Usefulness of diffusion-weighted magnetic resonance imaging for evaluating the effect of hemostatic radiotherapy for unresectable gastric cancer

Hemostatic Radiotherapy for Gastric Cancer: MRI as an Alternative to Endoscopy for Post-Treatment Evaluation

INTRODUCTION

Pretreatment diagnosis by diffusion-weighted magnetic resonance imaging (DW-MRI) is useful to determine the effect of chemotherapy for gastric cancer. Here, we investigated the relationship among DW-MRI, endoscopy, and tumor markers.

PATIENTS

Eight patients underwent hemostatic radiotherapy (RT) for gastric cancer in this prospective study from 2019 to 2021. The patients completed MRI, endoscopy, and blood tests before RT; MRI, endoscopy, and blood tests 1 month after RT; and MRI and blood tests 3 months after RT. Correlations between changes in apparent diffusion coefficient (ADC) derived from DW-MRI and the tumor marker carcinoembryonic antigen (CEA) were investigated.

RESULTS

Univariate analysis of overall survival showed that sex and chemotherapy treatment were statistically significant factors. The CEA values before and 1 month after RT decreased significantly. There was no statistical difference between the CEA value 1 and 3 months after RT. The ADC value before and 1 month after RT increased significantly but not between 1 and 3 months after RT. Comparing the ratio of ADC before RT to 1 (or 3) month(s) after RT with that of CEA before RT to 1 (or 3) month(s) after RT, we found an inverse relationship between the two ratios.

CONCLUSIONS

Therefore, changes in ADC and CEA are correlated. Additionally, 3 months after RT, the decrease in ADC appeared earlier than the decrease in CEA. ADC may indicate a biological change earlier than CEA, and the ratios of ADC and CEA may be important factors. These aspects warrant further confirmation in a larger sample population.

The role of MRI in the diagnosis and treatment of gastric cancer

Gastric cancer is the fifth most common malignancies and the third leading cause of cancer-related death worldwide, with more than 40% of new cases occurring in China. With the advancement of treatment methods, the application of adjuvant therapy and targeted drugs, the prognosis of patients with gastric cancer has been significantly improved. In recent years, more and more studies have reported that magnetic resonance imaging (MRI) showed great value in the clinical application among patients with gastric cancer, including preoperative staging, treatment response evaluation, predicting prognosis and histopathological features, treatment guidance, and molecular imaging. The remarkable research progress of MRI in gastric cancer will provide new evaluation and treatment approaches for clinical diagnosis and treatment. This article aims to review the current status of the application and research progress of MRI in patients with gastric cancer.

Optimized Parameters of Diffusion-Weighted MRI for Prediction of the Response to Neoadjuvant Chemoradiotherapy for Locally Advanced Rectal Cancer

Aim

To identify the optimal diffusion-weighted MRI-derived parameters for predicting the response to neoadjuvant chemoradiotherapy in locally advanced rectal cancer.

Methods

This prospective study enrolled 92 patients who underwent neoadjuvant chemoradiotherapy. Diffusion-weighted MRI sequences with two b-value combinations of b (0, 800) and b (0, 1000) were acquired before the start of neoadjuvant chemoradiotherapy and surgery. The pathological tumor regression grade was obtained according to the Mandard criteria, recommended by the seventh edition of the American Joint Committee on Cancer, to act as the reference standard. Pathological good responders (pathological tumor regression grade 1-2) were compared with poor responders (pathological tumor regression grade 3–5).

Results

The good responder group contained 37 (40.2%) patients and the poor responder group 55 (59.8%) patients. Both before and after neoadjuvant chemoradiotherapy, the mean ADC value for b = 1000 was significantly higher than that for b = 800. In the two patient groups, the post-ADC value and ΔADC for b = 800 were significantly lower than those for b = 1000, but percentages of ADC increase for b = 800 and b = 1000 showed no significant difference.

Conclusions

The percentage of ADC increase, as an optimized predictor unaffected by different b-values, may have a significant role in differentiating those patients with a good response to N-CRT from those with a poor response.

Successful treatment of unresectable advanced rectal cancer with liver metastases by hemostasis re-irradiation of the rectal cancer and palliative low-dose whole-liver radiation therapy: a case report

A 72-year-old man was admitted to the hospital with fatigue. Colonoscopy revealed a 50 × 50 mm rectal tumor with bleeding. Based on close inspection, he was diagnosed with unresectable advanced rectal cancer with multiple liver metastases. Chemotherapy was administered as 10 cycles of bevacizumab + mFOLFOX6 and 7 cycles of bevacizumab + FOLFIRI. Nine months later, he presented with hematochezia and progression of anemia. It was difficult to stop the bleeding via endoscopy. He underwent radiation therapy (39 Gy in 13 fractions), and hemostasis was confirmed. Then, further chemotherapy was performed with 3 cycles of bevacizumab + FOLFIRI and 2 cycles of TAS102. However 14 months after the initial visit, he presented with right hypochondralgia and abdominal fullness due to the progression of multiple liver metastases. Palliative low-dose whole-liver radiation therapy (WLRT) (30 Gy in 10 fractions) was performed. He developed Grade 2 nausea, but his right hypochondralgia reduced, liver dysfunction improved, and he successfully completed radiotherapy. At approximately the same time his anemia progressed, and colonoscopy revealed recurrent bleeding from the tumor. Re-irradiation (15 Gy in 5 fractions) of the rectal tumor was carried out and a blood transfusion was performed for the bleeding. He was discharged after confirmation the anemia had not progressed. Few reports have been published on the use of both palliative re-irradiation to stop bleeding from rectal cancer and palliative low-dose WLRT. Based on our experience with this case, we believe that palliative radiotherapy can be useful in treating patients with a poor prognosis.