Prognostic Value of PARS Classification for Locally Recurrent Rectal Cancer

With the introduction of total mesorectal excision (TME) and neoadjuvant chemoradiotherapy, the local recurrence rate of rectal cancer after surgery has markedly decreased; however, 5-18% of patients still experience recurrence in the pelvic field, significantly affecting their quality of life and contributing to high mortality rates. Several clinical and histologic features have been associated with the development of locally recurrent rectal cancer (LRRC), including higher primary T/N stage, positive margins, distal tumors, and histopathologic risk features such as tumor deposits (TD), lymphovascular invasion (LVI), and perineural invasion (PNI). Managing these recurrences is challenging, making risk stratification for re-recurrence through multidisciplinary evaluation essential for achieving personalized treatment in LRRC patients. Current imaging examinations typically stratify LRRC patients based on tumor recurrence patterns to guide clinical interventions. Due to primary treatment and varying local recurrence patterns, the pelvic fascial planes of LRRC patients are often altered or even absent, complicating surgery due to increased involvement of nearby organs or structures. Previous studies have indicated that surgical margin is the most crucial prognostic factor, with LRRC patients achieving R0 resections having a more favorable prognosis compared to those undergoing R1 or R2 resections or conservative treatments. Other potential features, such as gender, prior abdominoperineal resection, and advanced primary tumor stage, have been suggested to lead to poor post-recurrence prognoses; however, the prognostic impact of primary histologic risk features (TD, LVI, PNI) has rarely been addressed. Currently, there is no agreed-upon standardized treatment algorithm for LRRC, and nearly half of patients undergoing salvage radical surgery still experience re-recurrence within 12 months post-operation. The survival stratification of LRRC patients receiving salvage radical surgery remains underexplored.

Inclusion criteria

• (1) the primary tumor was located in the sigmoid colon or rectum, following prior radical tumor resection;
• (2) local recurrence was confirmed through CT, MRI, and serum cancer biomarker test, or endoscopic biopsy;
• (3) the recurrent site was confined to the pelvis;
• (4) the recurrent tumor underwent R0 or R1 surgical resection;
• (5) the absence of uncontrollable distant metastases at the time of salvage radical surgery.

Exclusion criteria

• (1) patients with unresectable tumors identified before salvage radical surgery, leading to palliative therapy;
• (2) a recurrence interval of less than three months;
• (3) incomplete baseline characteristics, including pathologic data from the initial treatment;
• (4) loss to follow-up.