The recent article by Laroche et al 1 is an eloquent reminder that standardised care, hopefully based upon evidence (or at least consensus), can help to ensure that the quality of care is based less on postcode and more upon clinical need. However, the authors and the accompanying editorial2 do not emphasise the problems in comparing surgical resection rates for lung cancer with other European countries and the USA.

Much international literature in this area is not directly comparable with that in the UK for at least one reason—namely, that the denominators used may be very different. One study quoted by Larocheet al from the Netherlands described a resection rate for lung cancer of over 20%,3 but used a denominator made up only of patients with a histological diagnosis seen at the related hospitals. The UK data commonly available comprise cases with and without histological verification, including those notified by death certification. The proportion of lung cancer notifications without histological confirmation registered at the West Midlands Cancer Intelligence Unit was over 40% in 1996. Many cases of lung cancer present in a terminal phase and, whilst it is recognised that some of these should perhaps have accessed the health care system earlier, a significant number of cases have truly malignant disease with very few symptoms right up until death.

This “denominator decrease” is also apparent in a frequently quoted paper from Belgium in which the study population was restricted to those who attended the hospital clinic.4 Examination of the paper quoted from the USA by Humphrey et al 5 shows that the denominator is reduced further as it excludes patients who had a histological diagnosis made at necropsy.

It is useful to refer back to a British paper published in the last decade based upon Cancer Registry data. Watkin et al 6 quoted a 45% surgical intervention rate in patients with a histological diagnosis, considerably higher than elsewhere in the world. However, this represented a resection rate of 12% for all registered lung cancer patients. Data from the West Midlands Cancer Intelligence Unit show that the resection rate in 1996 was 20% for patients who had their lung cancer histologically confirmed before death yet 10.4% if all notifications were included in the denominator. Comparisons of process measures have their problems which are only made worse when the denominator is not comparable.

The results published by Laroche et al are interesting but longer term figures are needed to ensure that the described resection rates do not fall and, more importantly, that better patient outcomes are also observed, which are to be expected, if more patients are undergoing curative procedures. Whilst important points have been emphasised about access and information for the population, we must also strive towards comparing outcomes of care rather than just process detail. Furthermore, if process is to be compared, let us ensure that like is compared with like, an argument rightly used with respect to outcomes (case mix, stage etc).

Patients with lung cancer should have good quality care and good outcomes: this is rightly the message made by Larocheet al, not a dogma based upon spurious process comparisons.

authors’ reply We agree with the letter by Dr Phillips and Dr Lawrence concerning the difficulty of defining the denominator for an accurate surgical resection rate. In Papworth we do know that the two stop lung cancer service has led to more than a doubling of the total number of patients undergoing surgical resections at Papworth. There was no increase in the number of patients undergoing pneumonectomy compared with lobectomy, failed thoracotomies, or increase in stage of disease. This surgical resection rate has persisted since the start of the two stop service in 1995 and has continued to increase. Interestingly, regions serviced by the surgical unit at Pap worth that do not use the two stop service have also reported an increase in the number of patients being referred for surgery in the last year. However, this increase has been associated with an increase in the failed thoracotomy rate and also with an increase in the number of patients undergoing pneumonectomy compared with lobectomy. We conclude that before the two stop service was established there was a significant number of patients with operable disease who were not being identified, but that multidisciplinary review of potentially operable patients is necessary to prevent inappropriate referrals for surgery.