Determinants of improved survival after oesophagectomy for cancer.
BACKGROUND
Survival after oesophagectomy for cancer seems to be improving. This study aimed to identify the most important contributors to this change.


METHODS
Patients who underwent oesophagectomy from 1999 to 2010 were extracted from the Netherlands Cancer Registry. Four time periods were compared: 1999-2001 (period 1), 2002-2004 (period 2), 2005-2007 (period 3) and 2008-2010 (period 4). Hospital type, tumour location, tumour type, tumour differentiation, neoadjuvant therapy, operation type, (y)pT category, involvement of surgical resection margins, number of removed lymph nodes and number of involved lymph nodes were investigated in relation to trends in survival using multivariable analysis.


RESULTS
A total of 4382 patients were identified. Two-year overall survival rates improved from 49·3 per cent in period 1 to 58·4, 56·2 and 61·0 per cent in periods 2, 3 and 4 respectively (P < 0·001). Multivariable survival analysis revealed that the improvement in survival between periods 3 and 4 was related to the introduction of neoadjuvant therapy. The improvement in survival between periods 1 and 2 could not be explained completely by the factors studied. The number of examined lymph nodes increased, especially between periods 2 and 3, but this increase was not associated with the improvement in survival.


CONCLUSION
The observed increase in long-term survival after surgery for oesophageal cancer between 1999 and 2010 in the Netherlands is difficult to explain fully, although the recent increase seems to be partly attributable to the introduction of neoadjuvant therapy.