What is the treatment for cancer?

Treatment of Cancer

Cancer treatment must be individualized based on cancer type, stage, molecular characteristics, and patient performance status, with the primary goal of maximizing survival and quality of life through evidence-based multimodality approaches including surgery, systemic therapy, radiation, and palliative care.

Treatment Selection Framework

The approach to cancer treatment depends fundamentally on three factors: cancer type and stage, treatment intent (curative vs. palliative), and patient functional status 1.

Early-Stage Disease (Potentially Curable)

For early-stage cancers, aggressive multimodality treatment is warranted to achieve cure:

• Surgery remains the cornerstone for stage I-II solid tumors, often achieving cure when the tumor can be completely resected 1
• Adjuvant chemotherapy should follow surgical resection for stage III disease and select stage II cancers to eliminate micrometastatic disease 1
• Radiation therapy is indicated for local control, either as definitive treatment or combined with surgery and chemotherapy 1
• Neoadjuvant therapy (chemotherapy ± radiation before surgery) may be used to downstage locally advanced tumors and facilitate complete resection 1

For specific examples: Stage III colon cancer requires surgery followed by adjuvant chemotherapy 1. Early-stage breast cancer (stages I-II) is treated with lumpectomy plus radiation or mastectomy, followed by adjuvant systemic therapy based on receptor status 2. Early esophageal cancer (T1N0M0) confined to mucosa can be treated with esophagectomy or endoscopic mucosal resection 1.

Advanced/Metastatic Disease (Stage IV)

For metastatic cancer, systemic therapy is the primary treatment modality, with the goal of prolonging survival and maintaining quality of life:

• Systemic chemotherapy remains standard for most metastatic solid tumors, though it typically controls disease for months rather than years 1
• Targeted therapies have revolutionized treatment for specific molecular subtypes, such as trastuzumab for HER2-positive breast cancer and imatinib for chronic myelogenous leukemia, which can dramatically alter disease course 1, 3
• Immunotherapy and novel targeted agents continue to expand treatment options with improved toxicity profiles 1
• Palliative surgery or radiation may be appropriate for symptom control or oligometastatic disease 1

Molecular and Receptor-Directed Treatment

Treatment selection increasingly depends on molecular characteristics rather than organ of origin:

• HER2-positive breast or gastric cancer requires trastuzumab-based therapy in combination with chemotherapy for metastatic disease, or as adjuvant therapy following surgery for early-stage disease 3
• Hormone receptor-positive cancers (breast, prostate) should receive endocrine therapy as first-line treatment for metastatic disease 2
• Hepatocellular carcinoma treatment algorithms are based on liver function (Child-Pugh class), tumor burden, and vascular invasion, with options including resection, ablation, liver transplantation (for Milan criteria), transarterial chemoembolization, or systemic therapy 1

Treatment by Disease Trajectory

Patients with Years to Months to Live

Anticancer therapy should be considered only when it has a reasonable chance of providing meaningful clinical benefit:

• Continue evidence-based cancer-directed therapy as outlined in disease-specific guidelines 1
• Discuss treatment intent, goals, benefits, burdens, and effects on quality of life explicitly 1
• Clinical trials should be considered the preferred option when available 1
• Integrate palliative care early, even while pursuing disease-directed therapy 1

Patients with Months to Weeks to Live

The focus shifts from prolonging life to maintaining quality of life:

• Discontinue anticancer therapy for patients with markedly poor performance status (ECOG ≥3, Karnofsky ≤50) or lack of response to two prior chemotherapies 1
• Offer best supportive care with referral to palliative care or hospice 1
• Consider palliative interventions such as esophageal stenting for dysphagia, radiation for bone pain, or drainage procedures for malignant effusions 1

Patients in Final Weeks to Days

Comfort-focused care becomes the sole priority:

• Discontinue all cancer-directed therapy 1
• Focus exclusively on symptom management and psychosocial support 1
• Ensure hospice enrollment for comprehensive end-of-life care 1

Critical Treatment Principles

When NOT to Treat

Oncologists should not provide interventions that clinical evidence suggests will provide no meaningful benefit and may cause harm:

• Avoid chemotherapy in patients with poor performance status who are unlikely to tolerate or benefit from treatment 1
• Do not offer interventions with insufficient evidence of efficacy outside of clinical trials 1
• Recognize that treating cancer should be viewed as an option for discussion rather than a given, particularly in advanced disease 1

Maintaining Dose Intensity

For chemosensitive cancers in the curative setting, maintaining chemotherapy dose intensity is crucial for optimal outcomes:

• Relative dose intensity should be maintained at ≥85% of standard dosing when treating with curative intent 1
• Myelosuppression (neutropenia, anemia, thrombocytopenia) is the primary cause of unplanned dose reductions and delays 1
• Use growth factors and supportive care to maintain planned dose intensity 1

Common Pitfalls to Avoid

• Undertreatment of elderly patients: Age alone should not preclude standard treatment; biological age and functional status are more important than chronological age 1
• Overtreatment near end of life: Avoid chemotherapy in the final weeks of life when it provides no benefit and detracts from quality of life 1
• Delayed palliative care integration: Palliative care should begin at diagnosis for cancers with limited expected survival (metastatic lung, pancreatic cancer, glioblastoma) rather than only in the final days 1
• Inadequate staging: Proper staging with CT, endoscopic ultrasound, and PET when appropriate is essential to guide treatment decisions 1
• Failure to assess molecular markers: HER2, hormone receptors, and other molecular markers must be tested to guide targeted therapy selection 3, 2