Survival of the Hmong population diagnosed with colon and rectal cancers in the United States.

BACKGROUND: The Hmong population constitutes an independent ethnic group historically dispersed throughout Southeast Asia; fallout from the Vietnam War led to their forced migration to the United States as refugees. This study seeks to investigate characteristics of the Hmong population diagnosed with in colorectal cancer (CRC) as well as survival within this population. METHODS: Cases of colon and rectal adenocarcinoma diagnosed between 2004 and 2017 were identified from the National Cancer Database (NCDB). Summary statistics of demographic, clinical, socioeconomic, and treatment variables were generated with emphasis on age and stage at the time of diagnosis. Cox-proportional hazard models were constructed for survival analysis. RESULTS: Of 881,243 total CRC cases within the NCDB, 120 were classified as Hmong. The average age of Hmong individuals at diagnosis was 58.9 years compared 68.7 years for Non-Hispanic White (NHW) individuals (p < 0.01). The distribution of analytic stage differed between the Hmong population and the reference NHW population, with 61.8% of Hmong individuals compared to 45.8% of NHW individuals with known stage being diagnosed at stage III or IV CRC compared to 0, I, or II (p = 0.001). However, there was no difference in OS when adjusting for potential confounders (HR 1.00 [0.77-1.33]; p = 0.998). CONCLUSIONS: Hmong individuals are nearly a decade younger at the time of diagnosis of CRC compared to the NHW individuals. However, these data do not suggest an association between Hmong ethnicity and overall survival, when compared to the NHW population.

Colon and rectal cancer: An emergent public health problem.

Colorectal cancer ranks third globally, with a high mortality rate. In the United States, and different countries in Europe, organized population screenings exist and include people between 50 and 74 years of age. These screenings have allowed an early diagnosis and consequently an improvement in health indicators. Colon and rectal cancer (CRC) is a disease of particular interest due to the high global burden associated with it and the role attributed to prevention and early diagnosis in reducing morbidity and mortality. This study is a review of CRC pathology and includes the most recent scientific evidence regarding this pathology, as well as a diagnosis of the epidemiological situation of CRC. Finally, the recommendation from a public health perspective will be discussed in detail taking into account the context and the most current recommendations.

Diverging likelihood of colon and rectal cancer in Yogyakarta, Indonesia: A cross sectional study.

OBJECTIVES: Colon and rectal cancer are associated with different risk factors and prognostic. However, this discrepancy has not been widely explored in the local population. This study aimed to investigate the site-specific likelihood of colorectal cancer (CRC) incidence in the Yogyakarta province, Indonesia. METHODS: This cross-sectional study analyses 1,295 CRC cases diagnosed in 2008-2019 registered in the Yogyakarta population-based cancer registry (PBCR) database. Cases were grouped into colon and rectal cancer. Log-binomial regression was used to determine the relative risk of either colon or rectal cancer across different gender, age group, and rurality of residence. The age-specific rates were calculated by age group and temporal trend for each group were analyzed using joinpoint regression. RESULTS: Females displayed higher odds of colon cancer (relative risk/RR = 1.20, 95%CI = 1.02-1.41) and lower odds of rectal cancer (RR = 0.92, 95%CI = 0.85-0.99). Elevated odds of colon cancer were observed in younger age group, especially 30-39 (RR = 1.87, 95%CI = 1.10-3.19), while decreased odds of rectal cancer was apparent in age group 30-39 and 40-49 (RR = 0.75, 95%CI = 0.60-0.93 and RR = 0.82, 95%CI = 0.69-0.98, respectively). Living in urban or rural areas did not significantly influence the odds of either having colon (RR = 0.98, 95%CI = 0.82-1.17) or rectal cancer (RR = 1.01, 95%CI = 0.93-1.10). During 2008-2019, trends of colon cancer in age <50 increased by 8.15% annually while rectal cancer displayed a 9.71% increase annually prior to 2017, followed by a 17.23% decrease until 2019. CONCLUSIONS: Yogyakarta population shows higher odds of young-onset colon cancer, especially between age 30-39 years old. Overall observation of trend shows increasing incidence in young-onset colon cancer, and non-significant decrease in rectal cancer.

Trends and Variation in the Use of Radiotherapy in Non-metastatic Rectal Cancer: a 14-year Nationwide Overview from the Netherlands.

AIMS: This study describes nationwide primary radiotherapy utilisation trends for non-metastasised rectal cancer in the Netherlands between 2008 and 2021. In 2014, both colorectal cancer screening and a new guideline specifying prognostic risk groups for neoadjuvant treatment were implemented. MATERIALS AND METHODS: Patients with non-metastasised rectal cancer in 2008-2021 (n = 37 510) were selected from the Netherlands Cancer Registry and classified into prognostic risk groups. Treatment was studied over time and age. Multilevel logistic regression analyses were carried out to identify factors associated with (i) radiotherapy versus chemoradiotherapy use for intermediate rectal cancer and (ii) chemoradiotherapy without versus with surgery for locally advanced rectal cancer. RESULTS: For early rectal cancer, the use of neoadjuvant radiotherapy decreased (15% to 5% between 2008 and 2021), whereas the use of endoscopic resections increased (8% in 2015, 17% in 2021). In intermediate-risk rectal cancer, neoadjuvant chemoradiotherapy (43% until 2011, 25% in 2015) shifted to radiotherapy (42% in 2008, 50% in 2015), the latter being most often applied in older patients. In locally advanced rectal cancer, the use of chemoradiotherapy without surgery increased (2-4% in 2008-2013, 17% in 2019-2021). Both neoadjuvant treatment in intermediate disease and omission of surgery following chemoradiotherapy in locally advanced disease varied with increasing age (odds ratio>75vs<50: 2.17, 95% confidence interval 1.54-3.06) and treatment region (Southwest and Northwest odds ratio 0.63, 95% confidence interval 0.42-0.93 and odds ratio 0.65, 95% confidence interval 0.44-0.95, respectively, compared with the North). CONCLUSION: Treatment patterns in non-metastasised rectal cancer significantly changed over time. Effects of both the national screening programme and the new treatment guideline were apparent, as well as a paradigm shift towards organ preservation (watch-and-wait). Observed regional variations may indicate adoption differences regarding new treatment strategies.

Value of Size and Malignant Features of Lateral Lymph Nodes in Risk Stratification at Lateral Local Recurrence of Rectal Cancer: A National Cohort Study.

BACKGROUND: Patients with rectal cancer who have enlarged lateral lymph nodes (LLNs) have an increased risk of lateral local recurrence (LLR). However, little is known about prognostic implications of malignant features (internal heterogeneity, irregular margins, loss of fatty hilum, and round shape) on MRI and number of enlarged LLNs, in addition to LLN size. METHODS: Of the 3,057 patients with rectal cancer included in this national, retrospective, cross-sectional cohort study, 284 with a cT3-4 tumor located ≤8 cm from the anorectal junction who received neoadjuvant treatment and who had visible LLNs on MRI were selected. Imaging was reassessed by trained radiologists. LLNs were categorized based on size. Influence of malignant features and the number of LLNs on LLR was investigated. RESULTS: Of 284 patients with at least 1 visible LLN, 122 (43%) had an enlarged node (≥7.0 mm) and 157 (55%) had malignant features. Of the 122 patients with enlarged nodes, 25 had multiple (≥2). In patients with a single enlarged node (n=97), a single malignant feature was associated with a 4-year LLR rate of 0% and multiple malignant features was associated with a rate of 17% (P=.060). In the group with multiple malignant features, their disappearance on restaging was associated with an LLR rate of 13% compared with an LLR rate of 20% for persistent malignant features (P=.532). The presence of intermediate-size LLNs (5.0-6.9 mm) with at least 1 malignant feature was associated with a 4-year LLR rate of 8%; the 4-year LLR rate was 13% when the malignant features persisted on restaging MRI (P=.409). Patients with multiple enlarged LLNs had a 4-year LLR rate of 28% compared with 11% for those with a single enlarged LLN (P=.059). CONCLUSIONS: The presence of multiple enlarged LLNs (≥7.0 mm), as well as multiple malignant features in an enlarged node contribute to the risk of developing an LLR. These radiologic features can be used for clinical decision-making regarding the potential benefit of LLN dissection.

Survival and Prognosis for Patients with Rectal Melanomas in the United States: A SEER-Based Study.

PURPOSE: Limited attention was paid to focus on rectal melanomas (RM). This study aimed to evaluate the survival rate and prognostic factors of RM. METHODS: The data for patients with RM from Surveillance, Epidemiology, and End Results (SEER) database were used to analyze tumor survival. Kaplan-Meier method and log-rank test were employed to estimate cancer-specific survival (CSS) and overall survival (OS). A nomogram was established based on the risk factors of survival by the forest plot for multivariate Cox regression analysis. Receiver operating characteristic (ROC) and calibration curve were conducted for validation. RESULTS: A total of 187 patients with RM were selected to perform survival analyses. The median survival time of OS was 12 months (range: 0-146 months), and the median survival time of CSS was 12 months (range: 0-74 months). Patients' age, tumor size, stage, the number of nodes examined, surgery, and radiation were identified as prognostic indicators for CSS by the forest plot for multivariate Cox regression analysis. The nomogram was validated as a reliable model for CSS. CONCLUSION: Clinicopathologic relevance with tumor prognosis was confirmed in this study. Our nomogram can provide a relatively accurate prediction of the survival rate of patients with RM.

Validity assessment of the POLARS score tool in the prediction of post rectal cancer surgery LARS score in a population-based Swedish cohort.

OBJECTIVE: Low anterior resection syndrome (LARS) is one of the most common functional impairments after rectal cancer surgery with a high impact on quality of life. The Pre-Operative LARS score (POLARS) nomogram and its online tool has been developed to predict the degree of postoperative LARS. The aim of this study was to analyse how accurately the POLARS score could predict LARS scores when compared with actual patient-reported LARS (PR-LARS) scores in a population-based Swedish cohort. DESIGN: This retrospective cohort study included patients who underwent curative rectal cancer surgery between 2007 and 2013 in Stockholm County and were identified using the Swedish Colorectal Cancer Registry (SCRCR). Information regarding preoperative risk factors, patient and treatment characteristics, and presence of LARS postoperatively were collected from patient charts, SCRCR and patient questionnaires. The POLARS model formula was used to predict LARS scores, which then were compared with the actual PR-LARS scores. Individual LARS score differences between the two estimates were shown with a modified Bland-Altman plot of difference. RESULTS: The cohort included 477 patients, of whom 359 (75%) of patients were categorised as having no/minor LARS based on the POLARS score. The correctly identified patients by the POLARS score were 80/255 (31%) in the major LARS group and 184/222 (83%) no/minor LARS group. The sensitivity was 31% for major LARS and the positive predictive value was 68%. CONCLUSION: The POLARS score has a low sensitivity for major LARS in this Swedish cohort. Other methods to predict the risk of LARS need to be developed.

Cancer and COVID-19: US cancer incidence rates during the first year of the pandemic.

BACKGROUND: The COVID-19 pandemic has had a profound global impact on health-care systems and patient outcomes. However, the specific effects of the pandemic on cancer incidence rates in the United States during its initial year remain unknown. METHODS: In this study, we analyzed data from the Surveillance, Epidemiology, and End Results-22 registries, which encompass approximately 50% of the US population. We investigated changes in monthly incidence rates stratified by various factors, including cancer type, stage, age group, sex, race and ethnicity, socioeconomic status, rural-urban status, and registry locations. We compared the incidence rates observed during the pandemic with those from the previous year. RESULTS: Our findings revealed a decline in incidence rates for all cancer sites combined starting in March 2020, coinciding with the implementation of stay-at-home orders. This decline reached its lowest point in April 2020 and persisted at a lower level until May 2020. Notably, compared with April 2019, the incidence rates in April 2020 dropped by 48.1% and did not consistently return to prepandemic levels. The reduction in cancer rates was more pronounced in urban and affluent counties. Across all cancer types, there was a statistically significant decrease in incidence rates during the pandemic, with the largest declines observed in thyroid (71.2%), prostate (57.9%), breast (54.9%), and colon and rectum cancers (54.1%). Furthermore, these decreases were primarily observed in early stage rather than late-stage disease. CONCLUSIONS: The COVID-19 pandemic had a statistically significant impact on cancer outcomes. Monitoring long-term consequences of the pandemic on cancer incidence, stage at diagnosis, and mortality trends will be crucial.

Temporal trends in age- and stage-specific incidence of colorectal adenocarcinomas in Germany.

BACKGROUND: A national colorectal cancer (CRC) screening programme was launched in 2002 in Germany. A comprehensive evaluation of the programme effectiveness using real-world data is still lacking. In addition, there are regional reports on increasing colorectal cancer incidence in younger populations. Therefore, we aimed to describe and compare the overall, age- and stage-specific incidence trends for colorectal, colon and rectal cancer. METHODS: We used data from seven population-based cancer registries in Germany. We report absolute and relative changes in incidence rates between the early screening phase (2003-2005) and the most recent time period available (2015-2017), as well as annual percent changes. We analysed incidences according to tumour site (colorectum, colon, and rectum) and to six age groups (young adults: 15-34, 35-39, 40-49, screening-entitled/older adults: 50-54, 55-69 and 70 + years old). RESULTS: In our sample of 271,011 colorectal adenocarcinomas, about two-thirds were located in the colon and 95% of them occurred in the age group 50+ (50-54: 5%, 55-69: 32.8%, 70+: 57.2%). For the time period 2003-2005 the age-specific incidence rates of individuals in the age group 55-69 were about 76/100,00 for colon and 54/100,000 for rectal cancer (age group 70 + colon: 179/100,000; rectum: 84/100,000). The incidence rates in young adults were less than 13% of that of individuals in the age group 55-69 (< 5% of individuals aged 70+; <33% of individuals aged 50-54). Over time, incidence decreased in individuals at the age of 55+, for all subsites considered as well as for early and late stage cancers (with few exceptions), while incidence of young adult CRC (both early and late stage) increased steepest in the youngest age groups. For late stage rectal cancer, a shift was observed in all age groups from UICC stage IV to stage III being the most frequent stage. CONCLUSIONS: Six years after the introduction of the national colonoscopy screening program, late stage CRC incidence began to decline substantially in the screening-eligible age groups (55-69, 70+). It is likely that this decline and the increase in early stage CRC observed in younger age groups can be attributed to the program. Long lasting public awareness campaigns for CRC screening might have led to opportunistic screening in younger adults. Whether these benefits outweigh the possible harm of screening in younger age groups remains unclear.

Post-colonoscopy rectal cancer in Swedish patients with Crohn's disease 2001-2015: a population-based case review study.

OBJECTIVE: Post-colonoscopy colorectal cancer (PCCRC) is a key quality indicator of colonoscopy, and PCCRC rates are high in the IBD population. Rectal cancer, an important risk factor for PCCRC among patients with Crohn's disease (CD), has not previously been examined. METHODS: Swedish adult patients with CD who underwent a colonoscopy within 36 months before a rectal cancer diagnosis between 2001 and 2015 were identified through the National Patient and Cancer registers. Their medical records were reviewed and a root-cause analysis and a sub-categorization according to the World Endoscopic Organization (WEO) were performed. RESULTS: Of 24 patients with CD and PCCRC in the rectum, 79% were men and the median age was 50 (IQR 45-59) years. The median disease duration was 21.5 (IQR 19-30) years. The cancer was located in the distal 5 cm of the rectum in 63% of the cases. Retroversion in the rectum was reported in only one case. The most common plausible explanation for PCCRC was 'possible missed lesion, prior examination adequate' (63%); when adding retroversion in the rectum, instead 77% of examinations were considered negative but deemed as inadequate. The most common PCCRC sub-category was non-interval type C (54%) and B (37%). Among those with type C, 38% should have been included in surveillance according to present guidelines. CONCLUSION: Better adherence to surveillance guidelines and more meticulous follow-up is warranted. The importance of performing rectal palpation and retroversion in the rectum is underscored and we suggest that this is included in the WEO algorithm.

Secondary Primary Cancer Risk After Radiation Therapy in Rectal Cancer: A Population-Based Cohort Study With Propensity Score Matching.

BACKGROUND: It remains unclear whether radiation therapy (RT) has an impact on the development of secondary primary cancer (SC) in rectal cancer (RC) patients, especially within the true pelvis. AIM: To examine the incidence of SC in a population-based cohort of RC after surgical treatment with or without radiation therapy (RT, NRT). PATIENTS AND METHODS: The epidemiological cohort consisting of 13,919 RC patients with primary M0 stage diagnosed between 1998 and 2019 was collected from cancer registry data of Upper Bavaria. Competing risk analyses were conducted regarding the development of SC on 11 687 first malignancies, stratified by RT/NRT. A propensity score (PS) was generated by logistic regression modeling of RT to repeat competing risk analyses on a PS-matched cohort. RESULTS: The median age (interquartile range) of the epidemiological cohort was 68.9 years (60.4-76.7). About 60.8%, were men, 38.7% had UICC III, 35.8% of tumors were localized lower than 8 cm, 41.3% underwent RT. Only 17.1% of patients older than 80 years at diagnosis received RT. In general, RT patients were 5 years younger than NRT patients (65.9 years [58.0-73.0] vs. 71.3 years [62.4-79.2], P < .0001). The 20-year cumulative incidence of SC was 16.5% in RT and 17.4% in NRT patients (P = .2298). Men with RT had a lower risk of prostate cancer (HR = 0.55, 95%CI [0.34-0.91], P = .0168). In the PS-matched cohort, RT patients had a significantly higher risk of bladder cancer during follow-up (10-year cumulative incidence of 1.1% vs. 0.6% in NRT). The direction of the RT effects in men and women and different tumor sites may cancel each other. CONCLUSION: A protective effect of RT in rectal cancer patients on developing prostate SC by half is reproduced. Further analyses studying the long-term SC risks of RT should essentially focus on stratification by sex, and focus on more recent data.

Age-related variations in colon and rectal cancer: An analysis of the national cancer database.

BACKGROUND: Characteristics of colorectal diseases may vary according to the patient's age. By using a large national database, we assessed age-related differences in characteristics and treatments of colorectal cancer and to evaluate the influence of age on outcomes. METHOD: Retrospective cohort analysis of all patients who underwent surgical resection for colorectal cancer in the US National Cancer Database between 2005 and 2019. Patients were divided into 3 age groups: young age onset (<50 years), middle age group (50-79 years), and very old (≥80 years). Differences in tumor characteristics among groups were assessed. The main outcomes were clinical and treatment characteristics and short-term mortality. RESULTS: In total, 662,102 patients with colon cancer and 114,460 with rectal cancer were included-36.1% of young patients with colon cancer presented with metastatic disease. Older patients underwent open surgery more often and received chemotherapy and radiation therapy less often than did the other 2 groups regarding disease stage. Very old patients, compared to middle-aged and young patients, had longer hospitalization and significantly higher rates of 30-day mortality after colon (7.6% vs 2.4% vs 0.7%; P < .001) and rectal (5.9% vs 1.3% vs 0.3%; P < .001) cancer surgery and higher 90-day mortality after colon (12.9% vs 4.6% vs 1.7% P < .001) and rectal (10.3% vs 2.6% vs 0.7%; P < .001) cancer surgery.Older patients had significantly shorter overall survival than the other 2 groups, regardless of pathologic stage, Charlson -Deyo comorbidity score, or tumor side. CONCLUSION: Significant age-related disparities in characteristics, treatments, and outcomes of colorectal cancer were found in this study. Recognizing these differences can be the first step toward reducing age-related treatment differences.

Management of the Rectal Stump after Subtotal Colectomy Operations for Inflammatory Bowel Disease in the Era of Immunologic Therapy: A Two-Centre Cohort Study.

INTRODUCTION: Inflammatory bowel disease (IBD) often requires surgical resection, such as subtotal colectomy operations to alleviate symptoms. However, IBD also has an inherently increased risk of colorectal dysplasia and cancer. Despite the well-accepted surveillance guidelines for IBD patients with an intact colon, contemporaneous decision-making models on rectal stump surveillance is sparse. This study looks at the fate of rectal stumps in IBD patients following subtotal colectomy. METHODS: This is a two-centre retrospective observational cohort study. Patients were identified from NHS Grampian and NHS Highland surgical IBD databases. Patients that had subtotal colectomy between January 01, 2010 and December 31, 2017 were included with the follow-up end date on April 1, 2021. Socio-demographics, diagnosis, medical and surgical management data were collected from electronic records. RESULTS: Of 250 patients who had subtotal colectomy procedures, only one developed a cancer in their rectal stump (0.4%) over a median follow-up of 80 months. A higher than expected 72% of patients had ongoing symptoms from their rectal stumps. Surveillance was varied and inconsistent. However, no surveillance, flexible sigmoidoscopy, or MRI identified dysplastic or neoplastic disease. CONCLUSION: Based on our results, we estimate that the prevalence of rectal cancer is lower than previously reported. Surveillance strategy of rectal stump varied as no current guidelines exist and hence is an important area for future study. Given the relatively low frequency of rectal cancer in these patients, and the low level of evidence available in this field, we would propose a registry-based approach to answering this important clinical question.

Development and validation of a competitive risk model in patients with rectal cancer: based on SEER database.

BACKGROUND: Rectal cancer is one of the most common malignancies. To predict the specific mortality risk of rectal cancer patients, we constructed a predictive nomogram based on a competing risk model. METHODS: The information on rectal cancer patients was extracted from the SEER database. Traditional survival analysis and specific death analysis were performed separately on the data. RESULTS: The present study included 23,680 patients, with 16,580 in the training set and 7100 in the validation set. The specific mortality rate calculated by the competing risk model was lower than that of the traditional survival analysis. Age, Marriage, Race, Sex, ICD-O-3Hist/Behav, Grade, AJCC stage, T stage, N stage, Surgery, Examined LN, RX SUMM-SURG OTH, Chemotherapy, CEA, Deposits, Regional nodes positive, Brain, Bone, Liver, Lung, Tumor size, and Malignant were independent influencing factors of specific death. The overall C statistic of the model in the training set was 0.821 (Se = 0.001), and the areas under the ROC curve for cancer-specific survival (CSS) at 1, 3, and 5 years were 0.842, 0.830, and 0.812, respectively. The overall C statistic of the model in the validation set was 0.829 (Se = 0.002), and the areas under the ROC curve for CSS at 1, 3, and 5 years were 0.851, 0.836, and 0.813, respectively. CONCLUSIONS: The predictive nomogram based on a competing risk model for time-specific mortality in patients with rectal cancer has very desirable accuracy. Thus, the application of the predictive nomogram in clinical practice can help physicians make clinical decisions and follow-up strategies.

Rectal cancer presentation during the COVID-19 pandemic: Are decreasing screening rates leading to an increase in acute presentations?

Nearly 23 million adults ages 50-75 are overdue for colorectal cancer (CRC) screening. In March 2020, the Centers for Medicare & Medicaid issued guidance that all non-urgent procedures be delayed due to the COVID-19 pandemic. Screening delays may have effects on the presentation of rectal cancer and the natural history of the disease. The aim of this study was to determine if procedural suspension due to the COVID-19 pandemic was associated with an increased proportion of acute presentations or more advanced stage at diagnosis for patients with rectal cancer. We conducted a single-center, retrospective review of adult patients with new or recurrent rectal adenocarcinoma from 2016-2021. We compared patients presenting before (pre-COVID) to those diagnosed after (COVID) March 1, 2020. Of 208 patients diagnosed with rectal cancer, 163 were diagnosed pre-COVID and 45 patients in the COVID group. Cohorts did not differ among age, sex, race, insurance status, marital status, rurality, or BMI. There was no difference in stage at presentation with the majority diagnosed with stage III disease (40.0% vs 33.3%, p = 0.26). Similar proportions of patients presented acutely (67.5% vs 64.4%, p = 0.71). Presenting symptoms were also similar between cohorts. On adjusted analysis, male sex, white race, and uninsured status were found to have significant impact acuity of presentation, while diagnosis before or after the onset of the pandemic remained non-significant (OR 1.25, 95% CI0.57-2.72; p = 0.59). While screening rates have decreased during the COVID pandemic, patients with rectal cancer did not appear to have an increased level of acuity or stage at presentation. These findings could result from the indolent nature of the disease and may change as the pandemic progresses.

Radiation Therapy Changed the Second Malignancy Pattern in Rectal Cancer Survivors.

Background and Objectives: Radiotherapy (RT) plays an important role in the treatment for locally advanced rectal cancer patients. It can bring radio exposure together with the survival benefit. Cancer survivors are generally at an increased risk for second malignancies, and survivors receiving RT may have higher risks than survivors not receiving RT. Whether the risk of an all-site second malignancy may increase after RT is still debated. This study aims to compare the second malignancy pattern in rectal cancer survivors after RT. Materials and Methods: The Surveillance, Epidemiology, and End Results (SEER) database was used for analysis. In total, 49,961 rectal cancer patients (20-84 years of age) were identified between 2000 and 2012 from 18 SEER registries. All patients underwent surgery. The occurrence of second malignancies diagnosed after rectal cancer diagnosis was compared in patients who received and did not receive RT. The standardized incidence ratios (SIRs) with 95% confidence intervals (CIs) were used. SEER*Stat was used to generate the 95% CIs for the SIR statistics using the exact method. Results: Of the total 49,961 patients, 5582 developed second malignancies. For all-site second primary malignancies, the age-adjusted SIRs were 1.14 (95% CI 1.1-1.18) and 1.00 (95% CI 0.96-1.04) in the no RT and RT groups, respectively. In 23,192 patients from the surgery-only group, 2604 had second malignancies, and in 26,769 patients who received RT, 2978 developed second malignancies. With respect to every site, the risk of secondary prostate cancer was significantly lower in the RT group (SIR = 0.39, 95% CI 0.33-0.46) than that in the surgery-only group (SIR = 1.04, 95% CI 0.96-1.12). Moreover, the risk of thyroid cancer was significantly higher in the RT group (SIR = 2.80, 95% CI 2.2-3.51) than that in the surgery-only group (SIR = 1.29, 95% CI 0.99-1.66). Conclusions: RT may change the second malignancy pattern in rectal cancer survivors; the risk of prostate cancer decreased, and the risk of thyroid cancer increased most significantly.

The Incidence and Prognosis Value of Perineural Invasion in Rectal Carcinoma: From Meta-Analyses and Real-World Clinical Pathological Features.

AIMS: Perineural invasion (PNI) is a special type of metastasis of several cancers and has been reported as being a factor for poor prognosis in colorectal carcinoma. However, investigations of PNI in only rectal cancer and a comprehensive analysis combining meta-analyses with real-world case studies remain lacking. MATERIALS AND METHODS: First, articles from 2000 to 2020 concerning the relationship between PNI and rectal cancer prognoses and clinical features were meta-analysed. Subsequently, we carried out a retrospective analysis of 312 rectal cancer cases that underwent radical surgery in the real world. The incidence of PNI and the relationship between PNI and prognosis, as well as clinicopathological factors, were investigated. RESULTS: The incidence of PNI was 23.09% and 33.01% in the meta-analysis and clinical cases, respectively. PNI occurred as early as stage I (2.94%). Moreover, neoadjuvant therapy significantly reduced the PNI-positive rate (20.34% versus 26.54%). Both meta-analysis and real-world clinical case studies suggested that PNI-positive patients had poorer prognoses than PNI-negative patients. We established an effective risk model consisting of T stage, differentiation and lymphovascular invasion to predict PNI in rectal cancer. CONCLUSION: PNI is a poor prognostic factor for rectal cancer and could occur even in stage I. Additionally, neoadjuvant therapy could sufficiently reduce the PNI-positive rate. T stage, lymphovascular invasion and differentiation grade were independent risk factors for PNI and the risk model that included these factors could predict the probability of PNI.