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.

Linkage relationships between ALPL, ENO1, GPI, PGD, and TGFB1 on porcine chromosome 6

A five-point linkage map has been established between the loci encoding liver/bone/kidney alkaline phosphatase (ALPL), enolase 1-alpha (ENO1), glucose-phosphate isomerase (GPI), phosphogluconate dehydrogenase (PGD), and transforming growth factor beta 1 (TGFB1) in swine. Linkage analysis was performed using the Meishan x Yorkshire three-generation reference pedigree at the University of Illinois (n = 91). Previously ENO1, GPI, PGD, and TGFB1 were mapped to porcine chromosome 6q by in situ hybridization but the linkage relations of TGFB1 and ENO1 with other loci in this group were not investigated. Based on mapping data from human chromosomes 1 and 19 and mouse chromosomes 4 and 7, it was postulated that ALPL should reside among or near these loci. Restriction fragment length polymorphisms were identified for ALPL, ENO1, and TGFB1. GPI (EC 5.3.1.9) and PGD (EC 1.1.1.44) phenotypes were determined by agarose gel electrophoresis of isozymes. Marker data were analyzed using the MLINK (two locus) and ILINK (multilocus) programs from LINKAGE (version 5.10). The most likely locus order between GPI-TGFB1-(PGD-ENO1)-ALPL with recombination rates of 0.049, 0.044, 0.000, and 0.156, respectively, could not be significantly determined. The maximum five-point lod score was the same to four decimal places irrespective of the order of ENO1 and PGD. This indicates that ENO1 and PGD are very closely linked and that ALPL is located telomeric to the established linkage group on pig chromosome 6.