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Table of Contents
ORIGINAL ARTICLE
Year : 2021  |  Volume : 4  |  Issue : 3  |  Page : 456-465

Conformal radiation therapy versus volumetric arc therapy in high dose concurrent chemoradiotherapy for carcinoma esophagus: A retrospective analysis


1 Department of Radiation Oncology, Homi Bhabha Cancer Hospital, Sangrur, Punjab, India
2 Department of Radiation Oncology, Tata Memorial Hospital, Homi Bhabha National Institute, Mumbai, Maharashtra, India
3 Department of Medical Oncology, Homi Bhabha Cancer Hospital, Sangrur, Punjab, India
4 Department of Medical Physics, Homi Bhabha Cancer Hospital, Sangrur, Punjab, India

Date of Submission28-May-2021
Date of Decision04-Jul-2021
Date of Acceptance05-Sep-2021
Date of Web Publication08-Oct-2021

Correspondence Address:
Tapas Kumar Dora
Department of Radiation Oncology, Homi Bhabha Cancer Hospital, Civil Hospital Campus, Sangrur - 148 001, Punjab
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/crst.crst_123_21

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  Abstract 


Background: Esophageal epithelium being primarily squamous, numerous studies have attempted to deliver a dose of more than 60 Gy as a part of radical chemoradiation for locally advanced esophageal cancer to achieve better tumor control. Various techniques have been explored in an attempt to spare the lung and heart from receiving high doses of radiation while delivering radiation to the primary tumor.
Objectives: We aimed to compare the doses received by different organs at risk (OARs) and toxicities. We also aimed to compare the overall survival (OS) and disease-free survival (DFS) between patients treated with conformal radiation therapy and Volumetric Modulated Arc Therapy (VMAT).
Materials and Methods: This was a retrospective audit of standard treatment offered to patients with esophageal cancer registered at our hospital between June 2015 and August 2019 using different radiotherapy techniques. Patients were treated using conformal radiation therapy or VMAT. The radiation dose delivered varied from 50.4 Gy in 28 fractions to 63 Gy in 35 fractions, depending on the OARs according to the tumor location and histology. Patients were followed up until December 2020. The Kaplan–Meier method was used for survival analysis. The log-rank test was used to compare the OS and DFS rates in the univariate analysis, and the Cox proportional-hazards model was used for the multivariate analysis.
Results: Of a total of 115 patients included in the study, 16 received radiation therapy using conventional telecobalt, 25 received three-dimensional conformal radiation therapy (3DCRT), 10 received 3DCRT plus intensity-modulated radiation therapy (IMRT) Phase-II, and 64 received VMAT. For the purpose of this analysis, the three modalities other than VMAT were categorized as conformal radiation therapy. The median follow-up period was 9 months (range, 0–55) in both groups. The mean doses and sub-volume doses received by the heart were significantly lower in VMAT compared to conformal radiotherapy (mean doses 20 Gy vs. 35 Gy, P = 0.001). There was no significant difference in acute (P = 0.39) or late (P = 0.36) pharyngoesophagitis between the two groups. The OS and DFS were not significantly different between the two groups; median OS was 13 months in the VMAT and 17 months in the conformal radiotherapy group, P = 0.8; the median DFS was 8 months versus 7 months, respectively, P = 0.16. None of the tumor-related factors, except concurrent chemotherapy, significantly affected the OS and DFS in the univariate and multivariate analyses.
Conclusion: The radiation dose received by the heart is significantly lower when using VMAT compared to conformal radiation therapy. However, there is no significant difference in the survival outcomes between the two techniques. The addition of concurrent chemotherapy significantly prolongs survival.

Keywords: Chemoradiotherapy, conformal radiation therapy, esophagus, volumetric arc therapy


How to cite this article:
Dora TK, Deshmukh J, Chatterjee A, Goel A, Bose S, Singh A, Saini A, Pahwa S, Laskar SG, Agarwal JP, Shrivastava SK, Kapoor R. Conformal radiation therapy versus volumetric arc therapy in high dose concurrent chemoradiotherapy for carcinoma esophagus: A retrospective analysis. Cancer Res Stat Treat 2021;4:456-65

How to cite this URL:
Dora TK, Deshmukh J, Chatterjee A, Goel A, Bose S, Singh A, Saini A, Pahwa S, Laskar SG, Agarwal JP, Shrivastava SK, Kapoor R. Conformal radiation therapy versus volumetric arc therapy in high dose concurrent chemoradiotherapy for carcinoma esophagus: A retrospective analysis. Cancer Res Stat Treat [serial online] 2021 [cited 2021 Dec 9];4:456-65. Available from: https://www.crstonline.com/text.asp?2021/4/3/456/327755




  Introduction Top


As per the Global Cancer Data 2020, esophageal cancer is the 10th most common cancer in the world, accounting for 3.1% of the new cases and 5.5% of the new deaths due to cancers. It is mostly diagnosed at a late stage and has a 5-year survival of 15%–25%.[1],[2],[3] Concurrent chemoradiation plays an important role in improving the overall survival (OS) and disease-free survival (DFS) compared to radiation alone in patients with esophageal cancer.[4],[5],[6] Radiation-induced pneumonitis and left ventricular ischemia are known toxicities of concurrent chemoradiotherapy.[7],[8] The use of intensity-modulated radiation therapy (IMRT) and volumetric intensity-modulated arc therapy (VMAT) has failed to show a survival benefit[9],[10] but have an advantage in terms of better target coverage compared to three-dimensional conformal radiation therapy (3DCRT).[11],[12],[13],[14] Additionally, there is no strong evidence in the literature to support the survival benefit of a radiation dose >60 Gy in patients with carcinoma esophagus.[15]

In our routine clinical practice over the past 4 years, we have treated patients with locally advanced carcinoma esophagus using both 3DCRT and IMRT, as we slowly evolved from the use of conventional radiotherapy to conformal radiotherapy and VMAT. Therefore, we performed an audit to compare the doses received by the different organs at risk (OARs) and the survival outcomes between patients treated with conformal radiotherapy and VMAT.


  Materials and Methods Top


General study details

This was a retrospective audit of standard treatment offered to patients with carcinoma esophagus registered at our hospital between June 2015 and August 2019 with different radiotherapy techniques after discussion in the multidisciplinary tumor board. There was no randomization to different radiotherapy techniques. As patients were treated according to the standard operating procedure (SOP) of the institution, routine consent to deliver radiotherapy was taken before starting the treatment, explaining all the side effects of standard radiotherapy techniques and the dose as planned individually. No written informed consent was obtained to perform this audit. As the patients were treated according to institutional SOP, ethical approval was not sought for this study. Being a retrospective audit, no funding was required. The study was not registered in any public clinical trial registry. The study was conducted according to the ethical guidelines outlined in the Declaration of Helsinki, Good Clinical Practice guidelines, and the Indian Council of Medical Research guidelines.

Participants

We included all patients with esophageal cancer (without any age limit) registered at our hospital between June 2015 and August 2019, who were planned for radical chemoradiotherapy after the multidisciplinary tumor board discussion, had an Eastern Cooperative Oncology Group performance status of 0–2, and who had completed treatment. The total number of patients who completed radical intent chemoradiotherapy for esophageal cancer was retrieved from the hospital server-based software, “radiation oncology information system (ROIS).”

Variables

The primary objectives were to compare the doses received by different OARs and the toxicities. The secondary objective was to measure and compare the OS and DFS based on the radiotherapy received. We also evaluated if any tumor-related prognostic factors (age, gender, endoscopic length, thickness on computed tomography [CT] scan, grade, T stage, N stage, stage group, radiation duration, concurrent chemotherapy, number of cycles of concurrent chemotherapy, gross tumor volume [GTV] length, planning target volume [PTV] length, and PTV) impacted the DFS and OS.

Study methodology

We treated patients with the conventional method on telecobalt from June 2015 to August 2016. With the installation of the linear accelerator in April 2016, we moved to 3DCRT, 3DCRT Phase-I plus VMAT Phase-II, and VMAT alone from May 2016 to June 2017. From July 2017 to June 2018, we treated the patients using both 3DCRT Phase-I plus VMAT Phase-II and VMAT alone. From July 2018 till August 2019, all patients were treated with VMAT alone. For the purpose of this analysis, the three modalities other than VMAT were categorized as conformal radiation therapy, and the outcomes of patients treated with this were compared with those of VMAT.

The GTV was contoured as per the visible primary tumor and node on endoscopy, CT, and positron emission tomography scanning. Esophageal wall thickening of more than 5 mm and a node with a short-axis diameter of 1 cm were considered pathological. The clinical target volume (CTV) was obtained with a 3–4 cm margin proximal and distal to the GTV, and the PTV was obtained with an additional 0.5 cm margin to the CTV. In either method, the dose delivered varied from 50.4 Gy in 28 fractions to 63 Gy in 35 fractions, depending on the OARs according to the tumor location and histology. Concurrent chemotherapy was planned with weekly paclitaxel (50 mg/m2) and carboplatin (area under the curve 2).

In patients who received a dose of 63 Gy as conformal radiotherapy, it was delivered in two phases (Phase-I being 39.6 Gy in 22 fractions with antero-posterior opposing fields and Phase-II being 23.4 Gy in 13 fractions with two oblique fields and one anterior/posterior field). In patients who received VMAT, radiotherapy was planned in one phase with a single PTV. A dose of 66 Gy in 33 fractions was delivered to 5 patients using VMAT and 1 patient using conformal radiation therapy because these patients had a post cricoid cervical esophagus primary in whom the radiation plan made was similar to that for a head and neck primary. Image-guided radiotherapy was employed during the treatment to reduce set up errors in VMAT and to enhance the treatment delivery.

For patients who were treated on conventional telecobalt, we used a “Virtual Simulation Workstation (Advantage V-SIM by GE)” which allows for contouring, like the treatment-planning system of a linear accelerator; it also allows for planning the placement of beams for telecobalt. For these patients, contouring was performed as in the case of those treated using VMAT. The part of normal lung falling within the radiation treatment field but outside the target PTV was blocked using conventional blocks for telecobalt equipment. Thus, the planning was similar to that of 3DCRT in a linear accelerator using multi-leaf collimators to block the normal lung region. Hence, we grouped them under conformal radiation therapy for the purpose of this analysis.

Patients were followed up every 3 months for the first 2 years, followed by every 6 months thereafter till December 2020. CT scan and upper gastrointestinal endoscopy were performed for symptomatic cases or once every 6 months for 2 years and yearly thereafter for asymptomatic cases. All clinical data were collected from the hospital's server-based electronic medical records. Radiation treatment-related data were collected from ROIS. Radiation dosimetric data of different organs were collected from the Treatment Planning System (MONACO TPS, version no 5.51.01) of the linear accelerator (Elekta Versa-HD, Elekta Instrument AB Stockholm) delivering radiotherapy.

Definitions

OS was defined in months from the date of diagnosis to the date of death or the last follow-up. DFS was defined in months from the date of completion of concurrent chemoradiation to the date of tumor recurrence (locoregional/metastasis) or the date of death or the last follow-up date. Follow-up period was defined in months from the date of completion of chemoradiation to the date of death or the last follow-up. Locoregional failure was defined as any recurrence that occurred at the local primary site or in the regional lymph nodes; distant failure was defined as any visceral metastasis beyond the regional lymphatic area.

Statistics

As this was a retrospective audit, all patients fulfilling the eligibility criteria within the time frame of the study were included. No sample size calculation was performed. All data were analyzed using the Statistical Package for the Social Sciences (IBM Corp. Released 2015. IBM SPSS Statistics for Windows, Version 23.0. Armonk, NY: IBM Corp.). The median follow-up in months was calculated for all patients (not only for surviving patients) using the simple median method of descriptive statistics. The Kaplan–Meier method was used to estimate the OS and DFS rates. Log-rank test was used to compare the estimates in the univariate analysis, and the Cox Proportional Hazards model was used for the multivariate analysis. A P < 0.05 was considered statistically significant. To assess if any tumor-related factors affected OS and DFS, univariate and multivariate analyses were performed for various factors like age, gender, length of the tumor on endoscopy(>10 cm), tumor thickness on CT scan (>15 mm), grade, T stage, N stage, stage grouping, concurrent chemotherapy, radiation duration >50 days, number of cycles of chemotherapy (>5 cycles), GTV length (>10 cm), PTV length (>15 cm), and PTV (>400 cc).


  Results Top


A total of 115 patients (55 male and 60 female) were included in the study. [Figure 1] shows our evolution from 3DCRT to VMAT between June 2015 and August 2019. Out of 115 patients, 16 received radiation therapy using conventional telecobalt, 25 using 3DCRT, 10 using 3DCRT plus IMRT Phase-II, and 64 using VMAT alone.
Figure 1: Patient recruitment flowchart (3DCRT: Three-dimensional conformal radiation therapy, VMAT: Volumetric modulated arc therapy)

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The patient demographics and disease-related parameters are shown in [Table 1]. Treatment details, toxicities, and survival-related parameters are shown in [Table 2]. Radiation doses received by different OARs are described in [Table 3]. We observed that only the doses received by the heart were significantly different between VMAT and conformal radiation therapy. The doses received by the lung were not significantly different between VMAT and conformal radiation therapy. Acute Grade 0, I, II, III pharyngoesophagitis was seen in 21.9% versus 31.4%, 45.3% versus 49.0%, 28.1% versus 17.6% and 4.7% versus 2.0% patients in VMAT versus conformal radiotherapy (P = 0.392). Late Grade 0, I, II pharyngoesophagitis was seen in 56.2% versus 64.5%, 37.5% versus 22.6% and 6.2% versus 12.9% patients (P = 0.355).
Table 1: Patient demography and disease-related parameters

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Table 2: Concurrent chemoradiation details and survival outcomes

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Table 3: Doses (median) received by organs at risk

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Of 64 patients treated with VMAT, at a median follow-up of 9 months (range, 0-49) (median follow-up for alive patients was 19 months [range, 14-49] and that for dead patients was 5 months [range, 0-29]), 22 (34.4%) patients were alive and 42 (65.6%) were dead. A total of 27 (42.2%) cases were clinically controlled without any disease. Residual disease was seen in 14 (21.9%) patients and recurrence in 7 (10.9%). The status of 16 (25%) patients was unknown as they were either lost to follow-up, had died after the conclusion of radiation therapy or their disease status had not been documented. Out of seven patients with recurrence, three had distant metastasis alone, two had loco-regional recurrence, one had both, and one developed a second primary (periampullary carcinoma) tumor and was treated with palliative chemotherapy and finally died. Out of 14 patients with residual disease, 5 developed distant metastasis. A total of nine patients had distant metastasis, with lung (four patients) being the most common site followed by non-regional nodes (two patients), bone (two patients), and liver (one patient). Out of 21 patients with residual recurrent disease, only 2 could be offered curative intent re-irradiation and the remaining 19 were treated with palliative intent. Finally, 18 (85.7%) patients died, and 3 (14.3%) had stable disease.

Out of 51 patients treated with conformal radiation therapy, at a median follow-up of 9 months (range, 0-55) (median follow-up for alive patients was 44 months [range, 20-55] and that for dead patients was 7 months [range, 0-46]), 8 (15.7%) patients were alive, 41 (80.4%) were dead, and the status of 2 (3.9%) was unknown. A total of 17 (33.3%) cases were clinically controlled without any evidence of disease. Residual disease was seen in 7 (13.7%) patients and recurrence in 13 (25.5%). The status of 14 (27.5%) patients was unknown as they were either lost to follow-up or had died after the conclusion of radiation therapy. Of the 13 patients with recurrence, 6 had loco-regional recurrence alone and 7 had distant metastasis along with loco-regional recurrence. Out of seven patients with residual disease, two developed distant metastasis. Thus, a total of nine patients developed distant metastasis, with the lung (four patients) being the most common site, followed by the liver (two patients), non-regional nodes (one patient), bone (one patient), and kidney (one patient). Out of 20 patients with residual and recurrent disease, only 2 could be offered curative intent re-irradiation and the remaining 18 were treated with palliative intent. Finally, 17 (85%) patients died, and 3 (15%) had stable disease.

The OS and DFS were not significantly different for conformal radiotherapy and VMAT [Figure 2] and [Figure 3]. Univariate and multivariate analyses revealed that none of the tumor related factors affected OS and DFS significantly [Table 4], except concurrent chemotherapy, which resulted in an OS benefit.
Figure 2: Overall survival

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Figure 3: Disease free survival

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Table 4: Univariate and multivariate analysis of tumor-related factors affecting survival or recurrence

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  Discussion Top


Our study showed that VMAT offered a significant advantage over conformal radiotherapy by reducing the doses received by the heart at a gradient of 5 Gy from 25 to 45 Gy. However, lung doses at a gradient of 5 Gy from 5 to 40 Gy were similar between 3DCRT and VMAT, but less with VMAT as a Phase-II boost after Phase-I 3DCRT. However, the difference in the lung dose was not statistically significant.

Wang et al. reported a dosimetric comparison of 3DCRT, IMRT, and VMAT and concluded that the volume of lung receiving a low dose (V5 and V10) was significantly higher in IMRT and VMAT plans than in 3DCRT plans, whereas the volume of lung receiving a high dose (V20 and V30) and mean dose were relatively lower.[16] Hsieh et al. showed that with a dose prescription of 40–56 Gy, the V5 and V20 for the lung were 67.8% and 23.4%, respectively, with a mean lung dose of 13.13 Gy.[17] The V5 and V20 lung doses in our patients who received VMAT were 73.05% and 29.15%, respectively, for a much higher prescription dose of 63 Gy. For the heart, the V30 and V35 were 30.2% and 21.5%, respectively, with a mean dose of 23.19 Gy. TheV30 and V35 in our patients were 29.33% and 22.61%, respectively, which were quite similar. Chandra et al. showed that in patients with tumors in the lower third of the esophagus, the dose-volume (V10, V20, mean lung dose) of exposed lung reduced significantly with IMRT compared to 3DCRT, with the median absolute improvement being 10% for V10, 5% for V20, and 2.5 Gy for the mean lung dose.[18] Ghosh et al. showed that the volume of lung receiving 30, 10, and 5 Gy was significantly lower in the 3DCRT plan compared to the IMRT plan, while the mean dose to the heart was higher with the 3DCRT plan.[19] Xu et al. in their meta-analysis reported that the mean dose to the lung, V20, and V30 was significantly lower in IMRT than in 3DCRT, while there was no significant difference in the V5 and V10 Gy. Similarly, the V50 for heart was significantly lower in IMRT than in 3DCRT, but there was no significant difference in V30 and V40 Gy. IMRT was also reported to lead to superior OS compared to 3DCRT (3-year OS P = 0.007).[20] In our study, we observed almost similar lung doses for VMAT and conformal radiation therapy. In a dosimetric comparison study on 10 patients with tumors in the middle third of the esophagus in the neoadjuvant setting, Kataria et al. showed that VMAT was a better option resulting in equivalent or superior dose distribution with a reduction in dose to the lung (statistically significant) and heart (statistically insignificant) compared to IMRT.[21] Similar findings were reported in patients with tumors in the cervical esophagus by Yin et al.[22] Even in our study, the difference in the heart dose was statistically significant, whereas there was no significant difference in the lung dose.

In our study, VMAT showed marginal improvement in OS (2/3/4-year) compared to conformal radiation therapy, whereas improvement in DFS was much higher; however, neither was statistically significant. In a similar study with fewer patients, Yang et al. reported no significant difference in the 2-year OS (53.6% vs. 60.6%, P = 0.965) and progression-free survival (PFS) (49.5% vs. 60.1%, P = 0.998), between 3DCRT and VMAT; however, the mean lung dose, V20 for lung, and the incidence of Grade-1 pneumonitis were significantly lower with IMRT compared to 3DCRT.[23] A Japanese study by Ito et al. on patients with cervical esophagus tumors treated with chemoradiotherapy showed significantly better 3-year OS (81.6% vs. 57.2%, P = 0.037) with IMRT compared to 3DCRT, but no difference in PFS.[24] In the multivariate analysis, IMRT was found to be the only favorable factor for OS (P = 0.045). Chen et al. in their study on 112 patients with cancers of the cervical esophagus showed no survival benefit in terms of the 3-year OS (49.6% and 54.4%, P = 0.927) and PFS (45.8% and 42.8%, P = 0.859) with 3DCRT when compared with IMRT.[25] Most of these studies were retrospective like ours, with a sample size ranging between 100 and 120. Similar to these studies, our study also did not show any survival advantage (OS and DFS) with VMAT when compared to 3DCRT. Lin et al. in their non-randomized study in 676 patients conducted over a period of 10 years showed that IMRT led to significantly better OS and locoregional recurrence rate than 3DCRT. The 3-year and 5-year OS was 43% versus 53% and 34% versus 44%, respectively between 3DCRT and IMRT; however, the difference was not statistically significant. No difference was seen in cancer-specific mortality or distant metastasis, but an increased incidence of cardiac death was seen in the 3DCRT group (11.7% vs. 5.4%).[26]

The standard radiation dose for chemoradiation is 50.4 Gy according to the INT0123 study, which also reported that a higher dose resulted in high mortality without any survival benefit. But in the INT0123 study, more than 60% of the patients had early-stage disease with a mix of adenocarcinoma and squamous carcinoma histology.[15] According to the Japanese series by Hayashi et al. and Kondo et al., patients with squamous cell carcinoma have a higher rate of local recurrence compared to adenocarcinoma, thus requiring a higher radiation dose of >60 Gy.[27],[28] Chang et al. in their study involving 2061 patients with advanced thoracic esophageal cancer receiving chemoradiation, showed significantly prolonged OS (32.45% vs. 20.88%, P < 0.0001) with high-dose (>60 Gy) IMRT compared to standard-dose (<60 Gy) IMRT.[29] In a retrospective cohort study on patients with cervical esophagus carcinoma, McDowell et al. reported an improved OS with high-dose (>60 Gy) IMRT with concurrent cisplatin than with 2DCRT (P = 0.005) and 3DCRT (P = 0.061).[30] Ren et al. in their study on 183 patients with esophageal squamous cell carcinoma showed that the high-dose group (60 Gy) had significantly better 3-year and 5-year OS (44.3% vs. 31.7% and 36.9% vs. 20.6%, P = 0.002)) and local control (60.9% vs. 50.8% and 57.6% vs. 46.4%, P = 0.032) than the standard-dose group.[31] Kim et al. showed that higher dose (>60 Gy) of radiation was associated with a significant increase in locoregional control (69.1% vs. 50.3%, P = 0.002), median OS (35.1 vs. 22.3 months, P = 0.043) and PFS (16.7 vs. 11.7 months, P = 0.029).[32] Clavier et al. in their retrospective study on 143 patients reported no significant difference in the local control (P = 0.89), loco-regional control (P = 0.62), DFS (P = 0.8), and OS (P = 0.7) between high-dose (66 Gy) and standard-dose (50.4 Gy) radiation.[33] Ke et al. have shown that higher (>50.4 Gy) than conventional radiation doses (<50.4 Gy) neither improve the OS (P = 0.21), DFS (P = 0.26) nor the locoregional or distant failures (P = 0.42).[34] In the recent randomized ARTDECO study by Hulshof et al. involving 260 patients with inoperable esophageal cancer including both squamous and adenocarcinoma, randomized between standard dose 50.4 Gy versus high dose 61.4 Gy, the 3-year local PFS was 70% versus 73% (not significantly different). The same for squamous carcinoma and adenocarcinoma was 75% versus 79% and 61% versus 61% (not significant) concluding an absence of dose escalation effect on local control even in squamous carcinoma.[35]

Xiao et al., in a recent meta-analysis involving 11 studies including 4946 patients, have shown that compared to the standard-dose group (50.4 Gy), the high-dose (>60 Gy) group had significantly improved locoregional failure (odds ratio [OR], 2.199, P < 0.001), 2-year locoregional control (OR, 0.478, P = 0.001), 2-year OS (hazard ratio [HR], 0.744, P < 0.001) and 5-year OS (HR, 0.683, P < 0.001) without any differences in the incidence of Grade-3 toxicities and treatment-related death rate.[36] Luo et al. in their meta-analysis of 8 studies including 3736 patients, also showed that there was a significant benefit with high-dose radiotherapy (>60 Gy) in terms of OS (P < 0.001), 2-year OS risk ratio (P < 0.001), PFS (P = 0.001), and locoregional recurrence-free survival (P < 0.001).[37] In our study, most patients had squamous cell carcinomas with advanced T stage (T3-T4 stage patient numbers were 54 [84.4%] in VMAT and 43 [84.3%] in conformal radiotherapy, equally distributed in both arms); therefore, we tried to deliver a dose of up to 63 Gy using two different techniques (conformal radiation therapy and VMAT), wherever possible, but no significant benefit in terms of OS or DFS was observed. We could not compare the outcomes on the basis of the radiation dose (> or <60 Gy) because very few patients received a dose of <60 Gy in our study (5 with VMAT and 3 with conformal radiotherapy).

Moreover, in our study, the addition of concurrent chemotherapy was the only factor that was significantly associated with an OS benefit in both the univariate (P = 0.00034) and multivariate (P = 0.048) analyses. Herskovic et al. reported improved 1-year and 2-year OS (P < 0.001) with the addition of chemotherapy to a radiation dose of 50.4 Gy compared to a radiation dose of up to 64 Gy alone. In addition, the concurrent chemotherapy arm had a lower rate of local (P < 0.02) and distant (P < 0.01) recurrence.[4] This was further validated by the significant 5-year OS benefit in a long-term analysis by Cooper et al.[5], and Al-Sarraf et al.; they reported a 5-year OS advantage with concurrent chemoradiotherapy with a radiation dose of 50.4 Gy (P < 0.0001) compared to a radiation dose of up to 64 Gy alone.[6]

Like most other studies, our study was limited by its small sample size and retrospective design. Therefore, in future, randomized studies comparing VMAT and conformal radiation therapy and various doses of radiation are warranted.


  Conclusion Top


In patients with locally advanced esophageal cancer treated with high-dose definitive chemoradiotherapy, the radiation dose received by the heart is significantly different between VMAT and conformal radiation technique. However, there is no significant difference in the survival outcomes between the two techniques. The addition of concurrent chemotherapy significant impacts the OS.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
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