🎗️ Neoadjuvant vs Adjuvant Chemotherapy Timing Simulator

Tumor Assessed — Large Relative to Breast Size

A large tumor is found relative to breast volume, raising the question of surgical extent.

• High: Tumor-to-breast ratio (placeholder ratio metric)
• Mastectomy: Baseline surgery leaning (before any chemo given)
• Now: Sequencing decision point (before first treatment step)
• 2: Options on table (neoadjuvant or adjuvant)

Why tumor size relative to breast matters

Large relative tumor size often forces mastectomy under standard surgery-first sequencing.

The sequencing fork in treatment planning

Clinicians choose chemo-before-surgery or chemo-after-surgery based on this size assessment.

A borderline-operable tumor is the classic case where timing changes the surgical outcome.

Neoadjuvant Path — Chemotherapy Before Surgery

Chemo is given first to shrink the tumor, potentially enabling breast-conserving surgery.

• Pre-surgery: Chemo timing (placeholder timing label)
• ~40–60%: Typical shrinkage (illustrative placeholder range)
• Possible: Surgery downstaging (mastectomy avoided sometimes)
• Directly: Response observed (informs prognosis in real time)

Shrinking the tumor before the knife

Chemo cycles reduce tumor volume, widening eligibility for breast-conserving surgery.

Observing response as a prognostic signal

Watching the tumor respond to chemo gives early information on treatment effectiveness.

Pathologic complete response after neoadjuvant chemo is linked to better long-term outcomes.

Adjuvant Path — Surgery Before Chemotherapy

Surgery is performed first when the tumor is already operable; chemo follows pathology.

• Post-surgery: Chemo timing (placeholder timing label)
• Original tumor: Surgery size (no pre-shrinkage occurs)
• Full: Staging completeness (pathology known before chemo choice)
• Operable tumors: Standard use case (smaller, clearly resectable)

Removing the tumor at its original size

Surgery happens immediately, so extent is set by the tumor as originally found.

Chemo guided by complete pathology

Post-surgical chemo decisions use full pathologic staging, not estimated response.

Adjuvant sequencing remains the standard for tumors that are clearly operable at baseline.

Comparison — Same Tumor, Two Different Sequences

Neoadjuvant offers downstaging and response data; adjuvant offers immediate removal and full staging.

• Downstaging: Neoadjuvant advantage (smaller surgery, response seen)
• Immediate removal: Adjuvant advantage (complete staging up front)
• Same tumor: Shared starting point (identical baseline size)
• Surgical extent: Diverging outcome (placeholder comparison metric)

Trade-offs between the two sequences

Each order trades one benefit for another — shrinkage versus immediate staging.

Why the same tumor can end differently

Identical starting tumors can reach different surgical extents purely from timing.

The comparison panel shows both tracks diverging from one identical starting tumor.

Outcome — Choosing Sequencing by Tumor Size

Large or borderline tumors often favor neoadjuvant; small operable tumors favor adjuvant.

• Neoadjuvant: Large tumor preference (enables less extensive surgery)
• Adjuvant: Small tumor preference (standard sequencing remains common)
• Tumor size: Decision driver (plus breast size and operability)
• Best surgical outcome: Shared goal (placeholder goal statement)

Matching timing to tumor size

Sequencing choice ultimately follows how large the tumor is at diagnosis.

Summary of the timing decision

Neither sequence is universally better — the right choice depends on the case.

This simulator lets you slide tumor size and sequencing to see the surgical outcome shift.