it is thought that cancer cells left in the colorectal tract are implanted following anastomosis . according to the japanese society for cancer of the colon and rectum ( jsccr ) guidelines 2010 for the treatment of colorectal cancer , anastomotic recurrence occurred in only 22 of all 5,230 ( 0.4% ) cases reported in the literature . in that study , over 95% of anastomotic recurrences developed within 3 years after surgery , and only one case occurred after 5 years from the initial surgery . we experienced a case of anastomotic recurrence of stage iia ( t3n0m0 ) sigmoid colon cancer 5 years and 4 months after surgery . there were no signs of recurrence at the time of surveillance performed 3 years after surgery . detecting recurrence while the lesion is still resectable can lead to a cure with operative treatment . this emphasizes the importance of conducting surveillance in cases of colorectal cancer , even more than 5 years after curative surgery . a 65-year - old female had a history of several cancers , including left breast cancer at 36 years of age , cecum cancer in her forties and right breast cancer at 64 years of age . her mother , younger sister and daughter also each had a history of breast cancer . at 60 years of age , the patient underwent sigmoidectomy and right colectomy with d3 lymph node dissection for both sigmoid colon cancer ( fig . 1 ) and transverse colon cancer . during that operation , lavage of the remnant colon the pathological diagnoses revealed both sigmoid colon cancer and transverse colon cancer of t3n0m0 , stage iia . both the oral and anal margins of the resected colon had a sufficient length : the transverse margin measured 135 mm ( oral wedge ) and 50 mm ( anal wedge ) , while the sigmoid margin measured 40 mm ( oral wedge ) and 50 mm ( anal wedge ) ( fig . at 3-year follow - up , colonoscopy and computed tomography revealed no signs of recurrence ( fig . , colonoscopy demonstrated surrounding flaring and swelling in the anastomotic area of the sigmoid colon ( fig . the levels of the tumor markers cea and ca19 - 9 were both within the normal limits at that time . there were no signs of recurrence in other locations , such as the liver and lungs , or other areas of the remnant colon . therefore , under a diagnosis of anastomotic recurrence over 5 years after surgery , we performed lower anterior resection . the tumor measured 45  35 mm and was located at the previous anastomotic site ( fig . pathology revealed histological features that resembled the pattern of the previous tumor , and there were masses of cancerous cells in the subserosal and muscular layers near the fissured muscular layer , which comprised the anastomotic area ( fig . in the mucous membranes surrounding the anastomotic area , there was hyperplasia of cancerous cells that pushed up layers from deeper mucous membranes . furthermore , there were no cancerous cells in the mucous membranes , which indicated that the cells were derived from the primary lesion ( fig . 3b ) . based on these observations , the final diagnosis was anastomotic recurrence of sigmoid colon cancer after surgery . there have been no signs of recurrence for the 2 years since the last surgery . the recurrence rate after curative resection for colorectal cancer depends on the tnm stage of the disease . the recurrence rate among stage i patients is only 3.7% . on the other hand , the recurrence rates among stage ii and stage iii patients are 13.3 and 30.8% , respectively . therefore , a careful follow - up may benefit patients with stage ii or iii cancer due to the higher recurrence rates observed in such cases . it is also known that the time to recurrence differs according to the tnm stage . the rate of recurrence has been found to increase gradually and consistently for 5 years in stage i patients , whereas in stage ii and iii patients , the rate increases rapidly for the first 3 years , then slowly for the next 2 years . therefore , intensive follow - up programs could be adopted for stage ii and iii patients for the first 3 years , followed by less intensive follow - up for the next 2 years . follow - up programs for patients who have undergone curative resection for colorectal cancer remain controversial . six randomized controlled trials of intensive versus non - intensive follow - up were recently reported [ 2 , 3 , 4 , 5 , 6 , 7 , 8 ] . in only two of these studies were there any significant differences in prognosis between the intensive follow - up group and the non - intensive follow - up group [ 6 , 7 ] . however , meta - analyses including these randomized controlled trials demonstrated that providing intensive follow - up after curative surgery improves survival [ 8 , 9 ] . compared to other types of recurrence , anastomotic recurrence is relatively easy to detect due to its apparent symptoms , such as bloody bowel discharge . however , in our case , there were no symptomatic signs of recurrence , and the recurrent tumor was detected only on colonoscopy performed as a routine examination 5 years after resection . therefore , the use of intensive follow - up programs including colonoscopy for 5 years after resection may benefit some populations of colorectal cancer patients . in conclusion , follow - up after curative resection for colorectal cancer should be continued for at least 5 years and must consist of an intensive follow - up program that includes colonoscopy . t. yamauchi , t. tanizawa and k. inada collected the data , administered the treatment and wrote the paper .
the incidence of anastomotic recurrence after curative resection of colorectal cancer is relatively low compared to that of other types of recurrence , such as hepatic , lung and local recurrence . 
 however , almost all cases of anastomotic recurrence of colorectal cancer occur within 3 years after surgery . 
 we experienced a rare case of anastomotic recurrence in whom colonoscopy revealed no signs of recurrence 3 years after surgery ; however , anastomotic recurrence was detected over 5 years after surgery . 
 a 60-year - old female with a history of surgery for cancer of the cecum in her forties underwent sigmoidectomy and right colectomy with d3 lymph node dissection for both stage iia sigmoid colon cancer and stage iia transverse colon cancer . computed tomography and 
 colonoscopy revealed no signs of recurrence 3 years after surgery ; however , 5 years and 4 months after surgery , colonoscopy demonstrated surrounding flaring and swelling in the anastomotic area of the sigmoid colon , and a biopsy revealed an adenocarcinoma . under the diagnosis of anastomotic recurrence 
 over 5 years after surgery , lower anterior resection was performed . 
 the patient has exhibited no other signs of recurrence in the 2 years since the last operation .