Some Older Breast Cancer Patients Could Skip Radiation
On the basis of the IHC results and microarray analysis, tumors were assigned to six categories:
luminal A
luminal B
luminal-HER2
HER2 enriched
basal-like
triple-negative phenotype-nonbasal
The patients included in the tissue analysis included 145 participants from the tamoxifen arm and 159 from the tamoxifen-radiotherapy arm.
The lowest rate of recurrence in both treatment arms was observed in patients with luminal A tumors (ER- or PR-positive, HER2-negative, and Ki-67
<14%). In those 133 patients, the recurrence rate was 8% with tamoxifen alone and 4.6% with tamoxifen and radiotherapy, a nonsignificant difference (P=0.3).
Liu and colleagues then looked at combinations of characteristics among patients with luminal A tumors.
Among 103 women who were 60 or older, the recurrence rate was 4.3% with tamoxifen alone and 6% with multimodality adjuvant therapy (P=0.9). The 114 women with grade I-II luminal A tumors had a recurrence rate of 4.9% with tamoxifen and 5.5% with tamoxifen plus radiotherapy (P=0.9).
In contrast, the 82 patients with luminal B tumors (Ki-67>
14%) had a recurrence rate of 16.1% with tamoxifen, declining to 3.9% when radiation therapy was administered (P=0.05). Tumors in the three remaining categories had even higher rates of recurrence with tamoxifen alone, although each category comprised a small number of women.
Side effects after treatment
The radiotherapy may have some lasting effects on your skin and any breast tissue left behind after breast conserving surgery. You may find that you have
Firmer breast tissue
Shrinking of breast tissue
Swelling of the breast area
Small red marks on your skin
Darker skin
For most women the appearance of the breast is very good after radiotherapy. But if you are concerned about the possible side effects, you can speak to your radiotherapist or breast care nurse.
Though preliminary, an analysis based on six tumor markers showed that “older luminal A patients with grade I/II tumors demonstrated the lowest risk of breast relapse, for which RT had minimal impact, suggesting that such patients could be managed with tamoxifen alone,” Liu and colleagues concluded in their presentation at the meeting.
Breast cancer radiotherapy - Long term side effects
By far the most common long term side effects of radiotherapy are the change in appearance described above.
Some women get a swelling in the arm called lymphoedema after radiotherapy to the armpit, particularly if they have had surgery there too. These days, specialists do not recommend having both surgery and radiotherapy to the armpit because of the increased risk of lymphoedema. But surgery and radiotherapy to the armpit may both be needed if the lymph nodes there contain cancer cells.
Other more severe, but much rarer, long term side effects may occur. They are not common though, because treatment planning is very exact these days.
Rarely, you can get a continuing cough or breathlessness some years after radiotherapy to the chest. This is due to the radiotherapy causing changes in the lung tissue called radiation fibrosis. Doctors cannot predict who will get this rare side effect.
Some people who have radiotherapy to the left side of their chest may have changes in their heart many years later. But this is very rare.
Women having radiotherapy for breast cancer are often treated from more than one angle. In the past, sometimes part of the shoulder was treated twice – once from each angle. Doctors call that overlapping treatment fields. Nerves in the shoulder were sometimes badly damaged by having a high radiotherapy dose. That caused severe pain and difficulty in using the arm. These days, modern radiotherapy planning includes checks for overlapping radiation fields and so this should not happen.
“It is of note that this subgroup represents a significant proportion of women in this trial - 133 of 304, or 43%,” they said. “In contrast, breast radiation therapy remains beneficial for women with higher-risk subtypes.”
Primary source: American Association for Cancer Research
Source reference: Shi W, et al. “Postmenopausal women with luminal A subtype might not require beast radiotherapy: Preliminary results from a randomized trial of tamoxifen ± radiation” AACR 2012;abstract 1032.