What investigations should be done for a 61-year-old female smoker with a complaint of weight loss?

Investigations for a 61-Year-Old Female Smoker with Weight Loss

For a 61-year-old female with a 47-year smoking history and unexplained weight loss, lung cancer screening with low-dose CT (LDCT) should be the primary investigation, along with a comprehensive cancer workup including complete blood count, comprehensive metabolic panel, and age-appropriate cancer screenings.

Initial Evaluation for Weight Loss

Essential First-Line Investigations:

• Complete blood count (CBC)
• Comprehensive metabolic panel (including liver and kidney function tests)
• Thyroid function tests (TSH, free T4)
• Fasting plasma glucose and HbA1c
• Urinalysis
• Chest X-ray (as initial imaging)
• Low-dose CT scan of the chest (highest priority given smoking history)

Cancer-Specific Screenings:

• Low-dose CT (LDCT) for lung cancer screening - This patient meets criteria with >30 pack-year smoking history and current smoking status 1, 2
• Mammogram (if not done within past year)
• Colonoscopy (if not done within recommended intervals)
• Fecal occult blood test or fecal immunochemical test 1

Rationale for Lung Cancer Focus

This patient has multiple high-risk factors that warrant particular attention to lung cancer screening:

1. Long-term smoking history - 47 years of smoking starting from age 14
2. Current age of 61 - Falls within the recommended screening age range of 55-74 years 1
3. Unexplained weight loss - A potential sign of malignancy
4. Female gender - Women may be more susceptible to smoking-related lung damage

According to USPSTF guidelines, patients aged 55-74 years with ≥30 pack-year smoking history who currently smoke or quit within the past 15 years should undergo LDCT screening 1. The American Thoracic Society further recommends that individuals aged 50 years or older with a 20 pack-year smoking history and additional risk factors should be offered LDCT screening 2.

Additional Investigations Based on Initial Findings

If Initial Tests Are Inconclusive:

• CT scan of abdomen and pelvis
• Upper endoscopy and/or colonoscopy (regardless of screening status)
• Serum protein electrophoresis
• HIV testing
• Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP)
• Tuberculosis testing

Specialized Tests If Indicated:

• PET scan (if lung nodules or other suspicious findings are detected)
• Bronchoscopy (if pulmonary lesions identified)
• Tissue biopsy of any suspicious lesions

Smoking Cessation Counseling

While investigating the cause of weight loss, smoking cessation counseling should be initiated:

• Assess readiness to quit and offer counseling 1
• Provide pharmacological interventions (nicotine replacement therapy, bupropion, or varenicline)
• Address weight concerns related to smoking cessation 3, 4, 5
• Explain that smoking cessation is critical regardless of diagnostic findings

Weight Loss Assessment

When evaluating weight loss in this patient, consider:

• Quantify the amount and timeframe of weight loss (>5% over 6-12 months is considered significant) 6
• Assess for decreased appetite, early satiety, difficulty swallowing, or changes in taste
• Evaluate for gastrointestinal symptoms (nausea, vomiting, diarrhea, constipation)
• Screen for depression and anxiety which may contribute to weight loss
• Review medication history for drugs that might cause weight loss

Common Pitfalls to Avoid

1. Attributing weight loss solely to smoking - While smoking can suppress appetite, new-onset weight loss in a long-term smoker should prompt thorough investigation
2. Overlooking non-pulmonary malignancies - Focus on lung cancer should not preclude evaluation for other cancers
3. Neglecting psychosocial causes - Depression, anxiety, and social factors can contribute to weight loss
4. Delaying lung cancer screening - Given the high-risk profile, LDCT should be prioritized rather than starting with less sensitive chest X-ray
5. Missing metabolic disorders - Diabetes, hyperthyroidism, and other metabolic conditions can cause weight loss and require specific testing

By following this structured approach to investigating weight loss in this high-risk patient, clinicians can ensure timely diagnosis of potentially serious underlying conditions while addressing the critical need for smoking cessation.