Before consenting to an aggressive, high-risk treatment regimen, cancer patients want to know if the therapies have the potential to improve their prognosis.
For many cancers — including peritoneal mesothelioma — oncologists rely on a set of personal and tumor-related factors to identify ideal candidates for curative treatment. However, the evaluation rarely predicts the impact the treatment will have on patient survival.
Most sources report a median peritoneal mesothelioma survival of six to 12 months. But patients like 10-year survivor Michelle Marshall and 12-year survivor Tammy Frank underwent extensive treatment programs that helped them defy the odds.
Marshall has completed a dozen rounds of chemotherapy, while Frank takes 12 medications a day to maintain the results of an elaborate multimodal regimen.
Some patients who are diagnosed with extensive cancer are less likely to improve their prognosis with curative therapies. These patients may have a better quality of life with a gentler palliative approach.
To create a more personalized prognostic scale — and in turn rule out surgical interventions that are unlikely to extend the patient’s life expectancy — researchers at the National Cancer Institute developed a novel program that can more accurately predict survival before surgery.
A Personalized Peritoneal Mesothelioma Nomogram
This specific calculation program, known in the scientific world as a nomogram, generates two statistics: three-year overall survival and five-year overall survival.
Researchers took 25 variables into consideration. These ranged from demographic factors (such as age and sex) to differences in laboratory testing to factors that were unique for each patient’s operation.
By the end of the study, the researchers identified three characteristics that produced the greatest impact on overall survival:
- The cancer’s cellular subtype
- The concentration of the CA-125 antigens in the patient’s blood
- Whether or not the patient received radiation before their operation
The nomogram assigns the heaviest weight to these factors. However, it also considers the patient’s score on the peritoneal carcinomatosis index.
For this index, doctors evaluate 12 distinct abdominal sections for the presence and size of cancerous growths. Patients receive a score on a scale of 0 to 39, with higher scores representing more extensive cancer. Patients studied for the development of the nomogram had a mean index score of 15.
The final model weighs each of these factors, then generates a color-coded survival chart that helps doctors quickly identify patient-specific pre-surgical survival rates.
Influence on Treatment
Each of the patients in the developmental study underwent the standard treatment regimen for malignant peritoneal mesothelioma: a cisplatin-based hyperthermic intraperitoneal chemotherapy regimen, followed by cytoreductive surgery (CRS).
In the 104-patient study, the three-year and five-year survival rates were 58 percent and 46 percent, respectively. Approximately 66 percent of the patients received a post-cytoreduction score of 0 or 1 (indicating that surgery removed all visible tumor nodules under 2.5 mm in size).
Researchers hope that the model can help patients know just how helpful surgery could be in their journey to cancer remission.
“Personalized survival times can potentially guide treatment and surveillance,” the team explained in Annals of Surgical Oncology.
“Pre-CRS estimation of survival times — might prevent CRS in patients unlikely to achieve favorable outcomes despite surgical intervention.”
These individualized estimates can help patients and doctors make more informed decisions on whether surgery will benefit their treatment goals.