All patients 8,503 (100%) 278 41 Survival was slightly better in females (median 304 days vs 274 days HR 0.91, p= 0.002) Subtype Unspecified 3,798 276 39.5 Epithelioid 2,300 388 53.2 Sarcomatoid 439 123 16.4 Biphasic 268 274 36.0