Spontaneous regression of peritoneal carcinomatosis from a rectal cancer

Spontaneous regression of adult solid tumours is rare. Here, we present the case of a 51-year-old man who underwent a curative resection for an adenocarcinoma of the rectum in 1989. He remained well until 12 months after surgery when he developed a large-fixed mass proximal to the anastomosis, which was treated with radiotherapy but did not respond. Shortly after, he presented with intestinal obstruction caused by extensive intraperitoneal metastases. At laparotomy, a palliative entero-enterostomy and ileostomy were performed. Biopsies from the peritoneal lesions showed features typical of metastatic adenocarcinoma. The patient did not receive any additional therapy. However, his condition continued to improve; he remains disease free and well at present (May 2005). A review of the literature revealed two cases of spontaneous regression of peritoneal carcinomatosis secondary to a rectal cancer; we report the third case and discuss some of the reasons potentially responsible for the regression.