BACKGROUND: The long-term effects of radiotherapy on mortality from breast cancer and other causes remain uncertain. METHODS: A meta-analysis was done of 10-year and 20-year results from 40 unconfounded randomised trials of radiotherapy for early breast cancer. It involved central review of individual patients' data on recurrence and cause-specific mortality from 20000 women, half with "node-positive" disease. Radiotherapy fields generally included not only chest wall (or breast) but also axillary, supraclavicular, and internal mammary nodes. FINDINGS: A reduction of approximately two-thirds in local recurrence was seen in all trials, largely independent of the type of patient or type of radiotherapy (8.8% vs 27.2% local recurrence by year 10). Hence, to assess effects on breast cancer mortality of substantially better local control, results from all trials were combined. Breast cancer mortality was reduced (2p=0.0001) but other, particularly vascular, mortality was increased (2p=0.0003), and overall 20-year survival was 37.1% with radiotherapy versus 35.9% control (2p=0.06). There was little effect on early deaths, but logrank analyses of later deaths indicate that, on average after year 2, radiotherapy reduced annual mortality rates from breast cancer by 13.2% (SE 2.5) but increased those from other causes by 21.2% (SE 5.4). Nodal status, age, and decade of follow-up strongly affected the ratio of breast cancer mortality to other mortality, and hence affected the ratio of absolute benefit to absolute hazard from these proportional changes in mortality. INTERPRETATION: Radiotherapy regimens able to produce the two-thirds reduction in local recurrence seen in these trials, but without long-term hazard, would be expected to produce an absolute increase in 20-year survival of about 2-4% (except for women at particularly low risk of local recurrence). The average hazard seen in these trials would, however, reduce this 20-year survival benefit in young women and reverse it in older women.
BACKGROUND: The long-term effects of radiotherapy on mortality from breast cancer and other causes remain uncertain. METHODS: A meta-analysis was done of 10-year and 20-year results from 40 unconfounded randomised trials of radiotherapy for early breast cancer. It involved central review of individual patients' data on recurrence and cause-specific mortality from 20000 women, half with "node-positive" disease. Radiotherapy fields generally included not only chest wall (or breast) but also axillary, supraclavicular, and internal mammary nodes. FINDINGS: A reduction of approximately two-thirds in local recurrence was seen in all trials, largely independent of the type of patient or type of radiotherapy (8.8% vs 27.2% local recurrence by year 10). Hence, to assess effects on breast cancer mortality of substantially better local control, results from all trials were combined. Breast cancer mortality was reduced (2p=0.0001) but other, particularly vascular, mortality was increased (2p=0.0003), and overall 20-year survival was 37.1% with radiotherapy versus 35.9% control (2p=0.06). There was little effect on early deaths, but logrank analyses of later deaths indicate that, on average after year 2, radiotherapy reduced annual mortality rates from breast cancer by 13.2% (SE 2.5) but increased those from other causes by 21.2% (SE 5.4). Nodal status, age, and decade of follow-up strongly affected the ratio of breast cancer mortality to other mortality, and hence affected the ratio of absolute benefit to absolute hazard from these proportional changes in mortality. INTERPRETATION: Radiotherapy regimens able to produce the two-thirds reduction in local recurrence seen in these trials, but without long-term hazard, would be expected to produce an absolute increase in 20-year survival of about 2-4% (except for women at particularly low risk of local recurrence). The average hazard seen in these trials would, however, reduce this 20-year survival benefit in young women and reverse it in older women.
Authors: Eleftherios P Mamounas; Stewart J Anderson; James J Dignam; Harry D Bear; Thomas B Julian; Charles E Geyer; Alphonse Taghian; D Lawrence Wickerham; Norman Wolmark Journal: J Clin Oncol Date: 2012-10-01 Impact factor: 44.544
Authors: G K B Halkett; M O'Connor; S Aranda; M Jefford; T Shaw; D York; N Spry; M Taylor; P Schofield Journal: Support Care Cancer Date: 2013-02-05 Impact factor: 3.603
Authors: R B Goody; J O'Hare; K McKenna; L Dearey; J Robinson; P Bell; J Clarke; J J A McAleer; J M O'Sullivan; G G Hanna Journal: Br J Radiol Date: 2013-02 Impact factor: 3.039
Authors: Chang-Lung Lee; Hooney Min; Nicholas Befera; Darin Clark; Yi Qi; Shiva Das; G Allan Johnson; Cristian T Badea; David G Kirsch Journal: Int J Radiat Oncol Biol Phys Date: 2014-03-01 Impact factor: 7.038