It’s hard to say if having a baby affects the growth of cancer cells. But patients need to understand the risk.

She walked into my room beaming from ear to ear.  “I’m pregnant!” she announced joyfully.

Eli was 33 years old when she was diagnosed to have stage II breast cancer in August 2006.

At that time, she had gone to see her local doctor when she noticed a lump in her left breast.  An ultrasound showed a tumour in her left breast with an enlarged lymph node in the armpit.

Upon hearing the diagnosis of possible cancer, she came to see me for a second opinion.

The lump in the breast measured about 2cm in size.  It was easily palpable.  I stuck a fine needle into the lump and aspirated some cells.  Within an hour, the pathologist confirmed that this was cancer.

Thankfully, investigations did not show any evidence of cancer spread.

As the tumour was small, she had the option of removing the whole breast (a mastectomy) or only removing the part of the breast with the cancer (partial mastectomy or wide excision).

As the lymph nodes were clinically involved, all the lymph nodes in the axilla had to be removed (axillary clearance) at the same time.

Eli opted for a wide excision with axillary clearance and this was carried out in August 2006.

The final pathology confirmed that the cancer was 2cm in size and only one out of the 17 axillary lymph nodes that were removed contained cancer cells.

The cancer cells stained positive for both estrogen and progesterone receptors.  This meant that the cancer cells were to some extent “driven” by hormones.

After the surgery, she went for eight cycles of chemotherapy.  She also received radiotherapy to the breast as this is a requirement for patients who have opted not to have a mastectomy.

By March 2007, Eli was essentially done with the major part of her treatment.

As Eli had hormone-receptor positive breast cancer, she was prescribed Tamoxifen, an anti-estrogen tablet, to be taken daily.  She came back for follow-up reviews every three to four months.

Tamoxifen was continued till March 2012 when we discussed various options.  One was to continue taking Tamoxifen and another was to switch to an enhanced hormone therapy which involved injections to stop her menses completely.  The last option was to stop hormone therapy and do nothing.

Eli had a son who was three and a half years old when Eli was first diagnosed to have breast cancer. The child was conceived after she had gone for IVF treatment.

One of the reasons Eli wanted to stop Tamoxifen after five years was because she was considering having a second child.

There was no certainty that she would be able to conceive again.  Factors against her getting pregnant included the fact that she had undergone extended chemotherapy, her age (she was already 40 years old) and the fact that she needed help to conceive the first time round when she was only 30 years old.

She told me of her pregnancy when she came for her follow-up visit in March 2014. Naturally, she was very happy. In July 2014, Eli gave birth to a baby girl.  With one boy and one girl, she felt blessed and complete.

In November 2014, she came back to see me after she stopped breast feeding, for her annual check-up which consisted of mammogram, chest x-ray, ultrasound and bone scan.  All was well.

Busy with the newborn baby, Eli missed her regular follow-up appointments and showed up only on June 2015.  At first, I wasn’t too perturbed by the delay.  After all, Eli had remained cancer-free for almost nine years since her surgery.

But the moment I felt her neck, I knew that there was trouble.

I felt two tiny lymph nodes, each measuring 0.5 cm in size just above her left collar bone.  When I broke the bad news that this could be cancer recurrence, Eli was shocked and devastated.

The diagnosis of cancer recurrence was confirmed on PET-CT scan and a fine needle aspiration of the lymph nodes showed cancer cells.

Eli is back on treatment again.

Why did this happen?  Isn’t cancer supposed to be cured after five years? Did her pregnancy cause her cancer to relapse?  How long does one need to wait before it is safe to conceive?

First, one must understand that despite the surgery, chemotherapy, radiotherapy and five years of Tamoxifen, we did not manage to eradicate all the breast cancer cells in Eli’s body. If we had eradicated all the cancer cells, Eli would not have relapsed.

Her pregnancy did not cause Eli to relapse.  However, her pregnancy is likely to have brought forward the time to relapse.  Even if Eli had not gotten pregnant, the likelihood is that some time in the future, she would still have relapsed.

The flush of hormones, during her pregnancy, may have played a part in driving the growth of the cancer cells which were already present in her body. Breast cancer is one of the malignancies well known to have the ability to relapse after five, 10 and even 15 years after initial diagnosis.

And yet there are many breast cancer survivors who have had children after completing their cancer treatment and never relapsed.

Does it mean that breast cancer survivors must never get pregnant?

No, I don’t think so.  But it is important for patients to understand the risks associated with pregnancy and choose for themselves what is important to them. For Eli, the focus now is not just on the why but on the need to get well, not just for herself, but for her two young children.

Written by Dr Ang Peng Tiam