Adjuvant Radiotherapy in the Treatment of Invasive Intraductal Papillary Mucinous Neoplasm of the Pancreas: an Analysis of the Surveillance, Epidemiology, and End Results Registry

Abstract

Background. Management and outcomes of patients with invasive intraductal papillary mucinous neoplasm (IPMN) of the pancreas are not well established. We investigated whether adjuvant radiotherapy (RT) improved cancer-specific survival (CSS) and overall survival (OS) among patients undergoing surgical resection for invasive IPMN. Methods. The Surveillance, Epidemiology, and End Results (SEER) registry was used in this retrospective cohort study. All adult patients with resection of invasive IPMN from 1988 to 2007 were included. CSS and OS were analyzed using Kaplan-Meier curves. Unadjusted and propensity-score-adjusted Cox proportional-hazards modeling were used for subgroup analyses. Results. 972 patients were included. Adjuvant RT was administered to 31.8% (n = 309) of patients. There was no difference in overall median CSS or OS in patients who received adjuvant RT (5-year CSS: 26.5 months; 5-year OS: 23.5 months) versus those who did not (CSS: 28.5 months, P = 0.17; OS: 23.5 months, P = 0.23). Univariate predictors of survival were lymph node (LN) involvement, T4-classified tumors, and poorly differentiated tumor grade (all P \ 0.05). In the propensity-scoreadjusted analysis, adjuvant RT was associated with improved 5-year CSS [hazard ratio (HR): 0.67, P = 0.004] and 5-year OS (HR: 0.73, P = 0.014) among all patients with LN involvement, though further analysis by T-classification demonstrated no survival differences among patients with T1/T2 disease; patients with T3/T4-classified tumors had improved CSS (HR: 0.71, P = 0.022) but no difference in OS (HR: 0.76, P = 0.06). Conclusion. On propensity-score-adjusted analysis, adjuvant RT was associated with improved survival in selected subsets of patients with invasive IPMN, particularly those with T3/T4 tumors and LN involvement.

The efficacy of adjuvant therapy for pancreatic invasive intraductal papillary mucinous neoplasm (IPMN)

“…In 2012, a propensity score‐matched analysis revealed that patients with advanced T‐classification and LN involvement demonstrated improved survival with adjuvant radiotherapy . The most recent study comparing adjuvant therapy with surgery alone for invasive IPMN reported that patients who received adjuvant chemotherapy experienced longer disease‐free survival than those who underwent surgery alone .…”

“…Indeed, several reports have indicated that, when controlling for the presence of these pathologic characteristics, survival disparities lose significance . Current adjuvant therapy recommendations for patients with invasive IPMN are often influenced by experiences with resected conventional PDAC . In reality, contemporary adjuvant therapy decisions for invasive IPMN have largely been derived from small, underpowered studies that were insufficient for subgroup assessments of long‐term survival.…”

“…3 IPMNs are considered invasive when neoplastic cells extend through the basement membrane of the involved ducts, 4 and these represent as much as 40% to 60% of resected IPMN lesions. 5 The reported 5-year survival rate for patients with resected invasive IPMN is between 22% and 45%, [6][7][8] which is typically greater than the 10% to 25% rate reported for those with resected conventional pancreatic ductal adenocarcinoma (PDAC). [9][10][11] Some studies have attributed this difference in survival to the earlier detection of carcinoma associated with IPMNs (which include a greater proportion of lymph node [LN]-negative tumors) and enrichment for well differentiated tumors.…”

Racial and Social Economic Factors Impact on the Cause Specific Survival of Pancreatic Cancer: A SEER Survey

“…Regional pancreatic cancer was an aggressive disease; there was a 55% risk of cause specific (Table 2). These are patients most likely to benefit from radiotherapy (Franko et al, 2012;Worni et al, 2012). Thus radiation oncologist should be more attentive in recommending RT for these patients.…”

Reply to survival after lumpectomy and mastectomy for early stage invasive breast cancer: The effect of age and hormone receptor status

“…The expected impact of such additional analyses on the reported point estimates is unclear, and the magnitude of this correction may in fact be small. A recent study suggests that such a correction for selection bias using a propensity score adjustment did not significantly change the findings of the unadjusted survival outcomes . Although the propensity score method cannot account for unmeasured confounders, this type of analysis will help establish whether the imbalance of measured factors between the 2 groups contributed to differences in outcome.…”