The gastrin-releasing peptide receptor (GRPR) is overexpressed in prostate cancer (PCa) and in hormone-driven breast cancer (BCa). The aim of this phase I clinical trial was to evaluate safety, biodistribution, and dosimetry after the administration of the recently developed GRPR-targeting antagonistic bombesin analogue [99mTc]Tc-maSSS-PEG2-RM26 in PCa and BCa patients. Planar and whole-body SPECT/CT imaging was performed in six PCa patients and seven BCa patients 2, 4, 6, and 24 h post the intravenous administration of 40 µg of [99mTc]Tc-maSSS-PEG2-RM26 (600–700 MBq). No adverse events or pathological changes were observed. The rapid blood clearance of [99mTc]Tc-maSSS-PEG2-RM26 was observed with predominantly hepatobiliary excretion. The effective doses were 0.0053 ± 0.0007 for male patients and 0.008 ± 0.003 mSv/MBq for female patients. The accumulation of [99mTc]Tc-maSSS-PEG2-RM26 in tumors was observed in four out of six PCa and in seven out of seven BCa patients. In four BCa patients, a high uptake of the agent into the axillary lymph nodes was detected. Immunohistochemistry revealed positive GRPR expression in 60% of primary PCa, 71.4% of BCa tumors, and 50% of examined BCa lymph nodes. In conclusion, a single administration of [99mTc]Tc-maSSS-PEG2-RM26 was safe and well tolerated. [99mTc]Tc-maSSS-PEG2-RM26 SPECT may be useful for tumor detection in PCa and BCa patients, pending further studies.

The purpose of the study was to develop and evaluate the technique for volumetric tumor segmentation based on diffusion-weighted magnetic resonance imaging (DW-MRI) in predicting and assessing the response to chemotherapy in patients with bladder cancer (BC). Material and Methods. We examined 26 patients with morphologically verified transitional cell carcinoma of the bladder. The group was characterized by the presence of one or several tumors with a size of 17 to 46 mm. Before planning chemotherapy according to the M-VAC scheme, a study and post-processing of DW-MRI with volumetric segmentation of lesions, assessment of the volume and apparent diffusion coefficient (ADC) in the entire tumor mass were performed. According to the ADC data, shape of the tumor and its relation to the bladder wall, the coefficient (C) for predicting the response to chemotherapy was calculated. Results. In the cases with a coefficient value below 0.51, a high risk of treatment failure was predicted, at C≥0.74, a positive effect of treatment was predicted. With a value of 0.51≤C<0.74, the prognosis was uncertain, stabilization was more likely. The sensitivity and specificity of the method were 92.3 % and 92.4 %, respectively. Conclusion. The method of volumetric segmentation makes it possible to predict and evaluate bladder cancer response to chemotherapy with a sufficiently high accuracy. The advantages of the method are the possibility of assessing the tumor regardless of the degree of filling of the bladder, with non-contrast MRI, and with large lesions.

Objective: Assessing short-term and long-term results of multivisceral resections (MVR) performed for rectal cancer (RC) with invasion into adjacent pelvic organs, as well as the effectiveness of bladder reconstruction with the formation of a urinary reservoir of «low» pressure. Methods: The work was based on the results of surgical treatment of 37 patients with locally advanced or primary multiple RC underwent MVR. Invasion of adjacent small organs was observed in 89.2%, primary multiple malignant tumors (PMMT) – in 10.8% of patients included in the study. Results: According to the preoperative examination of tumor infiltration of one adjacent organ was diagnosed in 20 (54.1%), two or more organs – in 17 (45.9%) observations; more often affected the bladder – in 18 (48.6%) cases. Volumes of performed operations: in 6 (16.2%) cases of complete pelvic organs evisceration, in 10 (27%) cases of MVR with rectal extirpation, in 21 (56.8%) cases of MVR with resection of the rectum and adjacent organs. More often in 27 (72.9%) patients, there was urinary tract resection, of which 11 (29.7%) patients underwent primary bladder repair with the formation of ortho- (n=3) or heterotopic (n=6) urinary reservoir of «low» pressure. Postoperative complications developed in 14 (37.8%) patients, what required re-surgery in 8 (21.6%) observed, of which urological complications occurred in 4 (10.8%) patients. Complications were not observed during the formation of the artificial bladder according to the presented method. Long-term results: RC – overall and disease-free 2-year survival – 78.1% and 65.6% respectively, PMMT – all patients are alive without signs of relapse, the timeline of observation is 24 months. Conclusions: The immediate results of MVR on locally advanced RC can be considered as satisfactory. The level of postoperative complications is primarily due to the prevalence of primary tumors. In case of urinary tract resection, primary plastic surgery is preferred. Long-term results allows to examine such operations as a method of choice in the treatment of RC with invasion in adjacent organs. Keywords: Rectal cancer, surgical treatment, multivisceral resection, bladder reconstruction, postoperative complications, disease-free survival.