The Effect of Clinical (Anatomical) and Prognostic Stage Groups on Survival in Patients Diagnosed with Breast Cancer: MULTI-Center Study Results, TROD Breast Cancer Study Group

PURPOSE/OBJECTIVE(S)

The American Joint Committee on Cancer (AJCC) anatomic stage groups have arguably been the most powerful method in predicting breast cancer outcomes. In the present study, we aimed to determine the differences between anatomical stage and clinical prognostic stage groups, which were obtained by adding biological markers such as histologic tumor grade, estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 status to patients diagnosed with breast cancer, the rate of change in stage, and the effect of stage change on survival.

MATERIALS/METHODS

The study protocol was sent to all radiation oncology centers in Türkiye. Four centers enrolled their patients to the study. A total of 1470 stage I-III breast cancer patients with complete information on biological markers (histologic tumor grade, hormone receptor, and c-erb B2 receptor status), haven't been treated with neoadjuvant therapy were included to the study and evaluated retrospectively. The 8th edition of AJCC consolidated biological markers in to clinical prognostic stage groups. Kaplan-Meier curves were used to estimate survival. The log-rank test was used to compare the difference between groups. The Cox proportional-hazards regression model was used to determine the association between anatomic-prognostic stage, disease-free survival (DFS), and overall survival (OS).

RESULTS

The median follow-up time was 82 (6-237) months. Median age of the patients was 52 years (20-88) and 865 cases (58.8%) were in the postmenopausal period. The axillary lymph node status was negative (N0) in 765 patients (52.1%). Tumor grade was grade I in 200 patients (13.6%), grade II in 812 patients (55.2%) and grade III in 452 patients (30.7%). Estrogen receptor status was positive in 1247 patients (84.8%), PR status was positive in 1178 patients and Her2-neu status was positive in 207 patients (14.1%). A stage change has been identified in a total of 777 patients (52.9%). Compared with the anatomic stage groups, application of the clinical prognostic stage groups assigned 46.4% cases lower and 6.5% cases higher stage. Five- and ten-year OS and DFS rates of the patients are 73.7%, 44.3% and 91.9%, 86.3% respectively. Age (p<0.001), tumor grade (p<0.001), ER status (p<0.001), PR status (p<0.001), cerbB2 receptor status (p = 0.025) were found to be statistically significant variables in multivariable analysis for OS. For DFS, multivariable analysis showed that age (p = 0.027), tumor grade (p = 0.005), anatomical stage (p<0.001) and assigned to higher stage (p = .001) were statistically significant variables.

CONCLUSION

Hormone receptors and c-erb B2 receptor status are independent variables which impact OS and DFS in our patient group which is mostly consisted of early-stage cases according to anatomical stage. In prognostic staging, upstaging stands out as an independent prognostic factor for DFS. The 8th edition of AJCC prognostic stage groups determines the prognosis much better in our patient cohort.

The Effect of Deep Inspiration Breath-Hold Technique on Right Coronary Artery, Heart, and Liver Doses in Right Breast Cancer Radiotherapy

PURPOSE/OBJECTIVE(S)

The deep inspiration breath-hold (DIBH) approach has been thoroughly researched with the aim of reducing radiation exposures to normal tissues in breast cancer patients. Although heart and lung toxicity are widely addressed in many literature, radiation-associated liver toxicity and dose constraints for the right coronary artery (RCA) are not well studied in relation to breast radiotherapy. Additionally, very few studies have investigated the relationship between doses to cardiac substructures. This study aimed to determine the effect of the DIBH technique on the right coronary artery (RCA) region, cardiac substructures, and liver dose in right breast cancer irradiation.

MATERIALS/METHODS

Between January 2022 and December 2022, thirty-five right breast cancer patients who previously received breast-surgery underwent computed tomography (CT) simulation with both free-breathing (FB) and DIBH techniques. Patients were contoured by a radiation oncologist on the scans using the Treatment Planning System. For cardiac substructures, reference atlas contours were used for accurate delineation and to reduce inter-observer variation. Each patient underwent two treatment plans for both the DIBH and FB datasets. The plan comprised the FB and DIBH techniques, and the doses to the cardiac substructures, ipsilateral lung, RCA region, and liver were compared using a two-tailed paired t-test. Radiotherapy was delivered with a Linac with the prescription dose of 50 Gy in 25 fractions.

RESULTS

For both FB and DIBH irradiation groups, the mean radiation doses to the ipsilateral lung, heart, and RCA region in patients with FB and DIBH techniques were; 14.67 Gy, 2.33 Gy, 4.88 Gy and 12.05 Gy, 1.34 Gy and 3.29 Gy respectively. The mean radiation doses to the cardiac substructures; for the left ventricle, right ventricle, left atrium, and right atrium for the FB were 1.08 Gy, 1.79 Gy, 4.11 Gy, and for DIBH, 0.49 Gy, 1.49 Gy, 0.95 Gy, and 2.61 Gy, respectively. For the DIBH group, the liver maximum dose (p<0.01), right lung mean dose (p = 0.001), heart maximum dose (p = 0.009), RCA mean dose (p = 0.020), RCA maximum dose (p = 0.008), RCA V5 dose (p = 0.035), right atrium maximum dose (p = 0.009) and right ventricle mean dose (p = 0.040) were significantly lower than in patients treated in the non-gated group.

CONCLUSION

DIBH resulted in considerable displacement of the liver away from the high-dose target region, such that the volume of liver in the high-dose region was reduced. Additionally, the use of the DIBH technique in right breast cancer irradiation effectively reduces the radiation doses to the cardiac substructures, such as the left ventricle, right ventricle, left atrium, right atrium, RCA region, and lungs. DIBH could lead to substantial sparing of these structures with the right breast cancer radiotherapy. Future prospective studies are required to determine whether improvements to dose-distribution will translate into improved toxicity outcomes.

Comparing ultrasound with computerized tomography images to choose electron energy for radiotherapy boost field in breast cancer patients with breast conserving surgery

PURPOSE

To compare ultrasonographic (US) with computerized tomographic (CT) images in order to choose electron energy for radiotherapy (RT) boost field in patients with breast conserving surgery (BCS).

METHODS

Thirty-seven consecutive patients with breast cancer treated by BCS and RT in our department were evaluated. Median age was 49 years (range 32-82). According to the Dokuz Eylul Breast Tumor Group Protocol (DEBTG), in patients with BCS, RT (5000 cGy to the whole breast ± lymphatic area) and boost with electron energy to the primary tumor bed (1000 cGy if surgical margin negative, or 1600 cGy if surgical margin positive was delivered. Before January 2003, the distances between skin-the deepest point of tumor bed (STD), skin-clips (SCD), and skin-fascia (SFD) were measured with US to choose electron energy in boost field. Since then, CT simulation images were used to this purpose. These two imaging systems were compared in this study. Electron energy was selected after measurement of the deepest metallic clips in CT simulation images (90%) or measurement of the STD if no clips were present (10%).

RESULTS

Median measurements with US and CT were as follows: STD: US 12 mm (range 4-35), CT 28 mm (range 2-54); SFD: US 25 mm (range 6-57), CT 31 mm (range 2-93); SCD: US 14 mm (range 7-26), CT 29 mm (range 2-68). The median electron energy was 9 MeV é (range 6-12) for US and 12 MeV é (range 6-21) for CT. Concordance in US and CT measurements was 27%.

CONCLUSION

This preliminary study reveals that CT-based SCD measurements are deeper than US measurements, and selected electron energy with CT is 3 MeV higher than US. These two factors can affect local control and side effects. We noticed only one local recurrence in 37 patients. We did not evaluate side effects in this study. These could be a subject of a future study.

Evaluation of contralateral breast skin doses by thermoluminescent dosimeters of patients receiving adjuvant radiotherapy for breast cancer

PURPOSE

It is reported that low dose radiation received by the contralateral breast (CLB) during adjuvant radiotherapy (RT) is carcinogenic. This trial was planned to evaluate the CLB skin doses received during adjuvant RT of breast carcinoma.

PATIENTS AND METHODS

Twenty-four breast carcinoma patients treated locally or locoregionally with adjuvant RT were included. RT was performed with only tangential fields (TA) in 6 patients whereas 9 patients had an extra internal mammary (IM) field (TAIM). The remaining 9 patients received 5-field locoregional RT (5FLR). All patients were treated with wedge filters except for 3 TA patients. Of 9 5FLR patients IM fields were treated with Co60 in 5 and with electrons in the remaining 4 patients. LiF(2)-based Ribbon type thermoluminescent dosimeters (TLD) were used for dose evaluation. An average of 10 TLD's, placed with 1 cm gaps beginning from the medial border of the treatment field along the central axis were used to obtain dose measurements. Median measure of TLD's between 2-8 cm and maximum dose point (MDP) values in the same range were used to evaluate the CLB dose.

RESULTS

In TA patients the CLB skin received 6.3% of the total dose in patients treated with wedge filters and 7.13% with half-beam blocks. For 6 TAIM patients with IM fields treated with Co60, the CLB dose was 7.24%. In 5 of 9 5FLR patients, whose IM fields were treated with Co60 the CLB skin received 8.8% of the total dose, while for electron beam therapy the CLB dose was 5.44%. CLB median MDP values were as follows: 12.76% in TA patients treated with wedge filters and 11.45% with half-beam blocking; 11.89% in TAIM patients with IM fields treated with Co60 and 7.83% with electron beams; 12.29% in 5FLR patients of whose IM fields were treated with Co60 and 8.94% with electron beams.

CONCLUSION

When compared to wedge filters, halfbeam blocks caused 13% increase in CLB doses. If IM fields were added, 27.5% and 62% increases at CLB doses were established with Co60 when compared to electron beam RT in 3-field and 5-field treatments, respectively. CLB doses increased by 15-40% with the increased number of treatment fields. MDP values were also found to be higher with IM fields treated with Co60, but the number of treatment fields and accessories used seemed to have no effect on MDP doses. We conclude that by using wedge filters instead of half-beam blocks and by increasing the number of fractions treated with electron energies for IM fields, apparent decreases in CLB doses can be obtained. Large number of cases is needed to statistically establish the significant differences between subgroups.

Detection of bilateral multifocal breast cancer using Tc-99m sestamibi imaging. The role of delayed imaging

PURPOSE

Early determination that breast cancer is bilateral and multifocal can change therapy strategy and, subsequently, mortality and morbidity rates. The authors present a case with bilateral, multifocal breast cancer detected only by Tc-99m sestamibi imaging.

METHODS

Early and delayed Tc-99m sestamibi imaging and dynamic MRI were performed in a patient with a right-sided lesion shown on mammography.

RESULTS

Although early Tc-99m sestamibi imaging detected bilateral breast cancer foci, both dynamic MRI and mammography missed the lesion in the left breast. Additional lesions seen on delayed Tc-99m sestamibi images of the left breast, which were initially thought to be benign, completely disappeared after concomitant chemotherapy and radiotherapy, suggesting multifocal malignant lesions in the left breast.

CONCLUSION

This case suggests that Tc-99m sestamibi may be useful for detecting bilateral cancer, and delayed imaging may give additional information regarding the possible multifocal nature of the disease.