Layer-Ordered Organooxotin Clusters for Extreme-Ultraviolet Photolithography.

Extreme-ultraviolet (EUV) photolithography, which enables the high-throughput production of well-defined patterns with critical dimensions on the scale of several nanometers, is essential for the fabrication of a highly integrated semiconductor. The full exploitation of EUV lithographic techniques necessitates the development of photoresist (PR) materials with both high EUV sensitivity and a long shelf-life. However, despite notable advances, the available library of EUV PR materials remains limited. Here we report EUV PRs capable of forming preorganized layers consisting of ladder-structured tetranuclear stannoxanes. Single-crystal X-ray structure analyses reveal a close interlayer distance of 8.5 Å through interdigitation of the pseudoaxial butyl chains. The developed EUV PR materials exhibit high solubility in organic solvents commonly used in semiconductor processing, enabling the preparation of PR solutions with superior wettability and uniform film-forming ability on Si wafer substrates. These PR solutions also demonstrate notable resistance to hydrolytic decomposition for as long as 1 month, indicating a long shelf-life. Our PR materials enabled negative-tone patterning processes that involved a solubility decrease upon irradiation. The presence of chromophoric ligands makes our PR materials compatible with conventional UV photolithography, through photochemical reactions involving carbonyl units. In addition, e-beam and EUV lithography could produce fine line patterns of our PRs, with critical dimensions of 20 and 15 nm, respectively. Our research showcases the potential of layer-ordered organooxotin clusters for EUV PR applications.

Extreme UV Resist Exhibiting Synergism between Chemical and Physical Crosslinking Mechanisms.

Carbon-fluorine bonds in fluorinated molecules can undergo homolytic cleavage reactions when electrons are injected, and the resulting radicals combine to form network structures characterized by reduced solubility. This crosslinking chemistry suggests a new category of patterning materials that function under electron beam (e-beam) and extreme ultraviolet (EUV) lithographic conditions. Although this chemistry enables the production of 50 nm or smaller-sized features of simple fluoroalkylated polymers, it is limited by the need for relatively large amounts of irradiation energy to achieve required solubility changes. Therefore, this study was undertaken to devise a sensitivity-enhancing strategy based on a synergistic combination of radical crosslinking and hydrogen-bonding interactions between highly fluoroalkylated copolymers. An alternating copolymer was synthesized using tert-butoxystyrene and a fluoroalkylated maleimide, the former of which produces active hydrogens through catalytic acidolysis reactions. When the polymer was blended with a catalytic amount of a photoacid generator and subjected to lithographic patterning tests under e-beam and EUV irradiation, the deprotection reactions of tert-butoxy moieties proceeded at room temperature and led to a solubility decrease. We presume the small number of hydroxyl moieties produced formed an intermolecular hydrogen-bonding network, which acted synergistically with the covalent crosslinks generated by C-F bonds. When 30 nm features of copolymer thin films were fabricated by EUV lithography, sensitivity was improved by 25-34% without significant deterioration of pattern quality, especially line-edge roughness. These results demonstrate that EUV resists with improved patterning capabilities can be achieved by combining catalytic acidolysis reactions and noncatalytic crosslinking chemistry.

A prospective analysis of two studies that used the 5-mm interval slices and 5-mm margin-free method for ipsilateral breast tumor recurrence after breast-conserving surgery without radiotherapy.

BACKGROUND: Breast-conserving surgery with radiotherapy is one of standard treatments for early breast cancer. However, it is regarded as an option to treat elderly patients with small hormone receptor-positive breast cancer with breast-conserving surgery and hormone therapy without radiotherapy. We conducted two sequential prospective studies to examine the feasibility of breast-conserving surgery without radiotherapy since 2002 and present the results. PATIENTS AND METHODS: Primary female breast cancer patients who fulfilled the strict eligibility criteria were prospectively enrolled in two sequential studies named WORTH 1 and 2. The surgical materials were sliced in 5-mm intervals and all slices were examined microscopically. Postoperative radiotherapy was not allowed, but tamoxifen or anastrozole was administered for 5 years. Ipsilateral breast tumor recurrence (IBTR)-free survival was the primary outcome. RESULTS: The data of the two studies were combined (N = 321). The median follow-up period for IBTR was 94 months (4-192 months). Only three patients were treated with adjuvant chemotherapy. The 5- and 10-year IBTR-free rates were 97.0% and 90.5%, respectively. The age at operation and PR status affected IBTR rates independently. When we calculated IBTR-free rates of patients who were 65 years of age or older at the time of surgery and had PR-positive tumors, the 5- and 10-year IBTR rates were both 98.4%. CONCLUSIONS:  Our "5-mm-thick slice and 5-mm free-margin" method may be effective to select patients who can be treated by breast-conserving surgery and hormone therapy without radiotherapy.

Perfluoroalkylated alternating copolymer possessing solubility in fluorous liquids and imaging capabilities under high energy radiation.

A highly fluorinated alternating polymer, P(RFMi-St), possessing improved thermal properties and patterning capabilities over perfluoroalkyl polymethacrylates under high energy radiation was achieved with semi-perfluorododecyl maleimide (RFMi) and styrene (St). RFMi could be synthesised efficiently via a Mitsunobu reaction condition and copolymerised with St by free radical and reversible-deactivation radical polymerisation protocols. P(RFMi-St) showed a satisfactory glass-transition temperature (108 °C) and intermolecular cross-linking behaviour under electron-beam and commercially more important extreme UV (λ = 13.5 nm) irradiation. The exposed regions lost their solubility, resulting in the successful formation of mechanically non-deteriorated negative-tone images down to 50 nm. In addition, P(RFMi-St) could be solution-processed with chemically non-damaging fluorous liquids, which enabled the polymer to be applied effectively on top of an organic semiconductor layer as a dielectric material (dielectric constant 2.7) for the organic field-effect transistor fabrication.

Phase I Study of Combination Therapy With Weekly Nanoparticle Albumin-bound Paclitaxel and Cyclophosphamide in Metastatic Breast Cancer Patients.

BACKGROUND/AIM: The objective of this phase I study was to determine the maximum-tolerated dose (MTD) and recommended dose (RD) of combination therapy with weekly nanoparticle albumin-bound paclitaxel (nab-paclitaxel) and cyclophosphamide (CPA) in metastatic breast cancer (MBC) patients. PATIENTS AND METHODS: Five patients who had human epidermal growth factor receptor 2 (HER2) negative MBC were recruited in this study. They received nab-paclitaxel at dose levels of 100-150 mg once a week for three weeks, repeated every 4 weeks, and CPA (600 mg/m2) administered on day 1. RESULTS: No patient had grade 4 toxicity, however, two patients discontinued protocol treatment due to adverse events at level 2. Thus, the Data and Safety Monitoring Committee recommended the MTD of nab-paclitaxel and CPA to be determined at level 2. CONCLUSION: The combination therapy with weekly nab-paclitaxel and CPA was tolerable, and the RD for these drugs for MBC were 100 and 600 mg/m2, respectively.

Identification of complications in mastectomy with immediate reconstruction using tissue expanders and permanent implants for breast cancer patients.

BACKGROUND: Since complications of postmastectomy breast reconstruction may reduce patient satisfaction, we investigated complications of reconstruction with tissue expanders (TEs), particularly surgical site infections requiring TE/permanent implant (PI) removal. PATIENTS AND METHODS: A retrospective review was performed of 234 primary breast cancer patients undergoing 239 postmastectomy breast reconstructions with TEs/PIs from 1997 to 2009. Clinicopathological findings and postoperative complications, particularly infections, were analyzed. Data were analyzed by the Chi-square test and a multivariate logistic regression model. TE infection risk factors considered for model inclusion were excisional biopsy, (neo) adjuvant chemotherapy, lymph node resection, body mass index (BMI), simultaneous bilateral reconstructions, and seroma aspiration. RESULTS: Removal of TEs/PIs was observed in 15.5% (37/239) of reconstructions, and 18/37 underwent re-reconstructions. Of the 19/37 reconstructions that were not achieved completely, the most frequent reason was TE infection (11 reconstructions). The completion rate was 92% (220/239 reconstructions) and it was significantly higher in reconstructions without TE infection than with infection (96 vs. 54%, p < 0.0001). Patients with BMI ≥ 25 kg/m² and seroma aspiration were more likely to develop TE infections (p = 0.0019, p < 0.001, respectively). By multivariate logistic regression analysis, seroma aspiration was a significant independent risk factor for TE infection (odds ratio 28.75, 95% confidence interval 5.71-40.03, p < 0.0001). CONCLUSION: To improve completion rates of breast reconstruction, prevention of TE infection plays a key role. We should reduce unnecessary seroma aspirations and delay elevation/exercise of the ipsilateral arm.

A case of femoral diaphyseal fracture after long-term treatment with zoledronic acid.

We report here a case of femoral diaphyseal fracture thought to be caused by oversuppression of bone remodeling due to long-term bisphosphonate treatment. The patient was a 63-year-old postmenopausal woman. She had undergone left lumpectomy and sentinel node biopsy for left breast cancer at age 57. The case was diagnosed as pT2N0M0, stage IIA breast cancer. The biopsy sample was positive for hormone receptors and negative for HER2 protein. Postoperatively, exemestane was administered as adjuvant therapy. Right axillary lymph node metastasis was found at age 59, and right axillary lymph node dissection was performed. Postoperatively, epirubicin/cyclophosphamide and paclitaxel were administered. Subsequently, letrozole was administered. However, bone metastases to the first thoracic vertebra and right ilium were found at age 60, and zoledronic acid administration (4 mg/month) for bone metastasis was initiated. The patient developed a transverse fracture in the proximal left femoral diaphysis when she walked on a flat surface after zoledronic acid was administered for 2 years, 10 months. She was treated with an intramedullary nail for left femoral diaphyseal fracture. Cancellous bone of the medullary cavity was histopathologically examined, but there were no metastatic lesions from the breast cancer and no osteoblasts or osteoclasts were observed. Zoledronic acid was immediately discontinued in this patient. In recent years, cases of atypical femoral diaphyseal fractures caused by minor trauma in patients undergoing long-term bisphosphonate treatment have been reported. Thus, careful observation is required for patients who are anticipating bisphosphonate treatment.

Clinical outcome of reconstruction with tissue expanders for patients with breast cancer and mastectomy.

BACKGROUND: Because the number of patients with breast cancer who have reconstruction after mastectomy is increasing, we analyzed the outcomes of reconstruction with tissue expanders (TEs). PATIENTS AND METHODS: From 2004 to 2009, 133 patients with unilateral primary breast cancer who required mastectomy concurrent with reconstruction using TEs (TE group) and 308 patients with breast cancer who underwent mastectomy without reconstruction (MT group) were examined. RESULTS: The median follow-up period was 47 months versus 44 months (TE group vs. MT group, respectively). The median age was 46 years in the TE group and 58 years in the MT group (P < .0001). The rate of hormone receptor positivity in the TE group was significantly higher than in the MT group (P = .0123). The incidence of local recurrence, time to detection of local recurrence, and size of tumor in local recurrence in the TE group and the MT group were 3.8% versus 1.6% (P = .1560), 17.2 months versus 12.4 months (P = .9166), and 1.9 cm versus 2.4 cm (P = .6742), respectively. In the TE versus the MT groups, relapse-free survival (RFS) and overall survival (OS) at 45 months were 89.0% versus 87.9% (P = .8706) and 93.9% versus 94.2% (P = .9947), respectively. The incidence of infection was significantly higher in the TE group than in the MT group-14.3 % versus 2.9%, respectively (P < .0001). CONCLUSION: Compared with mastectomy alone, immediate reconstruction with TEs did not impair prognosis or contribute to a delay in detection of local recurrence, although the incidence of surgical site infection in the TE group was significantly higher than in the MT group.

A case of mucinous carcinoma of the breast in which needle tract seeding was diagnosed by preoperative diagnostic imaging.

Herein we report a 62-year-old woman with an excisable breast tumor in whom needle tract seeding was suspected during preoperative ultrasound and magnetic resonance imaging (MRI). A tumor of the right breast was observed during initial examination, and she was referred to our hospital after fine-needle aspiration cytology led to diagnosis of breast cancer, even though core needle biopsy results were negative. Mammography showed a high-density mass with a portion of the margin exhibiting very fine serrations. Ultrasonography revealed a circular mass with a border that was indistinct in some regions, and a hypoechoic band that extended from the tumor toward the skin. A mass was observed on MRI, with a linear enhancement extending on the skin side, and needle tract seeding was suspected. Fine-needle aspiration cytology revealed malignancy, and the histological appearance was consistent with mucinous carcinoma. T1cN0M0 stage I breast cancer was diagnosed, and wide excision and sentinel lymph node biopsy were performed. The skin directly above the tumor was concurrently excised to remove the biopsy puncture site. Histopathological diagnosis confirmed mucinous carcinoma, with the tumor observed to extend linearly into the subcutaneous adipose tissue in a pattern corresponding to the biopsy puncture site. The stump of the excised breast was negative for cancer cells. The possibility of tumor seeding must be considered during fine-needle aspiration cytology and biopsy. As demonstrated in this case, diagnosis of such seeding through preoperative imaging may enable extraction of the entire lesion, including the needle tract.

Diabetic mastopathy of bilateral breasts in an elderly Japanese woman with type 2 diabetes: a case report and a review of the literature in Japan.

We report a case of diabetic mastopathy in an elderly woman with type 2 diabetes. The patient was a 69-year-old woman diagnosed with type 2 diabetes at the age of 33 years. She had been treated with insulin for 25 years, however, her blood glucose had been poorly controlled. She noticed bilateral breast lumps in September 2002. Mammography of the breast showed increased density in the glandular pattern and architectural distortion without focal mass and microcalcification. Ultrasonography of the breast showed an irregular-shaped hypoechoic mass with an acoustic shadow. As malignancy needed to be excluded, core needle biopsy was performed in the left breast and diabetic mastopathy was confirmed pathologically. Diabetic mastopathy is usually a complication of pre-menopausal type 1 diabetes and develops in a unilateral breast. This case developed in bilateral breasts in an elderly type 2 diabetic patient.

Ipsilateral breast tumor recurrence (IBTR) after breast-conserving treatment for early breast cancer: risk factors and impact on distant metastases.

BACKGROUND: The clinical features of ipsilateral breast tumor recurrence (IBTR) after breast conserving therapy (BCT) for early stage breast cancer were analyzed from long-term follow-up of BCT in Japan. The purpose of this study was to clarify risk factors of IBTR and the impact of IBTR on development of distant metastases in this ethnic group. METHODS: Patients (N = 1901)with unilateral breast cancer < or = 3 cm in diameter who underwent BCT at 18 Japanese major breast cancer treatment institutes from 1986 to 1993 were registered in this study. Survival rates, the incidences of IBTR and distant metastases, and annual rates of IBTR and distant metastases after primary operation were calculated by the Kaplan-Meier method. A Cox proportional hazards model was used to estimate the risks of IBTR and distant metastases. A Cox model was also used to estimate the risks of distant metastases after IBTR in the group of IBTR. RESULTS: At a median follow-up time of 107 months, the 10-year overall and disease-free survival rates were 83.9% and 77.8%, respectively. The 10-year cumulative rates of IBTR were 8.5% in the patients with postoperative irradiation and 17.2% in the patients without irradiation. The 10-year cumulative distant metastasis rate was 10.9%. On multivariate analysis, young age, positive surgical margin, and omission of radiation therapy were significant predictors of IBTR. In addition, IBTR significantly correlated with subsequent distant metastases (hazard ratio, 3.93; 95% confidence interval, 2.676-5.771; P < 0.0001). Among patients who developed IBTR, initial lymph node metastases and short interval to IBTR were significant risk factors for subsequent distant metastasis. CONCLUSIONS: Young age, positive surgical margin, and omission of radiation therapy seemed to be important factors in relation to local control. The authors' results also indicated that IBTR is significantly associated with subsequent distant metastasis. Patients with positive nodal status at primary operation or with short interval from primary operation to IBTR are at especially high risk of distant metastasis. It remains unclear, however, whether IBTR is an indicator or a cause of subsequent distant metastases.

1-hexylcarbamoyl-5-fluorouracil + cyclophosphamide + tamoxifen versus CMF + tamoxifen in women with lymph node-positive breast cancer after primary surgery: a randomized controlled trial.

We studied the usefulness of the oral 5-FU anti-cancer drug 1-hexylcarbamoyl-5-fluorouracil (HCFU) + cyclophosphamide (CPM) + tamoxifen (TAM) (HCT group) in comparison with CMF + TAM (CMFT group) in adjuvant therapy for breast cancer by a non-inferiority study based on a multi-institutional joint study. Clinical stage I, II primary breast cancers with histologically positive axillary lymph node metastasis were randomly assigned to the HCT group or the CMFT group after primary surgery. We registered 136 cases (HCT group 68 cases, CMFT group 68 cases). No significant difference in the 5-year overall survival rate (OS) and the 5-year disease-free survival rate (DFS) was found between the two groups. In the stratified analysis, DFS in cases in which the number of metastatic lymph nodes was 1-3 was significantly better in the HCT group (HCT group 84.3%, CMFT group 69.4%, log-rank test p=0.0496). No significant difference in the total incidence of adverse effects was found between the two groups, but there were significantly less adverse effects of grade 2 or over in the HCT group (p=0.034). The QOL survey at 3 months after surgery showed a significant decline of the QOL regarding lassitude, degree of difficulty in daily life, satisfaction with treatment and present mood in the CMFT group. Study results suggest that 2-year HCT therapy including the oral 5-FU anti-cancer drug HCFU is a useful adjuvant therapy which can replace CMFT therapy in early breast cancer cases with 3 or lower metastatic lymph nodes.

Long-term results of breast-conserving treatment for early-stage breast cancer in Japanese women from multicenter investigation.

BACKGROUND: Although many clinical data regarding breast-conserving treatment have already been reported from European and North American countries, few clinical data with long-term follow-up have been reported from Japan. METHOD: We collected information on therapeutic and possible or developed prognostic factors and follow-up data for Japanese women who had received breast-conserving treatment consisting of wide excision of the primary tumor, axillary dissection and radiotherapy for unilateral breast cancer considered suitable for breast-conserving treatment from 18 Japanese major breast cancer treating hospitals; 1561 patients were registered. RESULTS: The median follow-up period was 77 months. Five-year disease-free and overall survival rates were 89.4 and 95.9%, respectively. The 5-year local recurrence-free rate was 96.3%. The patients with histologically positive margins (P < 0.0001) or estrogen receptor negative tumor (P = 0.0340) or younger than 40 years old (P < 0.0001) developed statistically significantly more local recurrences. Adjuvant endocrine therapy was essential for the estrogen receptor positive patients to have a lower local recurrence rate. Endocrine therapy did not change the local recurrence rate among estrogen receptor negative patients at all. Multivariate analysis showed histological margin status and the combination of estrogen receptor status and endocrine therapy were independent prognostic factors for local recurrence. CONCLUSION: The 5-year local recurrence rate of Japanese breast cancer patients who were treated with breast-conserving treatment using radiotherapy was 3.7%. Independent prognostic factors for local recurrence were histological margin status and the combination of estrogen receptor status and adjuvant endocrine therapy.