Palliative radiotherapy for gastrointestinal malignancies

Indications for palliative radiotherapy

A diagnosis of pancreatic cancer is devastating; the 5-year overall survival for patients with locally-advanced unresectable disease is less than 5%, and for patients with metastatic disease is worse. At least 50% of patients present initially with metastatic disease, with many carrying a heavy burden of local and systemic symptoms. Patients often present with epigastric or more diffuse abdominal pain; back pain either on its own or radiating from the abdomen; altered stool and urine output; early satiety or gastric outlet obstructive symptoms; or more generalized symptoms such as jaundice, fatigue, and unexplained weight loss.

Many treatment options exist for unresectable non-metastatic disease. These options frequently incorporate systemic therapy and radiotherapy (RT) sequentially, concurrently, or both, and can last for weeks to many months. Unfortunately, despite the toxicities that accompany many of these aggressive approaches, patients are rarely cured, and local and systemic disease progression are common. Balancing disease control, treatment toxicities, and quality of life (QoL) are critical, as is regularly revisiting and re-evaluating goals of care and advance care plans. When aggressive therapy is not indicated but symptom relief is required, patients with both metastatic and non-metastatic disease commonly receive single modality palliative RT to their in situ primary pancreatic cancers. A review of the U.S. National Cancer Database data from 2003 to 2011 identified 68,075 patients with stage IV pancreatic cancer. Of these, 8.1% received palliative RT. Given the expected rise in pancreatic cancer incidence, there is a need to optimize practice in this setting.

Common histologies

Invasive ductal adenocarcinomas and their related subtypes comprise nearly 90% of adult pancreatic neoplasms, cystic and intraductal neoplasms (4% to 5%), pancreatic neuroendocrine tumors (3% to 4%), and acinar cell carcinomas and other uncommon neoplasms (2% to 3%).

Review of studies

This review focusses on studies that describe the use of conventional palliative RT for symptom control of primary pancreatic lesions. Studies describing the use of stereotactic body radiation therapy (SBRT) are only mentioned if their main objectives include evaluating its use for symptom control. Small series have examined the palliative roles of intraoperative RT and brachytherapy for pancreatic cancer, but they are beyond the scope of this review.

Guidelines

The clinical practice guideline on pancreatic cancer from the American Society for Radiation Oncology (ASTRO) recommends palliative RT for symptom management in select patients with metastatic pancreatic cancer. It suggests that for patients with symptoms warranting treatment to their primary tumors, 20 gray (Gy) in 5 fractions or 30 Gy in 10 fractions are reasonable regimens.

The clinical practice guideline on locally advanced unresectable pancreatic cancer from the American Society of Clinical Oncology (ASCO) states that a short course of 5 to 10 fractions of palliative RT may be offered to patients with prominent abdominal pain, worsening jaundice, or gastrointestinal bleeding, or to patients with impending gastric or duodenal obstruction. A recovery period of 3 to 4 weeks is suggested before restarting chemotherapy. ASCO’s guideline on metastatic pancreatic cancer makes no specific reference to any form of RT, but it recommends that patients with an ECOG performance status of ≥3, or those with poorly controlled comorbid conditions, only be offered cancer-directed therapy on a case-by-case basis. Among other suggestions pertaining to palliative care, it recommends that patients be offered aggressive treatment of the pain and other symptoms being caused by their cancers.

The clinical practice guideline on pancreatic adencarcinoma from the National Comprehensive Cancer Network (NCCN) suggests that in the palliative setting, if not previously used as part of a primary therapy regimen, RT can be used with or without chemotherapy to treat pain and bleeding or to relieve obstructive symptoms in patients who have progressed or recurred locally.