The evidence supporting these management guidelines is provided by expert consensus opinion.
Some types of cancer in NF1 are associated with poorer survival when compared with general population controls, particularly in those diagnosed at age <40 years.r Therefore, concerning symptoms should be investigated promptly.
The type, timing and degree of intervention/ surgery, chemotherapy or radiotherapy treatment of NF1 patients (if any) should be carefully made by a multidisciplinary team with experience in managing NF1.rr Radiotherapy should be avoided where possible due to increased risk of secondary tumours.r
Other possible NF1 associated cancers include juvenile myelomonocytic leukaemia, thyroid cancer, malignant fibrous histiocytomas and rhabdomyosarcoma.rr
Optic nerve pathway gliomas
Most optic nerve gliomas occur between 3–5 years of age, and do not require intervention.rr
Women with NF1 have poorer breast cancer survival rates, compared with women in the general population (67.9% vs 87.8% 5 year survival).r
Breast screening guidelines are based on expert consensus rather than solid evidence. Breast screening is recommended from 35 years given the increased risk of early breast cancer. Breast MRI is recommended due to the high sensitivity of MRI compared with MMG and ultrasound in young women. MRI detects tumours which are smaller and more likely to be node-negative than mammography. MRI is also preferred over MMG in young women with NF1, if available, to reduce ionizing radiation exposure. MRI has a recall rate (requiring further investigation and/or biopsy) of 15% for initial screening, which decreases with subsequent rounds of screening to <10%. The effectiveness of breast cancer screening in women with NF1 is still unclear and data about the utility of screening programs is mostly extrapolated from cancer screening studies in other groups at increased risk of breast cancer.
There is no evidence regarding the benefit of risk reducing mastectomy in women with NF1. The lifetime risk of breast cancer is considered to be in the moderate risk range, therefore risk reducing mastectomy is not recommended in this group.
Malignant peripheral nerve sheath tumour (MPNST)
MPNSTs are aggressive sarcomas that often arise in plexiform neurofibroma and are associated with a poor survival. The median age of diagnosis for MPNST is 30–34 years.r Individuals with deep, truncal location of plexiform neurofibroma, previous radiation and an NF1 microdeletion have an increased risk of MPNSTs.r