Research Article

RECURRENT RECTAL ADENOCARCINOMA WITH KRAS MUTATION POST-MFOLFOX6/BEVACIZUMAB REMISSION: A CASE REPORT

Yusuf Tukur1*, Abubakar M. Bello2, Usman M. Aliyu3, Oladapo B. Campbell4, Aisha Mustapha5, Abubakar Ibrahim Diggi6, Yusuf Dantani7, Shehu Salihu Umar8
1 Department of Radiation and Clinical Oncology, Usmanu Danfodiyo University Teaching Hospital (UDUTH), Sokoto, Nigeria
2 Department of Radiation and Clinical Oncology, National Hospital, Abuja
3 National Institute for Cancer Research and Treatment (NICRAT), 43 Agadez Crescent, Wuse II, 900288, FCT-Abuja, Nigeria.
4 Department of Radiation and Clinical Oncology, University College Hospital, Ibadan
5 Department of Obstetrics and Gynecology, Ahmadu Bello University, Zaria, Kaduna State, Nigeria
6 Department of Surgery, Usmanu Danfodiyo University Teaching Hospital (UDUTH), Sokoto, Nigeria
7 Department of Histo-Pathology, Usmanu Danfodiyo University Teaching Hospital (UDUTH), Sokoto, Nigeria
8 Department of Radiology, Ahmadu Bello University Zaria, Kaduna State, Nigeria
* Corresponding author: ytukur06@gmail.com
Published: Feb, 2026
DOI: 10.67579/njo.2026.1e4nz1ph
Pages: 130-138
Views: 278
Downloads: 173

Abstract

Background: This case report elucidates the clinical trajectory of a 41-year-old male diagnosed with low rectal adenocarcinoma, further complicated by pulmonary metastases, harboring a KRAS mutation, and characterized by microsatellite stability.

Case Presentation: This patient demonstrated a significant and favorable response to neoadjuvant chemotherapy with a modified FOLFOX6 (mFOLFOX6) regimen in combination with bevacizumab, an anti-VEGF monoclonal antibody. This therapeutic intervention culminated in a complete remission, meticulously confirmed through Positron Emission Tomography/Computed Tomography (PET/CT) imaging. Subsequently, the patient was transitioned to a maintenance therapy protocol involving intermittent cycles of the same regimen to consolidate the achieved remission. However, after a six-month period of maintenance therapy, the patient experienced metastatic recurrence, unequivocally identified by the emergence of Fluorodeoxyglucose-avid lesions in the lungs, mesenteric nodes, and left adrenal gland.

Biopsies of the mesenteric and adrenal lesions pathologically confirmed adenocarcinoma, exhibiting an identical KRAS mutation and microsatellite stability profile to the primary tumor, strongly indicating disease progression rather than the manifestation of a new primary malignancy. The patient was subsequently initiated on a regimen of bevacizumab and capecitabine as salvage therapy, and the patient was radiotherapy or surgery naive which provides an opportunity to further explore alternative treatment strategies in this complex scenario.

Conclusion: This case underscores the inherent challenges in the clinical management of advanced rectal cancer, specifically highlighting the potential for acquired resistance to anti-angiogenic therapies such as bevacizumab, despite an initial robust response. Furthermore, it emphasizes the critical importance of vigilant and continuous monitoring for disease recurrence, even in patients who have achieved complete remission following first-line treatment strategies.

Keywords

colorectal cancer Nigeria KRAS mutation microsatellite instability

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How to Cite

Tukur, Y., Bello, A. M., Aliyu, U. M., Campbell, O. B., Mustapha, A., Diggi, A. I., Dantani, Y., & Umar, S. S. (2026). RECURRENT RECTAL ADENOCARCINOMA WITH KRAS MUTATION POST-MFOLFOX6/BEVACIZUMAB REMISSION: A CASE REPORT. Nigerian Journal of Oncology, 2(1), 130-138. https://doi.org/10.67579/njo.2026.1e4nz1ph

Y. Tukur, A. M. Bello, U. M. Aliyu, O. B. Campbell, A. Mustapha, A. I. Diggi, Y. Dantani, and S. S. Umar, "RECURRENT RECTAL ADENOCARCINOMA WITH KRAS MUTATION POST-MFOLFOX6/BEVACIZUMAB REMISSION: A CASE REPORT," Nigerian Journal of Oncology, vol. 2, no. 1, pp. 130-138, February 2026. doi: 10.67579/njo.2026.1e4nz1ph

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