Brachytherapy in Gynecological Cancer: From Cervix to Endometrium

It depends heavily on where the tumour sits. In fractionated radiosurgery for brain tumours, the incidence of radiation necrosis runs below 10 percent, and brain edema is another recognised complication. Risk rises when the target is near a critical structure such as the motor cortex or brainstem; robust dosing data for the motor cortex are limited, but the working figure for a single SRS session is around 15 Gy to that structure. With fractionated SRT or SRS, clinicians have to be especially vigilant about the proximity of organs at risk during planning. Done with that vigilance, SRS can be delivered safely to metastatic brain lesions with minimal complications, though it demands real expertise and careful dose painting.

I have treated around ten pediatric patients from Ethiopia specifically, as part of a broader pediatric caseload. Pediatric malignancy needs to be treated very carefully. In medulloblastoma, for example, craniospinal irradiation planning has to be extremely precise to prevent radiation-related toxicity. Because survival in cancers like ependymoma and medulloblastoma is often good, the most important concern becomes preventing secondary malignancy later in life, which means paying close attention to low-dose spillage, or integral dose, across the whole treatment field. For pediatric cases needing long treatment fields, we generally use tomotherapy, and we get very good outcomes.

It depends on the site and the stage. In early-stage head and neck cancer, surgery alone can be sufficient, but high-risk features on post-surgical pathology can still require adjuvant radiotherapy. In locally advanced disease, radiotherapy is generally needed as part of definitive treatment. In stage IV disease, radiotherapy is mostly palliative: relieving pain, bleeding, cord compression or hemoptysis. More than 50 to 60 percent of patients need radiotherapy at some point, whether as radical treatment, adjuvant therapy or palliation, and we rely on a multidisciplinary tumour board to decide the exact timing for each patient.

We follow international guidelines. Using cervical cancer as an example: stage IA, IB and IIA disease is treated with surgery first. Adjuvant treatment then depends on the Sedlis and Peters criteria: positive margins or positive nodes call for concurrent chemoradiation; deep stromal invasion beyond one-third, a tumour over 4 centimetres, or lymphovascular space invasion, without positive margins or nodes, call for radiation alone; if none of those features are present, no adjuvant treatment is needed and the patient goes to follow-up. Locally advanced disease, stage IB3 to IVA, needs concurrent chemoradiation. Stage IVB generally starts with chemotherapy, though a bulky tumour or high nodal burden may call for six weeks of neoadjuvant chemotherapy before concurrent chemoradiation. Every site, endometrium, lung, breast, has its own guideline, and we make these calls through tumour board discussion.

They are complementary, not competing. Staging starts with clinical examination: if the tumour looks confined to the cervix, with no fornix or parametrial involvement and a size under 4 centimetres, surgery looks feasible on clinical grounds. MRI is then used specifically to confirm there is no parametrial invasion, which gives us a clinico-radiological diagnosis. Only after surgery does histopathology decide whether adjuvant treatment is needed. This stepwise approach, clinical exam, then imaging, then surgery, then histopathology, is important because operating on an advanced or bulky tumour without confirming operability first raises the risk of a positive margin, which then commits the patient to more aggressive treatment than necessary.

Brachytherapy places the radiation source directly inside or immediately adjacent to a tumor through a temporary implant or applicator, rather than aiming a beam from outside the body. Because the source sits so close to the target, it can deliver a very high dose to the tumor while sharply limiting exposure to surrounding normal tissue.

Treatment usually begins with external beam radiotherapy delivering roughly 45 to 50 Gy over 25 fractions, followed by intracavitary brachytherapy using a Fletcher-Suit applicator, with an intrauterine tandem and ovoids positioned in the vaginal fornices, to concentrate dose precisely within the tumor region.

Post-operative endometrial cancer typically uses vaginal cylinder brachytherapy. Where disease involves the lower third of the vagina, extends into the parametrium, or where the cervical os cannot be safely negotiated because of distorted anatomy, an interstitial technique using the MUPIT applicator allows more precise placement.

The department uses a GammaMed Plus system by Varian for gynecological brachytherapy procedures.