Daily CT guidance improves target coverage during definitive radiation therapy for gastric MALT lymphoma

Response-adapted ultra-low-dose 4 Gy radiation as definitive therapy of gastric MALT lymphoma: a single-centre, pilot trial

BACKGROUND

Given the favourable prognosis of patients with gastric mucosa-associated lymphoid tissue (MALT) lymphoma, treatment-related toxicity should be minimised. We aimed to evaluate the efficacy of 4 Gy radiotherapy given in a response-adapted approach.

METHODS

We conducted a single-centre, single-arm, prospective trial at MD Anderson Cancer Center (Houston, TX, USA) of response-adapted ultra-low-dose radiotherapy. Eligible patients were 18 years or older and had newly diagnosed or relapsed Helicobacter pylori-negative gastric MALT lymphoma, with stage I-IV disease. Given the expected low toxicity profile of treatment, performance status was not an exclusion criterion. Patients received external beam photon-based radiotherapy for a total dose of 4 Gy in two fractions. Patients with a complete response to 4 Gy via endoscopy and imaging at 3-4 months were observed; patients with a partial response were re-evaluated in 6-9 months. Residual disease at 9-13 months or stable or progressive disease at any time required additional treatment with 20 Gy. The primary endpoint was gastric complete response at 1 year (second evaluation timepoint) after 4 Gy treatment. All analyses were performed as intention to treat. This trial is registered at ClinicalTrials.gov (NCT03680586) and is complete and closed to enrolment.

FINDINGS

Between March 27, 2019, and Oct 12, 2021, we enrolled 24 eligible patients. The median age of participants was 67 years (IQR 58-74; range 40-85); 15 (63%) were female and nine (37%) male; 18 (75%) were White, four (17%) Asian, and two (8%) Hispanic; 20 (83%) had stage I disease, one (4%) stage II, and three (13%) stage IV. Median follow-up time was 36 months (IQR 26-42). 20 patients (83%) had a complete response to 4 Gy (16 at 3-4 months, four at 9-13 months); two patients received 20 Gy for symptomatic stable disease at 3-4 months and two for residual disease at 9-13 months; all had a complete response. The 3-year local control rate was 96% (95% CI 88-100), with one local relapse at 14 months after 4 Gy radiotherapy salvaged successfully with 20 Gy. One patient with stage IV disease had a distant relapse. The most common adverse events were grade 1 nausea (nine [38%] of 24 patients who received 4 Gy and two [50%] of four patients who received 20 Gy) and grade 1 abdominal pain (five [21%] of 24 and zero of four, respectively). No grade 3 or worse adverse events were noted, including no treatment-related deaths.

INTERPRETATION

Most patients had a complete response after 4 Gy radiotherapy; all who required an additional 20 Gy had a complete response within 12 months. This response-adapted strategy could be used to select patients who would benefit from additional radiotherapy and spare others potential associated toxicity.

FUNDING

National Cancer Institute.

Development of Organ-Preserving Radiation Therapy in Gastric Marginal Zone Lymphoma

Simple Summary

Gastric marginal zone lymphoma of the stomach is a rare cancer type primarily treated with oral proton pump inhibitors. If the disease does not respond to this, radiation is the treatment of choice. This review presents the development of radiation therapy over the last decades. Earlier, the stomach was surgically removed and irradiation was performed using large-field techniques and high doses of radiation. Currently, the standard treatment is the use of small-volume radiation therapy (with few side effects) with the preservation of the stomach, which provides excellent outcomes. In addition, this paper provides an outlook on current studies and possible future developments.

Abstract

Gastric marginal zone lymphoma (gMZL) of mucosa-associated lymphoid tissue (MALT) may persist even after H. pylori eradication, or it can be primarily Helicobacter pylori (H. pylori) independent. For patients without the successful eradication of lymphoma, or with progressive disease, treatment options have historically included partial or total gastrectomy. Presently, in these instances, curative radiation therapy (RT) is the current standard of care. This review emphasizes the historically changing role of radiation therapy in gMZL, progressing from large-volume RT without surgery, to localized RT, on its own, as a curative organ-preserving treatment. This overview shows the substantial progress in radiation therapy during the recent two to three decades, from high-dose, large-field techniques to low-dose, localized target volumes based on advanced imaging, three-dimensional treatment planning, and advanced treatment delivery techniques. RT has evolved from very large extended field techniques (EF) with prophylactic treatment of the whole abdomen and the supradiaphragmatic lymph nodes, applying doses between 30 and 50 Gy, to involved-field RT (IF), to the current internationally recommended involved site radiation therapy (ISRT) with a radiation dose of 24–30 Gy in gMZL. Stage-adapted RT is a highly effective and safe treatment with excellent overall survival rates and very rare acute or late treatment-related toxicities, as shown not only in retrospective studies, but also in large prospective multicenter studies, such as those conducted by the German Study Group on Gastrointestinal Lymphoma (DSGL). Further de-escalation of the radiation treatments with low-dose 20 Gy, as well as ultra-low-dose 4 Gy radiation therapy, is under investigation within ongoing prospective clinical trials of the International Lymphoma Radiation Oncology Group (ILROG) and of the German Lymphoma Alliance (GLA).

Target coverage of daily cone-beam computed tomography in breath-hold image-guided radiotherapy for gastric lymphoma

Objectives

We evaluated retrospectively the daily target coverage using cone-beam computed tomography (CBCT) in breath-hold image-guided radiotherapy (BH-IGRT) for gastric lymphoma.

Methods

BH-IGRT was performed using a prescribed dose of 30.6 Gy in 17 fractions for the whole stomach. We assessed the target coverage of the whole stomach on daily CBCT images [daily clinical target volume (CTV)], which was delineated individually by two observers. We evaluated V_95% (percentage of volume receiving ≥95% of the prescribed dose) of daily CTV.

Results

In total, 102 fractions from 6 patients were assessed. The mean V_95% of daily CTV was 97.2%, which was over 95%. In two of six patients, the V_95% of daily CTV was over 95% for either observer in all fractions. One patient had significant interobserver variation (p = 0.013). In 95 fractions (93%), the V_95% of daily CTV was over 95% for either observer.

Conclusion

Daily target coverage for CTV in BH-IGRT for gastric lymphoma seems to be favorable, even when using CBCT.

Advances in knowledge

A previous study ascertained good daily target coverage in BH-IGRT for gastric lymphoma using in-room CT. Even when using CBCT in our study, daily target coverage for CTV in BH-IGRT for gastric lymphoma seems to be favorable.

Involved-site radiotherapy for Helicobacter pylori-independent gastric MALT lymphoma: 26 years of experience with 178 patients

Treatment options for Helicobacter pylori-independent gastric mucosa-associated lymphoid tissue (MALT) lymphoma (GML) include surgery, immunotherapy, chemotherapy, and radiation therapy (RT). The purpose of this study was to investigate the efficacy and safety of RT and routine endoscopic surveillance, hypothesizing that most patients are curable with RT alone. We queried a single institution database at a tertiary referral cancer center for patients with H pylori-independent GML treated with RT between 1991 and 2017. Response was assessed by follow-up endoscopies (EGDs) starting 10 to 12 weeks post-RT. Computed tomography scans were also part of the follow-up program, and positron emission tomography was added when clinically appropriate. We identified 178 patients (median age, 63 years; range, 25-89 years); 86% had stage I disease, 7% had stage II disease, and 7% had stage IV disease. Median RT dose was 3000 cGy over 20 fractions. Ninety-five percent of patients exhibited complete pathologic response on posttreatment EGD. Two patients experienced grade 3 toxicity, and 2 patients experienced in-field secondary malignancies. Over a median follow-up of 6.2 years, 9.6% experienced local failures, and 11.8% developed distant sites of disease. Five-year and 10-year overall survival were 94% and 79%, respectively, from last date of RT. RT is a highly effective and safe treatment for GML with excellent overall survival and very rare acute or late treatment-related toxicities. Favorable outcomes from this large retrospective sample of patients provide credible and compelling support for RT as standard of care for H pylori-independent GML.

Impact of four-dimensional cone-beam computed tomography on target localization for gastric mucosa-associated lymphoid tissue lymphoma radiotherapy: reducing planning target volume

Background

Radiotherapy of gastric mucosa-associated lymphoid tissue (MALT) lymphoma should be delivered to the entire stomach with planning target volume (PTV) that accounts for variations in stomach volume, respiratory movement, and patient set-up error. In this study, we evaluated whether the use of four-dimensional cone-beam computed tomography (4D-CBCT) reduces the PTV.

Methods

Eight patients underwent radiotherapy with 15 fractions of gastric MALT lymphoma using 4D-CBCT. PTV structures of 5–30 mm margins (5 mm intervals) from the clinical target volume (CTV) delineated based on the 4D-CT images (CTV-4D) were generated. For the target localization, we performed matching based on skin marking (skin matching), bone anatomy (bone matching), and stomach anatomy (4D soft-tissue matching) based on registration between planning CT and 4D-CBCT images from 10 phases. For each patient, we calculated the covering ratio (CR) of the stomach with variable PTV structures, based on the 4D-CBCT images, with a total of 150 phases [CR (%) = (number of covering phases/150 phases) × 100], for three target localization methods. We compared the CR values of the different target localization methods and defined the PTV with an average CR of ≥ 95% for all patients.

Results

The average CR for all patients increased from 17.9 to 100%, 19.6 to 99.8%, and 33.8 to 100%, in the skin, bone, and 4D soft-tissue matchings, respectively, as the PTV structures increased from 5 to 30 mm. The CR obtained by 4D soft-tissue matching was superior to that obtained by skin (P = 0.013) and bone matching (P = 0.008) for a PTV structure of 15 mm margin. The PTV required an additional margin of 20 mm (average CR: 95.2%), 25 mm (average CR: 99.1%), and 15 mm (average CR: 98.0%) to CTV-4D for the skin, bone, and 4D soft-tissue matchings, respectively.

Conclusions

This study demonstrates that the use of 4D-CBCT reduces the PTV when applying 4D soft-tissue matching, compared to skin and bone matchings. Additionally, bone matching does not reduce the PTV as compared with traditional skin matching.

Decreased heart dose with deep inspiration breath hold for the treatment of gastric lymphoma with IMRT

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Radiation therapy to the stomach can result in unintended radiation to the heart.

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Deep inspiration breath-hold can provide spatial separation between the heart and stomach.

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Deep inspiration breath-hold permits decreased dose to organs at risk when treating the stomach.

We hypothesized that deep inspiration breath-hold (DIBH) and computed-tomography image-guided radiotherapy (CT-IGRT) may be beneficial to decrease dose to organs at risk (OARs), when treating the stomach with radiotherapy for lymphoma. We compared dosimetric parameters of OARs from plans generated using free-breathing (FB) versus DIBH for 10 patients with non-Hodgkin lymphoma involving the stomach treated with involved site radiotherapy. All patients had 4DCT and DIBH scans. Planning was performed with intensity modulated radiotherapy (IMRT) to 30.6 Gy in 17 fractions. Differences in target volume and dosimetric parameters were assessed using a paired two-sided t-test. All heart and left ventricle parameters including mean dose, V30, V20, V10, and V5 were statistically significantly lower with DIBH. For IMRT-FB plans the average mean heart dose was 4.9 Gy compared to 2.6 Gy for the IMRT-DIBH group (p < 0.001). There was a statistically significant decrease in right kidney dose with DIBH. For lymphoma patients treated to the stomach with IMRT, DIBH provides superior OAR sparing compared to FB-based planning, most notably reducing dose to the heart and left ventricle. This strategy could be considered when treating other gastric malignancies.

Assessment of setup uncertainty in hypofractionated liver radiation therapy with a breath-hold technique using automatic image registration-based image guidance

Background

Target localization in radiation therapy is affected by numerous sources of uncertainty. Despite measures to minimize the breathing motion, the treatment of hypofractionated liver radiation therapy is further challenged by residual uncertainty coming from involuntary organ motion and daily changes in the shape and location of abdominal organs. To address the residual uncertainty, clinics implement image-guided radiation therapy at varying levels of soft-tissue contrast. This study utilized the treatment records from the patients that have received hypofractionated liver radiation therapy using in-room computed tomography (CT) imaging to assess the setup uncertainty and to estimate the appropriate planning treatment volume (PTV) margins in the absence of in-room CT imaging.

Methods

We collected 917 pre-treatment daily in-room CT images from 69 patients who received hypofractionated radiation therapy to the liver with the inspiration breath-hold technique. For each treatment, the daily CT was initially aligned to the planning CT based on the shape of the liver automatically using a CT-CT alignment software. After the initial alignment, manual shift corrections were determined by visual inspection of the two images, and the corrections were applied to shift the patient to the physician-approved treatment position. Considering the final alignment as the gold-standard setup, systematic and random uncertainties in the automatic alignment were quantified, and the uncertainties were used to calculate the PTV margins.

Results

The median discrepancy between the final and automatic alignment was 1.1 mm (0–24.3 mm), and 38% of treated fractions required manual corrections of ≥3 mm. The systematic uncertainty was 1.5 mm in the anterior-posterior (AP) direction, 1.1 mm in the left-right (LR) direction, and 2.4 mm in the superior-inferior (SI) direction. The random uncertainty was 2.2 mm in the AP, 1.9 mm in the LR, and 2.2 mm in the SI direction. The PTV margins recommended to be used in the absence of in-room CT imaging were 5.3 mm in the AP, 3.5 mm in the LR, and 5.1 mm in the SI direction.

Conclusions

Manual shift correction based on soft-tissue alignment is substantial in the treatment of the abdominal region. In-room CT can reduce PTV margin by up to 5 mm, which may be especially beneficial for dose escalation and normal tissue sparing in hypofractionated liver radiation therapy.

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.

Outcomes After Reduced-Dose Intensity Modulated Radiation Therapy for Gastric Mucosa-Associated Lymphoid Tissue (MALT) Lymphoma

PURPOSE

In patients with gastric extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) lymphoma, the standard radiation therapy (RT) dose is ≥30 Gy. We report the outcome of patients treated with reduced dose 24 Gy compared with those treated with ≥30 Gy.

METHODS AND MATERIALS

We reviewed results from 32 patients who received a diagnosis of gastric MALT lymphoma between 2007 and 2017 who were treated with involved site RT using intensity modulated radiation therapy (IMRT). Response to therapy was based on post-RT endoscopic biopsy. Freedom from local treatment failure (FFLTF), freedom from treatment failure (FFTF), and overall survival (OS) outcomes were determined.

RESULTS

The median age of patients at diagnosis was 58 years. Therapy for MALT was given prior to RT in 14 patients with residual biopsy proven disease documented in all cases (anti-microbial, n=11; rituximab, n=2; rituximab, cyclophosphamide, doxorubicin, vincristine, n=1). One patient received RT (36 Gy) and concurrent rituximab. The median RT dose was 30 Gy; it was 30 to 36 Gy in 66% of patients (n = 21) and 24 Gy in 34% of patients (n = 11). Post-RT biopsy documented a complete response in all patients. Failures occurred in the stomach and duodenum, respectively, at 3.6 and 4.5 years, after 30 Gy. At a median follow-up of 55.2 months (73.8 for ≥30 Gy compared with 28.7 for 24 Gy; P < .001), the 2-year FFLTF, FFTF, and OS were 100%, 100%, and 97%, respectively. No association was found between the lower (24-Gy) dose and FFLTF (P = .819), FFTF (P = .819), or OS (P = .469).

CONCLUSIONS

Contemporary RT with involved site targeting using IMRT is associated with high complete response rates for patients with gastric MALT lymphoma, even using reduced doses of 24 Gy. Additional follow-up and increased patient numbers are required to confirm equivalent disease control.

Hitting a Moving Target: Successful Management of Diffuse Large B-cell Lymphoma Involving the Mesentery With Volumetric Image-guided Intensity Modulated Radiation Therapy

INTRODUCTION

We report successful treatment of mesenteric diffuse large B-cell lymphoma (DLBCL) using localized involved site radiation therapy (ISRT), intensity modulated radiation therapy (IMRT), and daily computed tomography (CT)-image guidance.

PATIENTS AND METHODS

Patients with mesenteric DLBCL treated with RT between 2011 and 2017 were reviewed. Clinical and treatment characteristics were analyzed for an association with local control, progression-free survival (PFS), and overall survival.

RESULTS

Twenty-three patients were eligible. At diagnosis, the median age was 52 years (range, 38-76 years), and 57% (n = 13) had stage I/II DLBCL. All patients received frontline chemotherapy (ChT) (R-CHOP [rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone], n = 19; dose-adjusted R-EPOCH [rituximab, etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin], n = 4) with median 6 cycles. Prior to RT, salvage ChT for refractory DLBCL was given to 43% (n = 10) and autologous stem cell transplantation was administered in 13% (n = 3). At the time of RT, positron emission tomography-CT revealed 5-point scale of 1 to 3 (48%; n = 11), 4 (9%; n = 2), and 5 (44%; n = 10). All patients received IMRT, daily CT imaging, and ISRT. The median RT dose was 40 Gy (range, 16.2-49.4 Gy). Relapse or progression occurred in 22% (n = 5). At a median follow-up of 37 months, the 3-year local control, PFS, and overall survival rates were 80%, 75%, and 96%, respectively. Among patients treated with RT after complete metabolic response to frontline ChT (n = 8), the 3-year PFS was 100%, compared with 61% for patients with a history of chemorefractory DLBCL (n = 15; P = .055). Four of the 5 relapses occurred in patients with 5-point scale of 5 prior to RT (P = .127).

CONCLUSION

Mesenteric involvement of DLBCL can be successfully targeted with localized ISRT fields using IMRT and daily CT-image guidance.