What were the basic results?

The researchers found that the RSPC had a significantly greater ability to determine risk of disease recurrence over 10 years than either RS values alone or pathological and clinical factors alone.

The researchers compared the proportions of patients each system classified in each risk category. They found that:

The researchers found that a high proportion of patients (71.9%) classified by RS as being at intermediate risk were moved to other risk categories under the RSPC system: 16.9% moved into the high-risk category and 55.1% into the low-risk category.

Many of the patients (68%) had RSPC values within 5% of the RS values.

How did the researchers interpret the results?

The researchers concluded that RSPC assessment is a refinement of the estimate provided by RS alone, and that RSPC can provide greater accuracy in the assessment of distant (10-year) risk of disease recurrence when the RS estimate and other clinical measurements are contradictory.

Conclusion

This study assessed a new combined test’s ability to predict the risk of disease recurrence in oestrogen-receptor-positive breast cancer patients whose disease had not spread to nearby lymph nodes. The test builds on an existing genetic measure, but adds clinical factors to classify a patient’s risk level.

The researchers found that the new test classified more patients at low risk for disease recurrence compared to the original test. However, it did not improve the ability to predict a patient’s potential benefit from receiving chemotherapy.

The researchers say that planning cancer treatments should be based on both the benefits and risks of treatment for each individual patient. The researchers say that their test is not going to be of benefit for all patients and that those who have been classified as either at low or high risk based on their recurrence scores are unlikely to benefit from the new combined test. Those classified as at intermediate risk based on their RS are more likely to benefit from the new test, as it appears to assess more accurately the recurrence risk for this group of patients.

The researchers conclude that RSPC can aid in making chemotherapy decisions in cases where RS and clinical measures do not agree, for instance, when RS predicts high risk of recurrence, but tumour size and other clinical factors predict low risk.

It should be noted that around one in three breast cancers is negative for oestrogen receptors, and this study cannot tell us about the model’s use on ER-negative cancers or those that have spread.

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