Distant complications of allogeneic HSCT refer to a variety of complications that occur 3 months after transplantation and affect the long-term quality of patient survival. They are usually classified as: non-tumor and tumor transplant-related complications.
Non-neoplastic long-term complications
Ocular complications
Ocular complications are more common and include cataracts or keratoconjunctivitis.
- Cataracts: often associated with the use of systemic radiation therapy in pretreatment regimens or pretreatment regimens with medications such as cyclophosphamide, leucovorin (leucovorin injection), etc., usually manifesting as vision loss.
- Keratoconjunctivitis: often associated with chronic graft-versus-host disease (GVHD), manifested by decreased tearing, dry eye, corneal irritation, aseptic conjunctivitis, corneal epithelial defects, and corneal ulcers.
Prevention: It is recommended to use regimens that do not include radiation therapy, or if necessary, to use a fractionated form of radiation therapy; to minimize the duration and dose of hormone use; and to pay attention to eye hygiene to prevent secondary ocular infections in patients with keratoconjunctivitis.
Skin, nail, and hair changes
Changes in the skin, including mucous membranes and skin appendages, nail and hair are closely associated with chronic GVHD skin lesions are very common in patients surviving long after transplantation and are closely associated with UV exposure and infection.
- Skin changes: manifest as dryness, rash, itching, scaling, lichenoid changes, skin pigmentation, scleroderma, and in severe cases, joint contractures.
- Nail changes: manifest as dystrophy, nail plate thinning, surface roughness, and fracture.
- Hair changes: manifesting as hair loss, thinning of hair, and graying of hair color.
Prevention: Try to avoid direct exposure of the skin to sunlight, wear sunscreen and long-sleeved clothes and pants.
Oral and dental complications
Often associated with systemic radiotherapy, chronic GVHD, manifesting as mucosal epithelial atrophy, erythema, hyperkeratosis, salivary gland dysfunction, abnormal taste, and dental lesions.
Prevention: Maintain oral hygiene, brush with a soft-bristled toothbrush and fluoride toothpaste, floss, avoid sugary drinks, and abstain from smoking.
Low thyroid function
Associated with systemic radiation therapy, usually without concomitant symptoms, and with thyroid index tests suggesting hypothyroidism.
Prevention: The only way to prevent it is to use a regimen that does not include systemic radiotherapy.
Fertility and hypogonadism
Gonadal hypogonadism is often related to the patient’s age at transplantation, systemic radiation therapy, and chemotherapy drug use. Infertility is more common in women than in men after transplantation, and gonadal function is more likely to be restored in patients who choose a cyclophosphamide-based pretreatment regimen and who are younger at the time of transplantation.
Prevention: Younger patients who present with menopausal manifestations require hormone replacement therapy; for patients with reproductive intentions, sperm and egg freezing can be done prior to transplantation.
Non-infectious respiratory complications
The most common occlusive fine bronchitis, idiopathic pneumonia syndrome, and cryptogenic mechanized pneumonia involving the large airways, bronchi, and lobar lung tissue are often associated with chronic GVHD. It presents with a dry cough, progressive dyspnea, and shortness of breath after activity.
Prevention: Avoid lung infections that exacerbate respiratory symptoms, abstain from smoking, and avoid passive smoking.
Patients who have survived transplantation for more than 10 years
Cardiac complications and cardiovascular disease, diabetes mellitus, hypertension, blood abnormalities, renal hypofunction, liver abnormalities, bone ischemic necrosis, and osteoporosis can occur.
Prevention: control blood pressure, patients with heart valve abnormalities need to prevent endocarditis; control lipids, blood glucose, abstain from smoking, avoid passive smoking, control weight, regular exercise; avoid the use of drugs with hepatic and renal toxicity.
Oncologic transplant-related complications
Transplant-related complications also include relapse of primary disease, treatment-related leukemia, and other solid tumors.
Prevention: Pay attention to monitoring for micro residual lesions and donor-recipient chimerism, and perform regular whole-body imaging for early detection and action to reduce recurrence rates.