Discussion

This case series extension reinforces that breast cancer metastases can masquerade as common musculoskeletal issues, such as sciatica-like symptoms or localized back pain, particularly in patients with a history of stable disease. In Case 1, the patient's symptoms post-hiking trip initially suggested a mechanical etiology, but her oncologic background prompted advanced imaging, uncovering progressive metastases with spinal involvement. Similarly, Case 2 revealed multilevel vertebral collapses mimicking degenerative changes, aligning with our previous cases (Cases 3-5) [4-6], where delays in recognition risked neurological compromise.

These findings compare with broader literature, where musculoskeletal presentations occur in metastatic cancer cases, often involving the axial skeleton and leading to underdiagnosis in primary care [7-9]. Integrative care, as demonstrated here, echoes studies showing chiropractic interventions (e.g., low-force adjustments) can improve pain and QOL in oncology patients, with VAS reductions of 30%-50% when combined with radiotherapy [10]. Key lessons include the utility of MRI and PET/CT for detecting occult progression, as X-rays alone may underestimate severity by missing early marrow changes [11].

Given the multi-modal nature of the management pathways in this series-where patients concurrently received local palliative radiotherapy, bone-targeted agents, and systemic anticancer therapies-the individual therapeutic contribution of supportive manual care cannot be isolated. The observed clinical and functional improvements must be interpreted cautiously as the cumulative outcome of an integrated, multidisciplinary care model. While radiotherapy remains the gold standard for achieving biological local tumor control and reducing bone pain, modified low-force rehabilitative care was integrated strictly to alleviate secondary mechanical strain and improve positional tolerance [12]. Future prospective studies are needed to delineate the specific interaction effects between manual supportive care and medical oncological regimens.

Limitations include the small series size, the retrospective nature potentially introducing recall bias, and selection bias toward cases presenting to chiropractic settings, limiting generalizability. Future studies could explore prospective protocols for screening musculoskeletal complaints in cancer survivors. Based on the diagnostic timelines observed in this case series, it is hypothesized that optimizing pathways for primary musculoskeletal clinicians-including potential direct-access frameworks for advanced diagnostic imaging such as MRI-could facilitate earlier detection of occult spinal metastases [13]. However, translating this clinical observation into systemic healthcare policy requires further investigation. Broad health economics and health service research are needed to formally evaluate the cost-effectiveness, safety, and diagnostic utility of such expanded access models within integrated oncology networks.