Two children in Japan ‘contracted’ their mothers’ cancer, in a rare medical phenomenon, reports of new cases.
They probably inhaled cancer cells from their mothers, each of whom unconsciously had cervical cancer.
Each child developed lung cancer years later.
A baby has to pass through the mother’s cervix during delivery and doctors think the cancer cells find their way into the amniotic fluid that surrounds the baby, which then inhales the cells when opening its mouth to breathe for the first time and cry .
It is extraordinarily rare – only 20 cases have been documented – and children have not been diagnosed for almost two and ten years after their respective births, the scientists reported in a case study in the New Ingland Journal of Medicine, published this month.
In rare cases, a baby can inhale cervical cancer cells that have drifted into the amniotic fluid in the birth canal, causing them to develop lung cancer years later.
Scientists estimate that about one in 500,000 mothers with cancer passes the disease to the baby during delivery.
And only one in 1,000 mothers has cancer during pregnancy in the first place.
Cervical cancer is the fourth most common cancer in women, affecting about 570,000 women a year and killing 311,000 worldwide.
And women are diagnosed at the average age of 50, with the majority of cases occurring between 35 and 44 years.
Doctors advise women to begin screening at age 25, through physical examinations and pap smears, but as cancer is not common during the most fertile years of women’s lives, it may not be the priority of those trying to conceive .
And almost half of all pregnancies – about 45% – have yet to be planned.
Therefore, women are often not tested through a prenatal examination before becoming pregnant.
Without it, cancer is difficult to detect.
In addition, even if a woman becomes pregnant while having cancer or is diagnosed with cancer during pregnancy, it is very rare that cancer affects her developing baby.
But there are, of course, exceptions – as was the case for the two children described in the case report.
There is no way to prove without a doubt that cancer was transmitted from mothers to babies, but there were some telltale signs.
On the one hand, the location of mothers’ cancers facilitated their transmission.
The cervix is located at the bottom of the uterus and at the top of the vaginal opening.
A baby develops in the womb, surrounded by amniotic fluid, which is like an insulating liquid to protect the baby and provide the mother with water, nutrients and other chemicals.
While in the womb, the baby does not breathe like adults. Instead, it absorbs oxygen through the umbilical cord and the placenta.
Therefore, even if the cervical tumor cells end up in the amniotic fluid, there is little opportunity to be transmitted to the baby.
But when the baby goes through the birth canal, there is a brief window of opportunity to inhale the amniotic fluid near the cervix, allowing tumor cells to enter the lungs.
The first child was diagnosed with lung cancer about 23 months after birth, when he developed a persistent cough.
After several rounds of chemotherapy, immunotherapy and surgery to remove a lobe from one of his lungs, the child finally went into remission and was cancer-free a year later.
Unfortunately, her mother’s cancer spread throughout her body and she died.
But before that, scientists sequenced genes in the mother and child tumors and saw a clear link between them, suggesting that the cancer had probably been transmitted from the mother to the 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 the age of six, he developed chest pain and was diagnosed with lung cancer as well.
Genomic sequencing showed that his tumor was also linked to that of the mother, and the tumor was positive for HPV, the STI that is a common cause of cervical cancer – but not lung tumors.
Together, this evidence suggested that he probably “got” his mother’s cancer.
The boy had to remove one of his lungs, but he was alive and without cancer 15 months later.