Role of neoadjuvant therapy(chemotherapy and/or radiotherapy) in lymph node and primary rectal tumor regression and prognosis (Preprint)

UNSTRUCTURED Background: Rectal tumors are important malignancies and prediction of prognosis after neoadjuvant therapy is important to improve the prognosis process. The purpose of this study was to determine therole ofneoadjuvant therapy in lymph node regression and primary rectal tumor as well as its association with prognosis. Methods and materials: In this descriptive study, 40 consecutive patients with rectal tumor who were referred toTaleghani Hospital for surgery from 2011 to 2018 were enrolled. Moreover, theneoadjuvant therapy role in lymph node regression and primary rectal tumor was determined as well as its association with prognosis. Results: The results of this study demonstrate that there was no tumor regression in 20% of patients and it wasalso less than 25%, 25-50%, 50-75%, and complete in 22.5%, 35%, 20%, and 2.5% of the patients,respectively. The lymph node regression was complete in 5% of the patients and it wasalso less than 25% in 20% and more than 25% in 50% of them. In addition, it was with no regression in 25% of the patients. The lymph node regression was related to N stage (P=0.018), primary tumor regression grade (P=0.001), yPT (P=0.008), and yPN (P=0.020); however, it was not related to prognosis (P > 0.05). Conclusions: Totally, according to the obtained results, it can be concluded thatneoadjuvant therapy plays a good role in lymph node regression and primary rectal tumor, but it has no association with prognosis. Keywords:Neoadjuvant therapy, Lymph node regression, Primary rectal tumor, Prognosis

Rectal Tumor Stiffness Quantified by In Vivo Tomoelastography and Collagen Content Estimated by Histopathology Predict Tumor Aggressiveness

PurposeTo investigate the significance of collagen in predicting the aggressiveness of rectal tumors in patients, examined in vivo based on tomoelastography quantified stiffness and ex vivo by histologically measured collagen volume fraction (CVF).Experimental Design170 patients with suspected rectal cancer were prospectively enrolled and underwent preoperative magnetic resonance imaging (MRI) and rectal tomoelastography, a technique based on multifrequency magnetic resonance elastography. Histopathologic analysis identified eighty patients with rectal cancer who were divided into subgroups by tumor-node (TN) stage, prognostic stage, and risk level. Rectal tumor stiffness was correlated with histopathologic CVF. Area-under-the-curve (AUC) and contingency analysis were used to evaluate the performance of rectal stiffness in distinguishing tumor stages which was compared to standard clinical MRIResultsIn vivo tomoelastography revealed that rectal tumor stiffened significantly with increased TN stage (p<0.05). Tumors with poorly differentiated status, perineural and lymphovascular invasion also displayed higher stiffness than well-to-moderately differentiated, noninvasive tumors (all p<0.05). Similar to in vivo stiffness, CVF indicated an abnormally high collagen content in tumors with perineural invasion and poor differentiation status. CVF was also positively correlated with stiffness (p<0.05). Most importantly, both stiffness (AUROC: 0.82) and CVF (AUROC: 0.89) demonstrated very good diagnostic accuracy in detecting rectal tumors that have high risk for progressing to an aggressive state with poorer prognosis.ConclusionIn human rectal carcinomas, overexpression of collagen is correlated with increased tissue stiffness and high risk for tumor advancing more aggressively. In vivo tomoelastography quantifies rectal tumor stiffness which improves the diagnostic performance of standard MRI in the assessment of lymph nodes metastasis. Therefore, in vivo stiffness mapping by tomoelastography can predict rectal tumor aggressiveness and add diagnostic value to MRI.

Synchronous multiple primary malignant neoplasms: a case report of malignant peritoneal mesothelioma and neuroendocrine rectal tumor

We report a rare case of synchronous malignant peritoneal mesothelioma of the biphasic histological type and neuroendocrine tumor (NET) of the rectum without history of asbestos exposure. During 2 years since manifestation of the disease the patient underwent 3 cytoreductive surgeries (CRS): removal of the tumor of the sigmoid mesentery, resection of the rectosigmoid junction completeness of cytoreduction (CC) 0 (2017), omentectomy and partial parietal peritonectomy CC-0 (2017), atypical resection of S2, S4, S5 liver, the removal of the abdominal tumor with left-sided en-block hemicolectomy, partial parietal peritonectomy, argon-plasma coagulation of tumor foci on the mesentery of the small intestine CC-2 (2018) and Transanal Minimally Invasive Surgery-removal of neuroendocrine rectal tumor (2017). The patient underwent hyperthermic intraperitoneal chemotherapy (HIPEC) twice (during 2nd and 3rd CRS). Different regimens of HIPEC were performed: cisplatin + doxorubicin (2017) and metamycin C (2018). The patient received 4 courses of adjuvant chemotherapy with cisplatin plus pemetrexed in 2017 and 3 courses of the chemotherapy with gemcitabine and carboplatin plus bevacizumab in 2018. The patient survived 21 months after the detection of malignant peritoneal mesothelioma in 2017 and died 4 months after the last cytoreductive surgery from the progression of the disease. Histological subtype of MPMP remains important factor in the prognosis of the disease even on the early stages though patient had received the most aggressive variant of special treatment. Minimally invasive treatment tactics of NET demonstrated clinical effectiveness.