A study tried to offer more information on whether women who have mastectomy to remove early-stage breast cancer (stage I or stage II) can benefit from radiation therapy after surgery. Unfortunately, there isn't a clear answer.
Radiation therapy is used after lumpectomy to remove early-stage breast cancer to lower the risk of the cancer coming back (recurrence). Research has shown that lumpectomy followed by radiation therapy is a good alternative to mastectomy for many women.
Still, many women choose to have mastectomy instead of lumpectomy. Because mastectomy removes the whole breast (as opposed to lumpectomy which removes only the cancer tumor and a portion of tissue around it), many women who have mastectomy don't have radiation therapy after surgery. But if the cancer has spread to the underarm lymph nodes, cancer experts have recommended that radiation therapy be considered after mastectomy:
- if cancer cells are in four or more lymph nodes, radiation is almost always given
- if cancer cells are in one to three lymph nodes, radiation is often given
Recommendations about using radiation therapy after mastectomy are based on studies done from 1964 to 1984. Since that time, breast cancer care has improved. We now have earlier diagnosis, better surgery methods, and better approaches to treatment. Because of advances in breast cancer care, researchers wanted to look at recurrence risk after mastectomy in more recent years and how much lymph node involvement affected that risk.
The researchers looked at the medical records of 1,019 women diagnosed with stage I or stage II (early-stage) breast cancer between 1997 and 2002. All the women had mastectomy and had from zero to three lymph nodes involved:
- 74% had zero positive lymph nodes
- 17% had one positive lymph node
- 7% had two positive lymph nodes
- 2% had three positive lymph nodes
Most of the women (77%) got chemotherapy, hormonal therapy, or both after mastectomy. None of the women had radiation therapy after surgery.
After about 10 years, only 2.3% of the women had a breast cancer recurrence after mastectomy. The risk of recurrence seemed to be somewhat linked to the number of positive lymph nodes:
- 2.1% for women with zero positive lymph nodes
- 3.3% for women with one positive lymph node
- 7.9% for women with two positive lymph nodes
The number of women with three positive nodes was too small to analyze.
The very small difference in recurrence risk between women with zero positive lymph nodes and women with one positive node wasn't statistically significant, which means it could be due to chance and not because of the difference in the number of positive lymph nodes.
The recurrence risk for women with two positive lymph nodes was significantly higher than recurrence risk for women with one or zero positive nodes, which means the difference was likely due to the larger number of positive nodes. Still, the 7.9% risk of recurrence is much lower than the 20% to 25% recurrence rates found in earlier studies looking at recurrence risk after mastectomy.
Recurrence risk after mastectomy also was significantly higher for women age 40 and younger compared to women who were older than 40.
Because the risk of recurrence was lower in this study than in older studies, the researchers suggested that routinely giving radiation therapy after mastectomy to remove early-stage breast cancer to women older than 40 who had zero to three positive lymph nodes may not make sense. It does seem clear that radiation therapy after mastectomy is very important for women younger than 40 with positive lymph nodes.
Other breast cancer experts feel that more research is needed before changing the recommendations about using radiation therapy after mastectomy to remove early stage-breast cancer in women with one to three positive lymph nodes.
If you've been diagnosed with early-stage breast cancer, you and your doctor will decide on the type of surgery -- lumpectomy or mastectomy -- that makes the most sense for you. If lumpectomy is your choice, it's very likely that your doctor will recommend radiation therapy after surgery. If mastectomy is your choice, you and your doctor will consider a number of factors, including:
- your age
- cancer stage
- number of lymph nodes involved
that can influence your risk of recurrence as you decide if radiation therapy after surgery makes sense for you and your unique situation.