Accessibility to ERCP-performing hospitals among patients with pancreatic cancer living in SEER regions.

BACKGROUND AND AIMS: The two most common interventions used to treat painless jaundice from pancreatic cancer are endoscopic retrograde cholangiopancreatography (ERCP) and percutaneous transhepatic biliary drainage (PTBD). Our study aimed to characterize the geographic distribution of ERCP-performing hospitals among patients with pancreatic cancer in the United States and the association between geographic accessibility to ERCP-performing hospitals and biliary interventions patients receive. METHODS: This is a retrospective cohort study using the Surveillance, Epidemiology, and End Results (SEER)-Medicare database for pancreatic cancer from 2005 to 2013. Multilevel models were used to examine the association between accessibility to ERCP hospitals within a 30- and 45-min drive from the patient's residential ZIP Code and the receipt of ERCP treatment. A two-step floating catchment area model was used to calculate the measure of accessibility based on the distribution across SEER regions. RESULTS: 7464 and 782 patients underwent ERCP and PTBD, respectively, over the study period. There were 808 hospitals in which 8246 patients diagnosed with pancreatic cancer in SEER regions from 2005 to 2013 received a procedure. Patients with high accessibility within both 30- and 45-min drive to an ERCP-performing hospital were more likely to receive an ERCP (30-min adjusted odds ratio [aOR]: 1.53, 95% confidence interval [CI]: 1.17-2.01; 45-min aOR: 1.31, 95% CI: 1.01-1.70). Furthermore, in the adjusted model, Black patients (vs. White) and patients with stage IV disease were less likely to receive ERCP than PTBD. CONCLUSIONS: Patients with pancreatic cancer and high accessibility to an ERCP-performing hospital were more likely to receive ERCP. Disparities in the receipt of ERCP persisted for Black patients regardless of their access to ERCP-performing hospitals.

Pandemic-Related Changes in Incidence and Mortality Rates of Gastrointestinal Cancers During 2020.

INTRODUCTION: Coronavirus Disease 2019 disrupted cancer-related care in early 2020. METHODS: We used population-based cancer registry data to estimate incidence and mortality rates of gastrointestinal cancers between 2016 and 2020. RESULTS: Incidence rates were unchanged from 2016 to 2019 but decreased in 2020, with the largest declines for colorectal cancer (rate ratio [RR] 0.88; 95% confidence interval [CI] 0.87-0.90) and hepatocellular carcinoma (RR 0.85; 95% CI 0.82-0.88). Mortality rates of colorectal cancer (RR 1.06; 95% CI 1.04-1.08) and esophageal adenocarcinoma (RR 1.06; 95% CI 1.00-1.13) increased in 2020. DISCUSSION: Incidence and mortality rates of gastrointestinal cancers may increase in the future given pandemic-related delays in 2020.

Transoral gastric outlet reduction for post-prandial hypoglycemia after Roux-en-Y gastric bypass.

BACKGROUND: Post-prandial hypoglycemia is an uncommon but disabling late complication of Roux-en-Y gastric bypass (RYGB). Most patients can be treated with dietary interventions and medications; however, some patients develop refractory hypoglycemia that may lead to multiple daily episodes and seizures. While RYGB reversal surgery is an effective treatment, complication rates are high, and patients inevitably experience weight regain. Transoral gastric outlet reduction (TORe) is a minimally invasive treatment that is effective for early and late dumping syndrome. However, prior studies have not distinguished the effectiveness of TORe specifically for patients with post-prandial hypoglycemia. This study aims to describe a single institution's experience of TORe for treating post-prandial hypoglycemia. METHODS: This is a case series of patients with prior RYGB complicated by post-prandial hypoglycemia who underwent TORe from February 2020 to September 2021. Pre-procedural characteristics and post-procedural outcomes were obtained. Outcomes assessed included post-prandial hypoglycemia episodes, dumping syndrome symptoms, and weight change. RESULTS: A total of 11 patients underwent TORe from 2020 to 2021 for post-prandial hypoglycemia. Three (27%) patients had a history of seizures due to hypoglycemia. All had been advised on dietary changes, and ten patients (91%) were on medications for dumping. All patients reported a reduction in post-prandial hypoglycemic events as well as the majority of dumping syndrome symptoms during an average follow-up time of 409 ± 125 days. Ten patients (91%) had experienced weight regain from their post-RYGB nadir weight. For these patients, the average total body weight loss 12 months post-TORe was 12.4 ± 12%. There were no complications requiring hospitalization. One patient experienced post-TORe nausea and vomiting requiring dilation of the gastrojejunal anastomosis with resolution in symptoms. CONCLUSION: TORe is a safe and effective treatment for post-prandial hypoglycemia and weight regain after RYGB in patients with symptoms refractory to medications and dietary changes.

Ethnic Disparities in Early-Onset Gastric Cancer Persist across Rural-Urban Geographies.

BACKGROUND: The incidence of noncardia gastric cancer is increasing in adults ages less than 50 years old. Early-onset gastric cancer (EOGC) is characterized by ethnic disparities occurring more in Hispanic persons than non-Hispanic persons. It is unknown whether rural-urban disparities exist in EOGC and if this intersects with ethnic disparities. METHODS: We utilized the Surveillance Epidemiology and End Results 17 Census Tract-level Socioeconomic Status and Rurality Database from 2006 to 2018 to calculate incidence rates and incidence rate ratios of EOGC among Hispanic and non-Hispanic persons by census tract rural-urban location, age, gender, persistent poverty, and stage of disease. We used the Tiwari Method to estimate incidence rate ratios with 95% confidence intervals (CI). RESULTS: Hispanic persons had higher incidence rates of EOGC compared with non-Hispanic persons in both rural [incident rate ratios (IRR), 2.12; 95% confidence interval (CI), 1.64-2.73] and urban census tracts (IRR, 2.03; 95% CI, 1.91-2.16). Similar findings were seen when comparing Hispanic to non-Hispanic persons in rural and urban census tracts by age, stage of disease, and persistent poverty. CONCLUSIONS: Higher incidence rates of EOGC among Hispanic persons persist across rural-urban locations. Further research is needed to understand the etiology of this elevated risk in young Hispanics and interventions that may help to modify their outcome. IMPACT: While other cancers have ethnic disparities which may differ by rural-urban location, the ethnic disparity in EOGC among Hispanic and non-Hispanic persons does not differ by rural-urban residence.

Endoscopic Sleeve Gastroplasty: A Practice Pattern Survey.

PURPOSE: Obesity is a complex, chronic disease that is strongly associated with complications which cost the US healthcare system billions of dollars per year. Endoscopic sleeve gastroplasty (ESG) has emerged as a safe and effective procedure for treatment of obesity, but without practice guidelines there are likely to be variations practice. We sought to describe current practice patterns amongst endoscopists who perform ESG to help define areas of focus for future research and guideline development. METHODS: We conducted an anonymous cross-sectional survey to examine practice patterns related to ESG. The survey was organized in 5 sections: Endoscopic Practice, Training, and Resources; Pre-ESG Evaluation and Payment Model; Perioperative/Operative Period; Post-operative Period; and Endobariatric Practice Other Than ESG. RESULTS: A variety of exclusion criteria were reported by physicians performing ESG. Most respondents (n = 21/32, 65.6%) would not perform ESG for BMI under 27, and 40.6% (n = 13/32) would not perform ESG on patients with BMI over 50. The majority of respondents (74.2%, n = 23/31) reported ESG was not covered in their region, and most reported patients covered residual costs (67.7%, n = 21/31). CONCLUSIONS: We found significant variability with respect to practice setting, exclusion criteria, pre-procedural evaluation, and medication use. Without guidelines for the selection of patients or standards for pre- and post-ESG care, substantial barriers to coverage will remain, and ESG will remain limited to those who can meet out-of-pocket costs. Larger studies are needed to confirm our findings, and future research should be focused on establishing patient selection criteria and standards in practices to provide guidance for endobariatric programs.

Anal Carcinoma, Version 2.2023, NCCN Clinical Practice Guidelines in Oncology.

This discussion summarizes the NCCN Clinical Practice Guidelines for managing squamous cell anal carcinoma, which represents the most common histologic form of the disease. A multidisciplinary approach including physicians from gastroenterology, medical oncology, surgical oncology, radiation oncology, and radiology is necessary. Primary treatment of perianal cancer and anal canal cancer are similar and include chemoradiation in most cases. Follow-up clinical evaluations are recommended for all patients with anal carcinoma because additional curative-intent treatment is possible. Biopsy-proven evidence of locally recurrent or persistent disease after primary treatment may require surgical treatment. Systemic therapy is generally recommended for extrapelvic metastatic disease. Recent updates to the NCCN Guidelines for Anal Carcinoma include staging classification updates based on the 9th edition of the AJCC Staging System and updates to the systemic therapy recommendations based on new data that better define optimal treatment of patients with metastatic anal carcinoma.

A Combined DNA/RNA-based Next-Generation Sequencing Platform to Improve the Classification of Pancreatic Cysts and Early Detection of Pancreatic Cancer Arising From Pancreatic Cysts.

OBJECTIVE: We report the development and validation of a combined DNA/RNA next-generation sequencing (NGS) platform to improve the evaluation of pancreatic cysts. BACKGROUND AND AIMS: Despite a multidisciplinary approach, pancreatic cyst classification, such as a cystic precursor neoplasm, and the detection of high-grade dysplasia and early adenocarcinoma (advanced neoplasia) can be challenging. NGS of preoperative pancreatic cyst fluid improves the clinical evaluation of pancreatic cysts, but the recent identification of novel genomic alterations necessitates the creation of a comprehensive panel and the development of a genomic classifier to integrate the complex molecular results. METHODS: An updated and unique 74-gene DNA/RNA-targeted NGS panel (PancreaSeq Genomic Classifier) was created to evaluate 5 classes of genomic alterations to include gene mutations (e.g., KRAS, GNAS, etc.), gene fusions and gene expression. Further, CEA mRNA ( CEACAM5 ) was integrated into the assay using RT-qPCR. Separate multi-institutional cohorts for training (n=108) and validation (n=77) were tested, and diagnostic performance was compared to clinical, imaging, cytopathologic, and guideline data. RESULTS: Upon creation of a genomic classifier system, PancreaSeq GC yielded a 95% sensitivity and 100% specificity for a cystic precursor neoplasm, and the sensitivity and specificity for advanced neoplasia were 82% and 100%, respectively. Associated symptoms, cyst size, duct dilatation, a mural nodule, increasing cyst size, and malignant cytopathology had lower sensitivities (41-59%) and lower specificities (56-96%) for advanced neoplasia. This test also increased the sensitivity of current pancreatic cyst guidelines (IAP/Fukuoka and AGA) by >10% and maintained their inherent specificity. CONCLUSIONS: PancreaSeq GC was not only accurate in predicting pancreatic cyst type and advanced neoplasia but also improved the sensitivity of current pancreatic cyst guidelines.

ACG Clinical Guideline: Diagnosis and Management of Biliary Strictures.

A biliary stricture is an abnormal narrowing in the ductal drainage system of the liver that can result in clinically and physiologically relevant obstruction to the flow of bile. The most common and ominous etiology is malignancy, underscoring the importance of a high index of suspicion in the evaluation of this condition. The goals of care in patients with a biliary stricture are confirming or excluding malignancy (diagnosis) and reestablishing flow of bile to the duodenum (drainage); the approach to diagnosis and drainage varies according to anatomic location (extrahepatic vs perihilar). For extrahepatic strictures, endoscopic ultrasound-guided tissue acquisition is highly accurate and has become the diagnostic mainstay. In contrast, the diagnosis of perihilar strictures remains a challenge. Similarly, the drainage of extrahepatic strictures tends to be more straightforward and safer and less controversial than that of perihilar strictures. Recent evidence has provided some clarity in multiple important areas pertaining to biliary strictures, whereas several remaining controversies require additional research. The goal of this guideline is to provide practicing clinicians with the most evidence-based guidance on the approach to patients with extrahepatic and perihilar strictures, focusing on diagnosis and drainage.

Survival of cancer survivors with a new pancreatic cancer diagnosis.

BACKGROUND: Persons newly diagnosed with pancreas cancer and who have survived a previous cancer are often excluded from clinical trials, despite limited evidence about their prognosis. We examined the association between previous cancer and overall survival. METHODS: This US population-based cohort study included older adults (aged ≥66 years) diagnosed with pancreas cancer between 2005 and 2015 in the linked Surveillance, Epidemiology, and End Results-Medicare data. We used Cox proportional hazards models to estimate stage-specific effects of previous cancer on overall survival, adjusting for sociodemographic, treatment, and tumor characteristics. RESULTS: Of 32,783 patients, 18.7% were previously diagnosed with another cancer. The most common previous cancers included prostate (29.0%), breast (18.9%), or colorectal (9.7%) cancer. More than half of previous cancers (53.9%) were diagnosed 5 or more years prior to pancreas cancer diagnosis or at an in situ or localized stage (47.8%). The proportions of patients surviving 1, 3, and 5 years after pancreas cancer were nearly identical for those with and without previous cancer. Median survival in months was as follows for those with and without previous cancer respectively: 7 versus 8 (Stage 0/I), 10 versus 10 (Stage II), 7 versus 7 (Stage III), and 3 versus 2 (Stage IV). Cox models indicated that patients with previous cancer had very similar or statistically equivalent survival to those with no previous cancer. CONCLUSIONS: Given nearly equivalent survival compared to those without previous cancer, cancer survivors newly diagnosed with pancreas cancer should be considered for inclusion in pancreas cancer clinical trials.

Patient Knowledge, Risk Perception, and Barriers to Barrett's Esophagus Screening.

INTRODUCTION: Most patients with esophageal adenocarcinoma (EAC) do not have a previous diagnosis of Barrett's esophagus (BE), demonstrating a failure of current screening practices. An understanding of patient attitudes and barriers is essential to develop and implement interventions to improve BE screening adherence. METHODS: We conducted a Web-based survey of patients aged >50 years with chronic gastroesophageal reflux disease at 3 academic medical centers and 1 affiliated safety net health systems. Survey domains included patient characteristics, endoscopy history, familiarity with screening practices, perceived BE/EAC risk, and barriers to screening. RESULTS: We obtained a response rate of 22.6% (472/2,084) (74% men, mean age 67.9 years). Self-identified race and ethnicity of participants was 66.5% non-Hispanic White, 20.0% non-Hispanic Black, 13.4% other race, and 7.1% Hispanic. Screening for BE was recommended in only 13.2%, and only 5.3% reported previous screening. Respondents had notable gaps in knowledge about screening indications; only two-thirds correctly identified BE risk factors and only 19.5% believed BE screening was needed for gastroesophageal reflux disease. More than 1 in 5 respondents believed they would get BE (31.9%) or EAC (20.2%) but reported barriers to screening. Compared with White respondents, more Black respondents were concerned about getting BE/EAC and interested in screening but report higher barriers to screening. DISCUSSION: Patients at risk for BE, particularly racial and ethnic minorities, are worried about developing EAC but rarely undergo screening and have poor understanding of screening recommendations.

Prospective, Multi-Institutional, Real-Time Next-Generation Sequencing of Pancreatic Cyst Fluid Reveals Diverse Genomic Alterations That Improve the Clinical Management of Pancreatic Cysts.

BACKGROUND & AIMS: Next-generation sequencing (NGS) of pancreatic cyst fluid is a useful adjunct in the assessment of patients with pancreatic cyst. However, previous studies have been retrospective or single institutional experiences. The aim of this study was to prospectively evaluate NGS on a multi-institutional cohort of patients with pancreatic cyst in real time. METHODS: The performance of a 22-gene NGS panel (PancreaSeq) was first retrospectively confirmed and then within a 2-year timeframe, PancreaSeq testing was prospectively used to evaluate endoscopic ultrasound-guided fine-needle aspiration pancreatic cyst fluid from 31 institutions. PancreaSeq results were correlated with endoscopic ultrasound findings, ancillary studies, current pancreatic cyst guidelines, follow-up, and expanded testing (Oncomine) of postoperative specimens. RESULTS: Among 1933 PCs prospectively tested, 1887 (98%) specimens from 1832 patients were satisfactory for PancreaSeq testing. Follow-up was available for 1216 (66%) patients (median, 23 months). Based on 251 (21%) patients with surgical pathology, mitogen-activated protein kinase/GNAS mutations had 90% sensitivity and 100% specificity for a mucinous cyst (positive predictive value [PPV], 100%; negative predictive value [NPV], 77%). On exclusion of low-level variants, the combination of mitogen-activated protein kinase/GNAS and TP53/SMAD4/CTNNB1/mammalian target of rapamycin alterations had 88% sensitivity and 98% specificity for advanced neoplasia (PPV, 97%; NPV, 93%). Inclusion of cytopathologic evaluation to PancreaSeq testing improved the sensitivity to 93% and maintained a high specificity of 95% (PPV, 92%; NPV, 95%). In comparison, other modalities and current pancreatic cyst guidelines, such as the American Gastroenterology Association and International Association of Pancreatology/Fukuoka guidelines, show inferior diagnostic performance. The sensitivities and specificities of VHL and MEN1/loss of heterozygosity alterations were 71% and 100% for serous cystadenomas (PPV, 100%; NPV, 98%), and 68% and 98% for pancreatic neuroendocrine tumors (PPV, 85%; NPV, 95%), respectively. On follow-up, serous cystadenomas with TP53/TERT mutations exhibited interval growth, whereas pancreatic neuroendocrine tumors with loss of heterozygosity of ≥3 genes tended to have distant metastasis. None of the 965 patients who did not undergo surgery developed malignancy. Postoperative Oncomine testing identified mucinous cysts with BRAF fusions and ERBB2 amplification, and advanced neoplasia with CDKN2A alterations. CONCLUSIONS: PancreaSeq was not only sensitive and specific for various pancreatic cyst types and advanced neoplasia arising from mucinous cysts, but also reveals the diversity of genomic alterations seen in pancreatic cysts and their clinical significance.

Rectal Cancer, Version 2.2022, NCCN Clinical Practice Guidelines in Oncology.

This selection from the NCCN Guidelines for Rectal Cancer focuses on management of malignant polyps and resectable nonmetastatic rectal cancer because important updates have been made to these guidelines. These recent updates include redrawing the algorithms for stage II and III disease to reflect new data supporting the increasingly prominent role of total neoadjuvant therapy, expanded recommendations for short-course radiation therapy techniques, and new recommendations for a "watch-and-wait" nonoperative management technique for patients with cancer that shows a complete response to neoadjuvant therapy. The complete version of the NCCN Guidelines for Rectal Cancer, available online at NCCN.org, covers additional topics including risk assessment, pathology and staging, management of metastatic disease, posttreatment surveillance, treatment of recurrent disease, and survivorship.

Ethnic Disparities in Early-Onset Gastric Cancer: A Population-Based Study in Texas and California.

BACKGROUND: Incidence rates of gastric cancer are increasing in young adults (age <50 years), particularly among Hispanic persons. We estimated incidence rates of early-onset gastric cancer (EOGC) among Hispanic and non-Hispanic White persons by census tract poverty level and county-level metro/nonmetro residence. METHODS: We used population-based data from the California and Texas Cancer Registries from 1995 to 2016 to estimate age-adjusted incidence rates of EOGC among Hispanic and non-Hispanic White persons by year, sex, tumor stage, census tract poverty level, metro versus nonmetro county, and state. We used logistic regression models to identify factors associated with distant stage diagnosis. RESULTS: Of 3,047 persons diagnosed with EOGC, 73.2% were Hispanic White. Incidence rates were 1.29 [95% confidence interval (CI), 1.24-1.35] and 0.31 (95% CI, 0.29-0.33) per 100,000 Hispanic White and non-Hispanic White persons, respectively, with consistently higher incidence rates among Hispanic persons at all levels of poverty. There were no statistically significant associations between ethnicity and distant stage diagnosis in adjusted analysis. CONCLUSIONS: There are ethnic disparities in EOGC incidence rates that persist across poverty levels. IMPACT: EOGC incidence rates vary by ethnicity and poverty; these factors should be considered when assessing disease risk and targeting prevention efforts.

Survival of patients newly diagnosed with colorectal cancer and with a history of previous cancer.

Patients with previous cancer are often excluded from clinical trials despite limited evidence about their prognosis. We examined the effect of previous cancer on overall and colorectal cancer (CRC)-specific survival of patients newly diagnosed with CRC. This population-based cohort study from the U.S.A. included patients aged ≥66 years and diagnosed with CRC between 2005 and 2015 in linked Surveillance, Epidemiology, and End Results-Medicare data. We estimated the stage-specific effects of a previous cancer on overall survival using Cox regression and on CRC-specific survival using competing risk regression. We also examined the effect of previous cancer type, timing, and stage on overall survival. Of 112,769 patients, 14.1% were previously diagnosed with another cancer--commonly prostate (32.9%) or breast (19.4%) cancer, with many (47.1%) diagnosed <5 years of CRC. For all CRC stages except IV, in which there was no difference, patients with previous cancer (vs. without) had worse overall survival. However, patients with previous cancer had improved CRC-specific survival. Overall survival for those with stage 0-III CRC varied by previous cancer type, timing, and stage; for example, patients with previous melanoma had overall survival equivalent to those with no previous cancer. Our results indicate that, in general, CRC patients with previous cancer have worse overall survival but superior CRC-specific survival. Given their equivalent survival to those without previous cancer, patients with previous melanoma and those with stage IV CRC with any type of previous cancer should be eligible to participate in clinical trials.

Substance Use, Mental Health, and Weight-Related Behaviors During the COVID-19 Pandemic Among Metabolic and Bariatric Surgery Patients.

PURPOSE: The impact of the COVID-19 pandemic on behavioral issues among those who have completed bariatric surgery (BS) is not well described in ethnically diverse populations. The aim of this study was to compare the impact of COVID-19 lockdown orders and after lockdown orders were lifted on substance use, mental health, and weight-related behaviors among a sample of post-BS adults. MATERIALS AND METHODS: A retrospective medical chart review identified BS patients from one university-based obesity medicine clinic and two BS practices. An online non-anonymous survey was implemented in two phases: during lockdown (April 1-May 31, 2020) and after lockdown orders were lifted (June 1, 2020-September 30, 2020) to obtain information about the COVID-19 pandemic's impact on BS patients. RESULTS: A total of 189 (during lockdown=39, post-lockdown=150) participants (90.4% female, mean age 52.4 years, SD 11.1, 49.8% non-Hispanic White, 30.6% non-Hispanic Black, 16.1% Hispanic) participated. Lockdown participants were more likely to have sleep problems (74.3% vs. 56.1%, P=.039) and feel anxious (82.0% vs. 63.0%, P=.024) versus post-lockdown participants. A majority (83.4%) reported depression in both lockdown/post-lockdown. Post-lockdown participants were more than 20 times more likely to report substance use compared those in lockdown (aOR 20.56, 95% CI 2.66-158.4). CONCLUSIONS AND RELEVANCE: The COVID-19 pandemic is having a substantial negative impact on substance use, mental health, and weight-related health behaviors in diverse BS patients. These findings have important implications for post-BS patient care teams and may suggest the integration of screening tools to identify those at high risk for behavioral health issues.

Early Palliative Care Is Associated With Reduced Emergency Department Utilization in Pancreatic Cancer.

OBJECTIVES: Most patients with pancreatic cancer have high symptom burden and poor outcomes. Palliative care (PC) can improve the quality of care through expert symptom management, although the optimal timing of PC referral is still poorly understood. We aimed to assess the association of early PC on health care utilization and charges of care for pancreatic cancer patients. MATERIALS AND METHODS: We selected patients with pancreatic cancer diagnosed between 2000 and 2009 who received at least 1 PC encounter using the Surveillance, Epidemiology, and End Results (SEER)-Medicare. Patients who had unknown follow-up were excluded. We defined "early PC" if the patients received PC within 30 days of diagnosis. RESULTS: A total of 3166 patients had a PC encounter; 28% had an early PC. Patients receiving early PC were more likely to be female and have older age compared with patients receiving late PC (P<0.001). Patients receiving early PC had fewer emergency department (ED) visits (2.6 vs. 3.0 visits, P=0.004) and lower total charges of ED care ($3158 vs. $3981, P<0.001) compared with patients receiving late PC. Patients receiving early PC also had lower intensive care unit admissions (0.82 vs. 0.98 visits, P=0.006) and total charges of intensive care unit care ($14,466 vs. $18,687, P=0.01). On multivariable analysis, patients receiving early PC were significantly associated with fewer ED visits (P=0.007) and lower charges of ED care (P=0.018) for all patients. CONCLUSIONS: Early PC referrals were associated with lower ED visits and ED-related charges. Our findings support oncology society guideline recommendations for early PC in patients with advanced malignancies such as pancreatic cancer.

Survival of women diagnosed with breast cancer and who have survived a previous cancer.

PURPOSE: Many women diagnosed with breast cancer have survived previous cancer; yet little is known about the impact of previous cancer on overall and cancer-specific survival. METHODS: This population-based cohort study using SEER-Medicare data included women (age ≥ 66 years) diagnosed with breast cancer between 2005 and 2015. Separately by breast cancer stage, we estimated effect of previous cancer on overall survival using Cox regression and on cause-specific survival using competing risk regression; all survival analyses adjusted for covariates. RESULTS: Of 138,576 women diagnosed with breast cancer, 8% had a previous cancer of another organ site, most commonly colorectal or uterine cancer or melanoma. Many of these women (46.3%) were diagnosed within 5 years of breast cancer. For all breast cancer stages except IV wherein there was no difference, women with vs. without previous cancer had worse overall survival. This survival disadvantage was driven by deaths due to the previous cancer and other causes. In contrast, women with previous cancer generally had favorable breast-cancer-specific survival, although this varied by stage. Overall survival varied by previous cancer type, timing, and stage; previous lung cancer, cancer diagnosed within 1 year of incident breast cancer, and previous cancer at a distant stage were associated with the worst survival. In contrast, women with a previous melanoma had equivalent overall survival to women without previous cancer. CONCLUSION: We observed variable impact of previous cancer on overall and breast-cancer-specific survival depending on breast cancer stage at diagnosis and the type, timing, and stage of previous cancer.