Tumour location and the effects of preoperative radiotherapy in the treatment of rectal cancer

Abstract

Preoperative radiotherapy improves local control and survival in rectal cancer, but may also increase postoperative morbidity and mortality rates. Establishing selection criteria for preoperative radiotherapy is crucial. The tumour level above the anus may be one such criterion. The effect of preoperative radiotherapy in relation to the distance between the tumour and the anus was therefore assessed. In 457 patients operated for cure included in the Stockholm II Trial the local recurrence rate in irradiated and non-irradiated patients was analysed in relation to the tumour location (low, mid or upper rectum). Radiotherapy reduced the local recurrence rate from 30 to 20 per cent in low rectal cancer, from 25 to 11 per cent in mid rectal cancer and from 21 to 5 per cent for tumours in the upper rectum. With conventional surgical techniques preoperative radiotherapy plays an important role in rectal cancer irrespective of the location of the tumour. To irradiate only patients with tumours in the lower rectum and to omit this treatment for patients with tumours in the mid and upper rectum cannot be recommended. Whether this statement is valid with standardized total mesorectal excision (TME) surgery is not known. Until this knowledge is available the current indications for preoperative radiotherapy should probably also be used with TME surgery.