Twenty-five studies (1,221 participants) were included in the review: four RCTs and 21 observational studies. Trial quality was generally low to moderate: two trials scored 2 and two trials scored 3 out of 5 on the Jadad scale. The quality of the included cohort studies was reported as high.
Compared with neoadjuvant short-course radiotherapy, neoadjuvant long-course radiochemotherapy/radiotherapy had a statistically significantly higher percentage diagnosed with locoregional recurrence after five years (4% versus 24%, OR 0.13, 95% CI 0.01 to 0.76; six studies). This effect was not seen at three years.
Primary surgery alone compared with neoadjuvant long-course chemoradiotherapy/radiotherapy revealed no statistically significant difference in time to local recurrence. There was a statistically significant difference in percentage diagnosed with locoregional recurrence two years (30% versus 72%, OR 6.46, 95% CI 2.83 to 16.24; 11 studies), three years (12% versus 44%, OR 5.88, 95% CI 1.54 to 16.67; five studies) and five years (7% versus 24%, OR 4.61, 95% CI 1.66 to 14.95; 10 studies).
Few data were available to compare primary surgery with neoadjuvant short-course radiotherapy. Results showed that short-course radiotherapy might prolong the time to locoregional recurrence only for a short period.
Where statistical analysis was possible, there were no significant influences of adjuvant therapy on time to locoregional recurrence and percentage diagnosed with locoregional recurrence after two years. The type of surgery did not significantly affect the results.