Q: Does pregnancy effect cancer progression?

A: Unlike endometriosis, cancer does not stop progressing during pregnancy. Pregnancy more often than not does not affect cancer progression. It was once thought that being pregnant with cancer was a reason to abort the fetus and start aggressive therapy for the cancer. Current research has found that aborting the fetus does not affect the progression of the cancer. Cancer treatment and the way the cancer is addressed during pregnancy is the only true deciding factor in how fast the cancer grows, in most cases.

There are some forms of cancer that do not follow these rules. These cancers grow more quickly as the estrogen and prolactin levels in the female body rise. Estrogen and prolactin are two hormones that increase during pregnancy. Even though these hormones can stimulate the growth of cancer, it is not always recommended to abort the fetus.
In cases where pelvic radiation or aggressive chemotherapy are needed to treat the cancer (most often when the cancer is quickly advancing) the fetus may be aborted in order to start cancer treatments. While this can be devastating to the mother, the oncologist will be able to assure the mother of the necessity for the abortion. If an aggressive cancer is not treated with the best possible treatment quickly, the mother may not live to see the birth of the baby.

Any woman who is being treated for cancer should use protection during intercourse. If the cancer patient becomes pregnant during treatment, the oncologist needs to know immediately. Depending on how far into the course of cancer treatment the patient is, the oncologist may choose (with the approval of the mother) to continue treatment in hopes of curing the cancer.