Cancer Radiation Therapy Resolves PCT, Case Study Reports

Radiation therapy for a woman with vaginal cancer completely resolved co-existing porphyria cutanea tarda (PCT), a form of porphyria that affects the skin, a case study reported. 

The case study, “Porphyria cutanea tarda exacerbation as a paraneoplastic syndrome in vaginal cancer resolved with chemoradiation,” was published in the journal Gynecologic Oncology Reports. 

PCT is caused by low levels of an enzyme called uroporphyrinogen decarboxylase (UROD), which is essential for the production of heme — a molecule involved in oxygen transport within red blood cells. The condition can be caused by mutations in the UROD gene, or be acquired due to a hepatitis C infection, alcohol consumption, and excessive iron in the liver.

While radiation therapy is a standard cancer treatment, its impact on cancer patients who also have PCT is not well understood. Only a few cases are reported in the medical literature. 

Here, researchers at the Johns Hopkins University School of Medicine, in Baltimore, described the case of a 55-year-old woman with PCT who underwent radiation therapy to treat recurrent vaginal squamous cell carcinoma — the most common type of vaginal cancer.

The case study reports that the radiation therapy resolved both conditions. 

In addition to PCT and cancer, the woman had a history of kidney transplant with rejection requiring hemodialysis. Hemodialysis is a treatment that filters waste and water from the blood, typically done by healthy kidneys.

The patient also had Stevens-Johnson syndrome — a disorder of the skin and mucous membranes that usually starts with flu-like symptoms — and hepatitis C, as well as a connective tissue disease believe to be related to lupus.

In 2015, she was treated at a dermatology clinic with scaly skin patches on her upper arms. Initially, the woman was thought to have the skin condition eczema. But after a few months without improvement, lab tests showed high levels of heme precursors (porphyrins) and low UROD, which supported the diagnosis of PCT, “potentially triggered by dialysis, hepatitis C, and/or iron infusions,” the researchers wrote. 

She discontinued iron infusions, was told to avoid sun exposure, and received medications to treat the underlying connective tissue disorder. However, she showed little improvement in her PCT symptoms. 

Following a previous Pap smear — a test for cervical cancer in women — that had shown atypical squamous cells, the patient had undergone vaginal biopsies. Those biopsies demonstrated squamous cell carcinoma, with positron-emission tomography (PET) scans confirming the diagnosis. 

She received 25 daily radiation treatments with an external beam directed at the primary vaginal mass, and at lymph nodes in her groin and pelvis. In addition, the patient was prescribed the chemotherapy cisplatin. 

The woman was given a break from radiation due to skin irritation in the groin, which was managed with a sitz bath, skincare, and a pain reliever. 

At a two-week follow-up appointment, her PCT appeared to be resolving. Overall, throughout the radiation therapy, her PCT lesions had dramatically eased. She also was treated for hepatitis C, resulting in an undetectable viral load. 

At 15 months following radiation, the patient had no signs of any PCT skin lesions.  

Follow-up four years after treatment showed complete resolution of PCT and no evidence of vaginal cancer. The radiation treatment did leave residual scarring in the irradiated groin area and vaginal narrowing.

“In this case, the patient’s curative approach to cancer has resulted in a resolution of her disease and PCT, and close management with frequent follow up is required to ensure that all toxicities that may occur are appropriately managed,” the scientists wrote.