|Ahead of print
A survey of the practice of stereotactic body radiotherapy for hepatocellular and pancreatic malignancies in India
Shirley Lewis1, Supriya Chopra2, Roshni Singh1, Reena Engineer1
1 Department of Radiation Oncology, Tata Memorial Hospital, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai, Maharashtra, India
2 Department of Radiation Oncology, Advanced Centre for Treatment Education and Research in Cancer, Tata Memorial Centre, Homi Bhabha National Institute, Navi Mumbai, Maharashtra, India
|Date of Submission||06-May-2019|
|Date of Decision||06-Sep-2019|
|Date of Acceptance||18-Sep-2019|
|Date of Web Publication||27-Jan-2021|
Department of Radiation Oncology, Advanced Centre for Treatment Education and Research in Cancer, Tata Memorial Centre, Homi Bhabha National Institute, Navi Mumbai, Maharashtra
Source of Support: None, Conflict of Interest: None
Background: Stereotactic body radiotherapy (SBRT) is increasingly being performed for hepatocellular cancer and liver metastases. The purpose of this study was to review the practice of SBRT for hepatocellular, pancreatic cancer and liver metastases in India.
Methods: A survey comprising of 25 questions was designed and served to radiation oncology professionals at two major conferences. The survey consisted of 25 multiple choice questions on SBRT infrastructure and caseload, simulation methods and immobilizations, organ motion control methods, simulation and delivery, indications of liver and pancreatic SBRT and prescribed dose. The responses were analyzed using descriptive statistics.
Results: From January to June 2017, about 200 professionals were approached and 71 professionals responded with a response rate of 35.5%. The duration of the SBRT practice among respondents was less than 3 years in 53% with 32% having formal training in SBRT. The most common sites for the use of SBRT were lung and brain followed by liver and spine. Liver SBRT was practiced by 29 (59.2%) for hepatic oligometastases, hepatocellular carcinoma (HCC), and cholangiocarcinoma. The most common fractionation used was 50–60 Gy/6 fractions and 45 Gy/3 fractions. Pancreatic SBRT was practiced by 37%, mostly for medically inoperable or locally advanced pancreatic cancer. SBRT was not practiced by 22 (31%) of the respondents, and the main reasons were lack of infrastructure and structured training.
Conclusion: The SBRT for liver has increased with a usage rate of over 50% amongst respondents. Pancreatic SBRT use is infrequent and limited to inoperable or advanced cases. Lack of infrastructure and training are the main challenges in the routine adaptation of SBRT.
Keywords: Hepatocellular cancer, pancreatic cancer, surveyKey Message Multi-disciplinary educational meetings and uniform training are needed for the adoption of stereotacticbody radiotherapy for the hepatocellular and pancreatic carcinoma.
|How to cite this URL:|
Lewis S, Chopra S, Singh R, Engineer R. A survey of the practice of stereotactic body radiotherapy for hepatocellular and pancreatic malignancies in India. Indian J Cancer [Epub ahead of print] [cited 2021 May 5]. Available from: https://www.indianjcancer.com/preprintarticle.asp?id=308041
| » Introduction|| |
Stereotactic body radiotherapy (SBRT) is a highly conformal radiation technique used to deliver a high dose to the tumor with high precision while sparing the surrounding normal tissues. The technique can deliver tumor ablative doses in 1 to 6 fractions. Therefore, the implementation requires high precision in all steps of the tumor identification, delineation, and treatment planning and execution. Also, the programme requires stringent quality assurance. Use of SBRT is associated with enhanced local control and is presently utilized in treatment for various extra-cranial sites like lung, prostate, liver, pancreas, head and neck recurrence and oligometastatic disease.,,,,,, The American Association for Physicists in Medicine (AAPM) Task Group 101 describes the quality control guidelines for the routine implementation of SBRT.
In recent years, SBRT is recommended as a non-surgical, equieffective alternative to surgery in early medically inoperable lung cancer. With increasing evidence of high local control rates within multiple phase II studies of hepatocellular cancer (HCC), intrahepatic cholangiocarcinoma (ICC) and liver metastasis, SBRT is now also listed as a therapeutic option for Barcelona Cancer Liver Clinic (BCLC) Stage A–C in some international guidelines.,, Local control rates of upwards of 90% are reported in patients with early-stage disease, and the complete pathological response has been reported in patients undergoing a liver transplant. However, as the phase III trials are still ongoing, the clinical utilization is varied and is often guided by the availability of expertise and physicians constituting the hepatobiliary multi-disciplinary team. Similarly, its utilization in the metastatic setting is dependent on institutional multi-disciplinary clinic practice.
In a practice survey in the United States of America (USA), it was reported that 64% of radiation oncologists were routinely practicing SBRT for lung, spine and liver subsites. A recent international survey of SBRT use in 43 countries with over 1000 radiation oncologist respondents by Lewis et al. showed that 83% radiation oncologists were practicing SBRT and over 60% planned to increase their use. With the emerging role of SBRT in the management of both hepatocellular and pancreatic malignancies, the current practice patterns of SBRT for these cancers is lacking in many countries. Therefore, we conducted a national survey to understand the patterns of SBRT practice for hepatic and pancreatic cancers in India.
| » Materials and Method|| |
Survey method and research participants
Radiation oncology professionals participating at two major conferences in India themed on SBRT between January to June 2017 were invited to participate in the survey. The survey was administered in-person before the session and was collected after the end of a day's session. Also, radiation oncology consultants and physicists practicing in India were invited to complete the survey during a national radiation oncology meeting. No incentives were given for the completion of the survey and the responses were anonymized.
A questionnaire with 25 questions with multiple choices was designed for the survey, and the themes assessed included professional qualification, SBRT infrastructure and number of patients seen, indications of liver and pancreatic SBRT, treatment simulation techniques and immobilizations preferences, organ motion control methods–simulation and delivery, machine for treatment delivery, prescribed dose and number of cases treated. Respondents could select multiple responses for a few questions. If the respondents did not practice SBRT, reasons for non-practice were sought. They ended the survey on question 5. The survey questionnaire is provided in Appendix 1.
The data was analyzed using the Statistical Package for the Social Sciences (SPSS) version 21. Descriptive analysis was used to report the frequency of the responses and presented as percentages. Partially filled surveys (responses in at least 50% of questions) were also evaluated. The difference in proportions was tested using Chi-square test. A P value of less than 0.05 was considered statistically significant.
| » Results|| |
From January to June 2017, 200 professionals were served the SBRT survey questionnaire. Seventy-one professionals responded to the survey. The response rate was 35.5%. Majority of the respondents (n = 63, 89%) were radiation oncology consultants. Four (5.5%) each were medical physicists and radiation oncology registrars. Forty-four per cent were junior consultants with less than 5 years of experience since certification, and only five (7%) had more than 15 years of radiation oncology experience. The most common practice among respondents (n = 33, 46.5%) was academic hospital-based. SBRT was routinely practiced by 49 (69%) of the respondents [Table 1].
The duration of practice of SBRT varied among the respondents. Majority practiced SBRT for less than 3 years (n = 26, 53%) followed by 3–6 years (n = 13, 26.5%). Very few had the experience of practicing SBRT for over 10 years (n = 2, 4%). There was no association between type of practice and duration of SBRT practice (P = 0.4) A minority had formal training within a stereotactic radiation oncology programme (n = 16, 32.7%).
SBRT disease site
The most common tumor sites for stereotaxy use were lung and brain (n = 37, 75.5% each) followed by liver and spine (n = 29, 59.2% each). The other sites of SBRT use were pancreas (n = 18, 37%), prostate (n = 15, 30.5%), recurrent head and neck cancer (n = 14, 28.5%), and recurrent pelvic cancers (n = 10, 20.5%). Majority of the respondents practiced SBRT for multiple sites (n = 39, 55%). Only five respondents practiced SBRT for single site (brain n = 2, liver n = 2 and prostate n = 1).
Linear accelerator with rotational intensity-modulated radiation therapy (IMRT) was the most common infrastructure available for SBRT (n = 34, 69.4%) and eight respondents used both rotational IMRT and static 3D conformal radiation therapy (CRT)/IMRT. Volumetric modulated arc therapy (VMAT) was the most commonly used linear accelerator type (n = 26, 53%). Two respondents used CyberKnife alone. Multiple linear accelerators were available at 15 centers (30.6%) [Table 2].
SBRT radiation planning
Most radiation oncologists/practitioners use alpha cradle/vacuum lock with or without knee rest for immobilization (n = 25, 51%) and nine reported the use of multiple immobilization devices, depending on the site [Table 2]. A 4D computed tomography (CT) scan was the most commonly used strategy for internal target volume generation (n = 19, 39%) followed by a combination of various methods. The deep inspiratory breath-hold (DIBH) technique was used by 15 respondents. A majority used different delivery methods, depending on site (n = 16, 33%) and in 13 (26.5%) respondents the delivery was free-breathing (3D CRT or IMRT). Fiducials were implanted before stereotaxy by 19 (38.8%) practitioners and of these 11 used tumor tracking using fiducials for treatment delivery.
Most respondents (n = 17, 35%) treated all the three indications for liver SBRT, i.e., hepatic oligometastases, HCC and cholangiocarcinoma [Table 3]. Forty-one per cent of the practitioners treat less than five cases of the liver (all indications) with SBRT in a year, and about 37% of the practitioners treat less than five cases of HCC/ICC in a year. The two most commonly used fractionations for liver SBRT were 50–60 Gy/6 fractions and 45/3 fractions (n = 12, 24% each). The hepatic function acceptable for SBRT by most of the respondents was Child A/B7 (n = 33, 67%). The most common dose fractionation for medically inoperable HCC was Adaptive dosing (36-60 Gy/3-6 fractions), depending on tumor volume and liver function (47%).
Pancreatic SBRT was offered to patients by only 18 respondents [Table 4]. Only two respondents treated 5–15 cases of the pancreas with SBRT in a year. Medically inoperable and locally advanced pancreatic cancer were the most common indications for pancreatic SBRT. 30-36 Gy/5-6 fractions was the most commonly used fractionation schedule.
Twenty-two respondents (31%) did not practice SBRT. The reasons for not practicing SBRT were lack of infrastructure in 17 (77.3%), lack of structured training in 3 (13.6%) and other causes in 2 (9.1%). The other causes were not mentioned by the respondents. Lack of formal training in a stereotactic programme was mentioned by 11, and the rest did not respond to this question.
| » Discussion|| |
This study reports on the practice of SBRT among radiation oncology professionals with a special focus on HCC and pancreatic cancer in India. The most common sites of SBRT use were lung and brain followed by liver and spine. Liver SBRT was practiced by about 59% while pancreatic SBRT was practiced by only 37%. Lack of infrastructure and training were the major hindrances towards the adoption of SBRT.
There are limited reports on SBRT practice patterns in India. Rathod et al. published the first survey of SBRT practice from India during 2012–2013. Only 32% of radiation oncology professionals were practicing SBRT at that time. Lung was the most common site treated followed by liver, bone and prostate. The current survey is the second survey of SBRT practice from India. In this survey, 69% of respondents reported using SBRT. The lung is still the most commonly practiced site. The use of SBRT for brain, liver and spine has increased in the last 5 years and may be representative of the evolving evidence. For example, the use of liver SBRT use was 24% in the study by Rathod et al. compared with 59% in the current study.
Majority of radiation oncologists in the current survey were with less than 5 years of professional experience and a majority (53%) practiced of SBRT for less than 3 years. Only 33% had formal training in stereotactic radiotherapy (SRT). Guckenberger et al. conducted a multi-centric audit in Germany to assess the safety and efficacy of SBRT practice in early-stage lung cancer. They found that the experience of SBRT or the number of SBRT performed per year had no impact on overall survival or recurrence rates. However, the authors emphasize that these results are attributed to the structured annual teaching courses on SBRT and presence of national guidelines detailing on all aspects (technical, clinical quality assurance) of SBRT. Implementation of a successful SRT/SBRT programme is a teamwork and requires high standards in all aspects of radiotherapy planning and delivery. The time and effort are high, and the margin for error is very small. Training and experience in SRT/SBRT technologies with certification is a mandate as specified in the executive summary on the quality and safety of SBRT by Solberg et al. The responsibilities of a radiation oncologist in the SRT/SBRT programme is paramount and critical and is detailed in the American Society for Therapeutic Radiology and Oncology (ASTRO) and American College of Radiology (ACR) Practice Guideline for the Performance of SRS and Stereotactic Body Radiation Therapy., This survey highlights the need for a dedicated SRT/SBRT fellowship and training programmes in India. Formation of a consortium involving trained professionals and developing consensus practice guidelines for implementation and practice is essential. There is also a need for a center and process credentialing for liver/pancreatic SBRT.
In the present survey, the cases of liver and pancreatic SBRT treated were ≥5 per year. This reflects the availability of various competing modalities like radiofrequency ablation (RFA), trans-arterial chemoembolization (TACE) and trans-arterial radioembolization (TARE). Whal et al. compared the outcomes of inoperable HCC with RFA or SBRT and both modalities were equivalent in terms of survival and toxicity. On the contrary, Rajyaguru et al. showed a survival advantage with RFA compared to SBRT. These studies are limited by the retrospective nature and a small number of patients treated with SBRT. Sapir et al. compared the outcomes of TACE and SBRT in HCC. There was no difference in overall survival and toxicity between them, and SBRT is a safe alternative to TACE. TACE could be supplemented with additional SBRT, and this approach has shown to be associated with improved local control., Two phase III randomized studies (TACE SBRT NCT number NCT02794337 and International Atomic Energy Agency [IAEA] study NCT number NCT03338647) are presently testing SBRT as a consolidative or stand-alone therapeutic option in patients with unresectable HCC (BCLC stage A-B). The greatest difference in practice patterns of SBRT for HCC lies in fractionation schemes. Fractionation schemes vary according to institutions and physicians and by the insurance coverage. In this survey, major (32.4%) dose schedule practice was based on tumor volume and liver function, which constituted 3-6 fractions delivering 36–60 Gy. The most common fractionation schedule practiced in the United States of America is three fractions and Japan, four fractions . According to Canadian guidelines, the most common number of fractions was six.
Poor referral from oncologists for SBRT for liver and pancreas is common. The plausible reasons are lack of knowledge on the efficacy of SBRT, absence of liver/pancreas-specific tumor boards, presumption of high toxicity (radiation-induced liver disease or duodenal damage) as per historical data and presence of various competing modalities. Two randomized trials comparing SBRT with surgery in lung cancer showed poor accrual because of referral bias. There is a need for educating the oncologists about SBRT (indications, advantages and efficacy) to improve referral base. Case-based discussions and debates comparing SBRT with other modalities in multi-disciplinary meetings should be undertaken.
It is the first survey from India exploring SBRT practice for liver and pancreas malignancies specifically and exploring indications and dose fractionations. This survey was comprehensive, simple and covered relevant questions of SBRT practice amongst radiation professionals. Patients often cannot afford advanced technology like SBRT because of financial constraints. Cost of treatment as a factor hindering SBRT among oncologists was not explored in this survey. Though we believe that the results of the survey may be representative, bias cannot be completely ruled out because of the methodology of circulating survey during conferences themed on stereotaxy. As this is not a national or professional body survey, the users are likely over-represented as responders.
| » Conclusion|| |
The use of SBRT for liver has increased with a usage rate of over 50%; however, even in large centers, the number of cases is less. A lack of infrastructure and training are the main challenges in the routine adaptation of SBRT. Multi-disciplinary educational and tumor boards are needed to further improve the utilization of highly effective techniques like SBRT.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]