Efficacy of Dose-Escalated Radiotherapy for Recurrent Colorectal Cancer

Carbon-ion Radiotherapy for Colorectal Cancer

Heavy-ion radiotherapy (RT) is a kind of particle RT, and carbon-ion beam constitutes the primary delivery method of heavy-ion RT. Unlike the conventional photon modalities, particle RT, in particular carbon-ion radiotherapy (CIRT), offers unique physical and biological advantages. Particle therapy allows for substantial dose delivery to tumors with minimal surrounding tissue damage. In addition, CIRT in particular possesses biological advantages such as inducing increased double-strand breaks in DNA structures, causing irreversible cell damage independently of cell cycle or oxygenation, more so than proton or photon. It can be expected that CIRT is effective on radioresistant cancers such as colorectal cancers (CRCs). We introduced the results of CIRT for local recurrent rectal cancer, lung metastasis, liver metastasis, and lymph node metastasis.

LncRNA TTN-AS1/miR-134-5p/PAK3 axis regulates the radiosensitivity of human large intestine cancer cells through the P21 pathway and AKT/GSK-3β/β-catenin pathway

Radiotherapy is an important adjuvant treatment for large intestine cancer even though it does not cause any response in many patients. The present study aimed to investigate the effects of the TTN antisense RNA 1 (TTN-AS1) long noncoding RNA (lncRNA) on radiotherapy dynamics of large intestine cancer cells and to explore the underlying molecular mechanisms. TTN-AS1 expression was evaluated by reverse-transcription quantitative polymerase chain reaction, western blot, and cellular immunofluorescence, and flow cytometry analysis was used to measure apoptosis. Radiotherapy was simulated in vitro by exposing cancer cells to X-ray. TTN-AS1 was highly expressed in large intestine cancer cells after an X-ray exposition for 24 hr. TTN-AS1 knockdown improved the radiosensitivity of large intestine cancer cells and promoted apoptosis by increasing Bax/Bcl2 protein expression and the active-caspase 3/caspase 3 ratios following X-ray treatment. In addition, TTN-AS1 negatively regulated miR-134-5p expression, and miR-134-5p-mimic transfection decreased PAK3 protein expression in large intestine cancer cells. Importantly, TTN-AS1 promoted PAK3 and P21 protein expression in HT29 cells after X-ray treatment. Moreover, the knockdown of P21 protein expression improved radiosensitivity and promoted X-ray-induced apoptosis of HT29 cells. Finally, PAK3 knockdown expression decreased the p-AKT/AKT and p-GSK-3β/GSK-3β ratios and promoted the β-catenin transfer from the nucleus to the cytoplasm. These data suggest that the TTN-AS1 lncRNA promoted resistance to radiotherapy of large intestine cancer cells by increasing PAK3 expression via miR-134-5p inhibition, and this may be related to the P21 and AKT/GSK-3β/β-catenin pathway.

Prospective Observational Study of High-Dose Carbon-Ion Radiotherapy for Pelvic Recurrence of Rectal Cancer (GUNMA 0801)

Background and purpose: Favorable clinical outcomes of carbon-ion radiotherapy for pelvic recurrence of rectal cancer have been described by previous prospective phase I/II and II studies; however, these studies were performed at a single institution. Therefore, we conducted a prospective observational study aimed at exploring whether carbon-ion radiotherapy for post-operative pelvic recurrence of rectal cancer provides a less invasive local treatment strategy with higher cure rates than other anticancer treatments.

Materials and methods: Patients (1) with pelvic recurrence of rectal cancer, as confirmed by histology or diagnostic imaging; (2) without distant metastasis; (3) who had undergone curative resection of their primary disease and regional lymph nodes, without gross or microscopic residual disease; and (4) with radiographically measurable tumors were included in this study. The total carbon-ion radiotherapy dose for all patients was 73.6 Gy [relative biological effectiveness (RBE)] administered in 16 fractions once daily for 4 days a week (Tuesday to Friday).

Results: A total of 28 patients were enrolled between October 2011 and July 2017. The median follow-up duration was 38.9 months. The 3-year overall survival, local control, and progression-free survival rates were 92, 86, and 31%, respectively. At the time of the analysis, 4 patients had local recurrence, and 7 had died of rectal cancer. None of the patients developed grade 3 or higher acute toxicities. Late toxicities occurred in 2 and 7 patients who developed grade 3 pelvic infection and grade 2 peripheral neuropathy, respectively.

Conclusion: Carbon-ion radiotherapy for pelvic recurrence of rectal cancer showed favorable clinical outcomes and is a highly curative and less invasive local treatment.

Comparison of overall survival and quality of life between patients undergoing anal reconstruction and patients undergoing traditional lower abdominal stoma after radical resection

BACKGROUND

Miles procedure is often necessary for patients with low rectal carcinoma. However, this operation often affects the quality of life of patients, to evaluate the advantages of improved operation (anal reconstruction), the quality of life and survival between patients undergoing anal reconstruction and patients undergoing traditional lower abdominal stoma after radical resection were analyzed.

METHODS

The clinical data of 43 patients with low situated rectal carcinoma were retrospectively analyzed. 23 patients with left lower abdominal stoma after radical resection (Miles procedure) were divided into group A, and 20 patients with reconstruction of the anus in situ after radical resection were in group B. All patients were investigated by the European Organization for Research and Treatment of Cancer (EORTC) QLQ-C30 and QLQ-CR38 questionnaire, the clinical data are recorded. Independent sample T test was used to analyze the difference in quality of life between group A and group B at 3, 6, and 12 months after surgery, and Kaplan-Meier was used to compare the difference in overall survival between group A and group B.

RESULTS

The results of T test showed that there were statistical significance in global health status and physical functioning between group A and group B at 3 and 6 months, but no statistical significance at 12 months (P = 0.024, P = 0.019, P = 0.115 for global health status; P = 0.004, P = 0.006, P = 0.065 for physical functioning, respectively). Emotional functioning and social functioning were also statistically significant between group A and group B at 3, 6, and 12 months (P = 0.041, P = 0.040, P = 0.034 for Emotional functioning; P = 0.020, P = 0.009, P = 0.032 for social functioning, respectively). This study also found that there was no statistical significance in body image and sexual functioning between group A and group B at 3 months, but there was statistical significance at 6 and 12 months(P = 0.098, P = 0.035, P = 0.045 for body image; P = 0.110, P = 0.048, P = 0.047 for sexual functioning, respectively). There were statistically significant about sexual enjoyment and defecation problems at 3, 6, and 12 months (P = 0.023, P = 0.028, P = 0.050 for sexual enjoyment; P = 0.013, P = 0.011, P = 0.050 for defecation problems, respectively).The results of Kaplan-Meier showed that the overall survival (OS) between group A and group B was not statistically significant (χ² = 0.600, P = 0.439).

CONCLUSIONS

There was no difference in survival time between group A and group B, but compared with the patients with left lower abdominal stoma(group A), the quality of life was better in patients with reconstruction of the anus in situ (group B). It is significant to improve the traditional lower abdominal stoma operation.

A Review on the Special Radiotherapy Techniques of Colorectal Cancer

Colorectal cancer is one of the commonest cancers worldwide. Radiotherapy has been established as an indispensable component of treatment. Although conventional radiotherapy provides good local control, radiotherapy treatment side-effects, local recurrence and distant metastasis remain to be the concerns. With the recent technological advancements, various special radiotherapy treatment options have been offered. This review article discusses the recently-developed special radiotherapy treatment modalities for various conditions of colorectal cancer ranging from early stage, locally advanced stage, recurrent, and metastatic diseases. The discussion focuses on the areas of feasibility, local control, and survival benefits of the treatment modalities. This review also provides accounts of the future direction in radiotherapy of colorectal cancer with emphasis on the coming era of personalized radiotherapy.

Effects of varying radiation dosages on MMP1 expression, and MMP1 knockdown on the viability and migration of SW620 cells

Colorectal cancer (CRC), also known as bowel cancer, is one of the leading causes of cancer-associated mortality worldwide at present. The aim of the present study was to detect the effects of matrix metalloproteinase 1 (MMP1) on the viability and migration of a CRC cell line in the presence or absence of variation X-ray radiation doses. The CRC cell line, SW620, was cultured and treated with different X-ray doses (0, 0.1, 0.5, 1, 3 and 6 Gy). MMP1 expression was downregulated via the application of a specific small interfering (si)-RNA. The viability and migration of SW620 cells prior to and following transfection were detected with MTT and Transwell chamber assays, respectively. The application of siRNA transfection to silence MMP1 in SW620 cells resulted in reduced cell viability and migration (P<0.05). Compared with the control, the cell viability and migration of cells were significantly reduced when exposed to 0.5, 1, 3, and 6 Gy X-ray radiation (P<0.05). In SW620 cells treated with different X-ray doses, the mRNA expression levels of MMP1 were significantly reduced (P<0.05). Cells treated with 0.5 Gy X-ray exposure exhibited the lowest mRNA expression levels of MMP1 when compared with other doses of X-ray radiation. The expression of MMP1 was associated with the promotion of the viability and migration of SW620 cells. X-ray radiation with 6 Gy dosages significantly reduced cell viability when compared with the control. Thus, MMP1-targeted therapy combined with radiotherapy could be used for treating CRC.