This population based study of all lung cancer patients resected during a 10 year period in Norway shows favourable long term survival. Even elderly patients, those with advanced stage disease and subgroups with small cell lung cancer, nodal invasion (N1–N2), and patients with multiple tumours may be cured with surgery. A high proportion of patients had substantial co‐morbidity and few received adjuvant treatment.
Norway is a small country of about 4.5 million inhabitants and hospital health services are free of charge. The use of multiple sources of information in the Cancer Registry makes reporting of the incidence of various cancers reliable and complete, and it is believed that all new cancers are reported to the Registry.16
We have no exact knowledge of the policy at each hospital in Norway regarding selection of patients for surgery. Similarly, we do not know how the relative contraindications are determined. A decision to offer surgery is generally based on the technical feasibility of resection and evaluation of the patient's co‐morbidity, provided that the patient consents to undergo a surgical procedure.
Relative survival in lung cancer is useful in making comparisons between different series of different origins possible.8
However, there are few population based reports on long term relative survival after lung cancer surgery in the literature, and detailed subgroup analyses have not been presented.9,17
Some of the hospitals in Norway have presented their survival results which partly or completely overlap this time period, and hence include the same patients. Their results correspond to ours when stratifying on these hospitals (data not shown).18,19
The survival rates in Norway are slightly inferior to those published in other comparable reports.10,20
Higher postoperative mortality could explain some of this, but the main reason is probably that the patients operated on are unselected in this population based study.21
The poor prognosis after sublobar resection compared with lobectomy, which was particularly evident in the multivariate analysis, was probably caused by local recurrence and co‐morbidity.22
Survival after lower lobectomy was significantly reduced compared with upper lobectomy in univariate and multivariate analyses of all patients. To the authors' knowledge, this finding has not been previously reported. Involved resection margins were an independent adverse risk factor, confirming findings in other reports.10
Adenocarcinomas, which are more frequent in women, were identified as a prognostic risk factor for reduced survival; in other studies this effect seems uncertain.23,24,25
In a previous report we found that 5 year survival was about 45% in patients resected with small cell lung cancer, which was significantly better than other treatment modalities.12
This is a highly selected group since few patients present with limited stage disease. The favourable survival rates in patients with bronchioloalveolar carcinoma could be explained by the high proportion with limited stage disease. This might explain why bronchioloalveolar carcinoma was not an independent risk factor for survival in multivariate analysis. Carcinoids, not surprisingly, represent a tumour group with excellent prognosis.26
Patients with advanced disease should be carefully examined and evaluated with the aim of performing a resection if technically possible. In our unselected series there seems to be a role for surgery in patients with N2 disease; 13.4% survived for more than 5 years, although this survival rate was lower than other series which have reported 5 year survival rates of 20–26% in this group.27,28
Also, for multiple tumours with the same histology, the results indicate that surgery is a curative treatment and it is questionable if they should be categorised as stage IIIb and IV.29
Tumour size (
3 or >3 cm) seems to be insufficiently accounted for in the current TNM classification system, and a 5 cm limit has been suggested as a new category.30
Our data support the conclusion that patients with tumours >5 cm have a significantly poorer prognosis than those with smaller tumours.
Large hospital volume has been found to have a positive effect on long term survival.31
This was not supported in our multivariate model of hospitals performing an average of more or less than 20 procedures per year. Similarly, surgeon volume has been shown to have an important effect on outcome.32
At some small volume hospitals in Norway there are high volume surgeons who could interfere with the hospital volume effect. Another source of confusion is the difference in selection of patients at the different centres. Small units may perform resection only in patients without major risk factors for surgery, although analysis of the subset of patients with co‐morbidity data did not change the absence of hospital volume effect.
In conclusion, we found favourable long term survival after lung cancer surgery in a population based study. Even subgroups with high age, advanced stage, small cell lung cancer, nodal involvement, and patients with multiple tumours at diagnosis should be operated upon when technically possible because the survival is better than with other treatment modalities. These results could therefore stimulate a more aggressive approach in the selection of patients for surgery.