8.1.2 Radiotherapy for Intraductal Carcinoma of th...
Patients with intraductal carcinoma of the breast have a higher rate of recurrence of ipsilateral breast tumors after breast-conserving surgery.Among them，50%of recurrent tumors are intraductal carcinoma and 50%are invasive carcinoma.Four randomized clinical studies have found that after intraductal cancer breast conserving surgery，radiotherapy has reduced the recurrence rate of ipsilateral breast tumors by half compared with non-radiotherapy，including reducing the recurrence rate of intraductal and invasive carcinomas，but did not improve overall survival.In all four studies，the whole breast was irradiated with a total dose of 50 Gy/5 weeks（the total dose of some patients in the SweDCIS study［1］was 54 Gy，with a 2 week rest）.In the NSABP B-17［2］and EORTO-10853 studies［3，4］，9%and 5%of patients in the radiotherapy group received a tumor bed supplement of 10 Gy，and no tumor bed replenishment was found in the SweDCIS and UKCCCR studies［5，6］.A meta-analysis of 3729 patients in the above 4 randomized studies showed that radiotherapy significantly reduced the recurrence rate of ipsilateral breast tumors.The 10-year ipsilateral breast tumor recurrence rates in the radiotherapy and non-radiation groups were 12.9%and 28.1%，respectively（P＜0.0000）.No subgroups were found who could not benefit from radiotherapy，including age＜50 and≥50，newly diagnosed tumors were detected by mammography or clinical symptoms，tumors were single or multifocal，tumors were low，medium or high graded.Local or resection of the operation，negative or positive margin，and the use of tamoxifen，postoperative breast-conserving radiotherapy can significantly reduce the recurrence rate of ipsilateral breast tumors.Even for patients with low grade，tumor size 1～20 mm，and negative margin，postoperative breast-conserving radiotherapy significantly reduced the recurrence rate of ipsilateral breast tumors in 10 years（30.1%and 12.1%，P=0.002）.Older patients benefit from the same local control in radiotherapy.The 10-year ipsilateral breast tumor recurrence rate of≥50 years old patients with radiotherapy and non-radiation was 10.8%and 27.8%，and the＜50-year-old patient had radiotherapy and 10 years of ipsilateral radiotherapy.The recurrence rate of breast tumors was 18.5%and 29.1%.Radiotherapy did not significantly reduce breast cancer mortality or total mortality compared with non-radiotherapy，nor did it significantly increase non-breast cancer mortality or heart disease mortality［7］.
The mortality rate of intraductal carcinoma of the breast is extremely low.NSABP B-17 and B-24 studies have shown that breast cancer mortality in the 15-year period is only 2.3%-4.7%.The recurrence of ipsilateral breast invasive carcinoma continued to increase after 15 years of surgery，and the recurrence of invasive cancer increased the risk of breast cancer death（HR=7.06）and total mortality（HR=1.75）.Radiotherapy significantly reduced the risk of recurrence of ipsilateral breast invasive carcinoma.The recurrence rate of ipsilateral invasive carcinoma in patients with simple breast-conserving surgery and postoperative radiotherapy was 19.4%and 8.9%，respectively.The recurrence of intraductal cancer continued to increase within 5 years after surgery，and the recurrence rate reached the platform after 5 years，but the recurrence of intraductal cancer did not affect the survival of the patient.The study found that age＜65，positive margin/unknown（vs margin negative），clinical detection（vs only mammography）is a high risk factor for invasive cancer recurrence［8］.The 15-year follow-up of the EORTC-10853 study also showed that the risk of breast cancer death in patients with ipsilateral breastinvasive cancer recurrence was 17 times higher than in patients without recurrence or intraductal cancer recurrence［4］.Solin et al reported that in the E5194 study，patients with non-radiotherapy after intraductal cancer breast-conserving surgery，12 gene scores can identify low-，medium-，and high-risk patients with recurrence.The 10-year local recurrence rates were 10.6%，26.7%，and 25.9%，respectively.The recurrence rate of invasive cancer was 3.7%，12.3%，and 19.2%（P≤0.006）［9］.Combined with clinical pathological factors and molecular markers，selection of high-risk patients with recurrence，especially high-risk patients with invasive cancer recurrence，can maximize the benefit of radiotherapy.(https://www.daowen.com)
Radiotherapy after breast-conserving surgery in patients with intraductal cancer is routinely segmented.Intraductal cancer patients with breast cancer after radiotherapy need to irradiate the whole breast 50Gy/25F，without the need to prevent lymph nodes in the irradiated area.There is no randomized evidence for the need for tumor bed replenishment after total breast irradiation.Irradiation is based on the extrapolation of the tumor bed after the retention of the breast in invasive cancer.patients is more extrapolated than the non-compensatory.Irradiation can further reduce the local recurrence rate.Retrospective studies have shown that intraductal carcinoma bed replenishment does not generally improve localization or survival，but young patients may benefit from tumor bed replenishment.At present，TROC07.01 and EORTC22085 are conducting phase Ⅲ randomized clinical trials on the need for postoperative radiotherapy for intraductal cancer to maintain postoperative radiotherapy.The results will provide a basis for treatment decisions.
There are few studies on partial breast irradiation after breast conserving surgery in patients with intraductal carcinoma of the breast.ASTRO partial breast irradiation consensus suggests that patients with intraductal cancer should be cautious with partial breast irradiation（tumor≤3cm）or unsuitable to do it（tumor＞3cm）.