11C-acetate for positron emission tomography imaging of clinical stage IA lung adenocarcinoma: comparison with 18F-fluorodeoxyglucose for imaging and evaluation of tumor aggressiveness

Background

To determine the usefulness of positron emission tomography (PET) with ¹¹C-acetate (AC) for imaging lung adenocarcinoma and evaluating its tumor aggressiveness, AC- and ¹⁸F-fluorodeoxyglucose (FDG)-PET were compared.

Methods

One hundred and sixty-nine adenocarcinomas with clinical stage IA and 53 benign nodules were examined by both AC- and FDG-PET before surgery. The sensitivity and specificity for discriminating benign/adenocarcinoma were compared between AC- and FDG-PET. The AC and FDG uptakes were examined to determine the relationship with tumor aggressiveness, i.e., pathological tumor stage, lymphatic, vascular, or pleural involvement, and proliferative activity determined by Ki-67 staining score.

Results

While the sensitivity of AC-PET was significantly higher than FDG-PET for bronchioloalveolar carcinoma (BAC) and well-differentiated (W/D) adenocarcinoma (p < 0.001 and 0.006, respectively), there was no significant difference for moderately or poorly differentiated adenocarcinoma. The specificity was not different between them. While FDG uptakes were significantly higher in tumors with pathological advanced stages or those with lymphatic, vascular and/or pleural involvements than in tumors with pathological stage IA or those without these tumor involvements (p = 0.04 to p < 0.001), AC uptake did not show significant differences between the respective sub-groups except according to the tumor stage. While both AC and FDG uptakes showed a significant correlation with Ki-67 staining scores (p = 0.03 and p < 0.001, respectively), the correlation coefficient of former was lower than that of latter (p = 0.07).

Conclusions

While AC-PET can image BAC and W/D adenocarcinoma with a higher sensitivity than FDG-PET, it cannot evaluate tumor aggressiveness of clinical stage IA lung adenocarcinoma as well as FDG-PET.     

What is the Effect of Laparoscopic Colectomy on Pattern of Colon Cancer Recurrence? A Propensity Score and Competing Risk Analysis Compared with Open Colectomy

Background

Variability in colon cancer recurrence after laparoscopic colectomy (LAC) remains poorly understood. The aim of our study was to quantify the influence of LAC on colon cancer recurrence patterns.

Methods

We included 986 patients undergoing curative colectomy at our institution between 1992 and 2008. Kaplan–Meier, multivariable Cox regression, propensity score adjustment, and competing risks modeling were used to evaluate the influence of laparoscopic surgery on the site of colon cancer recurrence, including the following: liver metastasis, lung metastasis, local recurrence, peritoneal dissemination, other, and multiple sites. We estimated the risk factors for each recurrence site.

Results

Laparoscopic surgery was used in 419 (42.5 %) of 986 patients, with an overall median follow-up time of 5.0 years (interquartile range 3.5). The overall 5-year disease-free survival rate was 86.1 % (open surgery 81.8 % vs. laparoscopic surgery 92.0 %; p < 0.001). However, after covariates and propensity score adjustment, laparoscopic surgery was not a significant risk factor for each type of recurrence: liver hazard ratio (HR) 0.93 (95 % CI 0.45–1.89), p = 0.84; lung HR 0.67 (95 % CI 0.26–1.70), p = 0.39; local HR 0.56 (95 % CI 0.12–2.63), p = 0.46; peritoneal HR 2.49 (95 % CI 0.75–8.27), p = 0.14; others HR 0.47 (95 % CI 0.04–5.13), p = 0.53; multiple HR 0.88 (95 % CI 0.25–3.14), p = 0.84. The risk factors for each type of recurrence were variable and characterized by specific clinicopathological features.

Conclusion

Our study reveals that LAC and open colectomy demonstrate comparable overall colon cancer recurrence rates and recurrence sites. Specific clinicopathological characteristics may have a stronger influence on colon cancer recurrence site compared with the surgical technique.     

Characteristics of recurrence and surveillance tools after curative resection for colorectal cancer: a multicenter study

BACKGROUND: The aim of this study was to clarify the characteristics of recurrence and the effectiveness of surveillance tools after curative resection for colorectal cancer. METHODS: We enrolled 5230 consecutive patients (stage I, 1367; stage II, 1912; stage III, 1951) who underwent curative resection at 14 hospitals from 1991 to 1996. All patients were followed up intensively, and their outcomes were investigated retrospectively. RESULTS: Of the 5230 patients, 906 developed recurrence. The recurrence rates of stage I, II, and III cancers were 3.7%, 13.3%, and 30.8%, respectively (P < .0001). The curves of the cumulative appearance rate of recurrence in stage II and III patients showed a rapid increase for the first 3 years. Recurrence after 5 years was less than 1% in each stage. Clinical visits combined with measurements of tumor markers detected the majority of recurrences except in the case of lung metastasis. In contrast, 43.4% of hepatic recurrences were detected by liver imaging, and 48.4% of pulmonary recurrences were noted by chest x-ray. The 5-year survival rates after primary colorectal surgery in patients who underwent resection for recurrence were better than in those without resection: 55% vs 11% in hepatic recurrence, 68% vs 13% in pulmonary recurrence, and 48% vs 22% in local recurrence (all P < .001). CONCLUSION: It is useful to take these characteristics of recurrence into account in the management of patients after curative resection for colorectal cancer and in the setting of clinical trial for follow-up after curative resection for colorectal cancer.     

Comparison of surgical outcomes of gastric cancer in elderly and middle-aged patients

BACKGROUND: We compared clinicopathological features and results of surgery for gastric carcinoma in elderly and middle-aged patients to develop appropriate treatment for elderly patients with gastric carcinoma. METHODS: Surgical results were assessed for 135 elderly patients (over 75 years old) and 665 middle-aged patients (between 45 and 65 years old) with gastric cancer. RESULTS: Distinct characteristics of elderly patients were male predominance; macroscopically well, or ill-defined, histologically differentiated tumors; and advanced stage disease. There was a significant difference in overall survival between the groups for early stage carcinomas but no difference in cause-specific survival. Postoperative morbidities did not differ between the curatively resected patients in the 2 groups. Moreover, deaths from other cancers or comorbid disease were frequent among the elderly. CONCLUSION: Meticulous treatment and follow-up not only for gastric carcinoma but also for other diseases would improve survival in elderly patients, particularly those with early-stage tumors.     

On donor–acceptor-bridging intramolecular hydrogen bonds in NIR-TADF molecules

Following a report that highlights the importance of intramolecular hydrogen bonds for improved NIR-TADF efficiency in CAT-1 [Leng et al., J. Phys Chem. A, 2021, 125, 2905], an intramolecularly doubly hydrogen-bonded base design is investigated and compared to singly and non-bonded derivatives. It is found that the potential to form more intramolecular hydrogen bonds correlates with decreasing internal reorganization energies in most of the designed structures. In addition, our proposed base design facilitates the desired interlocking of charge transfer donor-, linker- and acceptor-planes through steric gauche-interactions to both linker-plane sides, allowing to trap also smaller heterocyclic linkers.

Following a report that highlights the importance of intramolecular hydrogen bonds for improved NIR-TADF efficiency, an intramolecularly doubly hydrogen-bonded base design is investigated and compared to singly and non-bonded derivatives.     

Cell Inactivation and DNA Single- and Double-strand Breaks in Cultured Mammalian Cells Irradiated by a Thermal Neutron Beam

Summary

The effects on the cellular viability and induction and repair kinetics of DNA strand breaks in HeLa cells were examined after exposure to a thermal neutron beam and compared with those after γ-irradiation. The thermal neutron survival curve had no initial shoulder. The relative biological effectiveness (r.b.e.) value of the neutron beam was determined to be 2·2 for cell killing (ratio of D₀ values), 1·8 and 0·89 for single strand breakage (ssb) by alkaline sedimentation and alkaline elution respectively, and for double strand breakage (dsb) 2·6 by neutral elution. No difference was observed between thermal neutrons and γ-rays in the repair kinetics of ssb and dsb. It is suggested that the effect induced by the intracellular nuclear reaction, ¹⁴N(n,p)¹⁴C is mainly responsible for the high r.b.e. values observed.