Adjuvant Therapy for Resected Pancreatic Cancer

Patient Selection and Treatment Recommendations

• The American Society of Clinical Oncology recommends that all patients with resected pancreatic cancer, including those with R1 resection, receive 6 months of adjuvant chemotherapy in the absence of medical or surgical contraindications 1
• The dual regimen of gemcitabine and capecitabine is an option; alternatively, monotherapy with gemcitabine or fluorouracil plus folinic acid may be offered if there are concerns about toxicity or tolerance 1
• Adjuvant treatment should be initiated within 8 weeks after surgical resection, assuming complete recovery 1
• Patients with R1 resection benefit from adjuvant chemotherapy 2

Adjuvant Chemoradiation

• Adjuvant chemoradiation may be offered to patients with microscopic positive margins (R1) and/or positive lymph node disease after completion of 4-6 months of systemic adjuvant chemotherapy 1
• There is clinical equipoise regarding the benefit of adjuvant radiation in this scenario, pending results from an ongoing international randomized clinical trial 1

Prognostic Factors

• The presence of negative resection margins is a major prognostic factor for patients undergoing radical resection for pancreatic adenocarcinoma 3
• R1 resection (microscopic positive margins) is a common finding in pancreatic carcinoma (>75%) and correlates with survival 4

Special Considerations

• The European Society for Medical Oncology reports that patients with R1 resection have a higher risk of local recurrence, which may justify the additional benefit of local radiation therapy 2
• Intraoperative radiation therapy (IORT) is still experimental and cannot be recommended for routine use 5

Treatment Algorithm

• Initiate adjuvant chemotherapy within 8 weeks after resection (gemcitabine + capecitabine, gemcitabine monotherapy, or 5-FU + folinic acid) 1
• Complete 4-6 months of adjuvant chemotherapy 1
• Consider adding chemoradiation for additional local control after completing chemotherapy 1

Patient Selection and Treatment Considerations

• Adjuvant radiation therapy should not replace adjuvant chemotherapy but rather complement it after its completion 1
• Patients with advanced age (>75-80 years) or significant comorbidities may not be ideal candidates for intensive adjuvant treatments 4
• Delaying the start of adjuvant therapy beyond 8 weeks may compromise outcomes 1

Radioterapia Adjuvante para Câncer de Pâncreas com Ressecção R1

Evidência para Radioterapia Adjuvante em Ressecções R1

• Estudos que examinaram subgrupos de pacientes com ressecções R1 encontraram que a radioquimioterapia adjuvante beneficiou estes pacientes em comparação com apenas observação, de acordo com o Journal of the National Comprehensive Cancer Network 6

Algoritmo de Tratamento Recomendado

• A Sociedade Europeia de Oncologia Médica (ESMO) indica que a quimioterapia adjuvante deve ser iniciada dentro de 8 semanas após a ressecção cirúrgica, e a radioquimioterapia pode ser considerada após 4-6 meses de quimioterapia sistêmica adjuvante para pacientes com margens microscopicamente positivas (R1), de acordo com a Annals of Oncology 7
• A radioquimioterapia baseada em fluoropirimidina é geralmente preferida sobre a baseada em gemcitabina, de acordo com o Journal of the National Comprehensive Cancer Network 8

Controvérsias e Considerações Importantes

• Existe alguma controvérsia sobre o papel da radioquimioterapia adjuvante, com resultados mistos em diferentes estudos, de acordo com o Journal of the National Comprehensive Cancer Network e a Annals of Oncology 6, 7
• A Sociedade Europeia de Oncologia Médica (ESMO) indica que não há prova de vantagem da radioquimioterapia adjuvante em comparação com a quimioterapia adjuvante isolada, de acordo com a Annals of Oncology 7

Fatores Prognósticos e Considerações Especiais

• A radioterapia intraoperatória (IORT) ainda é experimental e não pode ser recomendada para uso rotineiro, de acordo com a Annals of Oncology 7

Adjuvant Radiotherapy in Pancreatic Cancer

Primary Indications for Adjuvant RT

• Patients with R1 resection (microscopic positive margins) may benefit from adjuvant chemoradiotherapy after completion of systemic chemotherapy, as recommended by the National Comprehensive Cancer Network, with a hazard ratio for death of 0.72 in the R1 subset 9, 10
• Patients with positive lymph nodes show improved survival with adjuvant RT compared to those with negative nodes, with a significant improvement in survival demonstrated in a large multi-institutional study of 747 patients with resected pancreatic cancer 10

Evidence Supporting RT in High-Risk Subgroups

• A meta-analysis of 4 randomized controlled trials found increased survival benefit with adjuvant chemoradiotherapy in the R1 subset (HR for death, 0.72) compared to the R0 subset (HR for death, 1.19), with moderate-strength evidence 10
• A large multi-institutional study of 747 patients with resected pancreatic cancer demonstrated significant improvement in survival with chemoradiotherapy only in patients with lymph node-positive disease, with high-strength evidence 10
• A retrospective review from Johns Hopkins Hospital comparing outcomes of 94 patients who underwent distal pancreatectomy showed that patients with positive lymph nodes derived greater benefit from adjuvant chemoradiotherapy than those with negative nodes, with low-strength evidence 10

Timing and Sequencing of RT

• When chemoradiotherapy is considered as adjuvant therapy, it should be administered after an adequate course (up to 4 months) of systemic chemotherapy, as recommended by the National Comprehensive Cancer Network 11, 12
• This sequencing approach is supported by emerging data in locally advanced disease suggesting that a period of chemotherapy followed by consolidated chemoradiotherapy may be preferable to up-front chemoradiotherapy, with moderate-strength evidence 12

RT Technical Considerations

• When postoperative RT is given, it should be administered at a dose of 45-54 Gy (1.8-2.0 Gy/day), with high-strength evidence 11, 12
• CT simulation and 3-dimensional treatment planning are strongly encouraged, with moderate-strength evidence 12
• Treatment volumes should be based on preoperative CT scans and surgical clips (when placed), targeting the location of the primary tumor and regional lymph nodes, with low-strength evidence 12
• RT is typically given in combination with concurrent fluoropyrimidine-based chemotherapy (continuous infusion 5-FU or capecitabine), with moderate-strength evidence 12

Limitations and Controversies

• Most data comparing chemotherapy versus chemoradiotherapy do not generally show a survival advantage for the addition of RT, with low-strength evidence 10
• The ESPAC-1 trial suggested that the addition of RT to adjuvant 5-FU chemotherapy may be unnecessary and potentially harmful (OS of 13.9 months for CRT vs. 21.6 months for chemotherapy alone), with moderate-strength evidence 10
• However, this trial has been criticized for lack of attention to quality control for RT, among other concerns, with low-strength evidence 10
• The RTOG 97-04 study, which used daily fractionated RT with prospective quality assurance, showed a non-statistically significant increase in OS in the gemcitabine arm compared with the 5-FU arm for pancreatic head tumors, with moderate-strength evidence 9, 12

Adjuvant Chemotherapy After Whipple Procedure for Pancreatic Adenocarcinoma

Primary Chemotherapy Recommendations

• The National Comprehensive Cancer Network recommends modified FOLFIRINOX (mFOLFIRINOX) as the preferred adjuvant regimen for fit patients with pancreatic adenocarcinoma after Whipple procedure, with gemcitabine plus capecitabine as the standard alternative 13
• The European Society for Medical Oncology states that gemcitabine plus capecitabine is a standard option based on ESPAC-4 trial data showing superiority over gemcitabine alone (HR 0.82, p=0.032) 14

Treatment Duration and Timing

• The European Society for Medical Oncology recommends 6 months of adjuvant chemotherapy 15
• The National Comprehensive Cancer Network suggests that patients with serious postoperative complications (Clavien-Dindo ≥IIIa) are less likely to receive adjuvant chemotherapy, which directly impacts survival 13

Special Populations

• The National Comprehensive Cancer Network recommends that patients who received neoadjuvant therapy may be candidates for additional chemotherapy after surgery and multidisciplinary review 13
• The European Society for Medical Oncology states that comorbidity may preclude otherwise feasible adjuvant treatment in elderly patients (>75-80 years) 15

Evidence Quality Notes

• The National Comprehensive Cancer Network guidelines (2019) represent the highest quality and most current guidance for the recommendation of mFOLFIRINOX as preferred therapy 13
• The ESPAC-4 trial definitively established gemcitabine plus capecitabine superiority over gemcitabine monotherapy 14