Tomotherapy as an adjuvant treatment for gastroesophageal junction and stomach cancer may reduce bowel and bone marrow toxicity compared to intensity-modulated radiotherapy and volumetric-modulated arc therapy.Oncotarget. 2017;8:39727-39735. [PMID: 28061474 DOI: 10.18632/oncotarget.14459]

Efficacy and toxicity of capecitabine combined with intensity-modulated radiotherapy after D1/D2 lymph node dissection in patients with gastric cancer

BACKGROUND

Adjuvant chemoradiotherapy (ACRT) with oral capecitabine and intensity-modulated radiotherapy (IMRT) were well tolerated in a phase I study in patients who had undergone partial or total gastrectomy for locally advanced gastric cancer (GC). This phase II study aimed to further determine the efficacy and toxicity of this combination after radical resection and D1/D2 lymph node dissection (LND) for patients with locally advanced GC.

AIM

To further determine the efficacy and toxicity of this combination after radical resection and D1/D2 LND for patients with locally advanced GC.

METHODS

Forty patients (median age, 53 years; range, 24-71 years) with pathologically confirmed adenocarcinoma who underwent D1/D2 LND were included in this study. The patients received ACRT comprising IMRT (total irradiation dose: 45 Gy delivered in daily 1.8-Gy fractions on 5 d a week over 5 wk) and capecitabine chemotherapy (dose: 800 mg/m² twice daily throughout the duration of radiotherapy). The primary study endpoint was disease-free survival (DFS), and the secondary endpoints were overall survival (OS), toxic effects, and treatment compliance.

RESULTS

The 3-year DFS and OS were 66.2% and 75%, respectively. The median time to recurrence was 19.5 mo (range, 6.1-68 mo). Peritoneal implantation (n = 10) was the most common recurrence pattern, and the lung was the most common site of extra-abdominal metastases (n = 5). Nine patients developed grade 3 or 4 toxicities during ACRT. Two patients discontinued ACRT, while eleven underwent ACRT without receiving the entire course of capecitabine. There were no treatment-related deaths.

CONCLUSION

The ACRT protocol described herein showed acceptable safety and efficacy for patients with locally advanced GC who received radical gastrectomy and D1/2 LND.

Tomotherapy as a neoadjuvant treatment for locally advanced esophageal cancer might increase bone marrow toxicity in comparison with intensity-modulated radiotherapy and volumetric-modulated arc therapy

This study compares dosimetric parameters in these following 3 neoadjuvant chemoradiotherapy (NCRT) methods in treating locally advanced esophagus cancer: helical tomotherapy (TOMO), volumetric modulated arc therapy (VMAT), and intensity-modulated radiotherapy (IMRT). It is aimed to ascertain the efficient technique that kept high target coverage and availed the dose sparing of bone marrow (BM). This research collected data on 11 patients from October 2014 to June 2017 who received NCRT for pathologically confirmed esophageal cancer. The prescription doses to the planning target volume (PTV) were all given as 60 Gy (2 Gy per fraction, 5 days a week). Three physicists via Varian Eclipse Treatment Planning System and Accuray planning stations redesigned 5 radiotherapy plans (fixed 5-field IMRT, fixed 7-field IMRT, 2-arc VMAT, 3-arc VMAT, and TOMO) for each of the patients. At the end of the planning, we then appraised the dosimetric quality based on the PTV parameters and the doses to organs at risk (OARs). In the study VMAT reached the highest conformity index (CI; 2 arcs VMAT: 0.74 ± 0.10; 3 arcs VMAT: 0.78 ± 0.07; p< 0.05), and IMRT the lowest homogeneity index (HI; fivefields IMRT: 0.12 ± 0.03; sevenfields IMRT: 0.10 ± 0.02; p< 0.05). Besides, 7 fields IMRT (0.10 ± 0.02) achieved superior HI to that of 5 fields IMRT (0.12 ± 0.03, p< 0.01). TOMO (p< 0.05) and VMAT (p< 0.05) were both significantly superior to IMRT in terms of the dose to lung (V₅, V₁₀, V₁₅, V₂₀, and V₃₀). These 5 radiation techniques were similar regarding the dose to heart (V₅, V₂₀, and V₃₀), but IMRT (5 fields IMRT: 19.27 ± 5.33; 7 fields IMRT: 20.05 ± 4.19) significantly raised the dose to the V₅₀ of the heart when compared to VMAT (2 arcs VMAT: 16.6 ± 5.68; 3 arcs VMAT: 15.04 ± 5.75; p< 0.05) and TOMO (15.05 ± 4.7, p< 0.05). VMAT reduced the dose to BM (V₅, V₁₀, V₂₀, and V₃₀) as compared to TOMO (p< 0.05) and IMRT (p< 0.05). The CI of VMAT was the supreme one in those of the techniques in this study, so was the HI of IMRT. VMAT also provided another advantage that it reduced the dose to the BM. TOMO ameliorated the dose sparing of the lung, but the dose that the BM absorbed from TOMO was of some concern about BM toxicity.

Comparisons between the Dosimetric and Clinical Outcomes of Tomotherapy and 3D Conformal Radiotherapy in Gastric Cancer Treatment

Introduction:

Previous studies comparing tomotherapy (TOMO) and three dimensional (3D) conformal radiotherapy (3DCRT) in gastric radiotherapy are limited and tend to be based on dosimetry. The aim of the present study was to evaluate the clinical outcomes of these two treatment modalities.

Methods:

A total of 51 patients diagnosed with gastric cancer who were treated with postoperative adjuvant chemoradiotherapy and had subtotal/total gastrectomy and D2 lymphatic dissection were recruited to the present study: 30 patients were treated with TOMO and 21 patients were treated with 3DCRT.

Results:

The 3DCRT and TOMO treatment regimens were compared. There was no difference in planning target volume (PTV) 95%, but TOMO was statistically significant in regard to PTV 105% (P<0.05). TOMO was also significantly different when compared with 3DCRT when evaluating liver mean dose, liver V40, right/left kidneys mean dose, right/left kidneys V20 and spinal cord mean dose values (P<0.05). Grade 2 acute side effects were more frequent (85.7%) following 3DCRT. In addition, the median overall survival time for TOMO treated patients was 62 months while in 3DCRT treated patients it was 22.05 months. The difference in disease free survival was also significantly increased in patients treated with TOMO (66.7% vs. 19.0%; P<0.05).

Conclusion:

TOMO treatment resulted in lower acute side effects with better patient survival following gastric cancer radiotherapy.

Dosimetric comparison of 3-dimensional conformal radiotherapy, volumetric modulated arc therapy, and helical tomotherapy for postoperative gastric cancer patients

PURPOSE

To compare dosimetric data for the planning target volume (PTV) and organs at risk (OARs) between 3-dimensional conformal radiotherapy (3DCRT), volumetric modulated arc therapy (VMAT), and helical tomotherapy [1].

MATERIALS AND METHODS

The dosimetric data for 15 gastric cancer patients treated with 3DCRT, VMAT, or HT techniques were used. Cumulative dosimetric parameters, homogeneity index (HI), and conformal index (CI) were compared for the PTV and OARs.

RESULTS

The average maximum doses of PTV were significantly higher in VMAT plans than in 3DCRT (p = 0.04) and HT (p = 0.02) plans, whereas minimum dose values were significantly lower in 3DCRT plans compared with VMAT (p < 0.001) and HT (p = 0.02) plans. Liver mean dose (D _mean) and D _mean values for both kidneys were significantly lower in HT plans than in 3DCRT and VMAT plans. The doses in high dose regions (V30-V45) using 3DCRT plans were significantly higher compared to both VMAT and HT plans. The bowel V5-V30 and V45 was significantly less in HT plans compared to VMAT plans. There were no significant differences in dose sparing of the spinal cord.

CONCLUSIONS

The HT plans reduced the maximum dose applied to the target and improved the conformality and homogeneity of radiation, while providing sufficient PTV coverage.