The implication of hot spots on bone scans within the irradiated field of breast cancer patients treated with mastectomy followed by radiotherapy.
OBJECTIVE
To analyze the implication of abnormal hot spots in the irradiated field of patients treated with mastectomy followed by radiotherapy for breast cancer.


METHODS
We reviewed 1842 consecutive bone scans performed on 292 patients treated with a modified radical mastectomy and followed by radiotherapy. If abnormal hot spots at the irradiated sites were detected in the bone scans, we evaluated further studies to determine whether bone metastases were present. Radiation was given using 4 or 6 MV X-rays at a dosage of 50.4 Gy during 5.5 weeks with a dosage per fraction of 1.8 Gy. The follow-up period was 25-136 months (median 57 months).


RESULTS
Sixty patients (20.6%) developed bone metastasis. Solitary rib metastases were identified in four patients; all were detected outside of the irradiated field. Of 232 patients who did not develop bone metastases, hot spots in the irradiated field were detected in 30 patients (12.9%). A simple rib fracture at the site of a hot spot was demonstrated in four patients. The cumulative incidence of hot spots at 5 years was 12.9%. The cumulative incidence of hot spots was more common in postmenopausal women, patients who were less than 60 kg, patients who received adjuvant hormonal therapy and patients who had radiation that included the supraclavicular area.


CONCLUSIONS
We confirmed that the hot spots within the irradiated fields might be benign, especially in patients who were postmenopause, had a low body weight, received adjuvant hormonal therapy and who had radiation that included the supraclavicular area.
Park
Won
W
Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Ilwon-dong 50, Gangnam-gu, Seoul, 135-710, Korea.
Huh
Seung Jae
SJ
Yang
Jung Hyun
JH
Nam
Seok Jin
SJ
Kim
Jeong Han
JH
Choi
Joon Young
JY
Woo
Sook Young
SY
Kim
Hae Young
HY
Noh
Jae Myoung
JM
Ryu
Jung Il
JI
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001859:Bone Neoplasms / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000556:secondary*; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000628:therapy*; D015897:Comorbidity; D005260:Female; D006801:Humans; D015994:Incidence; D007723:Korea; D008408:Mastectomy / Q000706:statistics & numerical data*; D008875:Middle Aged; D011379:Prognosis; D011877:Radionuclide Imaging; D018714:Radiotherapy, Adjuvant / Q000706:statistics & numerical data*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D012680:Sensitivity and Specificity; D016896:Treatment Outcome