Preoperative CarePreoperative PeriodPostoperative PeriodPostoperative ComplicationsTreatment OutcomeProspective StudiesRetrospective StudiesTime FactorsRectal NeoplasmsFollow-Up StudiesTomography, X-Ray ComputedPostoperative CarePredictive Value of TestsNeoadjuvant TherapyIntraoperative CareSurgical Procedures, ElectiveNeoplasm StagingPrognosisIntraoperative PeriodCombined Modality TherapyCardiac Surgical ProceduresSurgical Procedures, OperativeIntraoperative ComplicationsRisk FactorsMagnetic Resonance ImagingPremedicationReoperationPerioperative CareAdenocarcinoma