Colorectal cancer during pregnancy is rare but represents a major therapeutic challenge when standard oncological strategies conflict with fetal preservation. Locally advanced low rectal cancer is particularly complex because optimal management usually requires multimodal treatment, including pelvic radiotherapy, which is generally contraindicated during pregnancy.

We report the multidisciplinary management of a 44-year-old pregnant woman diagnosed at 15 weeks of gestation with a low rectal adenocarcinoma. Magnetic resonance imaging demonstrated a cT3N0 tumor located 2 cm from the anal verge with close contact with the levator ani muscles. In a non-pregnant patient, standard management would consist of neoadjuvant treatment followed by radical rectal surgery. However, pregnancy limited therapeutic options, as radiotherapy could not be administered and immediate radical surgery was considered technically challenging. After multidisciplinary discussion and comprehensive counseling, the patient expressed a strong preference to continue the pregnancy.

A sequential strategy was adopted, consisting of antenatal modified FOLFOX chemotherapy as a temporary disease-control approach until fetal maturity, followed by planned postpartum completion of standard oncological treatment. The patient tolerated chemotherapy well, with favorable clinical evolution and ongoing normal fetal development at the time of reporting.

This case highlights that management of locally advanced rectal cancer during pregnancy requires individualized multidisciplinary decision-making. When standard treatment pathways cannot be fully applied, carefully selected temporary strategies may allow pregnancy preservation while maintaining curative oncological intent. Early diagnosis, close maternal-fetal monitoring, and shared decision-making are essential components of care.