Early contralateral shoulder-arm morbidity in breast cancer patients enrolled in a randomized trial of post-surgery radiation therapy

Abstract

Introduction: Shoulder/arm morbidity is a common complication of breast cancer surgery and radiotherapy (RT), but little is known about acute contralateral morbidity.

Methods: Patients were 118 women enrolled in a RT trial. Arm volume and shoulder mobility were assessed before and 1-3 months after RT. Correlations and linear regression were used to analyze changes affecting ipsilateral and contralateral arms, and changes affecting relative interlimb differences (RID).

Results: Changes affecting one limb correlated with changes affecting the other limb. Arm volume between the two limbs correlated (R = 0.57). Risk factors were weight increase and axillary dissection. Contralateral and ipsilateral loss of abduction strongly correlated (R = 0.78). Changes of combined RID exceeding 10% affected the ipsilateral limb in 25% of patients, and the contralateral limb in 18%. Aromatase inhibitor therapy was significantly associated with contralateral loss of abduction.

Conclusions: High incidence of early contralateral arm morbidity warrants further investigations.

Keywords: breast cancer-related lymphedema; early breast cancer; image-guided radiation therapy; short-course radiation therapy; shoulder/arm morbidity.

Figures

Figure 1

Distributions of the pre- to post-radiotherapy changes (Δ) of the relative interlimb differences (RID).

Figure 2

Correlations among ipsilateral shoulder-arm changes. Notes: ΔI. = changes observed on the ipsilateral limb after breast radiotherapy, for measurements of abduction (abd.), retroflexion (retroflx.), anteflexion (anteflx.), endorotation (endo.), scapular distance (sc.dist.), and volume (vol.). Ellipses: 95% confidence density. Red colored ellipses indicate statistically significant correlations (P ≤ 0.05).

Figure 3

Correlations among contralateral shoulder-arm changes. Notes: ΔC. = changes observed on the contralateral limb after breast radiotherapy, for measurements of abduction (abd.), retroflexion (retroflx.), anteflexion (anteflx.), endorotation (endo.), scapular distance (sc.dist.), and volume (vol.). Ellipses: 95% confidence density. Red colored ellipses indicate statistically significant correlations (P ≤ 0.05).

Figure 4

Correlations between ipsilateral and contralateral shoulder-arm changes. Notes: Changes observed on the ipsilateral (ΔI.) and contralateral (ΔC.) limb after breast radiotherapy, for measurements of abduction (abd.), retroflexion (retroflx.), anteflexion (anteflx.), endorotation (endo.), scapular distance (sc.dist.), and volume (vol.). Ellipses: 95% confidence density. Red colored ellipses indicate statistically significant correlations (P ≤ 0.05).

Figure 5

Distribution of volume relative interlimb difference (RID) at baseline and after radiotherapy (RT). Notes: Top graph: At baseline pre-radiotherapy, 21% of the patients presented with limb edema, as defined by a volume RID of ≥5%. These patients are represented as blue bars. Bottom graph: Pre-radiotherapy, some patients improved (shift of the blue bars toward 0), some worsened (increase up to RID > 30). The dark green bars are patients who had no ipsilateral limb edema at baseline. The net result Pre-radiotherapy is an incidence of 24% patients with ipsilateral limb edema, composed of patients who had persistent edema (blue), minus those whose edema resolved, but incremented by patients with new onset of ipsilateral edema (dark green). Conversely, at baseline 17% of the patients presented with contralateral limb edema, shown as brown bars. Pre-radiotherapy, the incidence of contralateral limb edema is 18%. The 18% is composed of patients with prior contralateral edema that did not resolve (brown), incremented by patients with new onset of contralateral edema (yellow).