The American Society of Clinical Oncology (ASCO) recently released a new breast cancer follow-up and surveillance guideline update. The 2026 guideline update for Breast Cancer Follow-Up and Surveillance After Primary Treatment contains recommendations regarding surveillance groups, blood-based biomarkers, and supplemental surveillance imaging.

With a dozen recommendations, the 2026 ASCO guideline update presents reasonable options for patients depending on clinical circumstances and patient preference. The guideline will be updated when additional evidence-based tools become available to better support surveillance. For the complete look at the following recommendations, along with their accompanying qualifying statements, recommendation levels, and rationale, view the full-text version.

Intensity-Based Post-Treatment Surveillance
  • Low-Intensity Surveillance Group
    • Ductal carcinoma in situ (no endocrine therapy or off endocrine therapy)
    • Stage 1 HR-positive breast cancer (off endocrine therapy and any other systemic therapy after completion of treatment)
    • TNBC or HER2-positive breast cancer after at least five years from diagnosis.
  • Annual clinical visit, in person or via virtual consultation, by survivorship clinics or non-oncologists such as oncology advanced practice providers or within routine primary care or gynecology visits. Patients after breast-conserving surgery should be offered annual mammograms for the first 3 years after completion of treatment. Thereafter, surveillance mammography every 1-2 years is recommended for patients 50 years or older with low-risk features (T1, low-grade, node negative, estrogen receptor (ER)-positive tumors, who underwent BCS, and who are recurrence free at 3 years post diagnosis). The Expert Panel recommends annual surveillance mammography for patients less than 50 years old or with TNBC or HER2-positive tumors. Continued annual surveillance mammography is an option for patients who would prefer more frequent mammography after discussion with their clinician regarding the potential harms (e.g., increased anxiety due to false positive findings, further investigations for additional findings) and potential benefits (e.g., earlier detection of new or recurrent breast cancer reassurance, reduced anxiety) of annual mammographic surveillance.
  • Intermediate-Intensity Surveillance Group
    • Stage I TNBC or HER2-positive breast cancer within the first five years from diagnosis, stage II or stage III TNBC with pCR after completion of neoadjuvant therapy, stage II or stage III HER2-positive breast cancer with pCR after completion of neoadjuvant therapy
    • Patients on ongoing endocrine therapy (any stage, including those who did not achieve pCR)
    • Stage II or III ER-positive who did not take CDK 4/6 inhibitors or 5 years of endocrine therapy
    • Patients with HR-positive breast cancer on endocrine therapy who completed targeted adjuvant CDK4/6 inhibitor therapy, then transition to Low-Intensity group at the completion of endocrine therapy
  • Clinical follow-up (history and physical examination) with oncology team or cancer survivorship clinic every 6-12 months for 5-10 years after diagnosis. Following 5 years, patients can transition and be managed in the Low-Intensity group by survivorship clinics with advanced practice providers or non-oncologists, such as within routine primary care visits. Annual surveillance mammography is recommended for patients treated with breast-conserving surgery. For patients treated with unilateral mastectomy with or without reconstruction, annual contralateral surveillance mammography is indicated. For patients treated with bilateral mastectomy with or without reconstruction, mammography is not recommended unless warranted by clinical symptoms. For supplemental imaging, see Surveillance Imaging recommendations.
  • High-Intensity Surveillance Group
    • TNBC with residual disease after neoadjuvant chemotherapy and within 5 years of diagnosis
    • Patients with TNBC or HER2-positive breast cancer continuing on active systemic therapy
    • Patients with germline mutations (e.g., BRACA 1/2, PALB2)
    • HER2-positive breast cancer (any subtype) and within 10 years of diagnosis
    • Patients with hormone receptor-positive breast cancer on endocrine therapy and on CDK4/6 inhibitor therapy
  • After completing active treatment (e.g., targeted therapy, immunotherapy, other tha endocrine therapy), clinical follow-up (history and physical examination) with the oncology team every 3-6 months for up to ten years after diagnosis. Following that, patients can transition to the Low-Intensity group and be managed by survivorship clinics or non-oncologists such as within routine primary care visits. Annual surveillance mammography is recommended for patients treated with breast-conserving surgery. For patients treated with unilateral mastectomy with or without reconstruction, annual contralateral surveillance mammography is indicated. For patients treated with bilateral mastectomy with or without reconstruction, mammography is not recommended. Routine chest wall examinations are suggested every 6 months. For supplemental imaging, see Surveillance Imaging recommendations.
Use of Blood-Based Biomarkers in Breast Cancer
  • ASCO does not recommend routine blood tests like complete blood counts, chemistry panels, or tumor markers (CEA, CA 15-3, CA 27.29) for asymptomatic patients for the purpose of breast cancer surveillance.
  • ctDNA Recommendation (adapted from the ASCO ctDNA Testing Guideline): Fractional, percentage, or concentration-based measures of ctDNA or total cfDNA concentration are not recommended as a surrogate measure of disease burden to make treatment decisions outside the context of a clinical trial or clinical research. ctDNA testing cannot be recommended generally or, at this time, in any specific context for recurrence monitoring.
Supplemental Surveillance Imaging
  • Supplemental surveillance imaging with MRI may be offered and should be based on shared decision-making that considers individual patient characteristics (known germline mutation carriers, prior radiation therapy, additional factors in Recommendation 3.3.), the relative benefits (reducing interval cancers) and harms (anxiety due to false positive findings, increased fear of recurrence, further investigations for incidental findings, time toxicity and financial opportunity costs for patients and health systems) of more intensive surveillance, and patient preferences and values. There is no evidence to date for an overall survival benefit of MRI imaging in the post-treatment surveillance setting.
  • Other supplemental imaging options include contrast enhanced mammography or breast ultrasound for patients with heterogeneously or extremely dense breasts and other risk factors, which may be offered after discussion of the relative benefits and harms. There is no evidence to date for an overall survival benefit of these imaging modalities in the post-treatment surveillance setting.
  • Supplemental Imaging Recommendations:
    • Known germline mutation carriers and untested patients with first degree relatives with known germline mutations and intact breast tissue continue MRI* after primary breast cancer treatment; BRCA1, BRCA2, PTEN, STK11, TP53 Consider: ATM, BARD1, CDH1, CHEK2, NF1, PALB2, RAD51C, RAD51D
    • Radiation therapy with exposure to breast tissue, with intact breast tissue, continue MRI* after primary breast cancer treatment; Exposure between ages 10 and 30
    • Additional Factors: In the absence of above characteristics supporting supplemental MRI prior to breast cancer diagnosis, consider MRI* after completion of treatment for the following additional factors; Age at diagnosis <50, invasive lobular histology, primary breast cancer diagnosis within 12 months of a negative screening mammogram, primary breast cancer not detected on screening mammogram, heterogeneously or extremely dense breasts
    • Surveillance with contrast enhanced mammography if patient has contraindications to MRI, and ultrasound if contrast enhanced mammography is not available
    • Imaging surveillance for distant metastases is not recommended for the overall population of patients who have completed breast cancer treatment and who are asymptomatic.

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