Differential Diagnosis for Hematochezia in a 69-year-old Patient with Uterine Cancer Stage 4

Single Most Likely Diagnosis

• Radiation Proctitis: Given the patient's recent history of receiving paclitaxel and carboplatin (pacli carbo) for uterine cancer, and the onset of hematochezia, radiation proctitis is a highly plausible cause. This condition is a common side effect of radiation therapy, especially in the pelvic area, leading to rectal bleeding.

Other Likely Diagnoses

• Chemotherapy-induced Colitis: The patient's chemotherapy regimen could also lead to colitis, characterized by inflammation of the colon, which might cause hematochezia.
• Thrombocytopenia: Chemotherapy can induce thrombocytopenia (low platelet count), increasing the risk of bleeding, including hematochezia.
• Gastrointestinal Metastasis: Given the stage 4 cancer diagnosis, metastasis to the gastrointestinal tract could cause bleeding.

Do Not Miss Diagnoses

• Lower Gastrointestinal Bleed from a Different Source: Although less likely, a lower GI bleed from a source not related to the cancer or its treatment (e.g., diverticulosis, angiodysplasia) must be considered due to the patient's age and potential for other comorbid conditions.
• Infectious Colitis: Certain infections can cause colitis and subsequent bleeding, which would require immediate antibiotic treatment.

Rare Diagnoses

• Vasculitis: A rare condition characterized by inflammation of the blood vessels, which could potentially cause GI bleeding.
• Intussusception: Although more common in children, intussusception (the telescoping of one portion of the intestine into another) can occur in adults, especially with a lead point such as a tumor, and could cause hematochezia.