Clinical characteristics of metachronous colorectal tumors

Transcriptomic and genomic profiling of multiple primary colorectal cancers reveals intratumor heterogeneity and a distinct immune microenvironment

This study reported on the intratumor genomic and immunological heterogeneity of different tumor lesions from a single patient with multiple primary colorectal cancer (MPCC). The goal of this study was to explore the molecular and microenvironment characteristics of tumor lesions from different primary sites in a patient with MPCC. A total of three tumor lesions located in the hepatic flexure of the transverse colon, sigmoid colon, and rectum were collected from a 72-year-old male patient with MPCC. All three tumor samples were examined by using whole-exome sequencing (WES) and single-cell RNA sequencing (scRNA-seq). The transcriptome data of The Cancer Genome Atlas (TCGA) colon cancer (COAD) dataset were explored to characterize the biological impacts of certain immune cells. Only three nonsynonymous mutations were shared by all of the tumor lesions, whereas a number of single nucleotide variant (SNV) and copy number variation (CNV) mutations were shared by tumor samples from the sigmoid colon and rectum. Transcriptomic analysis showed that tumor lesions derived from the transverse colon had decreased levels of RTK, ERK, and AKT pathway activity, thus suggesting lower oncogenic properties in the transverse lesion compared to the other two samples. Further immune landscape evaluation by using single-cell transcriptomic analysis displayed significant intratumor heterogeneity in MPCC. Specifically, more abundant mucosal-associated invariant T (MAIT) cell infiltration was found in transverse colon tumor lesions. Afterwards, we found that higher MAIT cell infiltration may correlate with a better prognosis of patients with colon cancer (immunohistochemical status was MSI-L/pMMR) by using a publicly available TCGA dataset.

A novel risk prediction nomogram for early death in patients with resected synchronous multiple primary colorectal cancer based on the SEER database

BACKGROUND

Synchronous multiple primary colorectal cancer (SMPCC) involves the simultaneous occurrence of 2 or more independent primary malignant tumors in the colon or rectum. Although SMPCC is rare, it results in a higher incidence of postoperative complications and mortality compared to patients with single primary colorectal cancer (SPCRC).

METHODS

The clinical factors and survival outcomes of SMPCC patients registered on the Surveillance, Epidemiology, and End Results (SEER) database between 2000 and 2017 were extracted. The patients were divided into the training and validation cohorts using a ratio of 7:3. Univariate and multivariate logistic regression analyses were used to identify the independent risk factors for early death. The performance of the nomogram was evaluated using the concordance index (C-index), calibration curves, and the area under the curve (AUC) of a receiver operating characteristics curve (ROC). A decision curve analysis (DCA) was used to evaluate the clinical utility of the nomogram and standard TNM system.

RESULTS

A total of 4386 SMPCC patients were enrolled in the study and randomly assigned to the training (n = 3070) and validation (n = 1316) cohorts. The multivariate logistic analysis identified age, chemotherapy, radiotherapy, T stage, N stage, and M stage as independent risk factors for all-cause and cancer-specific early death. The marital status was associated with all-cause early death, and the tumor grade was associated with cancer-specific early death. In the training cohort, the nomogram achieved a C-index of 0.808 (95% CI, 0.784-0.832) and 0.843 (95% CI, 0.816-0.870) for all-cause and cancer-specific early death, respectively. Following validation, the C-index was 0.797 (95% CI, 0.758-0.837) for all-cause early death and 0.832 (95% CI, 0.789-0.875) for cancer-specific early death. The ROC and calibration curves indicated that the model had good stability and reliability. The DCA showed that the nomogram had a better clinical net value than the TNM staging system.

CONCLUSION

Our nomogram can provide a simple and accurate tool for clinicians to predict the risk of early death in SMPCC patients undergoing surgery and could be used to optimize the treatment according to the patient's needs.

Rates of metachronous adenoma after curative resection for left-sided or right-sided colon cancer

Background/Aims

We determined the rates of metachronous colorectal neoplasm in colorectal cancer (CRC) patients after resection for right (R)-sided or left (L)-sided cancer.

Methods

Consecutive CRC patients who had undergone surgical resection for curative intent in our hospital between 2001 and 2004 were identified. R-sided colonic cancers refer to cancer proximal to splenic flexure whereas L-sided cancers include rectal cancers. Patients were included only if they had a clearing colonoscopy performed either before or within 6 months after the operation. Findings of surveillance colonoscopy performed up to 5 years after colonic resection were included in the analysis.

Results

Eight hundred and sixty-three CRC patients underwent curative surgical resection during the study period. Three hundred and twenty-seven patients (107 R-sided and 220 L-sided) fulfilled the inclusion criteria and had at least 1 postoperative surveillance colonoscopy performed. The proportion of patients who had polyp and adenoma on surveillance colonoscopy was significantly higher among patients with L-sided than R-sided cancers (polyps: 30.9% vs. 19.6%, P=0.03; adenomas: 25.5% vs. 13.1%, P=0.01). The mean number of adenoma per patient on surveillance colonoscopy was also higher for patients with L-sided than R-sided tumors (0.52; 95% confidence interval [CI], 0.37–0.68 vs. 0.22; 95% CI, 0.08–0.35; P<0.01). Multivariate analysis showed that L-sided cancers, age, male gender and longer follow-up were independent predictors of adenoma detection on surveillance colonoscopy.

Conclusions

Patients with Lsided cancer had a higher rate of metachronous polyps and adenoma than those with R-sided cancer on surveillance colonoscopy.

Second primary colorectal cancer after the initial primary colorectal cancer

BACKGROUND

Initial primary colorectal cancer (IPCRC) has a high risk of developing into second primary colorectal cancer (SPCRC). Right-sided colon cancer (RCC) and left-sided colon cancer (LCC) have different characteristics and are considered to be two different entities. However, the different risks for SPCRC in categorized tumor sites and SPCRC subcategorized sites have not been fully elucidated to date. We aimed to compare incidence and survival of IPCRC and SPCRC and characterize the risk factors of SPCRC while also comparing the different SPCRC characteristics.

METHODS

We used the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) data to compute standardized incidence ratios (SIR) in order to estimate risk of SPCRC after IPCRC diagnosis. The most prominent risk factors for SPCRC were measured by multivariate regression analysis and the temporal trend of SPCRC incidence was assessed with Joinpoint regression. Survival of patients with SPCRC and IPCRC was compared by Kaplan-Meier analysis.

RESULTS

Patients with IPCRC were 1.73 times more likely to develop SPCRC (SIR = 1.73, 95% CI 1.69-1.78). SPCRC incidence declined since the first 8 years of IPCRC diagnosis to baseline. We demonstrated poorer survival with SPCRC compared with IPCRC while second RCC resulted in better survival compared with second LCC. Black ethnicity, age range 70-79, and LCC were associated with the highest risk of developing SPCRC.

CONCLUSION

The characteristic differences between second LCC and RCC were relatively narrow. Furthermore, in those with SPCRC, RCC had the best survival outcome.

Clinical characteristics and survival of patients with multiple metachronous esophageal tumor

BACKGROUND

The aim of this study is to determine the clinical characteristics and predictors of survival for patients with multiple metachronous esophageal tumors (MMET) and to compare the survival with patients that have single esophageal tumor (SET).

METHOD

We identified all cases of primary esophageal cancer from the Surveillance, Epidemiology and End Results program database from 2000 to 2013. The primary outcome was the development of a second esophageal cancer six months after the diagnosis of the first tumor. A secondary outcome was disease-specific death from esophageal cancer. Chi-square test was used to compare the tumor and demographic characteristics of patients with SET versus the first and second tumor characteristics of patients with MMET. Logistic regression was used to obtain the odds ratios between patients with secondary tumors and those with primary tumors. Accelerated life model was performed for patients with MMET to determine the predictors of survival.

RESULTS

Patients with MMET were more likely to have localized stage disease compared to those with SET (P < 0.0001). Distant stage disease for both first tumor (β = -0.402, P = 0.003) and second tumor (β = -0.301, P = 0.033) were predictors of increased mortality. The interval between the first and second tumor affected survival. Intervals of 2-5 years and > 5 years were associated with a reduced hazard with a β = 0.53 and 1.13, P < 0.0001, respectively.

CONCLUSION

Early development of a second tumor in MMET is associated with poorer survival. Patients with MMET may benefit from regular follow-up and intervention to prevent the development of a second tumor.

Various clinicopathological features of patients with metachronous colorectal cancer in relation to different diagnostic intervals

BACKGROUNDS

Clinicopathologic factors relating to developing metachronous colorectal cancer (CRC) have been reported. However, the effects of different diagnostic intervals on these risk factors required further analysis.

PATIENTS AND METHODS

This retrospective study comprised 14,481 patients diagnosed from January 1995 to December 2012. Metachronous CRC was defined as the occurrence of a second colorectal cancer at least 1 year post-operatively.

RESULTS

A total of 153 (1.06%) patients developed metachronous CRCs during the follow-up. Significantly higher rates of developing metachronous cancer occurred in male patients (1.2 vs 0.9%), patients with synchronous CRC (2.0 vs 1.0%), and patients with a positive family history of CRC (1.4 vs 0.9%). Pertaining to diagnostic intervals related to clinicopathological features, more severe staging was significant in the diagnostic interval between 2 and 3 years (35 vs 7.7%, 20.6%, 17.5%, P = .01) compared with other intervals. Male patients were more frequently detected to have CRC within 3 years compared with females (53.1 vs 29.1%, P = .005). For a diagnostic interval ≧ 5 years, a significantly higher rate of metachronous CRC located at the right colon was observed than that located at the left colon (36.6 vs 19.7%, p = 0.03).

CONCLUSIONS

We evinced that a diagnostic interval between 2 and 3 years was a key time for metachronous CRC diagnosis with worse staging distribution. Based on current findings, we recommend the stratification of metachronous CRCs into diagnostic intervals of 1-2, 2-3, and ≧ 3 years, as they exhibit significantly different characteristics.

Do Patients with Second Primary Colorectal Cancer Hold the Similar Prognosis and Therapeutic Benefits as Those with Initial Primary Colorectal Cancer?

Aim

The objective is to compare the differences on prognosis and the therapeutic benefits between initial and second primary colorectal cancer (pCRC).

Methods

A dataset containing 377,271 initial pCRC cases and 18,617 second pCRC cases from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) 1988-2015 was evaluated. Survival comparisons were made using the log-rank test. Cox proportional hazards models were used to assess the survival benefits.

Results

The cancer-specific survival rate of patients with initial pCRC was significantly higher than that of patients with second pCRC (5-years survival rate: 64.85% vs. 60.22%, P<0.001). The Chi-square of stratified log rank for age at diagnosis was lower than that for primary site, pTNM stage, sex, race, histology, and grade (Chi-square=86.73). There were almost no differences on therapeutic benefits between patients with initial and second pCRC except that treatments with chemotherapy were significantly associated with longer survival rate compared with treatments without chemotherapy among stage III surgical initial and second primary left-sided colon cancers patients (HR=0.764 vs. 0.581; P for interaction =0.008).

Conclusion

Patients with second pCRC have worse prognosis than those with initial pCRC primarily because of older age in the former group. The results evidenced that the therapeutic benefits on the prognosis for colorectal cancer were generally similar between patients with initial and second pCRC.

The risk and survival outcome of subsequent primary colorectal cancer after the first primary colorectal cancer: cases from 1973 to 2012

Background

Among colorectal cancer (CRC) survivors, how the prior tumor location affects the risk of subsequent primary colorectal cancer (SPCRC) and the outcome of those suffering from SPCRC remain unknown.

Methods

CRC cases diagnosed from 1973 to 2012 were screened for SPCRC development using the Surveillance, Epidemiology, and End Results database. The relative risk of SPCRC was estimated using the standardized incidence ratio. Survivals were analyzed using the Kaplan–Meier and Cox regression model.

Results

The overall risk of SPCRC increased by 27% in CRC survivors compared to that of the general population. The risk increased in patients with both prior right colon cancer (RCC) and left colon cancer (LCC), and was concentrated in the first 5 years after the prior diagnosis, and among young patients. Among the 6701 SPCRC patients identified, patients with prior RCC were more likely to be elderly, female, and with more low or undifferentiated disease than those with prior LCC or rectal cancer (ReC). The overall survivals differed by both prior tumor location (P < 0.0001) and age (P < 0.0001), and the difference by tumor location remained significant when adjusted or stratified by any other potential prognostic factor except age. The cancer specific survivals differed by age (P < 0.0001) rather than by prior tumor location (P = 0.455).

Conclusions

The overall risk of SPCRC increased among patients with both prior RCC and LCC, but not among those with ReC. The different survival outcomes in CRC survivors suffering from SPCRC were largely explained by the patient age but not by the prior tumor location.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3765-8) contains supplementary material, which is available to authorized users.

Risk of subsequent primary malignancies among patients with prior colorectal cancer: a population-based cohort study

BACKGROUND

The site-distribution pattern and relative risk of subsequent primary malignancies (SPMs) in colorectal cancer (CRC) patients remains to be determined.

MATERIALS AND METHODS

A population-based cohort of 288,390 CRC patients diagnosed between 1973 and 2012 from the Surveillance, Epidemiology, and End Results database was retrospectively reviewed. Standardized incidence ratios were calculated to estimate the relative risk for SPMs.

RESULTS

The overall risk of SPMs increased in CRC patients (standardized incidence ratio 1.02) in the first 5 years after CRC diagnosis compared with that in the general population, and was negatively related to age at diagnosis. Risk increased significantly for cancers of the small intestine, ureter, colorectum, renal pelvis, endocrine system, and stomach, and decreased significantly for cancers of the gallbladder, liver, myeloma, and brain, as well as lymphoma. Patients with different prior CRC subsites showed specific sites at high risk of SPM. Prior right-sided colon cancer was associated with cancers of the small intestine, ureter, renal pelvis, thyroid, stomach, pancreas, and breast and prior left-sided colon cancer associated with secondary CRC, whereas rectal cancer was associated with cancers of the vagina, urinary bladder, and lung.

CONCLUSION

Risk of SPMs increases in CRC survivors, especially in the first 5 years after prior diagnosis. Intensive surveillance should be advocated among young patients, with specific attention to the small intestine, colorectum, renal pelvis, and ureter. The common sites at high risk of SPM originate from the embryonic endoderm. Genetic susceptibility may act as the main mechanism underlying the risk of multiple cancers.

Incidence and risk factors of metachronous colorectal neoplasm after curative resection of colorectal cancer in Korean patients

OBJECTIVE

Early detection and endoscopic removal of metachronous neoplasms are important preventive strategies for patients with colorectal cancer (CRC) after curative tumor resection. We aimed to determine the incidence of and the risk factors for metachronous colorectal neoplasms after curative resection for CRC.

METHODS

We retrospectively reviewed clinical data of patients who underwent curative resection for CRC at the National Cancer Center, Korea, from July 2004 to July 2007 and were followed up for a mean duration of 40.7 months. The incidence of and the risk factors for developing metachronous neoplasms were analyzed.

RESULTS

A total of 1049 patients were included in this study. A follow-up colonoscopy showed that 454 (43.3%) patients developed metachronous neoplasms, including 46 (4.4%) with advanced adenoma or cancer. Univariate analyses revealed that age ≥ 60 years, male gender, diabetes mellitus, hypertension, synchronous adenoma, synchronous multiple adenoma and synchronous advanced adenoma were associated with the development of metachronous neoplasms. Baseline risk factors associated with metachronous advanced neoplasm were age ≥ 60 years, synchronous multiple adenoma and synchronous advanced adenoma. Multivariate analysis showed that age ≥ 60 years, synchronous adenoma and diabetes mellitus were risk factors for the development of metachronous neoplasms. The cumulative incidence of metachronous neoplasms was higher in patients with these risk factors than in those without.

CONCLUSIONS

Elder age, synchronous adenoma and diabetes mellitus are risk factors for developing metachronous neoplasia. Therefore, careful surveillance colonoscopy are necessary for these patients.

The incidence and risk factors of metachronous colorectal cancer: an indication for follow-up

BACKGROUND

Patients with colorectal cancer are at risk for developing metachronous colorectal cancer. The purpose of posttreatment surveillance is to detect and remove premalignant lesions to prevent metachronous colorectal cancer.

OBJECTIVE

The aim of this study was to investigate the incidence of and predictive factors for metachronous colorectal cancer in patients with newly diagnosed colorectal cancer.

DESIGN AND PATIENTS

The data on all patients with newly diagnosed colorectal cancer between 1995 and 2006 were obtained from the Rotterdam Cancer Registry in The Netherlands and studied for metachronous colorectal cancer.

MAIN OUTCOME MEASURES

The annual incidence rate and the standardized incidence ratios were calculated.

RESULTS

In total, colorectal cancer was diagnosed in 10,283 patients; there were 39,974 person-years of follow-up. The mean annual incidence rate of metachronous colorectal cancer was 314/100,000 person-years at risk during 10 years of follow-up, corresponding with a mean annual incidence of 0.3% and a cumulative incidence of 1.1% at 3 years, 2.0% at 6 years, and 3.1% at 10 years. The incidence of metachronous colorectal cancer after resection of a first colorectal cancer is significantly higher than the incidence of colorectal cancer in an age- and sex-matched general population (standardized incidence ratio 1.3, 95% CI 1.1-1.5). This difference is especially seen during the first 3 years after first colorectal cancer diagnosis (standardized incidence ratio 1.4, 95% CI 1.1-1.8). The presence of synchronous colorectal cancer was the only significant risk factor for developing metachronous colorectal cancer (relative risk 13.9, 95% CI 4.7-41.0).

CONCLUSIONS

Despite the availability of colonoscopy, metachronous colorectal cancer is still seen during follow-up in patients with colorectal cancer; the highest risk is during the first 3 years after initial diagnosis. For this reason, a follow-up colonoscopy is useful at a short-term interval after colorectal cancer diagnosis. The presence of synchronous colorectal cancer at the time of first colorectal cancer diagnosis is the only predictive risk factor for developing metachronous colorectal cancer. Tailored surveillance programs may be considered in patients with a diagnosis of synchronous tumors.

A study of aspects on gender and prognosis in synchronous colorectal cancer

AIM

To assess differences in demography, pathology and prognosis with tumor multiplicity in colorectal cancer.

METHOD

A retrospective single centre study of all patients surgically treated for a colorectal cancer during 1999-2008 (n = 2524). Patient characteristics, pathology and follow-up data were retrieved. Survival was assessed by overall and cancer specific survival.

RESULTS

60 (2.4%) patients had a synchronous cancer (SC), associated with right colon, higher age, more assessed lymph nodes but a lower frequency of stage III/IV disease (42% vs. 52%). There was no overall prognostic difference between single or multiple cancer patients but females with SC had better survival than corresponding males (P < 0.046).

CONCLUSION

The incidence of synchronous cancers was 2.4% with the second cancer often located in right colon. The SC patients were older than single tumor patients, had a lower frequency of stage III/IV disease and the females with SC had a better survival prognosis than corresponding males.

Clinicopathologic characteristics of metachronous colorectal cancer: an analysis of 31 cases

AIM: To investigate the clinicopathologic characteristics of metachronous colorectal cancer and to facilitate its diagnosis and treatment.

METHODS: Thirty-one cases diagnosed with metachronous colorectal cancer were treated and closely followed up. Clinical records such as the occurrence, distribution, and stage of index and secondary tumors were retrospectively reviewed. The prognosis after surgery was also analyzed.

RESULTS: Secondary tumors occurred in all 31 patients in an average of 5.1 years after the diagnosis of their index colorectal cancers. Three cases had a third tumor after an average of 3.8 years, and then two of them had a fourth tumor after an average interval of 3.5 years. Of the 31 cases, 45.2 percent of them had synchronous adenoma. The majority of index tumors (59.5%) were located in the rectum or sigmoid colon. Most of the secondary tumors were similar to or better than their index tumors in the levels of differentiation and pathological grades. An average survival of 8.3 years was achieved after the radical operation of the index tumor. The 5-year survival rate reached 84.8%.

CONCLUSION: In patients with metachronous colorectal cancer, the primary tumor is more commonly located in the rectum or sigmoid colon. With the occurrence of subsequent tumor, interval time was shortened gradually. An intensive periodic checkup after operation is strongly recommended for improvement of prognosis.

Clinical characteristics of multiple primary colorectal cancers

PURPOSE

Although multiple primary colorectal cancer has been recognized as a significant clinical entity, its clinical and pathological features and its prognosis are still controversial. The purpose of this study was to clarify clinical and pathological features of multiple primary colorectal cancer.

MATERIALS AND METHODS

Among 1669 patients who underwent surgery for primary colorectal cancer from January 1997 to June 2005, 26 patients (1.6%) with multiple primary colorectal cancer were identified. We reviewed clinical characteristics including diagnostic interval, lesions, operating methods, and TNM stage, and we defined the index lesion as the most advanced lesion among the synchronous lesions. For the purposes of the study, the colon and rectum were classified into three segments. The right-side colon included the appendix, cecum, ascending colon, hepatic flexure, and transverse colon, and the left-side colon included the splenic flexure, descending colon, and sigmoid colon.

RESULTS

Of the 26 patients with multiple primary colorectal cancers, nineteen patients were male and seven patients were female, with a mean age of 61.5 years. Nineteen patients had synchronous colorectal cancers and seven patients had metachronous colorectal cancers. In the metachronous cases, the mean diagnostic interval was 36.8 months. The site of the first lesion in metachronous colorectal cancers was the right colon in five cases (71.4%) and the left colon in two cases (28.6%), and the site of the second lesion was the rectum in six cases (55.5%), the right colon in three cases (33.3%), and the left colon in one case. The TNM stage of the second lesions in the metachronous colorectal cancers was stage II in four cases (57.1%), stage III in one case (14.3%), and stage IV in one case (14.3%). For the synchronous colorectal cancers, the operation methods were single-segment resection combined with endoscopic mucosal resection in five cases (26.3%), single-segment resection alone in six cases, two-segment resection in six cases, and total colectomy in two cases.

CONCLUSION

In metachronous colorectal cancers, the secondary lesions were later-stage cancer. Therefore, careful postoperative follow-up is necessary for patients who have undergone surgery for colorectal cancers. Further study of therapeutic modalities is important for synchronous colorectal cancers.

Clinical features, diagnosis, treatment and prognosis of multiple primary colorectal carcinoma

AIM: To investigate the clinical features, diagnosis, treatment and prognosis of multiple primary colorectal carcinomas (MPCC).

METHODS: A retrospective analysis of 37 patients with MPCC from 1974 to 1998 was carried out.

RESULTS: The incidence of MPCC was 2.74% (37/1348) in patients with primary colorectal carcinomas, 15 cases of them were patients with synchronous carcinomas (SC) and 22 cases were diagnosed as metachronous carcinomas (MC). Most tumors were located in the right colon and rectum. Fifty-five percent (12/22) of MC were diagnosed within 3 years after tumor resection and 41% (9/22) of MC occurred after 8 years. Radical resections were performed in all patients except for 1 case. The 5-year survival rate of SC was 72.7% (8/11) and that of MC after the first cancer and second cancer was 71.4% (15/21) and 38.9% (7/18), respectively.

CONCLUSION: The results indicate the importance of complete preoperative examination, careful intraoperative exploration and periodic postoperative surveillance. Early diagnosis and radical resection can increase survival rate of MPCC.

Microsatellite instability in double primary cancers of the colorectum and stomach

Little is known about genetic alterations of patients who present multiple primary cancers. We hypothesized that microsatellite instability (MSI) is one of the underlying genetic factors in the development of double primary cancers in colorectal cancer patients. We examined for MSI in 41 colorectal cancer patients who presented with extra-colonic primary cancers consisted of 17 gastric and 24 non-gastric cancers. Coincident MSI+ in tumors of two organs were observed in 3 (17.7%) of 17 patients with colon and stomach cancers and 0 of 24 patients with colon and non-gastric cancers (P =.03). In 17 patients with colon and stomach cancers, 6 (31.6%) of 19 colon cancers and 3 (17.7%) of 17 gastric cancers exhibited MSI+. Among four patients with metachronous colon cancers who were identified within the 41 double primary cancer patients, two patients were associated with the MSI+ phenotype. In summary, the prevalent coincidence of MSI suggests that genetic defect of mismatch repair deficiency may be responsible for a small subset of double primary cancers of the colorectum and stomach.

Microsatellite instability in multiple colorectal tumors

Tumor multiplicity is a hallmark of hereditary cancers: in the colon-rectum multiple tumors represent 5-10% of all colorectal cancer cases. A portion of these cases belongs to hereditary non-polyposis colorectal cancer (HNPCC), a genetic cancer syndrome due to mismatch repair (MMR) gene mutations, phenotypically expressed as microsatellite instability (MSI); the majority of multiple tumors, however, is apparently without any family history. We analyzed 78 (38 synchronous and 40 metachronous) neoplasms from 37 patients with multiple tumors of the large bowel, both HNPCC and sporadic, with the aim of identifying a common genetic basis in multiple tumors. DNA was extracted from normal and cancerous formalin-fixed tissue and was analyzed for MSI using 6 markers. Tumors showing MSI in at least 2 of 6 microsatellite loci were defined as MSI(+). The overall number of MSI(+) tumors was 22 (28.2% of the total). A significant difference in the rate of MSI(+) between HNPCC and sporadic tumors was observed (85% vs. 17%). In the same patients, the MSI phenotype of synchronous tumors (both HNPCC and sporadic) tended to be more concordant than that of the metachronous ones. The higher frequency of MSI in HNPCC than in sporadic tumors, even when multiple, suggests that the involvement of MMR genes in the pathogenesis of the sporadic cases may be uncommon, thus confirming that screening for MSI in multiple colorectal tumors could be a useful tool in the identification of HNPCC in the general population.

Metachronous colorectal cancers

BACKGROUND

Up to 9 per cent of patients who undergo resection for colorectal cancer develop metachronous cancers. There is no consensus on the detection and management of such cancers.

METHODS

The literature was reviewed exhaustively regarding the incidence, clinical characteristics, detection, treatment and molecular genetics of metachronous colorectal cancers. This was based on a Medline search from 1966 to December 1997 for articles on metachronous colorectal cancers. A manual search was also performed on references quoted in these articles. All publications relevant to this study were included.

RESULTS

Although the underlying causes for metachronous colorectal cancers are yet to be elucidated, risk factors for the disease have been identified. These include the presence of synchronous polyps or cancers, a history of metachronous cancers, and hereditary non-polyposis colorectal cancer (HNPCC).

CONCLUSION

Preoperative colonoscopy and postoperative colonoscopic surveillance are essential in identifying patients at risk of metachronous colorectal cancer. A total colectomy and ileorectal anastomosis should be considered for some patients, certainly for those with HNPCC.

Outcome after multiple colorectal tumours

BACKGROUND

Patients with primary colorectal cancers have a higher risk of development of second tumours synchronously or metachronously. This special group of patients raise a particular interest in their characteristics and outcome.

METHODS

The records of 1009 patients with colorectal cancer were scrutinized. A group with multiple cancers was identified. Perioperative investigations, patterns of follow-up, pathological variables and outcome were noted.

RESULTS

There were 22 patients with metachronous tumours and 39 with synchronous tumours following 'curative' operations in 20 and 28 respectively. There was no difference in Dukes classification between the two groups: Polyps were associated with metachronous lesions in ten of 22 patients and synchronous lesions in 17 of 39 patients. Five-year survival was 75 per cent for patients with metachronous tumours and only 18 per cent for those with synchronous tumours.

CONCLUSION

In this study patients with metachronous tumours seemed to do very well while those with synchronous lesions did very badly. There were no identifiable demographic or clinical characteristics to account for this. There is a need to study this group of patients and identify factors like tumour biology or host resistance which prevent spread of tumour.

Characteristics of metachronous colorectal carcinoma occurring despite colonoscopic surveillance

PURPOSE

Metachronous colorectal cancer still occurs in a small percentage of patients, despite colonoscopic surveillance. Cancers in hereditary nonpolyposis colorectal cancer for which there is a high risk of metachronous cancer show distinctive DNA changes termed replication errors (RER+). Ten to 20 percent of sporadic colorectal cancers are also RER+. The aim of this study was to identify factors predictive of metachronous colorectal cancer, despite colonoscopic surveillance. Clinicopathologic characteristics and RER status of cancers were examined.

METHODS

Colorectal cancer patients, who entered into a surveillance program of being examined with colonoscopy within six months of surgery and then at intervals of three years thereafter, were reviewed. The 433 patients compliant with the protocol who had had more than one colonoscopy had been followed up for a mean of 3.8 +/- 2.2 years. DNA was extracted from archival paraffin-embedded cancer tissue for determination of RER status.

RESULTS

Ten cases of metachronous cancer were identified, giving a rate of 0.61 percent per year. The site of the index cancer in patients who later developed metachronous cancer was predominantly proximal (P = 0.0007), and these cancers were more likely to have mucinous histology (P < 0.0005). Three of 10 (30 percent) index cancers were RER+, which was not significantly different from unselected series of control colorectal cancers in which 20 of 108 (18.5 percent) were RER+.

DISCUSSION

This study documents the rate of metachronous cancer among patients compliant with a defined colonoscopic screening program and suggests that the risk is highest in patients with a proximal mucinous cancer. RER status does not appear to be a very strong predictive factor, and this study does not support its use as a guide to the frequency of surveillance colonoscopy. More data would be required to determine if RER positivity conferred a relative risk of 3.3 or less.

Frequency and clinical features of multiple tumors of the large bowel in the general population and in patients with hereditary colorectal carcinoma

BACKGROUND

Reports on the frequency of multiple carcinomas of the colon and rectum have varied from 3-4% to more than 10% of all tumors of the large bowel.

METHODS

We reviewed the files of a specialized colorectal cancer registry with the following objectives: a) to determine the frequency of multiple tumors (synchronous or metachronous) in the general population; b) to compare these values with those observed in patients with hereditary nonpolyposis colorectal carcinoma (HNPCC); and c) to evaluate the clinical outcome of patients with multiple tumors and the role of other clinical parameters in the development of these neoplasms.

RESULTS

From 1984 to 1992, 53 patients with multiple tumors (of 1298 registered patients, 4%) had large bowel carcinoma; 33 (2.5%) were synchronous and 20 (1.5%) metachronous. The total number of multiple colorectal carcinomas was 95, which was 7% of all registered colorectal carcinomas (1337 carcinomas in 1298 patients). Multiple tumors occurred significantly more often in patients with HNPCC than in those with sporadic carcinomas (P < 0.001); this increased prevalence was more marked for metachronous lesions, which occurred almost 4 times more often in patients with HNPCC (5.8% vs. 1.3%; P < 0.001). The average interval of time between the first and the second malignancy was 8.7 years; there was no significant difference between hereditary and sporadic tumors. Patients with synchronous tumors did not show appreciable differences in survival when compared with individuals who had single neoplasms. In contrast, a poor clinical outcome was observed in patients with metachronous tumors after the development of the second carcinoma. Finally, polypoid adenomas of the large bowel were found significantly more often in patients with multiple primary tumors than in those with a single tumor.

CONCLUSIONS

These results emphasize the importance of preoperative pancolonoscopy for the identification of possible synchronous tumors (both benign and malignant) and long-lasting endoscopic follow-up for the detection of recurrent or metachronous lesions. The conclusions are even more pertinent for patients with HNPCC, whose risk of metachronous tumors is significantly higher than that of patients with sporadic carcinoma.