Breath analysis is a promising non-invasive method for the detection and management of lung cancer. Exhaled breath contains a complex mixture of volatile and non-volatile organic compounds that are produced as end-products of metabolism. Several studies have explored the patterns of these compounds and have postulated that a unique breath signature is emitted in the setting of lung cancer. Most studies have evaluated the use of gas chromatography and mass spectrometry to identify these unique breath signatures. With recent advances in the field of analytical chemistry and machine learning gaseous chemical sensing and identification devices have also been created to detect patterns of odorant molecules such as volatile organic compounds. These devices offer hope for a point-of-care test in the future. Several prospective studies have also explored the presence of specific genomic aberrations in the exhaled breath of patients with lung cancer as an alternative method for molecular analysis. Despite its potential, the use of breath analysis has largely been limited to translational research due to methodological issues, the lack of standardization or validation and the paucity of large multi-center studies. It is clear however that it offers a potentially non-invasive alternative to investigations such as tumor biopsy and blood sampling.

Background: Extra-pulmonary small-cell neoplasms are rare, and treatment planning is challenging for clinicians. The lack of guideline-based management undermines and isolates patients for whom these cancers are not just rare but also real. Small-cell breast cancer (SCBC) is a rare, aggressive disease that accounts for less than 1% of all invasive breast cancers. Here, we report a case of SCBC and discuss the complexities of case management. Case Presentation: A 46-year-old patient presented with a self-detected right breast lump. Mammogram and ultrasound examination showed a 69x47mm dense lesion in the upper outer aspect of the right breast and a 17mm pathologic node in the inferior right axilla. The triple assessment demonstrated a localised high-grade malignant neuroendocrine neoplasm. Management extrapolated from small cell lung cancer management and case reports, consisted of chemotherapy with carboplatin, and etoposide introduced with concurrent radiotherapy, followed by mastectomy with axillary lymph node dissection. A complete pathological response was obtained. Six months following her surgery, metastatic disease in the brain, chest wall, lymph nodes, and lungs developed. Rechallenge with carboplatin and etoposide led to a brief response, and subsequent immunotherapy was ineffective. Conclusion: This case report highlights the challenges of rare tumour management. Establishing registries for these and other rare tumors would facilitate care, reduce patient uncertainty and assist in founding protocol-based care.