The new ASTRO clinical practice guideline provides recommendations on the use of radiation therapy to treat patients diagnosed with the most common types of skin cancers
By Phillip M. Devlin, MD, FASTRO, and Anna Likhacheva, MD, PhD
Skin cancer is the most prevalent cancer in the United States, with more than five million cases diagnosed each year. More than 95% of these diagnoses are basal and cutaneous squamous cell carcinomas (BCC, cSCC), which, in contrast to melanomas, respond well to radiation therapy if treated promptly and properly. Although surgery to remove the lesion is considered the primary approach for definitive/curative treatment of these non-melanoma skin cancers, radiation therapy can play an integral role in both the curative and post-operative settings.
ASTRO's first guideline for skin cancer was published on December 9, 2019 in Practical Radiation Oncology. The guideline details when radiation treatments are appropriate as stand-alone therapy or following surgery for BCC or cSCC, and it suggests dosing and fractionation for these treatments. ASTRO developed the guideline to provide clarity about treatment options since there is wide variation in practice about when and how radiation should be used for non-melanoma skin cancers, largely because few randomized studies have compared modern treatment options head-to-head.
The guideline was based on a systematic literature review which produced more than 1,500 articles, of which 143 (published from May 1988 through June 2018) were then carefully evaluated. The task force included a multidisciplinary team of radiation, medical and surgical oncologists, a radiation oncology resident, medical physicist, dermatologists and dermatopathologists.
The guideline first defines appropriate indications for radiation therapy as the following: definitive/curative treatment for BCC and cSCC; adjuvant treatment following surgery; and definitive or adjuvant treatment for disease that has spread to a patient's regional lymph nodes.
Recommendations are as follows:
- In the definitive/curative setting, radiation is strongly recommended for patients with BCC or cSCC who cannot undergo or decline surgical resection. It is conditionally recommended for patients with BCC or cSCC located in anatomically sensitive areas such as the nose or lips, where surgery could compromise function or cosmetic outcomes. Definitive radiation therapy is discouraged, however, for patients with genetic conditions that predispose them to be more sensitive to radiation.
- In the adjuvant/post-operative setting, radiation following surgery is recommended for patients at high risk of cancer recurrence, including a strong recommendation when there is evidence that BCC or cSCC has spread to a patient's nerves. Post-operative radiation is also recommended for patients at high risk of recurrence following surgical resection, including strong recommendations for high-risk patients with cSCC and conditional recommendations for high-risk patients with the relatively less aggressive BCC. Recommendations also outline prognostic features that indicate which patients are at greater risk for recurrence and spread.
- For patients with BCC or cSCC that has spread to regional lymph nodes, surgical removal of the affected lymph nodes followed by radiation is strongly recommended for both BCC and cSCC, although not for patients with one small involved lymph node without extracapsular spread. The guideline also strongly recommends definitive radiation for patients with regional cSCC spread who cannot undergo surgery.
The guidelines also address technical aspects of radiation therapy, suggest dosing and fractionation schedules and include a brief discussion of the different types of radiation delivery methods.
The task force concluded that the appropriate use of any of the major radiation modalities results in similar cancer control and cosmetic outcomes. The guideline also considers the use of drug therapies such as chemotherapy, biologic and immunotherapy agents in combination with radiation.
Read the executive summary of Definitive and Postoperative Radiation Therapy for Basal and Squamous Cell Cancers of the Skin: An ASTRO Clinical Practice Guideline and the full-text of the guideline in PRO.
Phillip Devlin, MD, FASTRO, is a world renowned brachytherapist practicing medicine at Harvard Medical School. He is the author of two acclaimed textbooks and scores of academic articles regarding the development of brachytherapy and skin applications. He serves as chair of the task force that developed the guideline.
Anna Likhacheva, MD, is an internationally recognized radiation oncologist and brachytherapist who leads the teaching effort for ABS/ASTRO in the area of brachytherapy and skin cancer. She currently practices radiation oncology at Sutter Medical Center in Sacramento, California, and serves as vice-chair of the task force that developed the guideline.
By Manisha Palta, MD, and Albert Koong, MD, PhD
The role of radiation therapy (RT) in pancreatic cancer is rapidly evolving. Until recently, 3-D conformal RT was the primary technique for treating patients. However, the emergence of intensity-modulated radiation therapy (IMRT) has allowed greater dose conformality, resulting in reduced dose to organs at risk. Together with advancements in simulation and image guidance, these developments have facilitated the use of hypofractionated RT, including stereotactic body RT. Simultaneously, more effective systemic therapies have also been developed. As these systemic therapies improve overall survival, local regional treatments like RT and surgery have become more important.
To address the questions surrounding RT for patients with pancreatic cancer, ASTRO launched a guideline on this topic, published online in Practical Radiation Oncology on August 29. The guideline task force comprised of not only radiation oncologists, including those working in community practice and Veterans Affairs and a resident representative, but also members from medical and surgical oncology, medical physics and the patient community. The guideline considered indications for RT in the adjuvant, neoadjuvant and definitive settings, along with doses, target volumes and sequencing with systemic therapies. It also made recommendations on simulation and treatment planning, technique and use of prophylactic medications to mitigate toxicity. Recommendations are rated as either strong or conditional, and the quality of the evidence is also graded for each recommendation.
For conventionally fractionated RT, the task force made a conditional recommendation supporting its use in the adjuvant setting if patients have high-risk features such as positive lymph nodes and margins. It conditionally recommended neoadjuvant RT in patients with borderline resectable tumors following chemotherapy, as well as RT as an option for definitive therapy in those with locally advanced disease. In addition, for borderline and locally advanced pancreatic cancer, SBRT is conditionally recommended. However, the task force recognized that ongoing clinical trials, including the Alliance for Clinical Trials in Oncology study, may provide new data for patients with borderline pancreatic cancer.
For RT simulation, the guideline recommends that patient-specific motion assessment should be utilized along with image guidance. Use of IMRT is recommended for treatment delivery.
Finally, there was strong consensus, even with limited clinical data, that patients undergoing RT for pancreatic cancer should receive prophylactic anti-nausea medications and agreement that patients may benefit from anti-acid or acid-reducing drugs.
Throughout the guideline, the task force sought to promote a patient-centered approach that integrates the patient's values, preferences and ability to tolerate short and late toxicities, and how those considerations are balanced against outcomes like local control. Given the many controversies and nuances of RT, it is especially important that every patient who might be appropriate for RT have a nuanced discussion with a radiation oncologist about the risks and benefits of RT, ideally in a multidisciplinary setting that also includes a surgeon and a medical oncologist.
Although many of the current guideline recommendations are conditional recommendations, reflecting limitations in the available data, ongoing and recently completed trials continue to add to the evidence available to make decisions on RT for pancreatic cancer and may alter the guideline in future years.