Higher Per Daily Treatment-Dose Radiation Therapy or Standard Per Daily Treatment Radiation Therapy in Treating Patients With Early-Stage Breast Cancer That Was Removed by Surgery

OBJECTIVES:

Primary

- To determine whether an accelerated course of hypofractionated whole-breast irradiation
(WBI) including a concomitant boost to the tumor bed in 15 fractions following
lumpectomy will prove to be non-inferior in local control to a regimen of standard WBI
with a sequential boost following lumpectomy for early-stage breast cancer patients.

Secondary

- To determine whether breast-related symptoms and cosmesis from accelerated WBI that is
hypofractionated (in only 3 weeks) with a concomitant boost is non-inferior to standard
WBI with sequential boost.

- To determine whether the risk of late cardiac toxicity in patients with left-sided
breast cancer treated with hypofractionation will be non-inferior to conventional
fractionated radiation therapy (RT) based upon analysis of radiation dosimetry from
CT-based treatment planning and NTCP calculations.

- To determine whether CT-based conformal methods intensity-modulated radiation therapy
(IMRT) and three-dimensional conformal radiotherapy (3D-CRT) for WBI are feasible in a
multi-institutional setting following lumpectomy in early-stage breast cancer patients
and whether dose-volume analyses can be established to assess treatment adequacy and
likelihood of toxicity.

- To determine that cosmetic results and breast-related symptoms 3 years after
hypofractionated breast radiation with concomitant boost will not be inferior to that
obtained 3 years after WBI with sequential boost.

- To determine whether future correlative studies can identify individual gene expressions
and biological host factors associated with toxicity and/or local recurrence from
standard and hypofractionated WBI.

- If shown to be non-inferior, to then determine if accelerated course of hypofractionated
WBI including a concomitant boost to the tumor bed in 15 fractions following lumpectomy
will prove to be superior in local control to a regimen of standard WBI with a
sequential boost following lumpectomy for early-stage breast cancer patients.

- To determine whether treatment costs for hypofractionated WBI with concomitant boost are
not higher than WBI with sequential boost.

OUTLINE: This is a multicenter study. Patients are stratified according to age (< 50 vs. ≥ 50
years), prior chemotherapy (yes vs. no), estrogen-receptor status (+ vs. -), and histology
grade (1-2 vs. 3). Patients are randomized to 1 of 2 treatment arms. Treatment begins within
9 weeks of last surgery or chemotherapy delivery.

- Arm I: Patients undergo standard whole-breast radiotherapy (WBI) comprising
intensity-modulated radiation therapy (IMRT) or three-dimensional conformal radiotherapy
(3D-CRT) 5 days a week for 3-5 weeks followed by a sequential radiotherapy boost to the
lumpectomy area 5 days a week for 1-1½ weeks. Treatment continues in the absence of
disease progression or unacceptable toxicity.

- Arm II: Patients undergo accelerated hypofractionated WBI comprising IMRT or 3D-CRT with
a concurrent boost to the lumpectomy area 5 days a week for 3 weeks. Treatment continues
in the absence of disease progression or unacceptable toxicity.

Patients' tissue samples may be collected for future research studies.

After completion of study therapy, patients are followed at 1 month, at 6 months, and then
yearly.

DISEASE CHARACTERISTICS:

- Pathologically proven diagnosis of breast cancer resected by lumpectomy and
whole-breast irradiation (WBI) with boost without regional nodal irradiation planned

- Must meet one of the following three criteria:

- pStage I or II breast cancer AND at least one of the following:

- Age < 50 years or

- Positive axillary nodes or

- Lymphovascular space invasion (LVI) or

- At least 2 close resection margins (> 0 mm to ≤ 2 mm) or

- One close resection margin and extensive in-situ component (EIC) or

- Focally positive resection margins or

- Non-hormone-sensitive breast cancer (estrogen and progesterone receptor
negative (ER- and PR-) or

- Grade III histology or

- Oncotype recurrence score > 25 or

- pStage 0 breast cancer with nuclear grade 3 ductal carcinoma in situ (DCIS) and
patient age < 50 years or

- If multifocal breast cancer, then it must have been resected through a single
lumpectomy incision with negative margins

- Breast-conserving surgery with margins defined as follows:

- Negative margins defined as no tumor at the resected specimen edge

- Close resection margins > 0 mm to ≤ 2 mm as follows:

- One close resection margin and EIC

- Two or more close resection margins

- A focally positive resection margin

- Allowable options for mandatory axillary staging include:

- Sentinel node biopsy alone (if sentinel node is negative, pN0, pN0[IHC-,+])

- Sentinel node biopsy alone, OR followed by axillary node dissection, for
clinically node-negative patients as described below:

- Microscopic sentinel node (SN) positive (pN1mic)

- One or two SNs positive (pN1) without extracapsular extension

- Negative SN biopsy after neoadjuvant chemotherapy

- Axillary node dissection is required following SN biopsy with a minimum total of
6 axillary nodes if any of the following exist:

- For > 2 positive SN

- Any positive SN biopsy after neoadjuvant chemotherapy

- For clinically (by either imaging or examination) T3 disease

- For extracapsular extension

- Axillary dissection alone (with a minimum of 6 axillary nodes)

- CT-imaging of the ipsilateral breast within 28 days of study entry for the radiation
treatment planning.

- Must be able to delineate on CT scan the extent of the target lumpectomy cavity
for boost (placement of surgical clips to assist in treatment planning of the
boost is strongly recommended)

- No clinical evidence for distant metastases, based upon the following minimum
diagnostic workup:

- History/physical examination, including breast exam (inspection and palpation of
the breasts) and documentation of weight and Zubrod Performance Status of 0-2
within 28 days prior to study entry

- A mammogram of both right and left breast within only 1 time point of 90 days of
the diagnostic biopsy establishing the diagnosis

- No prior invasive or in-situ carcinoma of the breast (prior LCIS is eligible)

- No American Joint Committee on Cancer (AJCC) pathologic T4, N2 or N3, or M1 breast
cancer

- Must not have two or more breast cancers that are not resectable through a single
lumpectomy incision

- Must not be DCIS and ≥ 50 years old

- Must not be DCIS only (without an invasive component), nuclear grade 1 or 2 and < 50
years old

- No suspicious unresected microcalcification, densities, or palpable abnormalities (in
the ipsilateral or contralateral breast) unless biopsied and found to be benign

- No non-epithelial breast malignancies such as sarcoma or lymphoma

- No Paget disease of the nipple

- No male breast cancer

- Breast implants allowed

PATIENT CHARACTERISTICS:

- ANC ≥ 1,800/mm³

- Platelet count ≥ 75,000/mm³

- Hemoglobin ≥ 8.0 g/dL (transfusion or other intervention to achieve Hgb ≥ 8.0 g/dL is
acceptable)

- Negative urine or serum pregnancy test within 14 days of study entry

- Women of childbearing potential must not be pregnant or nursing and willing to use
medically acceptable form of contraception during radiotherapy

- No prior invasive non-breast malignancy (except non-melanomatous skin cancer or
carcinoma in situ of the cervix) unless disease free for a minimum of 5 years prior to
study entry

- No severely active co-morbidity, defined as follows:

- Unstable angina and/or congestive heart failure requiring hospitalization within
the last 6 months

- Transmural myocardial infarction within the past 6 months

- Acute bacterial or fungal infection requiring intravenous antibiotics at the time
of registration

- Chronic obstructive pulmonary disease exacerbation or other respiratory illness
requiring hospitalization or precluding study therapy within 30 days before
registration

- Hepatic insufficiency resulting in clinical jaundice and/or coagulation defects;
note, however, that laboratory tests for liver function and coagulation
parameters are not required for entry into this protocol

- Acquired Immune-Deficiency Syndrome (AIDS) based upon current CDC definition

- HIV testing is not required for entry into this protocol

- No active systemic lupus, erythematosus, or any history of scleroderma or
dermatomyositis with active rash

- Medical, psychiatric, or other condition that would prevent the patient from receiving
the protocol therapy or providing informed consent

PRIOR CONCURRENT THERAPY:

- See Disease Characteristics

- Study entry must be within 50 days of last breast/axillary surgery and/or last
chemotherapy

- No treatment plan that includes regional-node radiotherapy

- No prior radiotherapy to the breast or prior radiation to the region of the
ipsilateral breast that would result in overlap of radiation therapy fields

- No intention to administer concurrent chemotherapy for current breast cancer