Dosimetric prospective study comparing 2D and 3D planning for irradiation of supraclavicular and infraclavicular regions in breast cancer patients

Exposure of the lungs in breast cancer radiotherapy: A systematic review of lung doses published 2010-2015

BACKGROUND AND PURPOSE

We report a systematic review of lung radiation doses from breast cancer radiotherapy.

METHODS AND MATERIALS

Studies describing breast cancer radiotherapy regimens published during 2010-2015 and reporting lung dose were included. Doses were compared between different countries, anatomical regions irradiated, techniques and use of breathing adaptation.

RESULTS

471 regimens from 32 countries were identified. The average mean ipsilateral lung dose (MLDipsi) was 9.0 Gy. MLDipsi for supine radiotherapy with no breathing adaption was 8.4 Gy for whole breast/chest wall (WB/CW) radiotherapy, 11.2 Gy when the axilla/supraclavicular fossa was irradiated, and 14.0 Gy with the addition of internal mammary chain irradiation; breathing adaptation reduced MLDipsi by 1 Gy, 2 Gy and 3 Gy respectively (p < 0.005). For WB/CW radiotherapy, MLDipsi was lowest for tangents in prone (1.2 Gy) or lateral decubitus (0.8 Gy) positions. The highest MLDipsi was for IMRT in supine position (9.4 Gy). The average mean contralateral lung dose (MLDcont) for WB/CW radiotherapy was higher for IMRT (3.0 Gy) than for tangents (0.8 Gy).

CONCLUSIONS

Lung doses from breast cancer radiotherapy varied substantially worldwide, even between studies describing similar regimens. Lymph node inclusion and IMRT use increased exposure, while breathing adaptation and prone/lateral decubitus positioning reduced it.

Technique and outcome of post-mastectomy adjuvant chest wall radiotherapy-the role of tissue-equivalent bolus in reducing risk of local recurrence

OBJECTIVE:

Adjuvant chest wall radiotherapy is used in patients with high-risk histological features post-mastectomy to reduce the risk of locoregional recurrence. Treatment can be given with or without a tissue-equivalent bolus to increase skin surface dose. The additional benefit of using a bolus remains unclear; however, it is known to be associated with a higher incidence of skin toxicity. This study compared chest wall recurrence and skin toxicity in patients treated with and without a bolus.

METHODS:

This retrospective cohort study reviewed 314 consecutive patients who received chest wall radiotherapy between 2005 and 2010. Data were collected on histological, demographic and treatment parameters and on the incidence and grade of acute skin reactions. Treatment outcomes analyzed included chest wall recurrence, disease-free survival and overall survival (OS).

RESULTS:

101 patients received treatment with a bolus; 213 patients received treatment without a bolus. A significantly higher incidence of acute skin toxicity was seen in the bolus treatment group (p = 0.002). One patient treated with a bolus developed chest wall recurrence compared with four patients treated without a bolus. No statistically significant difference could be shown between the two groups. 66 (21%) patients had metastatic relapse. Median time to relapse was 29.5 months and OS was 76% in both treatment groups.

CONCLUSION:

No statistically significant difference in chest wall recurrence can be demonstrated between patients treated with and without a bolus.

ADVANCES IN KNOWLEDGE:

This study is consistent with limited previous literature and invites further evaluation of the role of a bolus in post-mastectomy chest wall radiotherapy, especially considering the increased toxicity that the use of a bolus generates.