Metastatic Patterns and Diagnostic Strategies in Women with Primary Lung Cancer

Epidemiology of Metastatic Sites

In women with primary lung cancer, the most frequent metastatic locations are lymph nodes, liver, adrenal glands, bone, brain, and pleura; women have a markedly higher propensity for nervous‑system metastases (43 % vs. 35 % in men)【1】【2】.
Lymph‑node involvement is common but usually clinically silent unless the adenopathy is bulky【1】【2】.
Bone metastases are present at initial diagnosis in 6–25 % of patients, most often affecting the vertebral bodies【1】【2】.
Approximately 70 % of cancers that first present with symptomatic brain metastases are lung cancers, making brain involvement a prominent feature【1】【2】.
Liver metastases occur frequently and are typically accompanied by weakness and weight loss, while liver‑function tests often remain normal until late disease【1】【2】.
Adrenal‑gland metastases are usually asymptomatic and rarely cause adrenal insufficiency; they must be differentiated from benign adrenal adenomas that are common incidental findings【1】【2】.
Pleural involvement most commonly manifests as a pleural effusion【1】【2】.

Systemic symptoms such as anorexia, weight loss, and fatigue are common in patients with distant metastases and correlate with a poorer prognosis even when cancer stage is otherwise identical【1】【2】.
Bone metastases typically cause localized pain and tenderness and may be associated with elevated serum calcium or alkaline phosphatase levels【1】【2】.
Brain metastases can produce headache, nausea, vomiting, seizures, altered mental status, or may be completely asymptomatic【1】【2】.
Liver metastases present with generalized weakness and weight loss, but laboratory liver tests often stay within normal limits until extensive disease【1】【2】.
Adrenal metastases are generally asymptomatic and discovered incidentally on imaging【1】【2】.

Image‑guided biopsy of accessible metastatic sites (e.g., lymph nodes, liver, adrenal gland) provides rapid histologic confirmation and accurate staging in patients with suspected systemic spread【1】【2】.
Contrast‑enhanced computed tomography (CT) of the chest, abdomen, and pelvis is the preferred imaging modality for detecting metastatic disease in these regions, as recommended by the American College of Radiology【3】.
Positron‑emission tomography/computed tomography (PET/CT) demonstrates higher sensitivity (92 %) than conventional bone scintigraphy (86 %) for identifying skeletal metastases【3】.

When adrenal masses are identified, clinicians should employ imaging criteria to distinguish metastatic lesions from benign adenomas, given the high prevalence of incidental adrenal adenomas【1】【2】.
Normal liver‑function tests do not exclude hepatic metastases; imaging should be pursued when clinical suspicion exists despite laboratory normalcy【1】【2】.
New‑onset bone pain accompanied by hypercalcemia or elevated alkaline phosphatase warrants prompt evaluation for osseous metastatic disease【1】【2】.

Lung adenocarcinoma most commonly metastasizes to the lymph nodes, liver, adrenal glands, bone, brain, and pleura, with lymph nodes being a common site for metastasis, though symptoms are typically absent unless there is very bulky adenopathy 4
Metastasis to the liver often presents with symptoms of weakness and weight loss, but liver function tests typically remain normal until advanced stages of involvement 4, 5
Adrenal gland metastases are typically asymptomatic and rarely cause adrenal insufficiency; they must be distinguished from benign adrenal adenomas 4, 5
Bone metastases occur in 6-25% of patients at presentation, with vertebral bodies being the most common site, though any bone may be involved 4, 5
Brain metastases are common, with the lung being the primary site of about 70% of cancers that initially present with symptomatic brain metastases 4, 5
Pleural metastases often manifest as pleural effusion, which should always raise concern for malignancy 4, 5

Patients with distant metastases often present with nonspecific systemic symptoms including anorexia, weight loss, and fatigue, which are associated with worse prognosis even within the same cancer stage 4, 6
Systemic symptoms are associated with worse prognosis even within the same cancer stage 6

Bone metastases present with pain, bony tenderness, and possibly elevated serum calcium or alkaline phosphatase 4, 5
Brain metastases may present with headache, nausea, vomiting, seizures, mental status changes, or may be asymptomatic 4, 5
Liver metastases are often accompanied by weakness and weight loss, but liver function tests typically remain normal until very advanced stages 4, 5

For patients with systemic symptoms suggesting metastatic disease, biopsy of a metastatic site can efficiently establish both diagnosis and stage 4, 5
CT imaging with IV contrast is the preferred modality for detecting metastases in the chest, abdomen, and pelvis 7, 8
Brain MRI is recommended for suspected brain metastases, with contrast increasing specificity for detection, especially for leptomeningeal spread 7
PET/CT has higher sensitivity (92%) than bone scan (86%) for detecting bone metastases 8

The presence of metastatic disease significantly impacts prognosis and treatment planning 4, 6