Colorectal cancer - Spontaneous Remission Database

Colorectal Cancer

Epidemiology:

Colorectal cancer (CRC) ranks among the most prevalent and lethal cancers globally, with approximately 152,810 new cases reported annually in the United States alone.¹ Despite significant advances in treatment, CRC remains the second leading cause of cancer-related deaths globally.² Spontaneous remission (SR) in CRC is extremely rare, constituting less than 2% of all reported SR cases linked to malignant neoplasms.³ SR events are usually recognized only when the remission is dramatic and sustained, which makes it difficult to accurately estimate their true prevalence, as less noticeable cases often go unreported.⁴

Clinical Characteristics:

To date, 28 well-documented cases of spontaneous remission involving primary or metastatic CRC have been reported between 1961 and 2025. The ages of affected individuals ranged from 42 to 90 years, with a peak incidence in the 60–80-year group. A modest male predominance (approximately 1.3:1) was observed, consistent with previous reports suggesting a higher SR frequency among men. Rectal cancer–associated SRs were more common in males. Overall, SR tended to occur in older adults, often in those with advanced-stage disease at initial presentation. See table 1 below for further information.

Histological Characteristics:

Patients who experienced spontaneous remission of CRC commonly presented with rectal bleeding, abdominal pain, altered bowel habits, or weight loss. Diagnosis was typically established by colonoscopy followed by histopathological confirmation of adenocarcinoma. In most cases, the disease was advanced or metastatic, frequently involving the liver, lymph nodes, or peritoneum. Remission was generally documented through imaging or histologic evaluation, which demonstrated replacement of tumor tissue with fibrotic or scar-like changes. Nearly all SR cases were associated with prolonged survival or durable remission, in some instances lasting more than a decade, substantially exceeding the expected prognosis for CRC.

Proposed Contributing Mechanisms:

Various potential SR mechanisms in CRC have been proposed. The most frequently reported involve immune-mediated antitumor responses, often triggered by infection, biopsy, or local inflammation. Other suggested contributors include autoimmune activation, ischemia or necrosis resulting from vascular compromise, and psychological or metabolic stress. More recent reports emphasize immune reactivation following biopsy or tumor manipulation, supporting the hypothesis that antigen exposure or immune priming plays a central role in tumor remission. Additional factors hypothesized to influence SR include concomitant viral or bacterial infections, psychological or spiritual influences such as meditation or religious practice, favorable psychosocial changes, underlying genetic predispositions, and interruption of the tumor’s blood supply.

Site and Extent of Remission:

The colon and rectum remain the most common primary sites affected by SR, although remission has also been reported in hepatic, lymphatic, and local recurrence sites. Among documented cases, SR involved metastatic lesions alone in several patients, both primary and metastatic sites in others, and isolated primary tumors in the remainder. Several recent cases (2020–2025) described biopsy-associated remission at the original lesion site. The median follow-up across published reports was approximately 10 years, with most patients surviving five years or longer after remission. Unlike many other malignancies in which SR may precede relapse, most CRC SR cases exhibited durable remission or long-term disease stability.

Table 1: CRC SR Cases and Clinical Characteristics

Author–year	Age/sex	Primary site	Remission site	Proposed mechanisms	Follow-up
Brown et al. 1961¹	54/F	Sigmoid colon	Not specified	Not reported	16 years
Mayo et al. 1963²	63/F	Left colon,	Not specified	Not reported	12 years
Rankin et al. 1965³	44/M	Colon	Liver	Not reported	10 years
Margolis et al. 1967⁴	71/M	Colon	Abdomen	Fecal redirection	Not reported
Snyder et al. 1968⁵	62/F	Colon	Not specified	Not reported	14.5 years
Bir et al., 2009⁶	86/F	Colon	Retroperitoneal and aortocaval lymph nodes	Possible autoimmune response (unconfirmed)	Not reported
Sakamoto et al. 2009⁷	80/M	Rectum	Not specified (Lesion in the middle part of the rectum)	Immune-mediated host responses	Not reported
Lee et al. 2011⁸	54/M	colon	The lymphatic system in the colon	Alternative routes of lymphatic drainage	2 year
Nakamura et al. 2013⁹	60/M	Rectum	Not specified (Lesion in the lower rectum)	Immunity activation, inflammation, ischemic change	Not reported
Karakuchi et al. 2019¹⁰	78/M	Colon	Scar tissue	Cancer cells as antigens	Not reported
Linuma et al. 2019¹¹	63/M	Rectum	Anterior rectal wall	Not reported	1 Month
Nishiura et al. 2020¹²	67/F	Colon	Scar-like lesion was observed around the preoperative inking.	Antitumor immune response	Not reported
Matsui et al. 2021¹³	70/M	Rectum	Lower rectum (scar tissue formation)	Not reported	14 months
Yokota et al. 2021¹⁴	76/F	Transverse colon	Biopsy site	Antitumor immune reaction	Not reported
Yokota et al. 2021¹⁴	64/F	Cecum	Biopsy site	Antitumor immune reaction	Not reported
Yokota et al. 2021¹⁴	64/M	Transverse colon	Biopsy site	Antitumor immune reaction	Not reported
Zwart et al. 2023¹⁵	59/F	Colon	Liver	Immune response	Not reported
Harata et al. 2023¹⁶	76/F	Transverse colon	Biopsy site	Immune response to biopsy	Not reported
Lee et al. 2024¹⁷	78/M	Kidney	Not reported	Not reported	Not reported
Ortigão et al. 2024¹⁸	42/F	Rectum	Rectal stump (scar with fibrosis)	None reported	Not reported
Ohno et al. 2025¹⁹	83/F	Transverse colon	Biopsy and resection site	Biopsy and stress-induced immune response	Not reported
Nakano et al. 2025²⁰	90/M	Ascending colon	Colon and lymph nodes	Not reported	Not reported
Kihara et al., 2015²¹	64-year-old male, medical history included distal gastrectomy for gastric ulcer and cholecystectomy for gallstones, 28 at 23 years previously, was taking metformin for diabetes for 15 years and glucosamine and chlorella as dietary supplements for 3 years	transverse colon	6 weeks after initial colonoscopy, right hemicolectomy was performed and examination of resected specimen showed that the tumour had disappeared, leaving only a discolored scar, histological examination showed marked inflammatory infiltration of lymphocytes, plasma cells and fibrosis between the submucosa and muscularis propria, and no cancer cells found in the scar; follow-up one year later confirms complete regression of cancer	None reported	6 weeks after initial colonoscopy, right hemicolectomy was performed and examination of resected specimen showed that the tumour had disappeared, leaving only a discolored scar, histological examination showed marked inflammatory infiltration of lymphocytes, plasma cells and fibrosis between the submucosa and muscularis propria, and no cancer cells found in the scar; follow-up one year later confirms complete regression of cancer
Shimizu et al., 2010²²	80-year-old man with hypertension	transverse colon	6 months later, a preoperative colonoscopy resulted in the tumour being reclassified to a IIc lesion, with disappearance of transverse colon cancer. A biopsy was performed at the location of the earlier lesion and the result was negative for cancer.	tumour dislodgement by some kind of physical stimulation such as peristaltic movement due to a laxative or the effect of some type of medical examination such as barium enema or colonoscopy	6 months later, a preoperative colonoscopy resulted in the tumour being reclassified to a IIc lesion, with disappearance of transverse colon cancer. A biopsy was performed at the location of the earlier lesion and the result was negative for cancer.
Abdelrazeq, 2005²³	51-year-old man	Colon + peritoneum mets	Five years later, he presented with haematuria and anemia. Computerized tomography imaging of the abdomen and pelvis and the tumour markers were normal. Multiple biopsies at the last laparotomy, done for frozen pelvis, and sigmoidoscopic biopsies showed fibrosis and extensive chronic inflammatory cells infiltration and no evidence of malignancy.	antigen-driven or carcinogen-driven and regressed following diminution in antigen or carcinogen exposure caused by faecal diversion by an ileostomy.	Five years later, he presented with haematuria and anemia. Computerized tomography imaging of the abdomen and pelvis and the tumour markers were normal. Multiple biopsies at the last laparotomy, done for frozen pelvis, and sigmoidoscopic biopsies showed fibrosis and extensive chronic inflammatory cells infiltration and no evidence of malignancy.
Matsuki, 2018²⁴	72-year-old woman	mets to liver with primary in colon	Intraoperative B-mode ultrasonography examination did not show the nodule clearly. we performed an anatomical resection of liver segment III, where the mass had been located according to preoperative imaging findings. A yellowish, necrotic nodule of 6 mm in diameter was macroscopically found in a surgical specimen of liver S3. The nodule was completely necrotized and necrotic columnar epithelial groups were found in this nodule, but no viable tumor cells were found	immunological mechanism	Intraoperative B-mode ultrasonography examination did not show the nodule clearly. we performed an anatomical resection of liver segment III, where the mass had been located according to preoperative imaging findings. A yellowish, necrotic nodule of 6 mm in diameter was macroscopically found in a surgical specimen of liver S3. The nodule was completely necrotized and necrotic columnar epithelial groups were found in this nodule, but no viable tumor cells were found
Matsuki, 2018²⁴	72-year-old woman	Liver	Intraoperative B-mode ultrasonography examination did not show the nodule clearly. anatomical resection of liver segment III, where the mass had been located according to preoperative imaging findings, was performed. A yellowish, necrotic nodule of 6 mm in diameter was macroscopically found in a surgical specimen. Microscopically, the nodule was completely necrotized	A host immune response to chronic biliary tract infection might have been involved in the spontaneous regression of liver metastasis	Intraoperative B-mode ultrasonography examination did not show the nodule clearly. anatomical resection of liver segment III, where the mass had been located according to preoperative imaging findings, was performed. A yellowish, necrotic nodule of 6 mm in diameter was macroscopically found in a surgical specimen. Microscopically, the nodule was completely necrotized
Shuttleworth, 2023²⁵	78-year-old female, medical history of bladder cancer, total abdominal hysterectomy and bilateral salpingo-oophorectomy for endometriosis, congestive cardiac failure, hypertension, diet-controlled type 2 diabetes, chronic kidney disease (CKD) stage 3, and gout. She was an ex-smoker.	Colon	Histological examination showed a small focus on non-specific mucosal ulceration, with an inflammatory reaction extending into the muscularis propria. A few small mucin pools were noted within the muscularis propria at this point, but there was no evidence of dysplasia or invasive malignancy. 27 lymph nodes were identified, which were negative. There was no evidence of malignancy within the resected specimen.	local trauma could have stimulated inflammation and an immune response, or it could be that the biopsies removed the only focus of cancer.	Histological examination showed a small focus on non-specific mucosal ulceration, with an inflammatory reaction extending into the muscularis propria. A few small mucin pools were noted within the muscularis propria at this point, but there was no evidence of dysplasia or invasive malignancy. 27 lymph nodes were identified, which were negative. There was no evidence of malignancy within the resected specimen.
Shuttleworth, 2023²⁵	86-year-old female. History of chronic lymphoid leukemia (CLL), stage A low-level lymphocytosis	Colon	Histological examination revealed no evidence of any significant mucosal lesion, tumor, or polyp. Thirteen lymph nodes were present, all negative for malignancy.	local trauma could have stimulated inflammation and an immune response, or it could be that the biopsies removed the only focus of cancer.	Histological examination revealed no evidence of any significant mucosal lesion, tumor, or polyp. Thirteen lymph nodes were present, all negative for malignancy.
Imai, 2020²⁶	75-year-old man. History of brain infarction, atrial fibrillation, chronic heart failure, and glaucoma	anus	Five days after diagnosis, follow-up CF, the previously exposed vessel was not observed, and the rectal ulcer did not get worse. On a subsequent follow-up CF, 34 days after diagnosis of his ulcer, mucosal restoration was observed. Six months after diagnosis (1 year after implantation), epithelialization was observed, which was consistent with healing	None reported	Five days after diagnosis, follow-up CF, the previously exposed vessel was not observed, and the rectal ulcer did not get worse. On a subsequent follow-up CF, 34 days after diagnosis of his ulcer, mucosal restoration was observed. Six months after diagnosis (1 year after implantation), epithelialization was observed, which was consistent with healing
Coulier, 2018²⁷	76-year-old man	Greater omentum	Symptoms disappeared, and C-reactive protein returned to 17mg/L eight days later. Three weeks later, CT revealed substantial volume reduction of the mass. The central fluid collections had disappeared. The mass was now distinctly surrounded by a two-layer enhancing pseudocapsule. Three months later the lesion had nearly completely resolved and 6 months later the lesion was not visible any more on CT.	complete avulsion of the infarcted omental segment from its insertion, as suggested by the presence of a complete peripheral pseudo capsule, has led to a strong, resorptive foreign body reaction.	Symptoms disappeared, and C-reactive protein returned to 17mg/L eight days later. Three weeks later, CT revealed substantial volume reduction of the mass. The central fluid collections had disappeared. The mass was now distinctly surrounded by a two-layer enhancing pseudocapsule. Three months later the lesion had nearly completely resolved and 6 months later the lesion was not visible any more on CT.
Thavaraj et al., 2005²⁸
Warenius et al., 2009²⁹
American³⁰
Iinuma et al.³¹

References:

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