Two children in Japan ‘caught’ cancer from their mothers, in a rare medical phenomenon, new case reports.
They likely inhaled cancer cells from their mothers, each of whom unwittingly had cervical cancer.
The children each developed lung cancer years later.
A baby has to pass through the mother’s cervix during childbirth and doctors think that cancer cells find their way into the amniotic fluid surrounding the infant, who then inhales the cells as they open their mouth to take their first breath and cry.
It’s extraordinarily rare – only 20 cases have been documented – and the children weren’t diagnosed for nearly two and 10 years after their respective births, scientists reported in a New ENgland Journal of Medicine case study, published this month.
In rare cases, a baby can inhale cervical cancer cells that have drifted into amniotic fluid in the birth canal, causing them to develop lung cancer years later
The scientists estimate that about one in every 500,000 mothers with cancer passes the disease on to her baby during childbirth.
And only one in every 1,000 mothers has cancer during pregnancy in the first place.
Cervical cancer is the fourth most common cancer for women, striking about 570,000 women a year and killing 311,000 worldwide.
And women are diagnosed at the average age of 50, with most cases occurring between ages 35 and 44.
Doctors advise that women start getting screened at age 25, via physical exams and pap smears, but because the cancer isn’t common during the most fertile years of women’s lives, so it may not be top-of-mind for those trying to conceive.
And nearly half of all pregnancies – about 45 percent – are still unplanned.
So women often don’t get screened via a prenatal exam before they become pregnant.
Without that, the cancer is hard to detect.
Plus, even if a woman gets pregnant while she has cancer or is diagnosed with cancer while pregnant, it’s very rare for the cancer to affect her developing baby.
But there are, of course exceptions – as was the case for the for the two children described in the case report.
There is no way to prove beyond a shadow of a doubt that cancer was transmitted from the mothers to the babies, but there were some tell-tale signs.
For one, the location of the mothers’ cancers made them easier to pass on.
The cervix is located at the bottom of the uterus, and at the top of the vaginal opening.
A baby develops in the uterus, surrounded by amniotic fluid, which is like liquid insulation to protect the baby, and provide it with water, nutrients and other chemicals form the mother.
While in the womb, a baby doesn’t breathe the way adults do. Instead, it absorbs oxygen through the umbilical cord and placenta.
So even if tumor cells from the cervix wind up in the amniotic fluid, there isn’t much opportunity for them to be transmitted to the baby.
But as the baby comes through the birth canal, there is a brief window of opportunity to inhale the amniotic fluid from near the cervix, allowing tumor cells to enter the lungs.
The first child was diagnosed with lung cancer about 23 months after his birth, when he developed a persistent cough.
After several rounds of chemotherapy, immunotherapy and surgery to remove a lobe of one of his lungs, the child eventually went into remission and was cancer free a year later.
Sadly, his mother’s cancer spread throughout her body and she eventually died.
But before then, scientists sequenced genes in the mother’s and child’s tumors, and saw a clear link between them, suggesting that the cancer had probably been transmitted from mother to baby.
The mother of the second child died when he was just two years old.
He showed no signs of illness for another four years, but at age six, developed chest pain and was diagnosed with lung cancer as well.
Genomic sequencing showed that his tumor, too, was linked to the mother’s, and the tumor was positive for HPV, the STI which is a common cause of cervical cancers – but not lung tumors.
Together, these pieces of evidence suggested that he probably ‘caught’ his mother’s cancer.
The boy had to have one of his lungs removed, but was alive and cancer-free 15 months later.