Gastric Side Effects and the Stomach Dosimetric Analysis in Left-Sided Breast Cancer Radiotherapy in Free-Breathing and Deep Inspiration Breath-Hold Technique

doi:10.21203/rs.3.rs-923894/v1

Background

Adjuvant radiotherapy following surgery reduces the local recurrence and improves the prognosis. However, a considerable part of patients developed digestive reaction in daily treatment. In order to explore the correlation between breast radiotherapy and gastric toxicity, we investigated the clinic symptoms and stomach dose during DIBH or FB mode while left-sided breast cancer patients (LSBCP) receiving radiotherapy.

Methods

In the study, 124 LSBCP received adjuvant radiotherapy after surgery at our department were analyzed clinical characteristics and enquired about gastrointestinal side effects after treatment. Moreover, dosimetric parameters were assessed.

Results

There was no statistically significant difference between the two groups in age, T staging, N staging, hormone receptors, human epidermal receptor-2 (HER2), surgical methods, fractionated regimen, and chemotherapy conditions. Stomach volumes, the use of the DIBH gating technique (FB/DIBH), and higher fractionated dose (Dmax/F) were associated with a statistically significantly greater risk for acute radiotherapy toxicity.

Conclusion

In order to cut down gastric side effects after breast radiotherapy, large meals should be avoided before treatment. DIBH treatment should be implemented in centers where conditions are satisfied to reduce radiotherapy side effects. Furthermore, dose limitation in stomach should be considered when the radiotherapy plan was formulated, especially for the patients treated with hypofractionated radiotherapy.

Oncology

Gastric side effects

breast cancer

radiotherapy

DIBH

Breast cancer is one of the most common cancers diagnosed in women [1]. Currently, breast cancer treatment is based on comprehensive therapy, consists of surgery, chemotherapy, radiotherapy, targeted therapy, and endocrine therapy [²]. Adjuvant radiotherapy following surgery reduces the local recurrence and improves the prognosis [3, 4]. But radiotherapy is associated with many side reactions in adjacent organs, including heart [5.6], lungs [7], contralateral breast [8], skin [9] and brachial plexus [10, 11]. Seldom studies to date have focused on gastric side effects of breast cancer radiotherapy. However, a considerable part of patients developed digestive reaction in daily treatment, especially in those suffered left-sided breast cancer. Digestive reaction might result in weight loss, even further cause changes in body shape, which should be rigorously avoided during radiotherapy. So it`s essential for radiation therapists to recognize the digestive symptoms during radiotherapy in left-sided breast cancer patients (LSBCP).

As gastric side effects have not been widely attracted attention to, the main objective of this study is to prove the existence of gastric side effects in the process of breast cancer radiotherapy. Possible related primary factors responsible for the detrimental effects might be found by analyzing the patients` characteristics. With the suspected factors, radiation therapists can keep the side effects occurrence as low as possible.

As is well known, digestive symptoms are always associated with radiation treatment to the upper abdomen, such as gastric, pancreatic, and bile-duct carcinomas [12]. Among all of the abdomen organs, stomach is the digestive organ that possesses the shortest distance to the left breast. So it`s important to realize the relationship between the dose in stomach and the digestive symptoms in LSBCP.

Nowadays, the deep inspiration breath-hold (DIBH) technique is widely used to decrease the radiation dose to many organs, such as the heart, left anterior descending coronary artery (LAD), lungs, contralateral breast, and other organs in LSBCP [^13–15]. But whether the radiation dose of stomach can be reduced in DIBH has not been noticed. To explore the correlation between the respiration control technique and gastric toxicity, we investigated the clinic symptoms and stomach dose during DIBH or FB mode while LSBCP were receiving radiotherapy.

Patient population

From June 2020 to December 2020, a total of 124 consecutive LSBCP received adjuvant radiotherapy after surgery (with or without adjuvant chemotherapy and targeted therapy) at our department was analyzed clinical characteristics and dosimetric parameters and enquired about gastrointestinal side effects after treatment. Patient characteristics are presented in Table 1. The fractionated dose schemes of this group of patients are listed in Table 2.

Table 1

patient characteristics
Category	FB	DIBH
Number of patients	74	50
Median age(years)	49(31–74)	45(33–56)
Breast conserving surgery (yes/no)	35/39	33/17
T category
Is	3	4
1	21	24
2	36	19
3	8	2
4	6	1
N category
0	31	25
1	24	17
2	13	3
3	5	4
x	1	1
Hormone receptor(+/-)	50/24	44/6
HER-2(+/-)	24/50	15/35
Hypofractionated RT /conventional RT	33/41	40/10
Chemotherapy (yes/no)	63/11	35/15
DIBH, deep inspiration breath-hold; FB, free-breathing ; RT, radiation therapy.

Table 2

The fractionated dose schemes of patients.
Category		Dose		FB	DIBH
		Course I	Course II
		Whole breast (lumpectomy bed)	Lumpectomy bed
Number of patients				74	54
Hypofractionated RT				31	40
	15F ± 5F	2.7Gy/F	2.0Gy/F	22	26
	16F ± 5F	2.7Gy/F	2.0Gy/F	4	7
	15F	2.7Gy/F (3.33Gy/F)	-	5	7
Conventional RT				43	10
	25F ± 5F	2.0Gy/F	2.0Gy/F	27	7
	27F	2.0Gy/F (2.22Gy/F)	-	16	3
RT = radiotherapy
In the hypofractionated RT cohort, most patients received the treatment regimen in which whole breast irradiation was followed by photon or electron boost of 10 Gy in five fractions to the tumor bed. For the patients whose treatment course was interrupted by holiday, one fraction was added in order to ensure treatment effect (16F ± 5F). Or the whole breast and boost planning target volumes were treated simultaneously. In the conventional team, the left breast and tumor bed were treated simultaneously for the patients who underwent breast-conserving radiotherapy. While for patients without metal clips in their tumor bed, electron boost of 10 Gy in five fractions was conducted after 25 fractions of left breast treatment.The radiotherapy dose of the second course was not collected in this study.

CT Simulation

All patients received computer tomography (CT)(Siemens SOMATOM Definition AS) scans in the supine position lying on a vacuum mat, with both arms abducted above the head. The patients treated in DIBH mode underwent a free-breathing CT scan and a breath-hold CT scan in the same treatment position. The breath-hold CT scan was conducted using the ELEKTA Active Breathing Coordinator™ device (ELEKTA). While other patients in FB mode just underwent a free-breathing (FB) CT scan. Single-slice CT images were obtained using 3-mm thickness from the third cervical vertebrae to the 15cm below the diaphragm, including the whole chest and stomach. CT images were transferred to the radiotherapy planning system (TPS).

Contouring and treatment planning

Target contouring was conducted in Eclipse 13.6. Clinical target volume (CTV) was contoured conformed to the Radiation Therapy Oncology Group breast atlas (www.rtog.org). Stomach was delineated along the serosa. The heart, lungs, contralateral breast, and spinal cord were also contoured. The planning target volume (PTV) was a 5mm isotropic expansion of the CTV but was limited to 1mm below the skin surface. For the sake of error reduced, all of the organs at risk (OAR) and target volumes were contoured by the same physician and reviewed by two senior physicians. As for the patients treated in DIBH mode, contouring was conducted on the DIBH CT.

Treatment for all the patients was planned using Elekta Monaco TPS v5.11.0 (Elekta) software. The prescription dose to the PTV was presented in Table 2. Radiotherapy was performed with 6MV X-ray using two tangential inverse planned conformal beams which directions were set to minimize the OARs dose (80% of total prescription), and two to five intensity-modulated fields (20% of total prescription). For the patients with breast-conserving surgery, an extra dose of 10Gy (5 fractions of 2Gy) was added for tumour bed volume in the hypofractionated radiotherapy treatment. The additional 10Gy was achieved with one or two IMRT beams or electron boost. For the patients whose treatment course was interrupted by holiday, one fraction was added to ensure treatment effect (16F ± 5F). Or the whole breast (2.7Gy/F) and boost (3.33Gy/F) PTVs were treated simultaneously to shorten the treatment period. While in the conventional radiotherapy group, the whole breast and boost PTVs were treated simultaneously for the patients who underwent breast-conserving radiotherapy, except those without metal clips in their tumour bed. Electron boost of 10Gy in five fractions was conducted after 25 fractions of left breast treatment for those patients without metal markers. As digestive symptoms often occurred during the whole breast radiotherapy, the treatment of the second course (if existed) was not taken into account in this study, probably because of the small volume of the tumour bed.

Treatment workflow

At the first outpatient visit, patients were asked to maintain a regular living habit and regular diet. Any chemotherapeutics couldn`t be carried out during the treatment, especially oral capecitabine. Then the radiotherapy treatment was delivered at the same time of a day with the CT scan. All patients were treated with Axesse linear accelerator (Elekta) with daily set-up according to the skin markers and cone-beam CT (CBCT) image registration once a week.

After the end of the therapy, patients were asked a set of questions about toxicity information in the clinic visits. Questions usually included the incidence and severity of nausea, vomiting, bad appetite, diarrhoea, loss of weight, and other common side effects. The upper digestive toxicities were graded according to the systems proposed by RTOG.

Statistical analysis

Student’s t test was used to compare continuous variables statistically, and chi-square and Fisher’s exact tests were used for categorical variables. Statistical analyses were performed using SPSS 23.0(SPSS IBM Inc., Armonk, New York). A p-value < 0.05 was considered statistically significant.

In our study, a total of 124 LSBCP was included with 74 in the FB cohort and 50 in the DIBH cohort. Of all the patients, 12.1% (15/124) patients developed gastric symptoms: 11 patients suffered grade I toxicity(loss of appetite, nausea), 3 patients with grade II toxicity(loss of appetite, nausea, vomit, lose weight ≤ 5%), and 1 with grade III toxicity (loss of appetite, nausea, vomit, lose weight ≥ 5%). The isodose distribution in the stomach on simulation CT of one of the patients who suffered grade II toxicity is shown in Fig. 1.

Among the cases with or without gastric symptoms, it was found that there was no statistically significant difference between the two groups in age (P = 0.367), T staging (P = 0.682), N staging (P = 0.279), hormone receptors (P = 0.355), human epidermal receptor-2 (HER2)(P = 1.000), surgical methods (P = 0.585), fractionated regimen (P = 0.273), and chemotherapy conditions (P = 1.000). However, stomach volume (P = 0.047) and the use of the DIBH gating technique (FB/DIBH)(P = 0.026) were associated with a statistically significantly greater risk for acute radiation toxicity (see Table 3). What`s more, higher fractionated dose in stomach was found statistically significant associated with the gastric toxicity, including Dmax/F (D1cc/F, dose delivered to a 1cm3 volume of the stomach/fraction)(P < 0.001), D60cc/F (dose delivered to a 60cm3 volume/fraction) (P = 0.001), D30cc/F (P = 0.001), and D10cc/F (P < 0.001).

Table 3

Analysis of characteristics of gastric complications in breast cancer patients [n(%)]
		Gastric side effects		χ2-value/t value	P-value
		No(%)	Yes(%)
Age				0.91	0.367
		47.5 ± 8.1	49.6 ± 10.8
T stage				1.50	0.682
	T1	48(88.9)	6(11.1)
	T2	47(87.0)	7(13.0)
	T3	8(80.0)	2(20.0)
	T4	6(100.0)	0(0.0)
N stage				1.35	0.279
	N0	48(84.2)	9(15.8)
	N1,N2,N3,Nx	61(91.0)	6(9.0)
hormone receptor(+/-)				0.78	0.355
	Negative	25(83.3)	5(16.7)
	Positive	84(89.4)	10(10.6)
HER2				0.03	1.000
	Negative	75(88.2)	10(11.8)
	Positive	34(87.2)	5(12.8)
Breast conserving surgery (yes/no)				0.46	0.585
	No	48(85.7)	8(14.3)
	Yes	61(89.7)	7(10.3)
Fractionated regimen				1.47	0.273
	Conventional radiotherapy	47(92.2)	4(7.8)
	Hypofractionated radiotherapy	62(84.9)	11(15.1)
Chemotherapy (yes/no)				0.01	1.000
	No	23(88.5)	3(11.5)
	Yes	86(87.8)	12(12.2)
Stomach volume(m3)				2.01	0.047
		371.6 ± 149.1	458.5 ± 209.4
Use of respiratory gating technique				5.17	0.026
	DIBH	48(96.0)	2(4.0)
	FB	61(82.4)	13(17.6)
Dmax/F				9.44	0.000
		122.5 ± 89.8	241.8 ± 35.8
D10cc/F				6.34	0.000
		63.3 ± 63.4	174.1 ± 63.6
D30cc/F				4.27	0.001
		34.4 ± 38.8	114.2 ± 71.0
D60cc/F				3.98	0.001
		18.7 ± 20.2	69.8 ± 49.2

The stomach irradiation dose and volume were associated with digestive reactions. As is shown in Table 3, the stomach Dmax/F was 122.5 ± 89.8Gy/F in the negative symptoms cohort vs. 241.8 ± 35.8Gy/F in the positive cohort (P < 0.001). Similar results can be observed in the stomach D10cc/F (63.3 ± 63.4vs174.1 ± 63.6 Gy/F), D30cc (34.4 ± 34.8vs114.2 ± 71.0 Gy/F), and D60cc/F (18.7 ± 20.2vs69.8 ± 49.2 Gy/F). Statistically significant reductions in the stomach dose of the negative cohort were observed in all of the four dosimetric parameters (see Fig. 2).

Consistent with clinical experience, 2/50(4.0%) patients suffered gastric symptoms received radiotherapy in DIBH mode and 13/74(17.6%) in the FB mode, with a statistically significant difference (P = 0.026). The different locations of the stomach during FB and DIBH can be presented in Fig. 3.

In addition, correlation can be demonstrated between stomach volumes and digestive reactions. A reduction in the stomach volume was seen in the patients with negative symptoms, from 458.5 ± 209.4m3 to 371.6 ± 149.1m3, with a significant difference (P = 0.047). The relationship between the stomach volume and the dose distribution can be depicted vividly in Fig. 4.

This article reports the initial experience, justifying that radiotherapy of the LSBCP led to an early gastric reaction, such as nausea, vomit, and loss of weight. It is well established that radiotherapy-induced gastric reaction is usually associated with irradiation for upper abdomen tumours, such as pancreatic, gastric, or liver cancer[12]. Total body irradiation can also cause vomiting. However, in clinical practice, a considerable section of patients was found to endure grade I-II gastrointestinal toxicity ever since the hyper-fractionated radiotherapy plan was conducted in our centre. Nausea and vomiting usually occurred immediately or several hours after breast radiotherapy. At the end of radiation, some patients had weight loss more or less.

In our study, acute radiation-related gastric complications were associated with the irradiation dose of stomach. With a higher Dmax/F, D60cc/F, D30cc/F, or D10cc/F, the incidence of gastric complications grew significantly. As is shown in Fig. 1, most of the patients who suffered from gastric poisoning had a considerable portion of the stomach in the high-dose zone. A higher max dose or a more extensive high-dose zone in stomach is usually correlated with a larger stomach volume, as is depicted in Fig. 4. The dosimetric distribution in the stomach is quite different on account of varying stomach volumes. A larger stomach volume leads to the closer distance between the stomach wall and the chest wall, and then shortens the gap between the stomach and the PTV.

Numerous publications have investigated the dosimetric advantages in heart, LAD, lung, and liver for breast cancer radiotherapy in DIBH mode [13–19] However, this is the first report that observed the stomach dose in DIBH and FB. Ever since the DIBH technique was applied in our centre, a considerable portion of LSBCP received radiotherapy in the new respiratory gating mode. There was a significant difference in the occurrence rate of gastric toxicity between the FB and DIBH groups. Variability in the stomach dose can be due to physiological factors: during DIBH, the lungs become enlarged and push the diaphragm downward, leading to a relatively long distance between stomach and PTV and lower radiation dose compared with FB. Therefore, in DIBH mode, advantageous dose distribution in the stomach can be achieved, resulting in a lower probability of gastric symptoms.

In addition, although there was no relationship between the gastric side effects and fractionated regimen in this study, fewer fractions always lead to higher PTV single dose irradiation. The prescription dose to PTV was 2.0Gyཞ2.22Gy/F in the conventional fraction cohort, while in hypofraction mode the dose was 2.7Gyཞ3.33Gy/F. Because of the short distance between left breast and stomach in certain situations, higher dose fractionated irradiation in PTV could result in more irradiation dose/F in the stomach. However, a considerable portion of the patients (40/124) was treated in hypofraction mode under the DIBH technique, the occurrence of gastric symptoms rate might be decreased because of the stomach movement.

As the application of the hypofractionated regimen becomes more widespread, more and more LSBCP might experience upper digestive tract side reactions. Poor appetite, nausea, and vomiting during radiotherapy could result in weight loss in patients, which will lead to changes in body shape. As a result, the safety and accuracy of treatment could be cut down, especially for the PTV located in body surfaces, such as in the breast and chest walls. In Mary Feng`s study focused on intrahepatic malignancies radiotherapy, gastric bleeds might occur after radiotherapy at a median time of 4 months [20]. In another study published in 2009, the risk of gastric cancer as a second malignant tumour rose with the increasing stomach mean dose (Dmean) [21]. Therefore, the gastric dose in left breast radiotherapy should be attached importance to.

Emami et al. [22] estimated doses with a 5% risk at 5 years (TD5/5) for late stomach toxicities in 1991. The TD5/5 estimated for severe gastric complications after the whole-stomach irradiation dose of 50Gy, and 1/3 volume of the whole-organ irradiation dose of 60Gy, had been widely accepted as a dose limit guideline. However, the dose limit was established in the era of three-dimensional conformal radiation therapy (3D-CRT). As new techniques, such as intensity-modulated radiation therapy (IMRT), volumetric modulated arc therapy (VMAT), tomotherapy, and even intensity-modulated proton therapy (IMPT)[23–25], had been widely implemented in breast cancer radiotherapy, new dose limitation of stomach should be recommended. There were no gastrointestinal symptom references to suggest a safe dose with the current radiotherapy techniques, a reduction to gastric symptoms should be conducted by proposing a new stomach dose limitation when the radiotherapy plan was formulated. Considering that most centres usually couldn`t scan the entire stomach in breast cancer simulation, we collected Dmax, D60cc, D30cc and D10cc as statistic variables. The current work demonstrated that Dmax/F, D60cc/F, D30cc/F and D10cc/F in stomach were associated with gastric side effects. So further study is required to validate a specific OAR limitation achievable for lower stomach side effects.

When appraising our products, both advantages and limitations should be taken into account in the meantime. Up to now, there is no evidence in the literature that radiotherapy of LSBCP is correlated with an increased risk of gastric reaction. In the current study, we showed an increased incidence rate in LSBCP received hyper-fractionated radiotherapy. What`s more, we suggested dose limitations that radiation oncologists can use to check their radiotherapy plan. Meanwhile, there are several limitations to the study. First, the stomach wall may change depending on the volume of the contents. Planned doses for 3D-CRT + IMRT cannot be flexibly modified or adjusted according to day-to-day or real-time organ displacements around the stomach, resulting in different digestive symptoms after everyday treatment. Second, seldom publications studied the stomach dose limitation as an OAR in breast cancer, so there weren`t enough applicable references. Third, gastroscopy was not conducted after radiotherapy to investigate acute radiation-related gastric toxicity. Moreover, real long-term side effects were not reported because of the short follow-up period.

In conclusion, a huge stomach could be closer to the breast PTV, so large meals should be avoided before treatment. DIBH treatment should be implemented in centres where conditions are satisfied to reduce radiotherapy side effects. Furthermore, dose limitation in stomach should be considered when the radiotherapy plan was formulated, especially for the patients treated with hypofractionated radiotherapy.

Acknowledgements

None.

Authors’ contributions

DY and YP was the major contributors in writing the manuscript. Data collection was performed by YP, DZ and HTC. Data analyses were performed by FSY. DY and YP designed the work. XML revised the manuscript. All authors contributed to the article and approved the final manuscript. Both PY and XML are corresponding authors.

Funding

The study did not receive any funding.

Availability of data and materials

The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

Ethics approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Competing interests

The authors declare that they have no competing interests.

Author details

¹Department of Radiation Oncology, Shenzhen People's Hospital, The First Affiliated Hospital of Southern University of Science and Technology, Dongmenbei Road 1017, Shenzhen 518000, Guangdong, People’s Republic of China. ²Center for AIDS/STD Control and Prevention, Sichuan Center for Disease Control and Prevention, Zhongxue Road 6, Chengdu 610051, Sichuan, People’s Republic of China.

Siegel RL, et al. Cancer statistics, 2021. CA: a cancer journal for clinicians. 2021;71(1): 7-33.
Gradishar WJ, et al. Breast cancer, version 3.2020, NCCN clinical practice guidelines in oncology. J Natl Compr Canc Netw. 2020;18(4): 452-78.
Early Breast Cancer Trialists' Collaborative Group. Effect of radiotherapy after breast-conserving surgery on 10-year recurrence and 15-year breast cancer death: meta-analysis of individual patient data for 10 801 women in 17 randomised trials. Lancet. 2011;378(9804): 1707-16.
Early Breast Cancer Trialists' Collaborative Group. Effects of radiotherapy and of differences in the extent of surgery for early breast cancer on local recurrence and 15-year survival: an overview of the randomised trials. Lancet. 2005; 366(9503): 2087-106.
Darby SC, et al. Risk of ischemic heart disease in women after radiotherapy for breast cancer. N Engl J Med. 2013; 368(11): 987-98.
Sardaro A, et al. Radiation-induced cardiac damage in early left breast cancer patients: risk factors, biological mechanisms, radiobiology, and dosimetric constraints. Radiother Oncol. 2012; 103(2): 133-42.
Grantzau T, et al. Risk of second primary lung cancer in women after radiotherapy for breast cancer. Radiother Oncol. 2014; 111(3): 366-73.
Takimoto CH. Cancer in the contralateral breast after radiotherapy for breast cancer. N Engl J Med. 1992; 327(6): 431-2.
Tortorelli G, et al. Standard or hypofractionated radiotherapy in the postoperative treatment of breast cancer: a retrospective analysis of acute skin toxicity and dose inhomogeneities. BMC Cancer. 2013; 13(1): 1-9.
Olsen NK, et al. Radiation-induced brachial plexopathy: neurological follow-up in 161 recurrence-free breast cancer patients. Int J Radiat Oncol Biol Phys. 1993; 26(1): 43-9.
Galecki J, et al. Radiation-induced brachial plexopathy and hypofractionated regimens in adjuvant irradiation of patients with breast cancer-a review. Acta Oncol. 2006; 45(3): 280-4.
Kris MG, et al. American Society of Clinical Oncology guideline for antiemetics in oncology: update 2006. J Clin Oncol. 2006; 24(18): 2932-47.
Lai J, et al. Meta-analysis of deep inspiration breath hold (DIBH) versus free breathing (FB) in postoperative radiotherapy for left-side breast cancer. Breast Cancer. 2020; 27(2): 299-307.
Testolin A, et al. Deep inspiration breath-hold intensity modulated radiation therapy in a large clinical series of 239 left-sided breast cancer patients: a dosimetric analysis of organs at risk doses and clinical feasibility from a single center experience. Br J Radiol.2019; 92(1101): 20190150.
Rafic KM, et al. Dosimetric and clinical advantages of adapting the DIBH technique to hybrid solitary dynamic portal radiotherapy for left-sided chest-wall plus regional nodal irradiation. Med Dosim. 2020; 45(3): 256-63.
Pandeli C, et al. Dose reduction to organs at risk with deep-inspiration breath-hold during right breast radiotherapy: a treatment planning study. Radiat Oncol. 2019; 14(1): 1-10.
Mast ME, et al. Left-sided breast cancer radiotherapy with and without breath-hold: does IMRT reduce the cardiac dose even further? Radiother Oncol. 2013; 108(2): 248-53.
Quirk S, et al. A retrospective analysis to demonstrate achievable dosimetry for the left anterior descending artery in left-sided breast cancer patients treated with radiotherapy. Radiother Oncol. 2020; 148: 167-73.
Nissen HD, et al. Improved heart, lung and target dose with deep inspiration breath hold in a large clinical series of breast cancer patients. Radiother Oncol. 2013; 106(1): 28-32.
Feng M, et al. Dosimetric analysis of radiation-induced gastric bleeding. Int J Radiat Oncol Biol Phys. 2012; 84(1): e1-6.
Van den Belt-Dusebout AW, et al. Roles of radiation dose and chemotherapy in the etiology of stomach cancer as a second malignancy. Int J Radiat Oncol Biol Phys. 2009; 75(5): 1420-9.
Emami B, et al. Tolerance of normal tissue to therapeutic irradiation. Int J Radiat Oncol Biol Phys . 1991; 21(1): 109-22.
McDonald MW, et al. Long-term outcomes of IMRT for breast cancer: a single-institution cohort analysis. Int J Radiat Oncol Biol Phys. 2008; 72(4): 1031-40.
Arsene-Henry A, et al. Evolution of radiation techniques in the treatment of breast cancer (BC) patients: From 3D conformal radiotherapy (3D CRT) to intensity-modulated RT (IMRT) using Helical Tomotherapy (HT). Radiother Oncol. 2017; 124(2): 333-4.
Lee HL, et al. The role of breath hold intensity modulated proton therapy for a case of left-sided breast cancer with IMN involvement. How protons compare with other conformal techniques? Tech Innov Patient Support Radiat Oncol. 2020; 15: 1-5.

Gastric Side Effects and the Stomach Dosimetric Analysis in Left-Sided Breast Cancer Radiotherapy in Free-Breathing and Deep Inspiration Breath-Hold Technique

Status:

Journal Publication

Version 1

Abstract

Background

Methods

Results

Conclusion

Figures

Introduction

Methods And Materials

Patient population

CT Simulation

Contouring and treatment planning

Treatment workflow

Statistical analysis

Results

Discussion

Declarations

References

Status:

Journal Publication

Version 1