Desley van Zoggel

Impact of metastases on survival 73 CHAPTER 5 Introduction The European Society forMedical Oncology guidelines for themanagement of patients withmetastatic (colo-)rectal cancer specify treatment strategiesbasedon thepossibility of achieving a resection with clear margins (R0 resection) of the primary tumour and an R0 resection or ablation of the solitary or oligometastatic disease.1 In marginally resectablemetastatic lesions, induction chemotherapymay enable conversion of these lesions to a resectable or ablatable state.1 This concept has led to the development of treatment strategies comprising a combination of neoadjuvant (chemo)radiotherapy and systemic treatment in patients with metastatic primary rectal cancer, resulting in long-term survival rates exceeding 50 percent.2,3 Similarly, the treatment of locally recurrent rectal cancer (LRRC) is intended to achieve an R0 resection – themost important prognostic factor for survival. Depending on local protocols, treatment may comprise neoadjuvant chemo(re)irradiation and extensive surgery with/without intra-operative radiotherapy.4–7 Induction chemotherapy is currently being evaluated as a promising addition to this treatment to improve resectability and oncological outcomes.8,9 Synchronous systemic disease is amajor problem in LRRC, as approximately 50 percent of patients present with distant metastases.10 In particular, patients who develop LRRC within 1 year after the primary resectionor those treatedwithneoadjuvant radiotherapy for the primary tumour are prone to early development of metastatic disease.10 Asmetastaticdisease is consideredan indicator of aggressive tumour biology, treatment options for LRRC patients with synchronous metastases or a history of metastases (m-LRRC) are usually limited to palliative intent, thereby resulting in poor survival rates.11–14 However, it is unclear whether these metastases progress rapidly or whether treatment with curative intent might be feasible in some patients. In our centre, the treatment principles for metastatic primary rectal cancer are applied in patients with m-LRRC. Metastatic disease is considered to be cured if patients with a history of metastases have no signs of recurrent metastatic disease. Synchronous metastases are considered curable if an R0 resection of the LRRC and radical treatment of the metastases can be achieved. This study aimed to comparatively evaluate oncological outcomes in LRRC patients without metastases, those with a history of metastases and those with synchronous metastases.