Know it, to control it

Medulloblastoma

Medulloblastoma is a common malignant tumor found in the pediatric age group. It is mainly seen in children below 10 years of age. It is highly invasive and spreads quickly from the brain to the central system. Less than 2% 0f Medulloblastomas occur in teenage and beyond.Therefore early diagnosis before the spread, carries a more favorable outcome.

Symptoms ranging from headaches, imbalance in walking,failure to feed, vomiting, clumsiness, and fatigue that are associated with common childhood conditions often delay prompt diagnosis. Persistence of symptoms should raise a red flag for brain imaging studies. Disease progression and spread produces more obvious symptoms including severe early morning headaches relieved by vomiting, double vision, facial weakness, tinnitus(a sound in the ears), hearing loss, stiff neck, back pain , weakness and instability to walk.

Medulloblastoma may be associated with some heritable syndromes such as Turcot, Gorlin, and Ataxia-Telangiectasia as well as chromosomal abnormalities.

Currently, medulloblastoma is clinically classified according to age ─ children more than 3 years into high risk and standard (average) risk. Infants below 3 years carry the worst prognosis. Staging followed is the Chang classification staging system, which is based on the pre-operative imaging and intra-operative findings to determine M (metastasis) stage and T (tumor) stage. M stage is better for assessing the prognosis of children with medulloblastoma than the T stage. Today, medulloblastomas are further classified by the presence and absence of genetic aberrations (MYC and MYCN amplification) as well as identified by transcription molecular profiling into four subgroups: WNT, SHH, Group 3 and Group 4.

The treatment strategies for medulloblastoma are maximal safe resection (plus/minus cerebrospinal fluid diversion), whole neuraxis radiotherapy for standard risk disease. Patients may need radiation and chemotherapy in case the risk of relapse is high.

Clinically, the prognosis of patients with medulloblastoma is often determined according to the pathological type, which also provides a reference for the application of adjunctive therapies, such as radiotherapy and chemotherapy.

In patients > 3 years post‐op radiotherapy is delivered to the entire craniospinal axis followed by a posterior fossa or tumor bed boost. Proton therapy, IMRT, or 3‐D conformal therapy are acceptable treatment modalities with pre‐operative and post-operative MRIs of brain and spine for accurate target volume delineation. Tomotherapy is an integrated machine for delivery of intensity modulated radiation(IMRT) with daily image guidance(IGRT).The goal of present day radiotherapy is to minimize the volumes irradiatied with sparing of hippocampus (memory),hearing apparatus and visual pathways to prevent late complications.

Proton therapy has also helped reduce the risk of second primary cancers in children by reducing the integral dose to the whole body in children.

Postoperative radiotherapy (PORT) to the craniospinal axis is currently standard-of-care for pediatric medulloblastoma.Craniospinal radiation is carried out by following a strict meticulous protocol to achieve a uniform dose throughout the subarachnoid space, although the method may differ according to specific institutions.