Do I Need Chemotherapy for Stage 1A Breast Cancer with Ki-67 at 30%?

In stage 1A breast cancer with a Ki-67 index of 30%, is chemotherapy necessary?

Hello, Doctor! I just underwent a lumpectomy, and the postoperative pathology report indicates that the original tumor size was 1.3 cm, with ER positive, 80% PR positive, 70% HER-2 positive, and Ki-67 negative at 30%.
Previously, during the core needle biopsy, the report showed ER positive, 85% PR positive, 30% HER-2 positive, Ki-67 negative at 18%, and Grade 1.
The sentinel lymph nodes showed no metastasis in the first three nodes.
I am unsure why there are discrepancies in the data above.
Which set of results holds more reference value? Given that Ki-67 is at 30%, is chemotherapy definitely required? If I only undergo radiation therapy combined with hormone therapy and receive an aromatase inhibitor, would that be sufficient to prevent recurrence? (Before the surgery, I took Tamoxifen for 1-2 weeks, and the tumor noticeably shrank before the lumpectomy.) What do the above data indicate regarding low or high recurrence risk? I look forward to your analysis and clarification.
Thank you!

Amily, 40~49 year old female. Ask Date: 2023/03/12

Dr. Chen Sirong reply Oncology

Amily / 46 years old / Female
Hello!
1.
Does the data above indicate a low or high risk of recurrence? I calculated the IHC4 score, and the postoperative specimen is 1.89, while the core needle biopsy specimen is 1530.
Both are classified as intermediate malignancy.
It is recommended to conduct genetic testing to determine whether chemotherapy is necessary.
If you are unwilling to undergo genetic testing (which is out-of-pocket), you may consider chemotherapy.
2.
I am unsure why there is a discrepancy in the data above.
Which one is more valuable for reference?
A: The difference may be due to the use of medication; the surgical specimen should be larger.
The IHC4 results indicate intermediate malignancy, showing no significant difference.
3.
Since the Ki-67 is 30%, is chemotherapy absolutely necessary? If I only undergo radiation therapy + hormone therapy + menopause injections, would that be sufficient to prevent recurrence?
A: Do not focus solely on one number; consider the IHC4 calculated results.
The five-year survival rate for Stage I is approximately 97% (with treatment as recommended by the physician).
However, for Stage IA breast cancer, even without chemotherapy, the chance of not recurring should still be greater than 50%.
The success rate after chemotherapy can be as high as 97%.
How you perceive the success rate and the side effects of chemotherapy is a personal decision you must make.

Wishing you good health,
Chen Si-Rong, Taoyuan Hospital

Reply Date: 2023/03/12

More Info

When considering whether chemotherapy is necessary for Stage 1A breast cancer with a Ki-67 index of 30%, several factors must be taken into account. Stage 1A breast cancer typically indicates a small tumor (up to 2 cm) that has not spread to lymph nodes. The Ki-67 index is a measure of how quickly cancer cells are dividing and can provide insight into the aggressiveness of the tumor. A Ki-67 of 30% is considered moderately high, suggesting that the tumor has a significant growth rate.

In your case, the tumor characteristics are as follows:
- Tumor size: 1.3 cm
- Estrogen Receptor (ER): Positive (80%)
- Progesterone Receptor (PR): Positive (70%)
- HER2: Positive (30%)
- Ki-67: 30%
- Grade: 1
- No lymph node metastasis (negative sentinel lymph node biopsy)
The presence of hormone receptors (ER and PR positive) indicates that the cancer may respond well to hormone therapy, which is a standard treatment for hormone receptor-positive breast cancers. The HER2 positivity also suggests that targeted therapies, such as trastuzumab (Herceptin), may be beneficial.

The decision to administer chemotherapy often depends on a combination of factors, including the tumor's characteristics, the patient's overall health, and the potential benefits versus risks of chemotherapy. In general, chemotherapy is more commonly recommended for higher-grade tumors, larger tumors, or those with a higher Ki-67 index, as these factors are associated with a greater risk of recurrence.

In your case, the tumor is classified as Grade 1, which typically indicates a lower risk of recurrence. However, the Ki-67 index of 30% raises some concern, as it suggests a more aggressive behavior than what would be expected from a Grade 1 tumor. This discrepancy may warrant further evaluation, such as genomic testing (e.g., Oncotype DX or MammaPrint), which can help assess the risk of recurrence and guide treatment decisions.

If you choose not to undergo chemotherapy, the combination of radiation therapy and hormone therapy (along with any necessary medications for menopausal symptoms) could be sufficient to manage the risk of recurrence, especially given the low stage of the cancer and the absence of lymph node involvement. However, it is essential to have a thorough discussion with your oncologist about the potential benefits and risks of chemotherapy in your specific case.

Regarding the differences in the pathology reports, variations can occur due to several factors, including the timing of the biopsy, the effects of preoperative treatments (like tamoxifen), and the inherent variability in tumor biology. The most recent surgical pathology report is generally considered more reliable, as it reflects the tumor's characteristics after any treatment.

In summary, the decision to proceed with chemotherapy should be made collaboratively with your healthcare team, considering all the factors mentioned above. It is crucial to weigh the potential benefits of chemotherapy against its side effects and to consider your personal preferences and values in the decision-making process.

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