Pattern of Distribution of Metastatic Lesions within Skeleton in Patients with Breast Carcinoma of Faisalabad and its Vicinity

Abstract

Objectives: Evaluation of pattern of distribution of skeletal metastases in patients with breast carcinoma. by using ^99mTc MDP Skeletal Scintigraphy Design: Retrospective Analysis Place and Duration of Study: Study was conducted at Punjab Institute of Nuclear Medicine (PINUM), Faisalabad Pakistan from January 2006 to June 2009. Material and Methods: A retrospective study was performed on 465 consecutive patients having CA Breast irrespective of preoperative/postoperative status, presenting for bone scan at Punjab Institute of Nuclear Medicine. Whole body bone scan was performed, along with additional spot views, where needed. The images were interpreted for metastatic deposits by three independent observers. Where needed, plain X-ray was performed to correlate in favor of benign pathology. Results: Out of 465 patients (453 female & 12 Male), 286 (62%) patients were having either normal bone scan or some benign pathology as correlated with plain x-ray of the suspected area. 179 (38%) patients were positive for metastases within skeleton. Among these, 61.4% patients were having multiple, 14% with two, while 24.6% were diagnosed as having solitary lesions within the skeleton. In patients having multiple skeletal lesions, highest number was noted in spine (84.5%- most  common  in  thoracolumbar), followed by ribs

 (55.5%), pelvis (37.3%---most frequent in iliac bone), skull (32%), scapula (27.3%), sternum (26.4%), femur (19.1%), humerus (14.5%), clavicle (3.6%) and tibia (0.9%). In humerus and femur, most lesions were located in their upper ends, followed by shafts. Right side of skeleton was more frequently involved than the left. In patients having lesions in ribs and pelvis, most of the lesions were bilateral. Patients with two lesions showed maximum number of lesions in rib cage (44%), followed by spine (32%-all being in thoracolumbar region), scapula (24%), pelvis & scapula (24% in each), sternum (16%), skull (8%), humerous and femur (4% in each). In patients having solitary focal lesion, highest number was noted in spine (45.5%-most common in thoracolumbar spine), followed by ribs (22.7%), sternum & pelvis (13.6% each), and skull (6.8%).  No lesion was noted in appendicular skeleton. Conclusion: Multiple skeletal metastases are much more common than solitary or two lesions in cases of known breast carcinoma. Axial skeleton including skull is most commonly involved. Spine (especially thoracolumbar) is the most frequent site of involvement followed by rib cage, pelvis and then skull. In peripheral bones, most frequent site is the upper end of femur followed by humerus.