CBCN cheat sheet

Average lifetime risk of invasive breast cancer in US women is about 12.9% (roughly 1 in 8); pathogenic BRCA1 carriers face approximately 55-72% lifetime risk and BRCA2 carriers about 45-69%.

A Gail (BCRAT) 5-year risk of 1.67% or higher is the usual threshold for discussing chemoprevention (tamoxifen, raloxifene, exemestane) in women aged 35 and older without LCIS or DCIS.

A Tyrer-Cuzick (IBIS) lifetime risk of 20-25% or higher is a common threshold for adding annual breast MRI to mammographic screening.

Risk-increasing factors include menarche before age 12, menopause after age 55, nulliparity or first live birth after age 30, atypical hyperplasia, LCIS, dense breasts, postmenopausal obesity, alcohol use of one or more drinks daily, and five or more years of combined hormone therapy.

Risk-reducing salpingo-oophorectomy in BRCA carriers lowers breast cancer risk by roughly 50% and ovarian cancer risk by more than 80%; risk-reducing mastectomy lowers breast cancer risk by about 90-95%.

LCIS is a marker of increased bilateral breast cancer risk of about 1% per year rather than a direct precursor lesion; management is surveillance with or without chemoprevention.

Spontaneous bloody unilateral nipple discharge warrants duct imaging or ductoscopy; bilateral milky discharge suggests hyperprolactinemia and a serum prolactin level is the first test.

About 75% of breast lymph drains to the axillary nodes; Cooper's ligaments suspend the breast and the Tail of Spence extends upper-outer breast tissue into the axilla.

ACS recommends annual mammography beginning at age 40; USPSTF recommends biennial mammography through age 74; screening generally stops when life expectancy is under 10 years.

BI-RADS categories: 0 incomplete, 1 negative, 2 benign, 3 probably benign (under 2% malignant, short-interval follow-up), 4A/4B/4C increasing suspicion, 5 highly suggestive (95% or greater), 6 biopsy-proven malignancy.

Annual MRI plus mammography is indicated for lifetime risk of 20-25% or higher, including BRCA carriers, chest radiation before age 30, Li-Fraumeni syndrome, and TP53 mutation carriers.

Diagnosis uses triple assessment: clinical examination, imaging, and tissue sampling; core needle biopsy is preferred over fine-needle aspiration because it preserves architecture and permits receptor testing.

AJCC T categories: T1 is 2 cm or less, T2 is greater than 2 to 5 cm, T3 is greater than 5 cm, T4 is any chest wall or skin involvement; N1 is movable ipsilateral axillary nodes; M1 disease is stage IV.

Stage IIA includes T2N0 and T1N1; stage IIIA includes T0-2N2; inflammatory carcinoma (T4d) is at least stage IIIB.

Sentinel lymph node biopsy is standard for clinically node-negative disease; ACOSOG Z0011 supports omitting completion axillary dissection for 1-2 positive sentinel nodes treated with breast conservation and whole-breast radiation.

Nottingham histologic grade (3-9) combines tubule formation, nuclear pleomorphism, and mitotic count; grade 3 is associated with a worse prognosis.

ER and PR are reported as percentages (Allred or H-score); HER2 positivity is IHC 3+ or in situ hybridization amplification; Ki-67 reflects proliferation.

Breast-conserving surgery plus radiation yields survival equivalent to mastectomy (NSABP B-06); the accepted margin is no ink on tumor.

Whole-breast radiation is delivered in 25-30 standard fractions or 15-16 hypofractionated fractions; a tumor-bed boost lowers local recurrence in higher-risk patients.

Tamoxifen is given for 5-10 years in premenopausal ER-positive disease; risks include venous thromboembolism, endometrial cancer, and hot flashes, and concurrent paroxetine or fluoxetine should be avoided (CYP2D6 inhibition).

Aromatase inhibitors (anastrozole, letrozole, exemestane) are effective only in postmenopausal ER-positive disease; bone density should be monitored and bone loss treated with bisphosphonates or denosumab.

Anthracyclines such as doxorubicin cause dose-dependent cardiotoxicity; LVEF is monitored at baseline and during therapy, and dexrazoxane serves as a cardioprotectant.

Trastuzumab and pertuzumab require baseline and every-3-month LVEF checks; the agent is held for clinically significant LVEF decline.

Taxanes cause peripheral neuropathy and myelosuppression; the absolute neutrophil count nadir occurs about 7-14 days after chemotherapy administration.

CDK4/6 inhibitors cause neutropenia (palbociclib, ribociclib, abemaciclib); ribociclib prolongs QTc and abemaciclib causes diarrhea, so CBC and ECG monitoring are required.

PARP inhibitors (olaparib, talazoparib) are used for germline BRCA1/2-associated disease and cause anemia, neutropenia, and fatigue.

Febrile neutropenia is a single oral temperature of 38.3 °C or higher, or 38.0 °C sustained for one hour, with an ANC below 500/µL; blood cultures and empiric broad-spectrum antibiotics should start within 60 minutes.

Prophylaxis for highly emetogenic chemotherapy is a 5-HT3 antagonist plus dexamethasone plus an NK-1 receptor antagonist, with olanzapine often added.

A distress thermometer score of 4 or higher on the 0-10 scale triggers referral to psychosocial services; PHQ-9 screens for depression.

Anthracycline extravasation antidote is dexrazoxane: stop the infusion, aspirate residual drug, apply cold compresses for anthracyclines and vinca alkaloids, and give dexrazoxane promptly.

Taxane-induced peripheral neuropathy is managed by dose reduction or delay; duloxetine has evidence for painful chemotherapy-induced peripheral neuropathy.

For hot flashes in tamoxifen users, venlafaxine or gabapentin is preferred; paroxetine and fluoxetine are avoided because they inhibit CYP2D6 and lower endoxifen levels.

Malignant hypercalcemia is treated with intravenous isotonic saline plus an IV bisphosphonate such as zoledronic acid, with monitoring of calcium and renal function.

Vaginal dryness from endocrine therapy is managed with nonhormonal moisturizers and lubricants; vaginal estrogen is avoided in ER-positive disease unless specifically discussed.

Mucositis care includes saline or sodium bicarbonate rinses, consistent oral hygiene, and pain control; alcohol-based mouthwashes are avoided.

A survivorship care plan contains the treatment summary, surveillance schedule, late-effect screening, and health-promotion recommendations, and is provided at the end of active treatment.

Post-treatment surveillance is history and physical every 3-6 months for 3 years, then every 6-12 months to year 5, with annual mammography; routine tumor markers, bone scans, and CT scans are not recommended in asymptomatic patients.

Fertility preservation referral should occur before gonadotoxic chemotherapy; options include oocyte or embryo cryopreservation and GnRH agonist ovarian suppression.

Fear of recurrence, body image concerns, and sexual dysfunction are the most common survivorship psychosocial concerns and should be screened at follow-up visits.

Multidisciplinary coordination includes tumor board review, nurse navigator support, and shared decision-making, all of which improve guideline concordance and adherence.

Early palliative care integrated with oncology care improves quality of life; hospice eligibility generally requires a prognosis of 6 months or less if the disease follows its natural course.