surgery was just as effective as chemoradiotherapy at keeping the cancer at bay (377). Researchers are also designing novel radiotherapeutics, to be used alone or in combination with other treatments, to target more cancer types and benefit more patients. Additionally, technological innovations, such as the development of advanced imaging and sophisticated computer analytic programs assisted by AI, are helping optimize the delivery of the radiation to the tumor while minimizing exposure to normal tissues (378). As one example, Magnetic Resonance Imaging (MRI)-guided radiotherapy (MRgRT) is a novel technology with the potential to transform radiotherapy for many patients including those with prostate cancer (379). MRgRT provides the ability to image tumors and internal organs with MRI and adapt the radiotherapy plan in real-time while the patient is undergoing the procedure. Unlike traditional radiotherapy, MRgRT allows monitoring of changes in tumor size and positional changes of internal organs during each treatment to achieve a more accurate delivery of the radiation dose. This is particularly critical for rapidly changing tumors and body regions, such as the prostate, where there could be dramatic changes in organ position during each treatment. Imaging Prostate Cancer More Clearly Prostate cancer is the most common type of cancer in men in the United States. In 2023, an estimated 288,300 new cases will be diagnosed and 34,700 men will die from the disease. Prostate cancer that is confined to the prostate is usually treated with surgery or radiation therapy. Unfortunately, many patients with primary prostate cancer have detectable metastases in their pelvic lymph nodes, which are correlated with a risk for cancer recurrence. Surgical procedures known as pelvic lymph node dissection or pelvic lymphadenectomy are used to detect pelvic node lesions, but their use is imprecise and limited to a planned surgical area. An ideal detection method for metastatic prostate cancer would locate tumors in pelvic nodes as well as more distant sites. The more precise a patient’s diagnosis, the easier it is for a health care provider to tailor the treatment to ensure that it is as effective and safe as possible. Notably, despite surgery or radiotherapy many patients with prostate cancer have local or distal recurrences within 10 years. Among the tools physicians use to make cancer diagnoses is positron emission tomography–computed tomography (PET–CT or PET), a form of imaging that can help physicians precisely locate the position of a patient’s cancer within the body and determine the extent to which the cancer may have spread. Before a PET scan, patients are injected with a radioactive imaging agent. The PET scan detects cancer by identifying where in the body the radioactive agent accumulates. In May 2023, FDA approved flotufolastat fluorine-18 (Posluma) for PET imaging of PSMA-positive lesions in patients with prostate cancer with suspected metastasis or with suspected recurrence based on elevated serum PSA level. PSA is a secreted biochemical marker that is used to screen individuals for prostate cancer and for predicted recurrence of the disease among patients who have received treatment. PSMA is a protein that is present in abundance on the surface of more than 90 percent of primary and metastatic prostate cancer cells. Flotufolastat F-18 contains a short peptide sequence that binds to PSMA and is internalized by cells that express PSMA. Flotufolastat F-18 also contains the radioisotope fluorine-18 which enables PET imaging of the prostate and other areas of the body where prostate cancer may have spread. Clinicians can use this information to decide which patient should receive treatment and spare others from unnecessary procedures. Findings from two clinical trials that FDA used to approve flotufolastat F-18 indicate that detection of prostate cancers using this approach may help physicians make the best treatment decisions for patients (380). One study demonstrated a higher specificity of flotufolastat F-18 for the detection of pelvic lymph node metastasis, compared to standard histopathology, in patients with PSMA-positive lesions. Flotufolastat F-18 provided valuable information that would likely result in changes in clinical management for these patients. In the second study, flotufolastat F-18 demonstrated high prostate cancer recurrence detection rates in patients who had suspected disease recurrence based on elevated PSA levels. Advances in Treatment with Cytotoxic Chemotherapy Cytotoxic chemotherapy—use of chemicals to kill cancer cells—was first introduced as a pillar of cancer treatment in the early to mid-20th century (349). Chemotherapy remains a backbone of cancer treatment and its use is continually evolving to minimize potential harms to patients with cancer, while maximizing its benefits. As with surgery, chemotherapy is more commonly used to treat cancer in combination with one or more additional types of treatments. Furthermore, FDA continues to grant approvals to newer and more effective chemotherapeutics. FDA also routinely expands the use of previously approved chemotherapeutics for additional cancer types through review of new clinical trials as well as by monitoring of current real-world use of such agents. The FDA Project Renewal leverages expertise of clinical researchers to review existing published literature on drug utilization and maintain updated labeling of older, commonly prescribed anticancer therapeutics. As one example of this approach, in December 2022, FDA approved updated labeling for the chemotherapeutic capecitabine (Xeloda) which included new indications and dosing regimens for capecitabine tablets. Treatment with cytotoxic chemotherapeutics can have adverse effects on patients. These effects can occur during treatment AACR Cancer Progress Report 2023 Advancing the Frontiers of Cancer Science and Medicine 82
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