DeCure for Cecum adenocarcinoma

Primary squamous-cell carcinoma of the cecum is an uncommon diagnosis, with only four cases cited in the literature before 1971 and a fifth reported then. A 2009 case describes a 34-year-old male with a well-differentiated, keratinizing squamous-cell carcinoma invading the bowel wall up to the subserosal fat space; he received six months of postoperative chemotherapy and was free of disease two years after resection. These tumours show no distinctive clinical or gross features to separate them from the usual adenocarcinoma, and diagnosis rests on microscopy, with keratin and prekeratin stains, intracellular bridges, and negative mucin stains as supportive evidence. Proposed origins include embryonic nests of undifferentiated epithelium, epidermoid implantation at operation, inflammation, radiation, or teratomatous derivation.

For adenocarcinoma of the cecum, a 2018 retrospective study of 162 patients treated with right hemicolectomy and chemotherapy, with 48 also receiving adjuvant radiation therapy, reported 5-year local control, disease-free survival, and overall survival rates of 72.7%, 57.2%, and 62.6% respectively. Multivariate analysis identified age over 55 years (HR 1.0), T4 stage (HR 6.8), node-positive disease (HR 4.2), and absence of adjuvant radiation therapy (HR 3.0) as independent negative prognostic factors for overall survival, leading the authors to conclude that adjuvant radiation significantly improves disease-free and overall survival. An earlier 1986 analysis of 106 patients followed a median of 25 months after hemicolectomy found a median overall survival of 73 months and median disease-free survival of 37 months, with 22 of 106 patients (21%) failing locally, and 7 of those 22 also having distal failure; that paper suggested a group might benefit from adjuvant radiotherapy but left the choice between total abdominal irradiation and locoregional radiotherapy undefined.

Adenosquamous carcinoma of the cecum is aggressive. A 2024 case report describes a 71-year-old woman with a history of breast cancer who presented with bowel obstruction and an ileocolic mass; right hemicolectomy revealed advanced metastatic disease, and she died very soon after the operation. A 2004 case in a 71-year-old man with no lymph node metastasis but infiltration into the subserosal layer was also reported, with only 19 cases documented in Japan at that time; the theory of squamous metaplasia of colonic adenocarcinoma is widely supported for its etiology. A 2007 case of an adenocarcinoid tumour in the cecum in a 64-year-old man showed lymph node metastases in three nodes containing only the carcinoid component, though the malignancy potential and prognosis of such tumours remain unclear.

What is still missing is prospective data: the 2018 radiation study is retrospective and from three tertiary centres, the 1986 analysis is older and smaller, and the rare histologies are limited to single case reports. No randomised trial has defined the optimal adjuvant regimen for cecal adenocarcinoma, the role of radiation in squamous or adenosquamous variants is unstudied, and patient stratification by molecular markers or histologic subtype is absent. Funding for a multicentre prospective registry or trial, and systematic collection of these rare tumours, would be required before any firm guidance could emerge.