title: Comparison of acute skin reaction following morning versus late afternoon radiotherapy in patients with breast cancer who have undergone curative surgical resection.
abstract: We investigated the relationship between the time of radiotherapy (RT) and treatment outcomes in breast cancer. Patients with pathologic T1-2N0-1 breast cancer who received adjuvant RT in the morning (before 10:00 AM) or late afternoon (after 3:00 PM) were eligible for inclusion in this study. We retrospectively compared the clinicopathologic characteristics, acute skin reaction, and survival outcomes according to the time of RT. The median follow-up duration was 83 months (range, 10-131 months). From the 395 eligible patients, 190 (48.1%) and 205 (51.9%) patients were classified into the morning RT group and the afternoon RT group, respectively. The clinicopathologic characteristics were relatively well balanced between the treatment groups, except for pathologic N-stage (P = 0.0409). Grade 2 or higher acute skin reaction according to the Radiation Therapy Oncology Group criteria was observed in 39 (9.9%) patients, with a higher frequency in the afternoon RT group than the morning RT group (13.7% vs 5.8%, respectively; P = 0.0088). There was no difference in the failure patterns or survival outcomes between the treatment groups. RT in late afternoon was associated with increased Grade 2 or more skin reaction after RT for breast cancer patients, but treatment outcomes did not differ according to the time of RT. Individualized considerations for treatment should be taken into account to reduce the risk of skin reactions.
authors.affiliation: Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, #50 Irwon-dong, Gangnam-gu, Seoul 135-710, Republic of Korea.
authors.forename: Jae Myoung
authors.initials: JM
authors.lastname: Noh
authors.forename: Doo Ho
authors.initials: DH
authors.lastname: Choi
authors.forename: Hyojung
authors.initials: H
authors.lastname: Park
authors.forename: Seung Jae
authors.initials: SJ
authors.lastname: Huh
authors.forename: Won
authors.initials: W
authors.lastname: Park
authors.forename: Seung Won
authors.initials: SW
authors.lastname: Seol
authors.forename: Bae Kwon
authors.initials: BK
authors.lastname: Jeong
authors.forename: Seok Jin
authors.initials: SJ
authors.lastname: Nam
authors.forename: Jeong Eon
authors.initials: JE
authors.lastname: Lee
authors.forename: Won-Ho
authors.initials: WH
authors.lastname: Kil
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000401:mortality* / Q000503:physiopathology / Q000628:therapy*; D015984:Causality; D002940:Circadian Rhythm; D015897:Comorbidity; D062109:Dermatologic Surgical Procedures / Q000401:mortality*; D005260:Female; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D011855:Radiodermatitis / Q000401:mortality* / Q000503:physiopathology; D018714:Radiotherapy, Adjuvant / Q000401:mortality; D056910:Republic of Korea; D012189:Retrospective Studies; D018570:Risk Assessment; D015996:Survival Rate; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
keywords: breast cancer; circadian rhythm; radiation-induced dermatitis; radiotherapy