What happened, in summary

A woman in her 70s developed rectal bleeding, changes in bowel habits, lower-abdominal pain, fatigue, reduced appetite, and a 5 kg weight loss over 4 months. Examination, imaging, and biopsy showed a rare rectal squamous cell carcinoma. The tumor was locally advanced, classified as cT4N1aM0, but there was no distant metastasis.

Rather than undergoing immediate radical surgery, she was treated with combined chemotherapy and radiation. Radiation covered the pelvis and inguinal lymph nodes, with an additional boost to the main tumor. Mitomycin C was given on days 1 and 29, and capecitabine was taken twice daily on treatment days. She completed therapy with only mild skin toxicity.

Imaging 8 weeks later showed that the tumor had partly responded. The team continued close assessment rather than moving directly to surgery. At 6 months, no tumor could be felt on examination. MRI, CT, colonoscopy, and laboratory testing also showed no remaining disease. Her squamous-cell-carcinoma antigen level was 0.6 ng/mL.

Because a complete response had been achieved, surgery was avoided. She entered close surveillance and received pelvic-floor rehabilitation for treatment-related bowel-control problems. Two years after chemoradiotherapy, she still had no clinical, laboratory, endoscopic, or imaging evidence of cancer. Her fecal incontinence had also improved from grade 2 to grade 1.

Because repeated examinations found a complete clinical response, she did not undergo radical rectal surgery. She continued close surveillance, and no local or distant recurrence appeared during 2 years of follow-up.