Neoadjuvant Chemoradiation With 5-FU(or Capecitabine) and Oxaliplatin Combined With Hyperthermia in Rectal Cancer

Inclusion Criteria: * Age ≥ 18 years * Histologically confirmed, locally advanced or recurrent (any recurrence of tumor within the lesser pelvis; resectable or non-resectable) adenocarcinoma of the rectum (UICC stage IIB-IV); distant oligo-metastases may be present. * ECOG-performance status \< 2 * Sufficient bone marrow function: * WBC \> 3,5 x 10\^9/l * Neutrophil granulocytes \> 1,5 x 10\^9/l * Platelets \> 100 x 10\^9/l * Hemoglobin \> 10 g/dl * Sufficient liver function: Bilirubin \< 2,0 mg%, SGOT, SGPT, alkaline phosphatase, gGT less than 3 times upper limit of normal * Serum creatinine \< 1,5 mg%, glomerular filtration rate (or comparable test) \> 50 ml/min * Signed study-specific consent form prior to therapy * Fertile patients must use effective contraception during and for 6 months after study treatment * Considered fit for oxaliplatin and 5-FU-containing combination chemotherapy Exclusion Criteria: * Pelvic radiotherapy during the last 12 months * Pregnant or lactating/nursing women * Drug addiction * On-treatment participation on other trials * Active intractable or uncontrollable infection * Prior or concurrent malignancy (≤ 5 years prior to enrolment in study) except rectal cancer or non-melanoma skin cancer or cervical carcinoma FIGO stage 0-1 if the patient is continuously disease-free * Chronic diarrhea (\> NCI CTC-Grad 1) * Chronic inflammatory disease of the intestine * Collagen vascular disease * The presence of congenital diseases with increased radiation sensitivity, for example teleangiectatic ataxia, or similar * Pre-existing uncontrolled cardiac disease, signs of cardiac failure, or rhythm disturbances requiring therapy * Myocardial infarction within the past 12 months * Congestive heart failure * Complete bundle branch block * New York Heart Association (NYHA) class III or IV heart disease * Known allergic reactions on study medication * Cardiac pacemaker * Disease that would preclude chemoradiation or deep regional hyperthermia * Any metal implants (with exception of non-clustered marker clips) * Psychological, familial, sociological, or geographical condition that would preclude study compliance * Patients deemed technically unsatisfactory for deep regional hyperthermia * Cardiac symptoms (\> NCI CTCAE Grade 1) due to pretreatment with fluoropyrimidines * Neurological symptoms (\> NCI CTCAE Grade 1) due to pretreatment with oxaliplatin * Rare hereditary problems of galactose intolerance, Lapp lactase deficiency or glucose-galactose malabsorption * Oral anticoagulation