Benefit of volumetric-modulated arc therapy over three-dimensional conformal radiotherapy for stage I-II extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue in the stomach: a dosimetric comparison

Analysis of Chronic Kidney Disease After Radiation Therapy for Gastric/Duodenal Mucosa-Associated Lymphoid Tissue Lymphoma

Purpose

This study aimed to evaluate the relationship between chronic kidney disease (CKD) after radiation therapy for gastric/duodenal mucosa-associated lymphoid tissue lymphoma and dose-volume histogram of the kidneys.

Methods and Materials

We retrospectively reviewed 40 patients who received 3-dimensional conformal radiation therapy. CKD was evaluated using the Common Terminology Criteria for Adverse Events version 5.0. The mean dose of bilateral kidneys/right kidney/left kidney (D_{mean of b-kidneys}) (D_{mean of r-kidney}) (D_{mean of l-kidney}), bilateral kidneys/right kidney/left kidney volume receiving ≥ x Gy (V_{x of b-kidneys}) (V_{x of r-kidney}) (V_{x of l-kidney}), and patients’ baseline clinical characteristics were analyzed.

Results

The median radiation therapy dose was 28 (range, 24-44.8) Gy in 14 fractions. The median follow-up period was 63.1 months, and the 5-year cumulative incidence of grade 2 CKD rate was 14.8%. Among several factors, V_{5 of b-kidneys} was most strongly associated with grade 2 or worse CKD, with an area under the curve of 0.81 in the receiver operating characteristic curve. The 5-year incidence rate in patients with V_{5 of b-kidneys} ≥ 58% was significantly higher than that in other patients (24.5% and 9.8%, respectively; P < .05).

Conclusions

In this study using 3-dimensional conformal radiation therapy, the rate of adverse events at 5 years was low, many patients showed toxicity after 5 years; thus, continuous follow-up is necessary to detect potential nephrotoxicity. Our data demonstrate that V_{5 of b-kidneys} was most strongly associated with the risk of CKD. With lower doses and more advanced techniques in recent years, the incidence of CKD may be further reduced.

The prognostic value of PET/CT evaluation with Deauville score on the recurrence and survival in diffuse large B-cell lymphoma: a multi-institutional study of KROG 17-02

The Korean Radiation Oncology Group (KROG) assessed the value of Deauville score (DS) on ¹⁸F-fluorodeoxyglucose Positron emission tomography-computed tomography (FDG PET/CT) as a predictor of recurrence and survival after rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) chemotherapy in diffuse large B-cell lymphoma (DLBCL). A total of 512 patients with stage I-III DLBCL who received six cycles of R-CHOP with or without radiation therapy (RT) and obtained treatment responses according to PET-CT imagings after R-CHOP ± RT were included. Patients were sorted into two arms; DS 4-5 arm (n = 24) was matched at a 1:2 ratio with DS 1-3 arm (n = 48) using propensity score matching method. After a median follow-up time of 37.2 months, the recurrence-free survival rate (86.6% vs. 66.8%, P = 0.041) and overall survival rate (86.9% vs. 62.2%, P = 0.009) at 5 years were significantly different between the DS 1-3 and DS 4-5 arms. DS 4-5 arm showed higher 5-years locoregional recurrence-free survival (88.8% vs. 74.3%, P = 0.155) and distant failure-free survival (91.1% vs. 84.3%, P = 0.333) than DS 1-3 arm. In the multivariate analysis, DS was still a significant factor for recurrence-free survival [hazard ratio (HR), 3.840 and confidence interval (CI), 1.068-13.806; P = 0.039] and overall survival rates (HR 4.453 and CI 1.274-15.562; P = 0.019). This study showed and validated that Deauville score of 4-5 of PET-CT imaging taken after full-course of R-CHOP chemotherapy with or without RT could predict recurrence-free survival and overall survival in DLBCL patients.

Low Expression of GLIS2 Gene Might Associate with Radiosensitivity of Gastric Cancer

Human gene GLIS family zinc finger 2 (GLIS2) is a member of GLI-similar zinc finger protein family. Previous studies indicated GLIS2 gene involved in tumorigenesis mechanisms. However, the association between GLIS2 expression and radiosensitivity of gastric cancer has not been well understood. In this study, we used the gastric cancer database in TCGA, and significant association was observed between the low expression of GLIS2 and radiosensitivity of patients with gastric cancer. The adjusted HR values for radiotherapy were 0.162(0.035-0.756) and 0.089(0.014-0.564), with p values 0.021 and 0.010, respectively, in training and testing data, for these patients with low expression of GLIS2, while for patients with high expression of GLIS2, there was no significant survival difference between radiotherapy and nonradiotherapy groups. The adjusted HR were 0.676(0.288-1.586) and 0.508(0.178-1.450), with p values 0.368 and 0.206 in training and testing data, respectively. Further study showed that, for low expression patients, radiotherapy did not significantly increase new tumor event rate and disease progression rate, which partially supported our assumption. These results suggested that low expression of GLIS2 might significantly associate with the radiosensitivity of patients with gastric cancer. The GLIS2 gene might be a potential effective molecular marker of gastric cancer for precise radiotherapy.

Combining deep-inspiration breath hold and intensity-modulated radiotherapy for gastric mucosa-associated lymphoid tissue lymphoma: Dosimetric evaluation using comprehensive plan quality indices

Background

Although there have been many attempts to increase the therapeutic ratio of radiotherapy for gastric mucosa-associated lymphoid tissue lymphoma (MALToma), only a few planning studies have reported the efficacy of the modern radiotherapy technique till date. Therefore, we performed the dosimetric comparison among 3-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT) plans, using deep-inspiration breath hold (DIBH) or free-breathing (FB) techniques, to determine the most optimal plan for gastric MALToma.

Methods

We evaluated 9 patients with gastric MALToma for whom 3D-CRT, step-and-shoot IMRT (_SIMRT), volumetric-modulated arc therapy (VMAT), and tomotherapy plans with identical prescribed doses were generated using DIBH or FB computed tomography (CT). Planning target volume (PTV) coverage and non-target doses were calculated for each plan and compared with plan quality metric (PQM) scores.

Results

All 72 plans of 9 patients satisfied our dosimetric goals, and the IMRT plans and 3D-CRT plans had similarly good conformity index values with no differences related to respiratory movement. IMRT plans yielded significantly better doses to the organs-at-risk, and DIBH plans yielded significantly lower liver, heart, and lung D_mean and spinal cord D_max with smaller irradiated volumes compared to FB plans. For the mean PQM scores, VMAT-DIBH and _SIMRT-DIBH yielded the best scores, whereas 3D plans provided reduced beam monitor unit values.

Conclusion

Our findings demonstrate that modern RT technologies (DIBH with VMAT or _SIMRT) could potentially provide excellent target coverage for gastric MALToma while reducing doses to organs-at-risk. However, the relevance of the most optimal plan considering clinical outcomes should be confirmed further in a larger patient cohort.

Electronic supplementary material

The online version of this article (10.1186/s13014-019-1263-7) contains supplementary material, which is available to authorized users.