This chapter talks about four case studies of radiotherapy for gastrointestinal malignancies. One of the case study, a 65-year-old female presents with painless jaundice and diarrhea for 1 month. Labs show an elevation in liver function tests and total bilirubin of 13.4. Computed tomography (CT) scan reveals a 2 cm lesion in the pancreatic head. CT scan confirms no involvement of major vessels and no evidence of distant metastases. The patient undergoes pancreaticoduodenectomy, revealing pT1N0 poorly differentiated adenocarcinoma with negative margins. The chapter talks about multiple questions and answers for the gastrointestinal malignancies.