Treatment of bilateral breast cancer and regional nodes using an opposed lateral beam arrangement

Mind the Gap: Recurrence of Oligometastatic Breast Invasive Ductal Carcinoma in the Sternal Gap of Two Tangential Photon Fields of Bilateral Whole Breast Irradiation a Decade Later

Despite bilateral breast cancer being a rare clinical entity compared to unilateral breast cancer, both share a treatment paradigm of breast-conserving therapy for limited disease and metastasis direct therapy for oligometastatic disease. We present a case of left breast invasive ductal carcinoma in the setting of original bilateral breast cancer, now with oligometastatic recurrence to the soft tissue of the sternum, notably in an area not previously irradiated, over a decade later.

A Dosimetric and Radiobiological Comparison of Intensity Modulated Radiotherapy, Volumetric Modulated Arc Therapy and Helical Tomotherapy Planning Techniques in Synchronous Bilateral Breast Cancer

OBJECTIVE

The present investigation intends to identify the optimal radiotherapy treatment plan for synchronous bilateral breast cancer (SBBC) using dosimetric and radiobiological indexes for three techniques, namely, helical tomotherapy (HT), volumetric modulated arc therapy (VMAT), and intensity-modulated radiotherapy (IMRT).

METHODS

Twenty SBBC treated female patients treatment planning data (average age of 52.5 years) were used as the sample for the present study. Three different plans were created using 50 Gy in a 25 fraction dose regime. Poisson, Niemierko, and LKB models were applied for calculating normal tissue complication probability (NTCP) and tumour control probability (TCP).

RESULT

The target average dose comparison between IMRT with HT and VMAT with HT was highly substantial (P=0.001). The percentage of TCP for IMRT, VMAT, and HT in the Poisson model were 93.70±0.28, 94.68±0.30, and 94.34±0.57, respectively (p<0.05). The dose maximum was lower for the whole lung in the HT plan, with an average dose of 49.31Gy±3.9 (p<0.009). The NTCP values of both Niemierko and LKB models were lower for the heart, lungs, and liver for the IMRT plan.

CONCLUSION

The sparing of organs at risk was higher in the HT plan dosimetrically, and the TCP was higher in the three techniques. The comparison between the three techniques shows that the IMRT and HT techniques could be considered for treating SBBC.

Synchronous bilateral chest wall irradiation with regional nodal irradiation: A literature review of techniques and a case study

The optimal radiotherapy technique for patients requiring both breasts or chest walls simultaneous irradiation with or without regional nodal irradiation is currently under investigation. In the last decade several publications present case reports and case series of patients treated with adjuvant radiotherapy in both breasts or chest walls for synchronous bilateral breast cancer (SBBC) with modern radiotherapy techniques. This article presents a systematic review of relevant literature as well as a case report of a SBBC patient who received bilateral chest wall radiotherapy with regional nodal irradiation at our institution with Truebeam - Edge Linear Accelerator. Solid evidence is provided that the practice of avoiding adjuvant radiotherapy in SBBC out of fear of toxicity with older radiotherapy techniques is outdated. Modern techniques can safely and effectively deliver treatment to patients requiring both sides irradiation and even in mastectomy patients in need of regional nodal irradiation.

Intensity Modulated Proton Therapy for Bilateral Breast or Chest Wall and Comprehensive Nodal Irradiation for Synchronous Bilateral Breast Cancer: Initial Clinical Experience and Dosimetric Comparison

Purpose

Synchronous bilateral breast cancer (SBBC) poses distinct challenges for radiation therapy planning. We report our proton therapy experience in treating patients with SBBC. We also provide a dosimetric comparison of intensity modulated proton therapy (IMPT) versus photon therapy.

Methods and Materials

Patients with SBBC who received IMPT at our institution were retrospectively analyzed. The clinical target volume (CTV) included the breast or chest wall and comprehensive regional lymph nodes, including axilla, supraclavicular fossa, and the internal mammary chain. Intensity modulated proton therapy and volumetric modulated arc therapy (VMAT) plans were generated with the goal that 90% of the CTV would recieve at least 90% of the prescription dose (D90>=90%). Comparisons between modalities were made using the Wilcoxon signed rank test. Physician-reported acute toxic effects and photography were collected at baseline, end of treatment, and each follow-up visit.

Results

Between 2015 and 2018, 11 patients with SBBC were treated with IMPT. The prescription was 50 Gy in 25 fractions. The median CTV D90 was 99.9% for IMPT and 97.6% for VMAT (P = .001). The mean heart dose was 0.7 Gy versus 7.2 Gy (P = .001), the total lung mean dose was 7.8 Gy versus 17.3 Gy (P = .001), and the total lung volume recieving 20 Gy was 13.0% versus 27.4% (P = .001). The most common acute toxic effects were dermatitis (mostly grade 1-2 with 1 case of grade 3) and grade 1 to 2 fatigue. The most common toxic effects at the last-follow up (median, 32 months) were grade 1 skin hyperpigmentation, superficial fibrosis, and extremity lymphedema. No nondermatologic or nonfatigue adverse events of grade >1 were recorded.

Conclusions

Bilateral breast and/or chest wall and comprehensive nodal IMPT is technically feasible and associated with low rates of severe acute toxic effects. Treatment with IMPT offered improved target coverage and normal-tissue sparing compared with photon therapy. Long-term follow-up is ongoing to assess efficacy and toxic effects.