gynaecologic

Cancers that grow from placental tissue after a pregnancy. They make a hormone (hCG) that acts as a perfect blood test, and they were the first solid cancer ever cured by chemotherapy. Immunotherapy now rescues the few that resist drugs.

High-risk gestational trophoblastic neoplasia is the aggressive form of this pregnancy-related cancer, usually choriocarcinoma that has spread to the lungs, liver or brain and produces very high hCG. It is treated with the multi-drug EMA-CO regimen, started gently in the sickest women to avoid early deaths, and most are cured; resistant disease gets platinum regimens, immunotherapy or surgery.

HPV-associated vulvar cancer is the type of vulvar squamous cell cancer caused by persistent HPV infection, growing out of the precancer called usual-type VIN and marked by the p16 protein. It tends to affect younger women, responds better to radiotherapy and recurs less often than the HPV-independent type, and it is preventable by HPV vaccination.

HPV-independent vulvar cancer is the commoner type of vulvar squamous cell cancer, arising in older women from the chronic skin condition lichen sclerosus rather than from HPV, and marked by faults in the p53 gene. It recurs locally far more often than the HPV type, so treatment centres on complete surgical removal, control of the surrounding skin disease and long follow-up.

Low-risk gestational trophoblastic neoplasia is the mild form of this rare pregnancy-related cancer, usually found when the pregnancy hormone hCG fails to fall after removal of a molar pregnancy. It is cured in almost every woman with a single chemotherapy drug, methotrexate or actinomycin D, given until the hormone level is normal, and most go on to have normal pregnancies afterwards.

Placental-site and epithelioid trophoblastic tumours are the rare, slow-growing forms of gestational trophoblastic neoplasia, arising from the intermediate trophoblast cells that anchor the placenta rather than the hormone-producing cells behind choriocarcinoma. They make little hCG and respond poorly to chemotherapy, so hysterectomy comes first, with platinum chemotherapy when they have spread.

Uterine sarcomas are rare cancers of the muscle and supporting tissue of the womb, distinct from the far commoner endometrial cancer. Removing the uterus intact is the main treatment and is followed by observation for stage I disease; low-grade stromal sarcomas respond to hormone-blocking pills, while advanced leiomyosarcoma is treated with doxorubicin and trabectedin.

Vaginal adenocarcinoma is a rare glandular form of vaginal cancer, best known through the clear cell type that struck young women whose mothers took the hormone DES in pregnancy. Unlike the common squamous form it is not caused by HPV, it is treated with surgery where possible because it often affects young women, and radiotherapy and platinum chemotherapy are used when it is advanced.

Primary vaginal cancer is rare and mostly caused by HPV, the virus behind cervical cancer. It is treated like cervical cancer, with weekly cisplatin alongside external and internal radiotherapy, which controls most tumours while preserving the organ; HPV vaccination and cervical screening, which also detects vaginal precursors, are steadily reducing it.

Vaginal squamous cell carcinoma is the commonest form of vaginal cancer, caused by the same HPV infection as cervical cancer and often following earlier cervical disease. It is treated much as cervical cancer is, with radiotherapy, brachytherapy and cisplatin for most stages and surgery only for small upper-vaginal tumours, and it is prevented by HPV vaccination and cervical screening.

An uncommon cancer of the external genitalia with two distinct causes: HPV infection in younger women and chronic skin inflammation in older women. Surgery is the mainstay, and sentinel-node biopsy has made it far less mutilating.