Survey on use of postmastectomy radiotherapy for breast cancer in China

Dosimetric comparison of two dose expansion methods in intensity modulated radiotherapy for breast cancer

BACKGROUND

To explore the dosimetric difference between IMRT-VB plan based on the establishment of external expansion structure and virtual bolus (VB) and IMRT-SF based on the skin flash (SF) tool of the Eclipse treatment planning system in postoperative chest wall target intensity modulation radiotherapy plan of breast cancer.

METHODS

Twenty patients with breast cancer were randomly selected as subjects to develop IMRT-VB plan based on virtual bolus and IMRT-SF plan based on skin flash tool of Eclipse treatment planning system. The planning target volume, monitor unit (MU) of every single treatment and the dosimetric parameters of organ at risk (OARs) were recorded. Paired t-test was used for normal distribution data while nonparametric paired Wilcoxon rank sum test was used for non-normal distribution data.

RESULTS

Both IMRT-VB and IMRT-SF plan can expand outward to the chest wall skin and meet the dose requirements of clinical prescription. The conformal index, the homogeneity index, D_2%, D_98% and D_50% were significantly better in IMRT-SF plan than those in IMRT-VB plan (P < 0.05). The average MU of the IMRT-SF plan was much higher than that of the IMRT-VB plan (866.0 ± 68.1 MU vs. 760.9 ± 50.4 MU, P < 0.05). In terms of organ at risk protection, IMRT-SF plan had more advantages in the protection of ipsilateral lung and spinal cord than IMRT-VB plan (P < 0.05).

CONCLUSION

Our study indicated that IMRT-SF plan displayed clinical application superiority compared to IMRT-VB plan, and the operation steps of which are simpler and faster. Besides, IMRT-SF plan took advantages in achieve effective external expansion of skin dose intensity and OARs protection.

3D-printed bolus ensures the precise postmastectomy chest wall radiation therapy for breast cancer

Purpose

To investigate the values of a 3D-printed bolus ensuring the precise postmastectomy chest wall radiation therapy for breast cancer.

Methods and materials

In the preclinical study on the anthropomorphic phantom, the 3D-printed bolus was used for dosimetry and fitness evaluation. The dosimetric parameters of planning target volume (PTV) were assessed, including D_min, D_max, D_mean, D_95%, homogeneity index (HI), conformity index (CI), and organs at risk (OARs). The absolute percentage differences (|%diff|) between the theory and fact skin dose were also estimated, and the follow-up was conducted for potential skin side effects.

Results

In preclinical studies, a 3D-printed bolus can better ensure the radiation coverage of PTV (HI 0.05, CI 99.91%), the dose accuracy (|%diff| 0.99%), and skin fitness (mean air gap 1.01 mm). Of the 27 eligible patients, we evaluated the radiation dose parameter (median(min–max): D_min 4967(4789–5099) cGy, D_max 5447(5369–5589) cGy, D_mean 5236(5171–5323) cGy, D_95% 5053(4936–5156) cGy, HI 0.07 (0.06–0.17), and CI 99.94% (97.41%–100%)) and assessed the dose of OARs (ipsilateral lung: D_mean 1341(1208–1385) cGy, V₅ 48.06%(39.75%–48.97%), V₂₀ 24.55%(21.58%–26.93%), V₃₀ 18.40%(15.96%–19.16%); heart: D_mean 339(138–640) cGy, V₃₀ 1.10%(0%–6.14%), V₄₀ 0.38%(0%–4.39%); spinal cord PRV: D_max 639(389–898) cGy). The skin doses in vivo were D_theory 208.85(203.16–212.53) cGy, D_fact 209.53(204.14–214.42) cGy, and |%diff| 1.77% (0.89–2.94%). Of the 360 patients enrolled in the skin side effect follow-up study (including the above 27 patients), grade 1 was the most common toxicity (321, 89.2%), some of which progressing to grade 2 or grade 3 (32, 8.9% or 7, 1.9%); the radiotherapy interruption rate was 1.1%.

Conclusion

A 3D-printed bolus can guarantee the precise radiation dose on skin surface, good fitness to skin, and controllable acute skin toxicity, which possesses a great clinical application value in postmastectomy chest call radiation therapy for breast cancer.

Patterns of Practice in Radiotherapy for Breast Cancer in Korea

Adjuvant radiotherapy (RT) is a well-established treatment for breast cancer. However, there is a large degree of variation and controversy in practice patterns. A nationwide survey on the patterns of practice in breast RT was designed by the Division for Breast Cancer of the Korean Radiation Oncology Group. All board-certified members of the Korean Society for Radiation Oncology were sent a questionnaire comprising 39 questions on six domains: hypofractionated whole breast RT, accelerated partial breast RT, postmastectomy RT (PMRT), regional nodal RT, RT for ductal carcinoma in situ, and RT toxicity. Sixty-four radiation oncologists from 54 of 86 (62.8%) hospitals responded. Twenty-three respondents (35.9%) used hypofractionated whole breast RT, and the most common schedule was 43.2 Gy in 16 fractions. Only three (4.7%) used accelerated partial breast RT. Five (7.8%) used hypofractionated PMRT, and 40 (62.5%) had never used boost RT after chest wall irradiation. Indications for regional nodal RT varied; ≥pN2 (n=7) versus ≥pN1 (n=17) versus ≥pN1 with pathologic risk factors (n=40). Selection criteria for internal mammary lymph node (IMN) irradiation also varied; only four (6.3%) always treated IMN when regional nodal RT was administered and 30 (46.9%) treated IMN only if IMN involvement was identified through imaging. Thirty-one (48.4%) considered omission of whole breast RT after breast-conserving surgery for ductal carcinoma in situ based on clinical and pathologic risk factors. Fifty-two (81.3%) used heart-sparing techniques. Overall, there were wide variations in the patterns of practice in breast RT in Korea. Standard guidelines are needed, especially for regional nodal RT and omission of RT for ductal carcinoma in situ.

Comparison of Radiotherapeutic Management of Operated Breast Cancer in 1999 and in 2006: A Sampling Survey on the Southeast Coast of China

Aims

To obtain a better understanding of the changes in radiotherapeutic management of breast cancer patients in the more developed areas of China over the past decade.

Methods

Four academic radiation therapy departments located on the Southeast Coast of China were selected for the study. The survey was conducted on female breast cancer patients who received radiotherapy in 1999 and 2006. The questionnaires were designed to determine the purposes of radiotherapy and to address the postoperative radiotherapy techniques used. The data for these two years were analyzed and compared.

Results

The percentage of breast-conserving treatment increased from 3% in 1999 to 13% in 2006, but the percentage of patients treated with postmastectomy radiotherapy dropped from 69% in 1999 to 66% in 2006 (P <0.05). As regards the changes in techniques from 1999 to 2006, the use of special immobilization devices, treatment planning systems, and CT simulations increased from 46% to 80%, 23% to 70%, and 0% to 14%, respectively (P <0.01). From 1999 to 2006, irradiation of the chest wall following mastectomy increased from 67% to 90%, but for internal mammary irradiation it decreased from 76% to 30% and for the axilla, from 69% to 37% (P <0.01). There were no obvious differences between 1999 and 2006 on the field design, boost treatment on the tumor bed, or dose prescription.

Conclusions

Breast-conserving treatment was performed more frequently in China in 2006 than in 1999, but postmastectomy radiotherapy did not change a great deal and it was still an essential option. Although the international treatment guidelines have been accepted and implemented by physicians in recent years, prompt improvement in the quality of breast cancer radiotherapy is needed.

Breast interest group faculty of radiation oncology: Australian and New Zealand patterns of practice survey on breast radiotherapy

INTRODUCTION

This patterns of practice study was conducted on behalf of the RANZCR Breast Interest Group in order to document current radiotherapy practices for breast cancer in Australia and New Zealand. The survey identifies variations and highlights potential contentious aspects of radiotherapy management of breast cancer.

METHODS

A fifty-eight question survey was disseminated via the Survey Monkey digital platform to 388 Radiation Oncologists in Australia and New Zealand.

RESULTS

In total, 156 responses were received and collated. Areas of notable consensus among respondents included hypofractionation (77.3% of respondents would 'always' or 'sometimes' consider hypofractionation in the management of ductal carcinoma in-situ and 99.3% in early invasive breast cancer); margin status in early breast cancer (73.8% believe a clear inked margin is sufficient and does not require further surgery) and use of bolus in post-mastectomy radiotherapy (PMRT) (91.1% of participants use bolus in PMRT). Areas with a wider degree of variability amongst respondents included regional nodal irradiation and components of radiotherapy planning and delivery (examples include the technique used for delivery of boost and frequency of bolus application for PMRT).

CONCLUSION

The results of these patterns of practice survey informs radiation oncologists in Australia and New Zealand of the current clinical practices being implemented by their peers. The survey identifies areas of consensus and contention, the latter of which may lead to a development of research trials and/or educational activities to address these areas of uncertainty.

Unintended irradiation of internal mammary chain - Is that enough?

AIM

To evaluate the unintentional coverage of the internal mammary chain (IMC) with tangential fields irradiation to the breast, and its relation with the type of surgery employed.

BACKGROUND

The dose distribution in regions adjacent to the treatment targets (mammary gland or chest wall), with incidental irradiation of the IMC, could translate into clinical benefit, due to the proximity of these regions.

MATERIALS AND METHODS

One hundred and twelve consecutive conformal radiotherapy plans were correlating the average dose to the IMC with the type of surgery employed, the extent of disease and the irradiation techniques.

RESULTS

The mean doses to IMC after modified radical mastectomy (MRM), modified radical mastectomy with immediate reconstruction (MRM + R), and breast conservative surgery (BCS) were 30.34 Gy, 30.26 Gy, and 18.67 Gy, respectively. Significant differences were identified between patients who underwent MRM or MRM + R over BCS (p = 0.01 and 0.003, respectively), but not between MRM and MRM + R (p = 0.88). Mean doses to IMC were greater in patients with T3-T4 tumors when compared with more initial stages (≤T2) (p = 0.0096). The lymph node involvement also correlated with higher average doses to IMC (node positive: 26.1 Gy × node negative: 17.8 Gy, p = 0.0017).

CONCLUSIONS

The moderate dose level to the IMC in the unintentional irradiation scenario seems to be insufficient to treat the subclinical disease, although it could have an impact in patients undergoing mastectomy.

Locoregional recurrence of pT3N0M0 breast cancer after mastectomy is not higher than that of pT1-2N0M0: an analysis for radiotherapy

The purpose of this study was to investigate the value of post-operative radiotherapy in the treatment of pT3N0M0 breast cancer after mastectomy. We analyzed the clinical data of 1390 patients with pT1-3N0M0 breast cancer who were admitted and treated from 1998 to 2007 at the Sun Yat-sen University Cancer Center. All patients underwent mastectomy and did not receive radiotherapy. The locoregional recurrence-free survival, distant metastasis-free survival and overall survival of different T stages of breast cancer were compared. The median follow-up duration was 72 months. The 10-year locoregional recurrence-free survival patients with pT1N0, pT2N0 and pT3N0 breast cancers were 95.3, 91.9 and 93.6%, respectively (χ(2) = 2.550, P = 0.279). The 10-year distant metastasis-free survival rates of patients with pT1N0, pT2N0 and pT3N0 breast cancers were 88.1%, 81.0% and 78.4%, respectively (χ(2) = 8.254, P = 0.016). The 10-year overall survival rates of patients with pT1N0, pT2N0 and pT3N0 breast cancers were 91.9%, 83.5% and 73.0%, respectively (χ(2) = 12.403, P = 0.002). Univariate analyses failed to identify any prognostic factors for locoregional recurrence in pT3N0 patients. Multivariate analysis showed that the T stage had no effect on locoregional recurrence. The locoregional recurrence rate in patients with pT3N0M0 breast cancer who underwent mastectomy and did not receive postoperative radiotherapy was not higher than that in patients with pT1-2N0M0 breast cancer who received the same treatment, suggesting that routine adjuvant post-operative radiotherapy should not be recommended in this patient population.

Epidemiologic study of compliance to postmastectomy radiation therapy guidelines in breast cancer patients in China between 1999 and 2008

PURPOSE

To evaluate compliance with postmastectomy radiation therapy (PMRT) guidelines in breast cancer patients in China over a 10-year period.

METHODS AND MATERIALS

A hospital-based, nationwide, multicenter retrospective epidemiologic study of primary breast cancer in women was conducted. Seven first-class, upper-level hospitals from different geographic regions of China were selected. One month was randomly selected to represent each year from 1999-2008 in every hospital. All inpatient cases within the selected months were reviewed and demographic, clinical, and pathologic characteristics and treatment patterns were collected. Patients enrolled in this study had to meet the following inclusion criteria: (1) treated with mastectomy and axillary dissection; (2) information regarding whether or not they received postmastectomy radiation therapy was available; and (3) information about staging was available. Patients were divided into 3 groups based on National Comprehensive Cancer Network guidelines. Utilization of PMRT in each group was analyzed and compared between different years and different hospitals.

RESULTS

A total of 2310 patients were analyzed. There were 643 (27.8%) patients in the PMRT recommended group, 557 (24.1%) patients in the controversial group, and 1110 (48.1%) patients in the nonrecommended group. PMRT was used in 48.8% of patients in the recommended group, 15.6% in the controversial group, and 5.7% in the nonrecommended group. There was a trend toward increasing use of radiation therapy in the recommended and controversial groups from 1999-2008. The use of PMRT in the nonrecommended group remained relatively stable from 1999-2008. Fewer positive nodes and nonreceipt of chemotherapy or hormone therapy were associated with underuse of PMRT in the recommended group. In the controversial group, a higher ratio of positive nodes was associated with use of PMRT.

CONCLUSIONS

There is an apparent underuse of PMRT in the PMRT recommended group. Efforts should be made to improve the compliance to PMRT guidelines.

Cancer control in developing countries: using health data and health services research to measure and improve access, quality and efficiency

Background

Cancer is a rapidly increasing problem in developing countries. Access, quality and efficiency of cancer services in developing countries must be understood to advance effective cancer control programs. Health services research can provide insights into these areas.

Discussion

This article provides an overview of oncology health services in developing countries. We use selected examples from peer-reviewed literature in health services research and relevant publicly available documents. In spite of significant limitations in the available data, it is clear there are substantial barriers to access to cancer control in developing countries. This includes prevention, early detection, diagnosis/treatment and palliation. There are also substantial limitations in the quality of cancer control and a great need to improve economic efficiency. We describe how the application of health data may assist in optimizing (1) Structure: strengthening planning, collaboration, transparency, research development, education and capacity building. (2) Process: enabling follow-up, knowledge translation, patient safety and quality assurance. (3) Outcome: facilitating evaluation, monitoring and improvement of national cancer control efforts. There is currently limited data and capacity to use this data in developing countries for these purposes.

Summary

There is an urgent need to improve health services for cancer control in developing countries. Current resources and much-needed investments must be optimally managed. To achieve this, we would recommend investment in four key priorities: (1) Capacity building in oncology health services research, policy and planning relevant to developing countries. (2) Development of high-quality health data sources. (3) More oncology-related economic evaluations in developing countries. (4) Exploration of high-quality models of cancer control in developing countries. Meeting these needs will require national, regional and international collaboration as well as political leadership. Horizontal integration with programs for other diseases will be important.

Adjuvant regional irradiation after breast-conserving therapy for early stage breast cancer: a survey of canadian radiation oncologists

AIMS

To document the use of adjuvant regional irradiation after breast-conserving therapy for early stage breast cancer by Canadian radiation oncologists and to identify the factors influencing their clinical decisions.

MATERIALS AND METHODS

We conducted a survey to assess the above aims. In April 2008, a questionnaire was sent to 167 members of the Canadian and Quebec Associations of Radiation Oncologists with interest in breast cancer management. The answers were obtained through a dedicated website, which collected the raw data collected for analysis.

RESULTS

In total, 67 radiation oncologists completed the survey, corresponding to a 40% response rate. Most respondents were experienced and high-volume providers. We identified several areas of variation in the decision-making regarding regional lymph node irradiation after breast-conserving therapy. Regarding the decision to combine regional nodal irradiation with irradiation of the breast, the number of positive nodes after axillary dissection (1-3 vs > or =4) was a crucial determinant. For patients with between one and three positive nodes and a nodal ratio of 50%, most respondents added regional irradiation. Similarly, the same nodal ratio of 50% was the main factor for inclusion of the axillary nodal region in the radiation field. However, few radiation oncologists have chosen to include the internal mammary chain in their treatment plan. The number of positive lymph nodes, the nodal ratio, the number of lymph nodes removed and the presence of extracapsular extension were the primary self-reported factors that directed the decision to offer regional radiotherapy.

CONCLUSIONS

This survey showed that there is a wide variation of practices among radiation oncologists in Canada. These results support the need for treatment guidelines and provide guidance on which factors should be included in a decision-making algorithm.