When faced with a rare cancer diagnosis, patients and their families often encounter a profound sense of uncertainty. Rare cancers—those affecting fewer than 6 in 100,000 people annually—pose unique challenges due to limited research, fewer standardized treatment protocols, and reduced awareness. However, brachytherapy, a highly targeted form of radiation therapy, is emerging as a promising treatment option for some of the world’s most uncommon malignancies. 

Understanding Brachytherapy 

Brachytherapy, also known as internal radiation therapy, involves placing radioactive material directly inside or near the tumor through specific applicators or needles. This technique minimizes damage to surrounding healthy tissues and organs at risk by delivering a concentrated dose of radiation precisely where needed. Brachytherapy is already well-established in treating more common cancers such as prostate, breast, and cervical cancers. Still, its adaptability and precision make it an invaluable tool for tackling rarer cancer types. 

Rare Cancers: A Treatment Challenge 

Rare cancers often require specialized, individualized approaches because they do not benefit from the same level of clinical research and treatment standardization as more prevalent cancers. Delayed diagnosis and limited therapeutic options are common obstacles. This is where brachytherapy’s precision, versatility, and effectiveness come into play. 

By allowing clinicians to customize radiation doses based on tumor size, location, and behavior, brachytherapy provides a promising solution for treating rare cancers that might otherwise have limited treatment options. 

Brachytherapy in Treating Rare Cancers 

Head and Neck Cancers 

Rare head and neck cancers, such as those affecting the nasal cavity and paranasal sinuses, are challenging to treat due to their proximity to critical structures like the eyes, brain, and spinal cord. Brachytherapy offers an effective way to deliver high doses of radiation directly to the tumor while sparing vital tissues. 

For example, brachytherapy has been shown to be effective in treating primary nasal vestibule cancer, a rare cancer that accounts for less than 1% of all head and neck cancers. ⁽¹⁾ 

Soft Tissue Sarcomas 

Soft tissue sarcomas are a diverse group of rare cancers that develop in connective tissues such as muscles, fat, and blood vessels. Brachytherapy, often used with surgery, has effectively managed localized sarcomas. By placing radioactive sources in the tumor bed post-surgery, clinicians can reduce the risk of recurrence without requiring extensive radiation to the surrounding area. 

A study published in Anticancer Research evaluated the efficacy of interstitial brachytherapy in treating metastatic liver sarcomas, highlighting its ability to provide effective local control even in challenging cases. ⁽²⁾ 

Gynecologic Cancers 

While cervical and endometrial cancers are more common, rarer gynecologic cancers, such as vaginal or vulvar cancers, often benefit from brachytherapy. Vaginal cancers are considered rare, as they account for only about 1% to 2% of cancers in the female genital tract and a very small portion of cancers overall. They frequently occur in anatomically complex areas, making precision treatment essential. 

High-dose-rate (HDR) brachytherapy allows for the precise targeting of tumors in these regions, delivering effective doses of radiation while minimizing exposure to nearby organs such as the bladder and rectum. The international RetroEMBRAVE study demonstrates that image-guided adaptive brachytherapy (IGABT) for primary vaginal cancer offers high local control rates and acceptable morbidity compared to traditional methods. ⁽³⁾ 

Eye Cancers 

Brachytherapy is an effective treatment for rare eye cancers like uveal melanoma. This technique offers high local tumor control rates while preserving vision, making it a vital option for patients. ⁽⁴⁾  

Why Brachytherapy Offers Hope 

1. Precision and Adaptability: The ability to tailor radiation doses makes brachytherapy particularly effective for rare cancers located in sensitive or anatomically complex regions. 

2. Reduced Side Effects: By sparing healthy tissues, brachytherapy minimizes complications, allowing patients to maintain a better quality of life. 

3. Combination Therapy: Brachytherapy works well alongside other treatments, such as surgery, chemotherapy, external beam, enhancing overall outcomes. 

4. Shorter Treatment Time: Brachytherapy often involves fewer treatment sessions than conventional radiation therapy, reducing patient burden. 

For patients with rare cancers, the journey to finding effective treatment can be fraught with challenges. With its precision, adaptability, and proven success, Brachytherapy offers a much-needed source of hope. Tailoring treatment to the unique needs of each patient not only improves survival rates but also prioritizes quality of life—a vital consideration for anyone navigating a rare cancer diagnosis. 

References 

1. Brachytherapy for primary nasal vestibule cancer using Au-198 grains. Harada, H., Ishikawa, Y., Tanaka, S. et al. Int Canc Conf J 11, 184–187 (2022). Brachytherapy for primary nasal vestibule cancer using Au-198 grains | International Cancer Conference Journal 

2. Interstitial Brachytherapy for Limited (<4 cm) and Large (≥4 cm) Hepatic Metastases from Rare and Less Common Cancers C. Heinze, J. Omari, R. Damm et al. Anticancer Research Aug 2020, 40 (8) 4281-4289; DOI: 10.21873/anticanres.14430

3. Image-Guided Adaptive Brachytherapy (IGABT) for Primary Vaginal Cancer: Results of the International Multicenter RetroEMBRAVE Cohort Study.  Westerveld H, Schmid MP, Nout RA, et al. Cancers (Basel). 2021 Mar 23;13(6):1459. doi: 10.3390/cancers13061459

4. Treatment for a Rare Form of Eye Cancer Has Shifted From Removing the Eye to Preserving Vision and Extending Lives, Says Expert. Author(s): Ryan McDonald