Repeat Cytoreduction and Hyperthermic Intraperitoneal Chemotherapy for Recurrent Mucinous Appendiceal Adenocarcinoma: A Viable Treatment Strategy with Demonstrable Benefit.

INTRODUCTION: Many patients with mucinous appendiceal adenocarcinoma experience peritoneal recurrence despite complete cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). Prior work has demonstrated that repeat CRS/HIPEC can prolong survival in select patients. We sought to validate these findings using outcomes from a high-volume center. PATIENTS AND METHODS: Patients with mucinous appendiceal adenocarcinoma who underwent CRS/HIPEC at MD Anderson Cancer Center between 2004 and 2021 were stratified by whether they underwent CRS/HIPEC for recurrent disease or as part of initial treatment. Only patients who underwent complete CRS/HIPEC were included. Initial and recurrent groups were compared. RESULTS: Of 437 CRS/HIPECs performed for mucinous appendiceal adenocarcinoma, 50 (11.4%) were for recurrent disease. Patients who underwent CRS/HIPEC for recurrent disease were more often treated with an oxaliplatin or cisplatin perfusion (35%/44% recurrent vs. 4%/1% initial, p < 0.001), had a longer operative time (median 629 min recurrent vs. 511 min initial, p = 0.002), and had a lower median length of stay (10 days repeat vs. 13 days initial, p < 0.001). Thirty-day complication and 90-day mortality rates did not differ between groups. Both cohorts enjoyed comparable recurrence free survival (p = 0.82). Compared with patients with recurrence treated with systemic chemotherapy alone, this select cohort of patients undergoing repeat CRS/HIPEC enjoyed better overall survival (p < 0.001). CONCLUSIONS: In appropriately selected patients with recurrent appendiceal mucinous adenocarcinoma, CRS/HIPEC can provide survival benefit equivalent to primary CRS/HIPEC and that may be superior to that conferred by systemic therapy alone in select patients. These patients should receive care at a high-volume center in the context of a multidisciplinary team.

Preoperative CA 19-9 Predicts Disease Progression in Colorectal Peritoneal Metastases Treated with Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy: An Analysis from the US HIPEC Collaborative.

INTRODUCTION: Patients with colorectal peritoneal metastases (CRPM) are increasingly treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC). Unfortunately, data identifying preoperative risk factors for poor oncologic outcomes after this procedure are limited. We aimed to determine the prognostic value of preoperative CEA, CA 125, and CA 19-9 on disease progression after CRS/HIPEC. METHODS: Patients with CRPM treated with curative intent CRS/HIPEC from 12 participating sites in the United States from 2000 to 2017 were identified. Progression-free survival (PFS), defined as disease progression or recurrence, was the primary outcome. RESULTS: In 279 patients who met inclusion criteria, the rate of disease progression was 63.8%, with a median PFS of 11 months (interquartile range [IQR] 5-20). Elevated CA 19-9 was associated with dismal PFS at 2 years (8.9% elevated vs. 30% not elevated, p < 0.01). In 113 patients who underwent upfront CRS/HIPEC, CA 19-9 emerged as the sole tumor marker independently predictive of worse PFS (hazard ratio [HR] 2.88, p = 0.048). In the subgroup of patients who had received neoadjuvant therapy (NAT), no variable was independently predictive of PFS. CA 19-9 levels over 37 U/ml were highly specific for accelerated disease progression after CRS/HIPEC. Lastly, there was no association between PFS and elevated CEA or CA 125. CONCLUSIONS: Elevated CA 19-9 is associated with decreased PFS in patients with CRPM. While traditionally CEA is the main tumor marker assessed in colon cancer, we found that CA 19-9 may better inform preoperative risk stratification for poor oncologic outcomes in patients with CRPM. However, prospective studies are required to confirm this association.

Treatment Variation and Long-Term Outcomes of Low-Grade Appendiceal Neoplasms.

BACKGROUND: Heterogenous nomenclature describing appendiceal neoplasms has added to uncertainty around their appropriate treatment. Although a recent consensus has established the term low-grade appendiceal neoplasm (LAMN), we hypothesize that significant variation remains in the treatment of LAMNs. METHODS: We retrospectively reviewed our prospectively maintained appendiceal registry, identifying patients with LAMNs from 2009 to 2019. We assessed variability in treatment, including whether patients underwent colectomy, spread of disease at presentation, and long-term outcomes. RESULTS: Of 136 patients with LAMNs, 88 (35%) presented with localized disease and 48 (35%) with disseminated peritoneal disease. Median follow-up was 2.9 years (IQR 1.9-4.4), and 120 (88%) patients underwent pre-referral surgery. Among 26 pre-referral colectomy patients, 23 (88%) were performed for perceived oncologic need/nodal evaluation; no nodal metastases were identified. In patients with resected LAMNs without radiographic evidence of disseminated disease, 41 (47%) underwent second look diagnostic laparoscopy (DL) to evaluate for occult metastases. No peritoneal metastases were identified. Patients with disseminated disease were treated with cytoreductive surgery/heated intraperitoneal chemotherapy (CRS/HIPEC). For patients undergoing CRS/HIPEC, 5-year recurrence-free survival was 94% (95% CI 81-98%). For patients with localized disease, 5-year RFS was 98% (95% CI 85-99%). CONCLUSIONS: Significant variation exists in treatment patterns for LAMNs, particularly prior to referral to a high-volume center. Patients frequently underwent colectomy without apparent oncologic benefit. In the current era of high-quality cross sectional imaging, routine use of DL has low yield and is not recommended. Recurrence in this population is rare, and low-intensity surveillance can be offered. Overall prognosis is excellent, even with peritoneal disease.

Neighborhood-Level Socioeconomic Disadvantage Predicts Outcomes in Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy for Peritoneal Malignancy.

BACKGROUND: Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) improves survival in select patients with peritoneal metastases (PM), but the impact of social determinants of health on CRS/HIPEC outcomes remains unclear. PATIENTS AND METHODS: A retrospective review was conducted of a multi-institutional database of patients with PM who underwent CRS/HIPEC in the USA between 2000 and 2017. The area deprivation index (ADI) was linked to the patient's residential address. Patients were categorized as living in low (1-49) or high (50-100) ADI residences, with increasing scores indicating higher socioeconomic disadvantage. The primary outcome was overall survival (OS). Secondary outcomes included perioperative complications, hospital/intensive care unit (ICU) length of stay (LOS), and disease-free survival (DFS). RESULTS: Among 1675 patients 1061 (63.3%) resided in low ADI areas and 614 (36.7%) high ADI areas. Appendiceal tumors (n = 1102, 65.8%) and colon cancer (n = 322, 19.2%) were the most common histologies. On multivariate analysis, high ADI was not associated with increased perioperative complications, hospital/ICU LOS, or DFS. High ADI was associated with worse OS (median not reached versus 49 months; 5 year OS 61.0% versus 28.2%, P < 0.0001). On multivariate Cox-regression analysis, high ADI (HR, 2.26; 95% CI 1.13-4.50; P < 0.001), cancer recurrence (HR, 2.26; 95% CI 1.61-3.20; P < 0.0001), increases in peritoneal carcinomatosis index (HR, 1.03; 95% CI 1.01-1.05; P < 0.001), and incomplete cytoreduction (HR, 4.48; 95% CI 3.01-6.53; P < 0.0001) were associated with worse OS. CONCLUSIONS: Even after controlling for cancer-specific variables, adverse outcomes persisted in association with neighborhood-level socioeconomic disadvantage. The individual and structural-level factors leading to these cancer disparities warrant further investigation to improve outcomes for all patients with peritoneal malignancies.

Peritoneal recurrence after resection for Stage I-III colorectal cancer: A population analysis.

BACKGROUND: Colorectal cancer (CRC) often recurs in the peritoneum, although the pattern of peritoneal recurrence (PR) has received less attention. We sought to describe the presentation and risk factors for PR following CRC resection. METHODS: We performed a cohort study of patients undergoing resection of Stage I-III CRC from 2006 to 2007 using merged data from a Commission on Cancer Special Study and the National Cancer Database. We estimated the timing, method of detection, and risk factors for isolated PR. RESULTS: Here, 8991 patients were included and isolate PR occurred in 77 (0.9%) patients. The median time to PR was 16.2 months (intrquartile range = 9.3-28.0 months) and most patients were identified via new symptoms (36.4%). Pathologic factors associated with increased odds of PR included higher T stage (T3 vs. T2, odds ratio [OR] = 4.8, 95% confidence interval [CI] = 1.5-15.7), N stage (N1 vs. N0, OR = 2.00, CI = 1.1-3.7), and signet ring (OR = 8.2, CI = 3.0-22.3) or mucinous histology (OR = 2.6, CI = 1.5-4.7). CONCLUSIONS: The majority of PR was detected within 18 months and few were identified by surveillance. Advanced T/N stage and signet ring/mucinous histology were associated with increased odds of PR.

Prognostic significance of acellular mucin in patients undergoing cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) for appendiceal neoplasms.

INTRODUCTION: Appendiceal neoplasms have a propensity for peritoneal dissemination. The standard of care for select individuals is CRS/HIPEC. In the current 8th AJCC Staging system, a finding of only intraperitoneal acellular mucin (M1a) is classified as Stage IVa. There is concern that the current AJCC system may over-stage patients. METHODS: This was a single-institution retrospective review of 164 cases of mucinous appendiceal neoplasm. Patients undergoing CRS/HIPEC with M1a disease were compared to patients with peritoneal deposits containing tumor cells (well-differentiated adenocarcinoma; low-grade mucinous carcinoma peritonei-M1b,G1). Overall and recurrence-free survival were assessed. RESULTS: Median age was 51 years, 70% were female, and 75% White. Sixty-four patients had M1a disease and 100 M1b,G1 disease. M1a disease had a lower median PCI score (11 vs. 20, p = .0001) and a higher rate of complete CRS (62% vs. 50%, p = .021). Median follow-up was 7.6 years (IQR 5.6-10.5 years). For M1a disease, there were no recurrences and only one patient died during the study interval. In comparison, for M1b disease, 66/100 (66%) recurred with a 5-year RFS of 40.5% (HR 8.0, 95% CI 4.9-15.1, p < .0001), and 31/100 (31%) died with a 5-year OS of 84.8% (HR 4.5, 95% CI 2.2-9.2, p < .0001). CONCLUSIONS: Acellular mucin (M1a disease) after CRS/HIPEC for appendiceal neoplasm is associated with longer OS and RFS compared to M1b, G1 disease. Current AJCC staging does not accurately reflect the differing outcomes of these two patient populations. The presence of acellular mucin in the peritoneal cavity should not be perceived as a metastatic equivalent.

What is the Risk for Peritoneal Metastases and Survival Afterwards in T4 Colon Cancers?

BACKGROUND: Patients with T4 colon adenocarcinomas have an increased risk of peritoneal metastases (PM) but the histopathologic risk factors for its development are not well-described. OBJECTIVE: The purpose of this study was to determine factors associated with PM, time to recurrence, and survival after recurrence among patients with T4 colon cancer. PATIENTS AND METHODS: Patients with pathologic T4 colon cancer who underwent curative resection from 2005 to 2017 were identified from a prospectively maintained institutional database and classified by recurrence pattern: (a) none - 68.8%; (b) peritoneal only - 7.9%; (c) peritoneal and extraperitoneal - 9.9%; and (d) extraperitoneal only - 13.2%. Associations between PM development and patient, primary tumor, and treatment factors were assessed. RESULTS: Overall, 151 patients were analyzed, with a median follow-up of 66.2 months; 27 patients (18%) developed PM (Groups B and C) and 20 (13%) patients recurred at non-peritoneal sites only (Group D). Median time to developing metastases was shorter for Groups B and C compared with Group D (B and C: 13.7 months; D: 46.7 months; p = 0.022). Tumor deposits (TDs) and nodal stage were associated with PM (p < 0.05), and TDs (p = 0.048) and LVI (p = 0.015) were associated with additional extraperitoneal recurrence. Eleven (41%) patients with PM underwent salvage surgery, and median survival after recurrence was associated with the ability to undergo cytoreduction (risk ratio 0.20, confidence interval 0.06-0.70). CONCLUSION: PM risk after resection of T4 colon cancer is independently associated with factors related to lymphatic spread, such as N stage and TDs. Well-selected patients can undergo cytoreduction with long-term survival. These findings support frequent postoperative surveillance and aggressive early intervention, including cytoreduction.

Malignant Peritoneal Mesothelioma Associated With Endometriosis: A Clinicopathologic Study of 15 Cases.

Only a few cases of malignant peritoneal mesothelioma (MPeM) associated with endometriosis have been published; with chronic inflammation of the peritoneum associated with the latter being postulated as an inducing factor in the pathogenesis of this tumor. We assessed the clinicopathologic characteristics of MPeM associated with endometriosis to determine if there were other factors besides inflammation that may contribute to the pathogenesis in this patient population. Fifteen MPeM associated with endometriosis were retrieved from our files. Most presented with abdominal/pelvic pain, mass or distention; median age was 45 yr. Only 16% of patients had a history of asbestos exposure. In contrast, a third of the patients had a personal history of other neoplasms, and >80% had a family history of malignancies. Although most tumors had gross and microscopic features typical of MPeM, some had confounding features including "adhesion-like" appearance or gelatinous cysts/nodules, and signet ring cells. Tumors were epithelioid (9) and biphasic (6). MPeM was misdiagnosed as Müllerian carcinoma in 40% of cases. All patients (n=15) had cytoreductive surgery in addition to other therapies. Only 2/12 patients died of disease (17%). The 3- and 5-yr overall survival was 90%. MPeM associated with endometriosis tends to occur in patients with personal/familial history of malignancies, which may be a predisposing factor. In light of this finding, the role of endometriosis in the pathogenesis of MPeM is likely less relevant. The favorable outcome seen in these patients may be related to germline mutations or the hormonal milieu and needs further investigation.

Impact of Perioperative Blood Transfusions on Outcomes After Hyperthermic Intraperitoneal Chemotherapy: A Propensity-Matched Analysis.

BACKGROUND: Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) is a major operation frequently necessitating red blood cell transfusion. Using multi-institutional data from the U.S. HIPEC Collaborative, this study sought to determine the association of perioperative allogenic blood transfusion (PABT) with perioperative outcomes after CRS/HIPEC. METHODS: This retrospective cohort study analyzed patients who underwent CRS/HIPEC for peritoneal surface malignancy between 2000 and 2017. Propensity score-matching was performed to mitigate bias. Univariate analysis was used to compare demographic, preoperative, intraoperative, and postoperative variables. Factors independently associated with PABT were identified using multivariate analysis. RESULTS: The inclusion criteria were met by 1717 patients, 510 (29.7%) of whom required PABT. The mean Peritoneal Cancer Index (PCI) of our cohort was 14.8 ± 9.3. Propensity score-matching showed an independent association between PABT and postoperative risk of pleural effusion, hemorrhage, pulmonary embolism, enteric fistula formation, Clavien-Dindo grades 3 and 4 morbidity, longer hospital stay, and reoperation (all P < 0.05 in the multivariate analysis). Compared with the patients who received 1 to 5 red blood cell (RBC) units, the patients who received more than 5 units had a greater risk of renal impairment, a longer intensive care unit (ICU) stay, and more postoperative infections. Finally, PABT was an independent predictor of worse survival for patients with appendiceal and colorectal primaries. CONCLUSION: Even low levels of PABT for patients undergoing CRS/HIPEC are independently associated with a greater risk of infectious and non-infectious postoperative complications, and this risk is increased for patients receiving more than 5 RBC units. Worse survival was independently predicted by PABT for patients with peritoneal carcinomatosis of an appendiceal or colorectal origin.

Institutional variation in recovery after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy: An opportunity for enhanced recovery pathways.

BACKGROUND: Variations in care have been demonstrated both within and among institutions in many clinical settings. By standardizing perioperative practices, Enhanced Recovery After Surgery (ERAS) pathways reduce variation in perioperative care. We sought to characterize the variation in cytoreductive surgery (CRS)/heated intraperitoneal chemotherapy (HIPEC) perioperative practices among experienced US medical centers. METHODS: Data from the US HIPEC Collaborative represents a retrospective multi-institutional cohort study of CRS and CRS/HIPEC procedures performed from 12 major academic institutions. Patient characteristics and perioperative practices were reported and compared. Institutional variation was analyzed using hierarchical mixed-effects linear (continuous outcomes) or logistic (binary outcomes) regression models. RESULTS: A total of 2372 operations were included. CRS/HIPEC was performed most commonly for appendiceal histologies (64.2%). The rate of complications (overall 56.3%, range: 31.8-70.9) and readmissions (overall 20.6%, range: 8.9-33.3) varied by institution (P < .001). Institution-level variation in perioperative practice patterns existed among measured ERAS pathway process/outcomes (P < .001). The percentages of variation with each process/outcome measure attributable solely to institutional practices ranged from 0.6% to 66.6%. CONCLUSIONS: Significant variation exists in the perioperative care of patients undergoing CRS/HIPEC at major US academic institutions. These findings provide a strong rationale for the investigation of best practices in CRS/HIPEC patients.

Nodal Downstaging in Gastric Cancer Patients: Promising Survival if ypN0 is Achieved.

BACKGROUND: The American Joint Committee on Cancer's 8th edition introduced ypStage, a separate staging system for patients with gastric cancer having undergone preoperative therapy. Overall, ypN0 patients have better survival outcomes than ypN+ patients. However, whether patients with cN+/ypN0 disease ("downstaged N0") and those with cN0/ypN0 disease ("natural N0") have similar survival is unknown. METHODS: An institutional database was reviewed to identify gastric adenocarcinoma patients who underwent potentially curative R0 resection after induction chemotherapy or chemoradiation. Patients were categorized into three groups based on nodal status: cN0/ypN0, cN+/ypN0, and ypN+. Univariable and multivariable Cox regression models were used to identify clinicopathologic factors associated with overall survival (OS). RESULTS: We identified 316 patients who met the study criteria. Ninety-four patients (30%) had cN0/ypN0 disease, 93 (29%) had cN+/ypN0 disease, and 129 (41%) had ypN+ disease. The median OS was 7.7 years, and the 5-year OS was 60.3%. In the multivariate analysis, OS did not differ between the cN0/ypN0 and cN+/ypN0 patients (hazard ratio, 0.90 [95% CI 0.54-1.48]; p = 0.666), but it was shorter in ypN+ patients (hazard ratio, 1.82 [95% CI 1.15-2.87]; p = 0.01). CONCLUSIONS: In gastric cancer patients who underwent preoperative therapy, we found similar OS in cN0/ypN0 and cN+/ypN0 patients. Because ypN+ patients had poor OS, achieving ypN0 status is an important hallmark demonstrating the effectiveness of preoperative therapy for gastric cancer.

Desmoplastic Small Round Cell Tumor Treated with Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy: Results of a Phase 2 Trial.

BACKGROUND: Desmoplastic small round cell tumor (DSRCT) is a rare sarcoma that primarily affects adolescents and young adults. Patients can present with many peritoneal implants. We conducted a phase 2 clinical trial utilizing cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) with cisplatin for DSRCT and pediatric-type abdominal sarcomas. PATIENTS AND METHODS: A prospective cohort study was performed on 20 patients, who underwent CRS-HIPEC procedures, with cisplatin from 2012 to 2013. All patients were enrolled in the phase 2 clinical trial. Patients with extraabdominal disease and in whom complete cytoreduction (CCR0-1) could not be achieved were excluded. All outcomes were recorded. RESULTS: Fourteen patients had DSRCT, while five patients had other sarcomas. One patient had repeat HIPEC. Patients with DSRCT had significantly longer median overall survival after surgery than patients with other tumors (44.3 vs. 12.5 months, p = 0.0013). The 3-year overall survival from time of diagnosis for DSRCT patients was 79 %. Estimated median recurrence-free survival (RFS) was 14.0 months. However, RFS for patients with DSRCT was significantly longer than for non-DSRCT patients (14.9 vs. 4.5 months, p = 0.0012). Among DSRCT patients, those without hepatic or portal metastases had longer median RFS than those with tumors at these sites (37.9 vs. 14.3 months, p = 0.02). In 100 % of patients without hepatic or portal metastasis, there was no peritoneal disease recurrence after CRS-HIPEC. CONCLUSIONS: Complete CRS-HIPEC with cisplatin is effective in select DSRCT patients. DSRCT patients with hepatic or portal metastasis have poorer outcomes.

The ypT category does not impact overall survival in node negative gastric cancer.

BACKGROUND: Although the eighth-edition American Joint Committee on Cancer (AJCC) gastric cancer staging system created ypTNM staging for patients who underwent preoperative therapy, the ideal ypTNM grouping is unknown. We sought to investigate risk factors for OS in ypT0-3N0M0 gastric cancer. METHODS: From an institutional database of The University of Texas MD Anderson Cancer Center and the National Cancer Database (NCDB), we identified patients with ypT0-3N0M0 gastric adenocarcinoma who underwent R0 gastrectomy after chemotherapy or chemoradiation during 1995-2015 (MD Anderson) or 2006-2014 (NCDB). RESULTS: The study included 175 MD Anderson and 3200 NCDB patients. By multivariable analysis, ypT category was not associated with OS (hazard ratio [HR] for ypT3 vs ypT1: MD Anderson, 0.83 [95% CI, 0.36-1.92], P = 0.669; NCDB, 0.96 [95% CI, 0.85-1.08], P = 0.472). cN-positive disease was not associated with OS in the MD Anderson cohort (HR, 0.96 [95% CI, 0.55-1.67]; P = 0.873) but was weakly associated with shorter OS in the NCDB cohort (HR, 1.11 [95% CI, 1.01-1.21]; P = 0.031). CONCLUSIONS: The ypT category does not impact OS in ypT0-3N0M0 gastric cancer. The impact of cN status on OS appeared limited. These findings should be considered in future systems of post-neoadjuvant pathologic staging.

Evaluation of the American Joint Committee on Cancer 8th edition staging system for gastric cancer patients after preoperative therapy.

BACKGROUND: The American Joint Committee on Cancer (AJCC) recently released its 8th edition staging system, which created a separate staging system for gastric cancer patients who have undergone preoperative therapy (ypStage). The objective of this retrospective study was to apply the new ypStage to patients who have undergone preoperative therapy and potentially curative gastrectomy. METHODS: We collected data from a prospectively maintained institutional database of gastric cancer patients who underwent potentially curative gastrectomy after preoperative therapy (1995-2015). Kaplan-Meier survival estimations and log-rank tests were performed to compare survival. Univariable and multivariable analyses were performed to determine risk factors for overall survival. RESULTS: A total of 354 patients met our criteria. Most patients completed planned preoperative therapy (94%; 332/354) and received chemoradiation therapy (75%; 265/354). Although clinical stage (cStage) provided a poor discrimination of survival, postneoadjuvant pathological stage (ypStage) identified significant variation in survival (p < 0.001). Multivariable analysis showed the following factors were associated with survival after adjustment for ypStage: Asian race (HR 0.52; p = 0.028), linitis plastica (HR 1.66; p = 0.037), and R1 resection (HR 1.91; p = 0.016). Survival was not longer in ypT0N0 patients than in ypStage I patients (HR 1.29; p = 0.377). CONCLUSIONS: The AJCC 8th edition staging system for gastric cancer demonstrated reasonable survival prediction by ypStage, but not cStage, in patients who had undergone preoperative therapy. ypT0N0 patients, although not defined in the 8th edition, may be considered for inclusion in the ypStage I group.

Preoperative chemoradiation therapy induces primary-tumor complete response more frequently than chemotherapy alone in gastric cancer: analyses of the National Cancer Database 2006-2014 using propensity score matching.

BACKGROUND: The benefit of preoperative chemoradiation (CXRT) over preoperative chemotherapy alone ("chemotherapy" hereafter) is unknown. By analyzing the National Cancer Database (NCDB), we investigated whether preoperative CXRT improves the incidence of primary tumor pathologic complete response (ypT0) and overall survival (OS) compared with preoperative chemotherapy in patients with gastric cancer. METHODS: Patients with non-metastatic gastric adenocarcinoma who underwent CXRT or chemotherapy followed by gastrectomy were included. Propensity score matching with a ratio of 1:1 was implemented to reduce selection bias. A conditional logistic regression model was used to compare incidences of ypT0 between groups, and Cox proportional hazards model was used to compare OS. RESULTS: We identified 8464 patients. Median patient age was 63 years; 76% were male and 79% were white. ypT0 was observed in 16.1% of patients in the CXRT group and 6.6% in the chemotherapy group (p < 0.001). After propensity score matching, a total of 2408 patients were matched. CXRT was associated with a higher incidence of ypT0 (OR 2.28, 95% CI 1.76-2.95; p < 0.0001) and higher frequency of R0 resection (92 vs. 86%; p < 0.001). However, CXRT was not associated with longer OS (HR 1.03, 95% CI 0.92-1.15; p = 0.63). Safety profiles (30-day mortality, 30-day readmission, and length of hospital stay) were equivalent between groups. CONCLUSIONS: In this study of gastric cancer patients from the NCDB, CXRT was associated with a higher incidence of ypT0 and R0 resection compared with chemotherapy, although it was not associated with a longer OS.

Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy for Moderately and Poorly Differentiated Appendiceal Adenocarcinoma: Survival Outcomes and Patient Selection.

BACKGROUND: Moderately and poorly differentiated adenocarcinoma of the appendix represents an aggressive histological variant with a high risk of recurrence and death. METHODS: Overall, 178 patients with moderately and poorly differentiated appendiceal adenocarcinoma were identified from a prospective database. Clinical, pathologic, and treatment factors were analyzed for outcomes. RESULTS: Diagnostic laparoscopy (DL) identified radiographic occult peritoneal metastasis in 25 (42%) patients. These patients had a significantly lower peritoneal carcinomatosis index (PCI) and improved overall survival (OS) compared with those with radiographic disease. Twenty-seven (41%) patients were excluded from cytoreductive surgery (CRS) because of findings on DL, while 116 (65%) patients underwent CRS and hyperthermic intraperitoneal chemotherapy (HIPEC), with a median disease-free survival (DFS) of 23 months. Mucinous histology (hazard ratio [HR] 0.52, p = 0.04) and PCI (HR 1.054, p = 0.02) were independent predictors of DFS. The median OS following CRS and HIPEC was 48 months. Mucinous histology (HR 0.352, p = 0.018), signet ring cells (HR 3.34, p = 0.02), positive peritoneal cytology (HR 0.081, p = 0.04), and PCI (HR 1.076, p = 0.004) were independently associated with OS. Eight-five (73.3%) patients received neoadjuvant chemotherapy, and 40 (47.1%) patients achieved a radiographic response; 36 (42.3%) had stable disease, while 9 (10.6%) had progressive disease. Stable or responsive disease was associated with improved median OS of 44 months, compared with 21 months for those with progressive disease (p = 0.011). CONCLUSIONS: In selected patients, long-term survival can be obtained. Mucinous histology, absence of signet ring cells, negative peritoneal cytology, PCI ≤ 20, and response/stable disease after neoadjuvant chemotherapy are important selection criteria for CRS and HIPEC.