Search

Accumulation and flow mechanisms in unconventional reservoir are different compared to conventional. This requires a special approach of field management with drilling and stimulation treatments as major factor for further production. Integrated approach of unconventional reservoir production optimization assumes coupling drilling project with full scale reservoir simulation for determine best well placement, well length, fracturing treatment design and mid-length distance between wells. Full scale reservoir simulation model emulate a part of polish shale – gas field. The aim of this paper is to establish influence of technical factor for gas production from shale gas field. Due to low reservoir permeability, stimulation treatment should be direct towards maximizing the hydraulic contact. On the basis of production scenarios, 15 stages hydraulic fracturing allows boost gas production over 1.5 times compared to 8 stages. Due to the possible interference of the wells, it is necessary to determine the distance between the horizontal parts of the wells trajectories. In order to determine the distance between the wells allowing to maximize recovery factor of resources in the stimulated zone, a numerical algorithm based on a dynamic model was developed and implemented. Numerical testing and comparative study show that the most favourable arrangement assumes a minimum allowable distance between the wells. This is related to the volume ratio of the drainage zone to the total volume of the stimulated zone.

The paper describes shale gas borehole axes trajectories (vertical, horizontal, multilateral). The methodology of trajectory design in a two-and three-dimensional space has been developed. The selection of the profile type of the trajectory axes of the directional borehole depends on the technical and technological possibilities of its implementation and the results of a comprehensive economic analysis of the availability and development of the field. The work assumes the possibility of a multivariate design of trajectories depending on the accepted (available or imposed) input data.

Nowadays, scientists from all over the world are focused on environmental issues connected with the greenhouse gases. The carbon dioxide is one of those gases. Therefore, researches are carried out to limit the emission or utilization the already ones. The aim of laboratory research was to find additives and admixtures resistant to CO2 presence and at the same time, able to modify rheological parameters of fresh cement slurry, as it is desirable during cementing of the wellbore. Moreover, research included the effect of newly synthesized polymers on the cement parameters. Laboratory research included filtration of the cement slurry, rheological parameters – Yield point, mechanical properties of hardened cement slurry obtained from hydraulic press and photographs of changes in mineralogical structure of cement from the electron microscope. The research was divided into two parts. The first one was based on the cement mixtures with commonly used superplastifier (SPL). In the second one, the SPL was replaced with newly synthesized polymer.

Abstract Background CYP1B1 is a P450 enzyme which is involved in the activation of pro-carcinogens to carcinogens as well as sex hormone metabolism. Because differences in the activity of the enzyme have been correlated with variant alleles of single nucleotide polymorphisms (SNPs), it represents an attractive candidate gene for studies into colorectal cancer susceptibility. Methods We genotyped 597 cancer patients and 597controls for three CYP1B1 SNPs, which have previously been shown to be associated with altered enzymatic activity. Using the three SNPs, eight different haplotypes were constructed. The haplotype frequencies were estimated in cases and controls and then compared. The odds ratio for each tumour type, associated with each haplotype was estimated, with reference to the most common haplotype observed in the controls. Results The three SNPs rs10012, rs1056827 and rs1056836 alone did not provide any significant evidence of association with colorectal cancer risk. Haplotypes of rs1056827 and rs10012 or rs1056827 and rs1056836 revealed an association with colorectal cancer which was significantly stronger in the homozygous carriers. One haplotype was under represented in the colorectal cancer patient group compared to the control population suggesting a protective effect. Conclusion Genetic variants within the CYP1B1 that are associated with altered function appear to influence susceptibility to a colorectal cancer in Poland. Three haplotypes were associated with altered cancer risk; one conferred protection and two were associated with an increased risk of disease. These observations should be confirmed in other populations.

Pathogenic mutations in BRCA1 (BReast CAncer gene 1) confer high risks of both breast (up to 70%) and ovarian (up to 40%) cancers. Zinc (Zn) and copper (Cu) are essential for various physiological functions, including antioxidant reactions. Their balance, reflected in the Zn/Cu ratio, plays a crucial role in maintaining redox homeostasis, which is vital for cancer prevention. This study examines the antioxidant properties of Zn and Cu, specifically focusing on the blood Zn/Cu ratio as a potential marker for cancer risk among BRCA1 mutation carriers. The study cohort consisted of 989 initially unaffected women, followed up for 7.5 years. Blood samples were analyzed using inductively coupled plasma mass spectrometry. Although individual Zn and Cu levels did not significantly correlate with overall cancer risk, those women with a Zn/Cu ratio above 6.38 experienced a significantly lower cancer risk than women with a ratio below this cut-off point. This suggests that the Zn/Cu ratio may be a valuable biomarker for cancer prevention in this high-risk group. Given the increased cancer risk in BRCA1 mutation carriers, optimizing Zn and Cu levels through dietary and active interventions could provide a preventive strategy.

Breast cancer and ovarian cancer pose a significant risk for BRCA1 carriers, with limited risk-reduction strategies. While improved screening helps in the early detection of breast cancer, preventive measures remain elusive. Emerging evidence suggests a potential link between iodine levels and modulation of cancer risk, but comprehensive studies are scarce. We conducted a prospective study among 989 BRCA1 carriers to assess the association between blood iodine levels and breast and ovarian cancer risk. Using inductively coupled plasma mass spectrometry, we measured blood iodine levels and observed a negative association with breast cancer risk, with a significantly lower risk observed in quartile 4 (iodine > 38.0 µg/L) compared with quartile 1 (iodine < 30 µg/L) (HR = 0.49; 95%CI: 0.27-0.87; p = 0.01). Conversely, a suggestive increase in ovarian cancer risk was observed at higher iodine levels (HR = 1.91; 95%CI: 0.64-5.67; p = 0.25). No significant association was found between iodine levels and overall cancer risk. Our results suggest the potential of iodine to reduce breast cancer risk in BRCA1 carriers after prophylactic oophorectomy but require further validation and investigation of its effect on ovarian cancer risk and overall mortality. These findings highlight the need for personalized strategies to manage cancer risk in BRCA1 carriers.

Background: This was an observational study prospectively evaluating the effectiveness and safety of aflibercept/FOLFIRI administered in second-line mCRC per the reimbursement criteria in Poland., Methods: Consecutive mCRC patients who progressed with first-line oxaliplatin-based chemotherapy received aflibercept (4 mg/kg IV) followed by FOLFIRI every 2 weeks until progression or unacceptable toxicity. The primary endpoint was progression-free survival (PFS); overall survival (OS) and safety were the secondary endpoints., Results: A total of 93 patients were treated at 17 Polish sites. A median of 10 cycles was administered. Over a median treatment duration of 5.3 months, median PFS and median OS were 8.4 months [95% CI, 6.9-9.9] and 27.0 months [95% CI, 23.9-30.1], respectively. There was no significant impact of primary tumor location, metastatic site, or KRAS status on PFS and OS. Main grade ≥ 3 adverse events were neutropenia (16%), hypertension (8%), diarrhea (4%), and stomatitis (4%)., Conclusions: The benefits/risks of Aflibercept plus FOLFIRI administered per the Polish reimbursement criteria in second-line treatment of mCRC after failure of a prior oxaliplatin-based regimen is confirmed.

BRCA1 mutations predispose women to breast and ovarian cancer. The anticancer effect of zinc is typically linked to its antioxidant abilities and protecting cells against oxidative stress. Zinc regulates key processes in cancer development, including DNA repair, gene expression, and apoptosis. We took a blood sample from 989 female BRCA1 mutation carriers who were initially unaffected by cancer and followed them for a mean of 7.5 years thereafter. There were 172 incident cases of cancer, including 121 cases of breast cancer, 29 cases of ovarian cancers, and 22 cancers at other sites. A zinc level in the lowest tertile was associated with a modestly higher risk of ovarian cancer compared to women with zinc levels in the upper two tertiles (HR = 1.65; 95% CI 0.80 to 3.44; p = 0.18), but this was not significant. Among those women with zinc levels in the lowest tertile, the 10-year cumulative risk of ovarian cancer was 6.1%. Among those in the top two tertiles of zinc level, the ten-year cumulative risk of ovarian cancer was 4.7%. There was no significant association between zinc level and breast cancer risk. Our preliminary study does not support an association between serum zinc level and cancer risk in BRCA1 mutation carriers.

BRCA1 mutations substantially elevate the risks of breast and ovarian cancer. Various modifiers, including environmental factors, can influence cancer risk. Lead, a known carcinogen, has been associated with various cancers, but its impact on BRCA1 carriers remains unexplored. A cohort of 989 BRCA1 mutation carriers underwent genetic testing at the Pomeranian Medical University, Poland. Blood lead levels were measured using inductively coupled plasma mass spectrometry. Each subject was assigned to a category based on their tertile of blood lead. Cox regression analysis was used to assess cancer risk associations. Elevated blood lead levels (>13.6 μg/L) were associated with an increased risk of ovarian cancer (univariable: HR = 3.33; 95% CI: 1.23-9.00; p = 0.02; multivariable: HR = 2.10; 95% CI: 0.73-6.01; p = 0.17). No significant correlation was found with breast cancer risk. High blood lead levels are associated with increased risk of ovarian cancer in BRCA1 carriers, suggesting priority for preventive salpingo-oophorectomy. Potential risk reduction strategies include detoxification. Validation in diverse populations and exploration of detoxification methods for lowering lead levels are required.

Anti-EGFR antibodies combined with chemotherapy doublets are a cornerstone of the upfront treatment of colorectal cancer. RAS and BRAF mutations are established negative predictive factors for such therapy. The primary tumour located in the proximal colon has recently emerged as another negative predictive factor. We have conducted a retrospective multicentre study to collect data on real-world population characteristics, practice patterns, and outcomes in patients with metastatic colorectal cancer treated in a first-line setting with either cetuximab or panitumumab in combination with either FOLFOX or FOLFIRI chemotherapy. The presented analysis focuses on the impact of the primary tumour location. 126 of 842 patients analysed (15.0%) had proximal primary. It was associated with a lower BMI at diagnosis, mucinous histology, and peritoneal metastases. It was also associated with inferior treatment outcomes in terms of response ratio: 59.4% vs. 74.22% (odds ratio [OR] 0.51, 95% CI 0.33-0.78, p = 0.010), and median depth of response: -36.7% vs. -50.0% ( p = 0.038). There was only a borderline non-significant trend for inferior PFS in patients with proximal tumours. OS data was incomplete. The presented analysis confirms the negative impact of tumour sidedness on the efficacy of an upfront anti-EGFR-chemotherapy combination and provides valuable data on real-world population characteristics.

Background: To estimate the impact of oophorectomy and other treatments on the survival of breast cancer patients with a CHEK2 mutation., Methods: Women with Stage I-III breast cancer who were treated at 17 hospitals in Poland were tested for four founder mutations in the CHEK2 gene. 974 women (10%) were positive for a CHEK2 mutation. Control patients without a CHEK2 mutation were selected from a database of patients treated over the same time period. Information on treatments received and distant recurrences were retrieved from medical records. Treatments included chemotherapy, hormonal therapy (tamoxifen) and radiation therapy. Oophorectomies were performed for the treatment of breast cancer or for benign conditions. Dates of death were obtained from the Polish Vital Statistics Registry. Causes of death were determined by medical record review. Predictors of survival were determined using the Cox proportional hazards model., Results: In all, 839 patients with a CHEK2 mutation were matched to 839 patients without a mutation. The mean follow-up was 12.0 years. The 15-year survival for CHEK2 carriers was 76.6% and the 15-year survival for non-carrier control patients was 78.8% (adjusted HR = 1.06; 95% CI: 0.84-1.34; P = 0.61). Among CHEK2 carriers, the 15-year survival for women who had an oophorectomy was 86.3% and for women who did not have an oophorectomy was 72.1% (adjusted HR = 0.59; 95% CI: 0.38-0.90; P = 0.02). Among controls, the 15-year survival for patients who had an oophorectomy was 84.5% and for women who did not have an oophorectomy was 77.6% (adjusted HR = 1.03; 95% CI: 0.66-1.61; P = 0.90)., Conclusion: Among women with breast cancer and a CHEK2 mutation, oophorectomy is associated with a reduced risk of death from breast cancer., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)

Methylation of the promoter of the BRCA1 gene in DNA derived from peripheral blood cells is a possible risk factor for breast cancer. It is not clear if this association is restricted to certain types of breast cancer or is a general phenomenon. We evaluated BRCA1 methylation status in peripheral blood cells from 942 breast cancer patients and from 500 controls. We also assessed methylation status in 262 paraffin-embedded breast cancer tissues. Methylation status was assessed using methylation-sensitive high-resolution melting and was categorized as positive or negative. BRCA1 methylation in peripheral blood cells was strongly associated with the risk of triple-negative breast cancer (TNBC) (odds ratio [OR] 4.70; 95% confidence interval [CI]: 3.13-7.07; p < 0.001), but not of estrogen-receptor positive breast cancer (OR 0.80; 95% CI: 0.46-1.42; p = 0.46). Methylation was also overrepresented among patients with high-grade cancers (OR 4.53; 95% CI: 2.91-7.05; p < 0.001) and medullary cancers (OR 3.08; 95% CI: 1.38-6.88; p = 0.006). Moreover, we detected a significant concordance of BRCA1 promoter methylation in peripheral blood and paired tumor tissue (p < 0.001). We found that BRCA1 promoter methylation in peripheral blood cells is associated with approximately five times greater risk of TNBC. We propose that BRCA1 methylation in blood-derived DNA could be a novel biomarker of increased breast cancer susceptibility, in particular for triple-negative tumors., (© 2019 UICC.)

Introduction: Previous studies showed that high and low body mass index (BMI) was associated with worse prognosis in metastatic CRC (mCRC). Whether BMI is a prognostic or predictive factor in mCRC is unclear. We aimed to assess efficacy outcomes according to BMI in patient with metastatic colorectal cancer treated with bevacizumab plus FOLFOX chemotherapy regimen in second-line treatment., Material and Methods: The analysis of 237 patients with metastatic colorectal cancer treated with bevacizumab plus FOLFOX in the second line (treated from January 2014 to August 2018) in 4 reference oncological centers in Poland., Results: The median age of the patients was 65 years (range 34-82). The median overall survival (OS) and progression-free survival (PFS) of the all 237 patient was 14.6 and 8.8 months, respectively. Comparison of obese patient (BMI > 30 kg/m 2 ) vs. overweight patients (BMI ≥ 25 to < 30 kg/m 2 ) vs. normal BMI range patients revealed a significant improvement of median OS (17.5 vs. 14.3 vs. 13.1 months, p = 0.01) and median PFS (9.4 vs. 9.1 vs. 7.3 months, p = 0.03). The Cox hazard model showed that the BMI class is an important risk factor. However, the Cox model also showed that the significance of the BMI class applies only to patients with BMI < 25 kg/m 2 . This rule applies to both OS and PFS. The regression analysis also confirmed that there is a statistically significant relationship between the length of OS and PFS and the BMI value. Higher BMI was associated with a better prognosis. There were no differences in responses to treatment bevacizumab and FOLFOX chemotherapy and number adverse events according to BMI values., Conclusions: Patients with mCRC treated with chemotherapy with bevacizumab in second-line treatment with higher BMI compared with normal weight patients have better prognosis in terms of PFS and OS. In this group, we found no evidence of changes in safety profile depending on BMI. Nevertheless, further large randomized studies are needed to assess the body weight on the effectiveness of chemotherapy in combination with bevacizumab., Competing Interests: The authors declare no conflict of interest., (Copyright: © 2020 Termedia Sp. z o. o.)