Tumor-stroma ratio as a new prognosticator for pseudomyxoma peritonei: a comprehensive clinicopathological and immunohistochemical study

Background

As a rare clinical tumor syndrome with an indolent clinical course and lack of pathognomonic symptoms, pseudomyxoma peritonei (PMP) is usually diagnosed at an advanced stage. In-depth pathological analysis is essential to assess tumor biological behaviors, assist treatment decision, and predict the clinical prognosis of PMP. The tumor-stroma ratio (TSR) is a promising prognostic parameter based on the tumor and stroma. This study explored the relationship between TSR and the pathological characteristics and prognosis of PMP.

Methods

PMP patients with complete data who underwent cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy were enrolled. The TSR of postoperative pathological images was quantitatively analyzed by Image-Pro Plus. Then the relationship between TSR and the clinicopathological characteristics, immunohistochemical characteristics and prognosis of PMP was analyzed.

Results

Among the 50 PMP patients included, there were 27 males (54.0%) and 23 females (46.0%), with a median age of 55 (range: 31–76) years. 25 (50.0%) patients were diagnosed with low-grade PMP (LG-PMP), and 25 (50.0%) were diagnosed with high-grade PMP (HG-PMP). There were 4 (8.0%) patients with vascular tumor emboli, 3 (6.0%) patients with nerve invasion, and 5 (10.0%) patients with lymph node metastasis. The immunohistochemical results showed that the Ki67 label index was < 25% in 18 cases (36.0%), 25 - 50% in 18 cases (36.0%) and > 50% in 14 cases (28.0%). The range of TSR was 2 - 24% (median: 8%). The cutoff value of TSR was 10% based on the receiver operating characteristic (ROC) curve and X-Tile analysis. There were 31 (62.0%) cases with TSR < 10% and 19 (38.0%) cases with TSR ≥ 10%. The TSR was closely related to histopathological type (P < 0.001) and Ki67 label index (P < 0.001). Univariate analysis showed that preoperative carcinoembryonic antigen (CEA), preoperative carbohydrate antigen 19–9, pathological type, vascular tumor emboli and TSR influenced the prognosis of PMP patients (P < 0.05). Multivariate analysis showed that preoperative CEA, vascular tumor emboli and the TSR were independent prognostic factors.

Conclusions

The TSR could be a new independent prognosticator for PMP.

Consensuses and controversies on pseudomyxoma peritonei: a review of the published consensus statements and guidelines

Background

Pseudomyxoma peritonei (PMP) is a clinical malignant syndrome mainly originating from the appendix, with an incidence of 2–4 per million people. As a rare disease, an early and accurate diagnosis of PMP is difficult. It was not until the 1980s that the systematic study of this disease was started.

Main body

As a result of clinical and basic research progress over the last 4 decades, a comprehensive strategy based on cytoreductive surgery (CRS) + hyperthermic intraperitoneal chemotherapy (HIPEC) has been established and proved to be an effective treatment for PMP. Currently, CRS + HIPEC was recommended as the standard treatment for PMP worldwide. There are several consensuses on PMP management, playing an important role in the standardization of CRS + HIPEC. However, controversies exist among consensuses published worldwide. A systematic evaluation of PMP consensuses helps not only to standardize PMP treatment but also to identify existing controversies and point to possible solutions in the future. The controversy underlying the consensus and vice versa promotes the continuous refinement and updating of consensuses and continue to improve PMP management through a gradual and continuous process. In this traditional narrative review, we systemically evaluated the consensuses published by major national and international academic organizations, aiming to get a timely update on the treatment strategies of CRS + HIPEC on PMP.

Conclusion

Currently, consensuses have been reached on the following aspects: pathological classification, terminology, preoperative evaluation, eligibility for surgical treatment, maximal tumor debulking, CRS technical details, and severe adverse event classification system. However, controversies still exist regarding the HIPEC regimen, systemic chemotherapy, and early postoperative intraperitoneal chemotherapy.

[Clinical evaluation of tumor-stroma ratio in pseudomyxoma peritonei from the appendix]

OBJECTIVE

To evaluate the effect of tumor-stroma ratio (TSR) on disease progression and prognosis of pseudomyxoma peritonei (PMP) from the appendix.

METHODS

The study included 30 PMP patients with complete individual patient data, who underwent cytoreductive surgery (CRS) plus hyperthermic intraperitoneal chemotherapy (HIPEC) in Beijing Shijitan Hospital. Image-Pro Plus was used to quantitatively analyze the proportion of tumor and stromal areas in hematoxylin-eosin staining pathological images, from which TSR was derived. Correlation studies were conducted to evaluate the relationships between TSR and clinicopathological features, immunohistochemical characteristics, and prognosis of PMP.

RESULTS

Among 30 PMP patients, there were 16 males (53.3%) and 14 females (46.7%), with the mean age of (54.9±2.3) years. There were 15 cases (50.0%) of low-grade mucinous carcinoma peritonei (LMCP) and high-grade mucinous carcinoma peritonei (HMCP), respectively, with vascular tumor emboli occurring in 4 cases (13.3%), nerve invasion occurring in 3 cases (10.0%), and lymphatic metastasis occurring in 4 cases (13.3%). The median peritoneal cancer index (PCI) score was 36 (range: 3-39). The median TSR was 8% (range: 2%-24%), with TSR≤10% in 19 cases (63.3%) and TSR>10% in 11 cases (36.7%). Immunohistochemistry showed that 16 cases (53.3%) had Ki67 label index ≤ 50% and 14 cases (46.7%) > 50%. The mutation rate of p53 was 56.7% and the loss rate of MMR protein was 11.8%. In addition, the expression rates of MUC2, MUC5AC, CDX2, CK7, and CK20 were 66.7%, 100.0%, 82.6%, 56.0%, and 92.3%, respectively. There were significant correlations between TSR and histopathological types, nerve invasion, Ki67 label index, and p53 mutation (P<0.05 for all). At the end of the last follow-up, 21 patients (70.0%) died and 9 patients (30.0%) survived, including 6 patients survived with tumor. The median overall survival (OS) was 12.7 months (95%CI: 10.4-11.5 months), and the 1-, 2-, and 3-year survival rates were 60.5%, 32.3%, and 27.7%, respectively. The median OS was 19.4 months (95%CI: 3.0-35.9 months) in the TSR≤10% group, versus 12.6 months (95%CI: 0.7-24.5 months) in the TSR>10% group (χ2=3.996, P=0.046).

CONCLUSION

TSR is correlated with histopathological types, tumor proliferation, invasion behaviors and prognosis of PMP, thus could be a new prognostic indicator for PMP.

Perioperative safety after cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy for pseudomyxoma peritonei from appendiceal origin: Experience on 254 patients from a single center

OBJECTIVE

Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) is a standard treatment for pseudomyxoma peritonei (PMP) recommended by Peritoneal Surface Oncology Group International (PSOGI). The study is to analyze the incidence of perioperative serious adverse events (SAEs) of CRS + HIPEC to treat PMP patients, and identify the risk factors, for guiding the prevention of SAEs.

METHODS

This is a retrospective study on the PMP database established at our center. The clinicopathological features, treatment details and SAEs information on the PMP patients are systematically established in this database. The incidence, organ system distribution and severity of perioperative SAEs are analyzed. Univariate and multivariate analyses are performed to identify the independent risk factors.

RESULTS

Among the 272 CRS + HIPEC procedures for 254 PMP patients, there are 93 (34.2%) SAEs. Six systems are involved in the SAEs, including infections (9.6%), digestive system (8.1%), respiratory system (6.3%), cardiovascular system (5.5%), hematological system (2.9%), and urinary system (1.5%), in terms of frequency. In terms of severity, the majority is grade III SAEs (27.9%), followed by grade IV SAEs (4.8%) and grade V SAEs (1.5%). Univariate analysis reveals 4 risk factors for perioperative SAEs: HIPEC regimens (P = 0.020), PCI (P = 0.025), intraoperative red blood cell transfusion volume (P = 0.004), and intraoperative blood loss volume (P = 0.002). Multivariate and logistic regression model analysis identifies only one independent risk factor for perioperative SAEs: intraoperative blood loss volume (P = 0.001, OR = 0.344, 95%CI: 0.182-0.649).

CONCLUSIONS

PMP patients treated by CRS + HIPEC at experienced centers could have acceptable safety. Improving the surgical techniques and developing the integrated hemostasis techniques are essential to reduce intraoperative blood loss and decrease SAEs rate.

[Establishment of patient derived xenograft model of high-grade mucinous carcinoma peritonei accompanied with signet ring cells and identification of biological characteristics]

Objective: To establish the patient derived xenograft (PDX) model of pseudomyxoma peritonei (PMP), and identify the key characteristics of tumor biology of this model, in order to provide a reliable model for studying the pathological mechanisms and new therapeutic strategies of PMP. Methods: PMP tumor tissue was obtained from surgery and cut into pieces after washing. Then tumor pieces were implanted subcutaneously in BAL B/c-nu mice for 6 stable passages. In the 7th passage, tumor tissue was implanted orthotopically into abdomen. Subcutaneous tumor and orthotopic tumor were then homogenized to make tumor cell suspension, implanted into abdomen of 10 BAL B/c-nu mice through midline laparotomy, 100 μl for each. The key experimental parameters including body weight changes in the observation period, experimental peritoneal cancer index (ePCI) score at the autopsy, histopathological and immunohistochemical characteristics, and gene expression profiles by high-throughput whole-genome exon sequencing were detected and recorded. Results: The successful rate of established orthotopic PDX model of human PMP was 100% (10/10). The animals showed smooth body weight increases after tumor inoculation until day 27, then the body weight began to decrease steadily. Widespread tumor dissemination of PMP tumor through the whole abdomen was found by autopsy, including the diaphragm, liver, spleen, stomach, kidney, parietal peritoneum, bowel and mesenterium. Gelatinous ascites was also observed in abdominopelvic cavity. The ePCI score ranged from 5 to 9, with a 8 of median ePCI. Histopathological studies showed peritoneal mucinous carcinomatosis accompanied with signet ring cells (PMCA-S), obvious tumor cell atypia and parenchymal invasion.Immunohistochemistry showed the expressions of MUC1, MUC2, MUC5AC, CEA, CA199, CK20, CDX-2 and Ki-67 were positive, MUC6, CK7 and p53 were negative. Whole-exome sequencing identified that the most significant genetic alteration is the exon10 missense mutation c. 1621A>C of KIT gene, the mutation abundance was 89.7%. Conclusion: PDX model of PMCA-S is successfully established, which displays the characters of high-degree malignancy, high proliferation and strong aggressiveness.

Establishment of patient-derived xenograft model of peritoneal mucinous carcinomatosis with signet ring cells and in vivo study on the efficacy and toxicity of intraperitoneal injection of 5-fluorouracil

BACKGROUND

Pseudomyxoma peritonei (PMP) is an indolent malignancy and insensitive to systemic chemotherapy. The authors established patient-derived xenograft (PDX) model of PMP, and evaluated the efficacy and toxicity of intraperitoneal (i.p.) administration of 5-fluorouracil (5-FU) in this model.

METHODS

Human PMP sample was collected to establish subcutaneous (s.c.) and i.p.

MODEL

In vivo study of i.p. injection of 5-FU was performed in i.p. model, with experimental peritoneal cancer index (ePCI) score and pathological examinations for evaluating the efficacy and toxicity.

RESULTS

Both s.c. and i.p. models were constructed. The average passage interval of s.c. model was 44.2 ± 5.2 days, and the i.p. model was characterized by disseminated solid tumor nodules in abdominal-pelvic cavity. Both models were diagnosed as peritoneal mucinous carcinomatosis with signet ring cells (PMCA-S). Immunohistochemical characteristics was similar to human. GNAS mutation was detected in both model and patient. In the in vivo study, average ePCI of treatment group was lower than control and vehicle group (P = .004). Histopathology revealed obvious tumor necrosis in treatment group, and decreased Ki67 positive rate (P = .010). In toxicity study, 5-FU significantly influenced body weight (P = .010) and 1 animal from treatment group died on day 14. Congestive splenomegaly was observed (88.9%). Hepatotoxicity presented as acidophilic body (55.6%), cholestasis (100%), bile canaliculus hyperplasia and obstruction (22.2%), and lymphocyte accumulation (77.8%).

CONCLUSIONS

PDX model of PMCA-S was established successfully, and i.p. 5-FU could inhibit tumor proliferation and progression, with decreased Ki67 positive rate and ePCI score. Hepatotoxicity was the main side effect.

[Pathological prognostic factors of pseudomyxoma peritonei]

Objective: To analyze the pathological features of pseudomyxoma peritonei (PMP) in correlation with the survival status and independent prognostic factors. Methods: One-hundred and fifty-five PMP specimens were collected at Beijing Shijitan Hospital, Capital Medical University, from 2012 to 2018. Conventional histopathological evaluation was performed to document the primary tumor site, histopathological type, lymph nodes metastasis, tumor emboli in the blood and lymph vessels, nerve invasion and cellular density. The immunohistochemical parameters including Ki-67, p53, MMR-related protein, MUC2 and MUC5AC were analyzed. Clinical follow-up data were reviewed to correlate with pathological prognostic factors using Kaplan-Meier estimator and Cox proportional hazards regression model for univariate and multivariate analysis. Results: Among 155 PMP patients, there were 77 males and 78 females. There were 98 cases (63.2%) of low-grade peritoneal mucinous carcinomatosis, 49 cases (31.6%) of high-grade peritoneal mucinous carcinomatosis, 8 cases (5.2%) of high-grade mucinous carcinoma peritonei with signet ring cells; only 15 cases (9.7%) with lymph node metastasis; 18 cases (11.6%) with tumor emboli in the blood and lymph vessels; 8/126 (6.3%) were positive dMMR; 100 cases (64.5%) had Ki-67 label index <50%, and 56 cases(36.1%) presented with mutant type p53. Univariate analysis revealed 11 survival-related pathological parameters including gender, age, primary tumor site, histopathological type, lymph node metastasis, tumor emboli in the blood and lymph vessels, nerve invasion, cellular density, Ki-67 label index rate, p53 and dMMR. Multivariate analysis identified 4 independent prognostic factors including the histopathological type (HR 59.78, P<0.01), lymph node metastasis (HR 3.74, P=0.028), nerve invasion (HR 7.81, P=0.007) and dMMR (HR 9.82, P<0.01). Conclusions: Histopathological type is the most important prognostic factor of PMP with dMMR as an independent molecular prognostic indicator.

[Establishment and biological characteristics of lung cancer cell line XWLC-05]

BACKGROUND & OBJECTIVE

The incidence of lung cancer is high at Xuanwei, Yunnan Province, at where the mortality rate of this disease in women is the highest in China. This study was to establish a Xuanwei woman lung adenocarcinoma cell line, and provide an in vitro experimental model for the study of preventing and treating lung cancer.

METHODS

The cells derived from a surgical specimen of a woman patient with lung cancer were primarily cultured. The biological characteristics of the cell line were studied with light and electron microscopes, determination of doubling time and growth curve, culturing in soft agar, flow cytometry (FCM), chromosome and G-band detection, c-12 multiple tumor markers detection, and inoculation in mice.

RESULTS

Morphologic study, proliferation dynamics, and invasive growth showed that the cultured cells have malignant characteristics. Their chromosome numbers ranged from 55 to 69, with a mode number of 60-63. The tumor formation rate in mice was 100% after axillary transplantation of the cells; the morphology of the tumor cells was similar to that of the pathologic specimen of the patient. The cell line was named XWLC-05.

CONCLUSION

According to the newest rules of establishing a cell line in vitro, XWLC-05 is proved to be a new cell line of human lung adenocarcinoma.

Combination preoperative radiation and endocavitary hyperthermia for rectal cancer: long-term results of 44 patients

Long-term results of 122 patients with advanced rectal cancer who were randomly treated with three different methods from July 1984 to July 1986. Of 122 patients, 44 were treated with endocavitary 915 MHz microwave applicators combined with 10 MeV X-ray or 60CO followed by surgery (group A), 38 with preoperative radiation (group B) and 40 with surgery (group C) as a control group. The temperature on the surface of the applicator touching the middle of the caudad to cephaladic extent of disease was 45-50 degrees C for 45 min twice a week for 6-8 sessions. Radiation dose was 30 Gy or 40 Gy/4 weeks. Of cases with stages 0 and A, 45.5% (20/44) were in group A, 23.7% (9/38) in group B and 12.5% (5/40) in group C (chi 2 test p < 0.05 and p < 0.01, respectively). Five-year survival rate was 66.7% (24/36) in group A, 50% (14/28) in group B and 40.5% (15/37) in group C. Percentage of survival at 5 years was 73.7% (14/19) for 40 Gy plus heat, 57.1% (8/14) for 40 Gy alone, 58.8% (10/17) for 30 Gy plus heat, and 42.9% (6/14) for 30 Gy alone. Data suggest a survival advantage for patients treated with preoperative radiation combined with endocavitary hyperthermia.

Cytogenetic studies of five primary esophageal cancers

In direct preparation of five primary esophageal cancers, chromosomes 1, 3, and 12 were most frequently involved in structural abnormalities; 12p- was consistently seen in all five cases and, thus, could be considered as one of the characteristic chromosome changes in esophageal cancer. Moreover, 2p-, 4p-, and 7q- were seen in three cases.

[Clinicopathological study of combined preoperative radiotherapy with intracavitary hyperthermia in rectal cancer]

118 specimens of rectal cancer were studied pathologically. 40 cases were treated by both preoperative radiotherapy and intracavitary hyperthermia (group 1), 38 treated by preoperative radiotherapy alone (group 2) and 40 by operation alone (group 3). The tumor disappearance rates by gross observation were 57.5% and 5.3% in groups 1 and 2 (P less than 0.001). The moderate to severe damage of cancer cells (X2-X4) was observed in 90% of cases in group 1 and 31.6% in group 2 (P less than 0.05). In the former, the cancer cell disappearance was observed in 8 cases, while in the latter, only 1 case. The cell degenerations by 30 Gy plus hyperthermia were similar to those by 40 Gy plus hyperthermia, but both were more marked than by 30 Gy alone or 40 Gy alone (P less than 0.05). The lymphocyte, plasma cell infiltration and hyperplasia of fibrous tissue around the tumor in group 1 were more marked than those in groups 2 and 3 (P less than 0.05). The thrombosis around the tumor was more in group 1 than in group 2 (P less than 0.01). Every histological type of the tumor was sensitive to radiotherapy combined with hyperthermia. The lymph node metastatic rates were 35% in group 1 and 31.6% in group 2, both being lower than that in group 3 (52.5%). Immune function of the lymph nodes and the damage of the normal tissues around the tumor are observed. It has been clinically confirmed that neither resection rate is influenced nor postoperative complications are increased by preoperative radiotherapy combined with hyperthermia.

[Extent of lymph node dissection in rectal carcinoma]

Basing on 170 specimens of advanced rectal cancers radically resected, metastatic rule and extent of lymph node dissection were studied in order to guide future surgical treatment. In 170 cases, 77 had lymph node metastases. The lymph node metastatic rate was 45.3% and metastatic degree was 8.9% (527/5 912). Metastasis of the rectal cancer, according to the lymphatic anatomy, can be divided into upward, lateral and downward drain. Because the rectal cancer at any site can lead to the upward metastasis, the upward lymph node dissection, up to the base of inferior mesenteric artery (the third line of lymph nodes), must be done in all rectal cases, otherwise, 10% of patients would have residual cancer. In view of the lateral metastasis occurring only in rectal cancers under the peritoneal reflection, for which lateral lymph node dissection is necessary or one eighth of patients would have residual lesion. Generally, no lateral lymph node dissection is needed in cancers above the peritoneal reflection. Pathologic factor influencing the lymphatic metastasis is the form of tumor growth, such as poorly differentiated and mucoid adenocarcinomas aggressively growing deeply and extensively resulting in a higher lymph node metastatic rate, for which lymph node dissection must be performed.